IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

April 2011 

IMPORTANT 

1. The motherboard described in this document is the 

first motherboard, the 16KB-64KB one. 

2. If the BIOS on the 16KB-64KB motherboard has 

been upgraded to the third revision one, then the 

switch settings shown for SW2 (“switch 2”) on the 

motherboard no longer apply. 

The BIOS revision can be determined by examination 

of the seven digit number on motherboard chip U33. 

First revision: 5700051 

Second revision: 5700671 

Third revision: 1501476

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- - - Personal Computer 

Hardware Reference 

Library 

Technical 

Reference

FEDERAL COMMUNICATIONS COMMISSION 

RADIO FREQUENCY INTERFERENCE STATEMENT 

WARNING: This equipment has been certified to comply with the 

limits for a Class B computing device, pursuant to Subpart J of Part .~ 

15 of FCC rules. Only peripherals (computer input/output devices, 

terminals, printers, etc.) certified to comply with the Class B limits 

may be attached to this computer. Operation with non-certified 

peripherals is likely to result in interference to radio and TV 

reception. 

First Edition (August 1981) 

Changes are periodically made to the information herein; these changes will be 

incorporated in new editions of this publication. 

Products are not stocked at the address below. Requests for copies of this 

product and for technical information about the system should be made to 

your authorized IBM Personal Computer Dealer. 

A Product Comment Form is provided at the back of this publication. If this 

form has been removed, address comment to: IBM Corp., Personal Computer, 

P.O. Box 1328, Boca Raton, Florida 33432. IBM may use or distribute any of 

the information you supply in any way it believes appropriate without incurring 

any obligations whatever. 

© Copyright International Business Machines Corporation 1981

PREFACE 

~ The IBM Personal Computer Technical Reference Manual is designed 

to provide hardware design and interface information. This publication 

also provides Basic Input Output System (BIOS) information as well as 

programming support matter. 

This manual is intended for programmers, engineers involved in 

hardware and software design, designers, and interested persons who 

have a need to know how the IBM Personal Computer is designed and 

works. 

This manual has three sections: 

Section - 1 

"HARDWARE OVERVIEW," features an overview ofthe system as 

a whole calling out specific items such as the System Unit, Keyboard, 

IBM Monochrome Display and the 80 CPS Matrix Printer. 

Section - 2 

" HARDWARE," contains a description for each functional part ofthe 

system. This section also contains specifications for power, timing, and 

interface. Programming considerations are supported by coding tables, 

command codes and registers. 

Section - 3 

"ROM and SYSTEM USAGE," describes BIOS as well as how to use 

BIOS, interrupt vector listings, memory map, vectors with special 

meanings, a cassette section, a keyboard encoding section, and a 

set of Low Memory Maps. 

"APPENDICES," to address the ROM BIOS listing, an instruction 

set, logic diagrams, and expanded charts used to support specific 

hardware descriptions.

CONTENTS 

SECTION 1. HARDWARE OVERVIEW......... 1-1 

System Block Diagram ............................ 1-4 

SECTION 2. HARDWARE...................... 2-1 

System Board ................................... 2-3 

System Board Data Flow .......................... 2-6 

I/O Channel ..................................... 2-8 

I/O Channel Diagram ............................ 2-9 

System Board I/O Channel Description ............. 2-10 

System Board Component Diagram ................. 2-13 

Keyboard........................................ 2-14 

Keyboard Interface Block Diagram ................. 2-15 

Keyboard Diagram ............................... 2-16 

Keyboard Scan Codes ............................. 2-17 

Keyboard Interface Connector Specifications ......... 2-18 

Cassette User Interface ............................ 2-19 

Cassette Jumpers ............................... 2-19 

Circuit Block Diagrams ......................... 2-19 

Cassette Interface Connector Specifications .......... 2-21 

Speaker Interface ................................. 2-22 

Speaker Drive System Block Diagram ............. 2-22 

I/O Address Map ................................. 2-23 

System Memory Map ............................. 2-25 

System Board And Memory Expansion Switch Settings ... 2-28 

5 1/4" Diskette Drives Switch Settings .............. 2-29 

Monitor Type Switch Settings .... , ..... , ........... 2-29 

System Board Memory Switch Settings .............. 2-30 

32/64 KB Memory Expansion Option Switch Settings ... 2-31 

Power Supply ................................... 2-33 

Power Supply Location ............................ 2-34 

Input Requirements ............................... 2-34 

DC Output ...................................... 2-34 

AC Output ...................................... 2-34 

Power Supply Connectors And Pin Assignments ...... 2-35 

Important Operating Characteristics ................. 2-36 

Over Voltage/Current Protection ................. 2-36 

Signal Requirements ............................ 2-36 

iii

IBM Monochrome Display and Parallel 

Printer Adapter................................. 2-37 

Parallel Interface Description ...................... 2-37 

IBM Monochrome Display Adapter Block Diagram ... 2-38 

System Channel Interface .......................... 2-39 

Lines Used .................................... 2-39 

Loads ......................................... 2-39 

Special Timing ................................. 2-39 

Data Rates .................................... 2-39 

Interrupt and DMA Response Requirements ....... 2-39 

Modes Of Operation .............................. 2-40 

Programming Considerations ....................... 2-41 

Programming the 6845 CRT Controller ........... 2-41 

Sequence of Events ............................. 2-41 

Memory Requirements .......................... 2-41 

DMA Channel ................................. 2-42 

Interrupt Levels ................................ 2-42 

I/O Address and Bit Map ....................... 2-42 

IBM Monochrome Display ........................ 2-43 

Operating Characteristics ........................ 2-43 

IBM Monochrome Direct Drive Interface and 

Pin Assignment ................................. 2-44 

Color/Graphics Monitor Adapter ................. 2-45 

Color/Graphics Monitor Adapter Block Diagram ..... 2-47 

Major Components Definitions ..................... 2-48 

Motorola 6845 CRT Controller .................. 2-48 

Mode Set and Status Registers ................... 2-48 

Display Buffer ................................. 2-48 

Character Generator ............................ 2-48 

Timing Generator .............................. 2-48 

Composite Color Generator. ..................... 2-48 

Modes of Operation ............................... 2-49 

Alphanumeric Mode ............................ 2-49 

Color TV ...................................... 2-49 

Color Monitor ................................. 2-50 

IBM Monochrome Display Adapter V s. Color/Graphics .. . 

Adapter Attribute Relationship ..................... 2-51 

Color/Graphics Modes ............................ 2-51 

Graphics Storage Map .......................... 2-52 

Description of Basic Operations .................. 2-54 

Summary of Available Colors .................... 2-55 

iv


Programming The 6845 Controller ................ 2-55 

6845 Register Description ....................... 2-56 

Programming the Mode Control and Status Register ... 2-57 

Color Select Register ........................... 2-57 

Mode Select Register ........................... 2-58 

Mode Register Summary ........................ 2-58 

Status Register ................................. 2-59 

Sequence of Events ............................. 2-59 

Memory Requirements .......................... 2-60 

Interrupt Level ................................. 2-60 

I/O Address and Bit Map ....................... 2-61 

Color/Graphics Monitor Adapter Direct Drive, and 

Composite Interface Pin Assignment ............... 2-62 

Color/Graphics Monitor Adapter Auxiliary 

Video Connectors ............................... 2-63 

Parallel Printer Adapter .......................... 2-65 

Parallel Printer Block Diagram ..................... 2-66 


Parallel Printer Adapter Interface Connector 

Specifications ................................... 2-69 

IBM 80 CPS Matrix Printer ....................... 2-70 

Printer Specifications .............................. 2-71 

Setting The DIP Switches ......................... 2-72 

Functions and Conditions of DIP Switch 1 ........ 2-72 

Functions and Conditions of DIP Switch 2 ........ 2-73 

Parallel Interface Description ...................... 2-73 

Connector Pin Assignment and Descriptions of 

Interface Signals .............................. 2-74 

Parallel Interface Timing Diagram ................ 2-77 

ASCII Coding Table .............................. 2-78 

ASCII Control Codes ............................. 2-79 

5 1/4" Diskette Drive Adapter .................... 2-89 

5 1/4" Diskette Drive Adapter Block Diagram ....... 2-90 

Functional Description ............................ 2-91 

Digital Output Register .......................... 2-91 

Floppy Disk Controller. ......................... 2-91 


Symbol Descriptions ............................ 2-94 

Command Summary ............................ 2-96 

Command Status Registers ...................... 2-100 

v

Progranuning Summary ............................ 2-103 

DPC Registers ................................. 2-103 

Drive Constants ................................ 2-104 

Comments ..................................... 2-104 

System I/O Channel Interface ...................... 2-104 

Drive A and B Interface ........................... 2-106 

Adapter Outputs ............................... 2-106 

Adapter Inputs ................................. 2-107 

5 1/4" Diskette Drive Adapter Internal Interface 


5 1/4" Diskette Drive Adapter External Interface 


5 1/4" Diskette Drive ............................. 2-110 

Diskettes ........................................ 2-111 

Mechanical and Electrical Specifications ............ 2-112 

Memory Expansion Options ...................... 2-113 

Operating Characteristics .......................... 2-113 

Memory Module Description ....................... 2-114 

Memory Module Pin Configuration ................. 2-114 

Switch Configurable Start Address .................. 2-115 

Game Control Adapter ........................... 2-117 

Game Control Adapter Block Diagram .............. 2-117 

Functional Description ............................ 2-118 

Address Decode ................................ 2-118 

Data Buss Buffer/Driver ........................ 2-118 

Trigger Buttons ................................. 2-118 

Joystick Po~tions .............................. 2-118 

I/O Channel Description .......................... 2-119 

Interface Description .............................. 2-119 

Joystick Schematic ................................ 2-121 

Game Control Adapter (Analog Input) Connector 


Asynchronous Communications Adapter .......... 2-123 

Asynchronous Communications Adapter Block 

Diagram ....................................... 2-124 

Modes of Operation ............................... 2-125 

I/O Decode for Communications Adapter ......... 2-125 

Interrupts...................................... 2-126 

Interface Description .............................. 2-126 

Current Loop Interface .......................... 2-127 

Voltage Interchange Information .................. 2-128 

vi

INS 8250 Functional Pin Description ............... 2-129 

Input Signals ................................... 2-129 

Output Signals ................................. 2-132 

Input/Output Signals ............................ 2-133 

Programming Considerations ....................... 2-13 3 

Asynchronous Communications Reset Functions ... 2-133 

INS 8250 Accessable Registers .................. 2-134 

INS 8250 Line Control Register. ................. 2-134 

INS 8250 Programmable Baud Rate Generator .... 2-135 

Line Status Register ............................ 2-137 

Interrupt Identification Register .................. 2-139 

Interrupt Enable Register ........................ 2-141 

Modem Control Register ........................ 2-142 

Modem Status Register. ......................... 2-143 

Receiver Buffer Register ......................... 2-144 

Transmitter Holding Register .................... 2-145 

Selecting The Interface Format. .................... 2-146 

Asynchronous Communications Adapter Connector 

Interface Specifications .......................... 2-147 

SECTION 3. ROM and SYSTEM USAGE....... 3-1 

ROM BIOS ..................................... 3-2 

Use of BIOS ..................................... 3-2 

Parameter Passing ................................ 3-2 

Interrupt Vector Listing ............................ 3-3 

Vectors With Special Meaning ..................... 3-5 

Interrupt 1 CH - Timer Tick ...................... 3-5 

Interrupt IDH - Video Parameters ................ 3-5 

Interrupt lEH - Diskette Parameters .............. 3-5 

Interrupt IFH - Graphics Character Extensions .... 3-6 

Other Read/Write Memory Usage ................ 3-6 

BIOS Programming Tip ........................... 3-6 

BIOS Memory Map ............................... 3-7 

BIOS Cassette Logic ............................. 3-8 

Interrupt 15 ...................................... 3-8 

Cassette Write ................................... 3-8 

Cassette Read .................................... 3-9 

Data Record Architecture .......................... 3-10 

Error Recovery ................................... 3-10 

vii

Keyboard Encoding and Usage ................... 3-11 

Encoding ........................................ 3-11 

Character Codes .................................. 3-11 

Extended Codes .................................. 3-13 

Extended Functions ............................ 3-13 

Shift States .................................... 3-14 

Shift Key Priorities ............................. 3-15 

Special Handling ................................. 3-15 

System Reset .................................. 3-15 

Break ......................................... 3-16 

Pause ......................................... 3-16 

Print Screen ................................... 3-16 

Keyboard Usage .................................. 3-17 

BASIC Screen Editor Special Functions ............. 3-19 

DOS Special Functions ........................... 3-19 

Low Memory Maps .............................. 3-21 

0-7F Interrupt Vectors ............................ 3-21 

BASIC and DOS Reserved Interrupts (80-3FF)...... 3-22 

Reserved Memory Locations (400-5FF) ............. 3-22 

BASIC Workspace Variables ...................... 3-23 

APPENDICES.................................. A-O 

Appendix A: ROM BIOS Listing ................. A-I 

Appendix B: Assembly Instruction Set Reference... B-1 

Appendix C: OfCharacters Keystrokes and Color .... C-l 

Appendix D: Logic Diagrams..................... D-l 

Appendix E: Unit Specifications .................. E-l 

Glossary ......................................... G-l 

Bibliography .................................... Bib-l 

Index ........................................... 1-1 

viii

FIGURE LISTING 

1. System Block Diagram ........................ 1-4 

2. System Board Data Flow ...................... 2-6, 7 

3. I/O Channel Diagram ......................... 2-9 

4. System Board Component Diagram ............. 2-13 

5. Keyboard Interface Block Diagram .............. 2-15 

6. Keyboard Diagram ............................ 2-16 

7. Cassette Interface Read Hardware .............. 2-19 

8. Cassette Interface Write Hardware .............. 2-20 

9. Cassette Motor Control. ....................... 2-20 

10. Speaker Drive System Block Diagram ........... 2-22 

11. System Memory Map ......................... 2-25 

12. System Memory Map (Increments of I6KB) ..... 2-26 

13. Power Supply and Connectors .................. 2-35 

14. IBM Monochrome Display AdapterBlockDiagram ... 2-38 

15. Color/Graphics Monitor Adapter Block Diagram ... 2-47 

16. Parallel Printer Adapter Block Diagram ......... 2-66 

17. Location of (Printer) DIP Switches ............. 2-72 

18. Parallel Interface Timing ....................... 2-77 

19. 5 1/4" Diskette Drive Adapter Block Diagram ... 2-90 

20. Game Control Adapter Block Diagram .......... 2-117 

21. Joystick Schematic ............................ 2-121 

22. Asynchronous Communications Adapter 

Block Diagram ............................... 2-124 

23. Current Loop Interface ........................ 2-127 

24. Selecting The Interface Format ................. 2-146 

25. BIOS Memory Map ........................... 3-7 

ix

TABLE LISTING 

1. lCeyboard Scan Codes ......................... 2-17 

2. 6845 Initialization Parameters .................. 2-41 

3. Monochrome Vs Color/Graphics Attributes ...... 2-51 

4. Color/Graphics Modes ........................ 2-51 

5. Summary of Available Colors .................. 2-55 

6. 6845 Register Description ..................... 2-56 

7. Printer Specifications .......................... 2-71 

8. Functions and Conditions of DIP Switch 1 ....... 2-72 

9. Functions and Conditions of DIP Switch 2 ....... 2-73 

10. Connector Pin Assignment and 

Description of Interface Signals ................. 2-74 

11. ASCII Coding Table .......................... 2-78 

12. DCl/DC3 and Data Entry ..................... 2-82 

13. Symbol Description ........................... 2-94 

14. Status Register O.............................. 2-100 

15. Status Register 1. ............................. 2-101 

16. Status Register 2 .............................. 2-102 

17. Status Register 3 .............................. 2-103 

18. Mechanical and Electrical Specifications ......... 2-112 

19. Memory Module Pin Configuration ............. 2-114 

20. DIP Module Start Address ..................... 2-115 

21. I/O Decodes (3F8 - 3FF) ..................... 2-125 

22. Asynchronous Communications Reset Functions ... 2-133 

23. BAUD Rate at 1.843 Mhz..................... 2-137 

24. Interrupt Control Functions (Asynchronous) ..... 2-140 

25. Character Codes .............................. 3-11 

26. lCeyboard Extended Functions .................. 3-14 

27. lCeyboard - Commonly Used Functions .......... 3-17 

28. Basic Screen Editor Special Functions ........... 3-19 

29. DOS Special Functions ........................ 3-19 

30. 0-7F Interrupt Vectors ........................ 3-21 

31. Basic & DOS Reserved Interrupts (80-3FF) ..... 3-22 

32. Reserved Memory Locations (400-5FF) ......... 3-22 

x

SECTION I. 

HARDWARE OVERVIEW 

The IBM Personal Computer has two major elements; a System Unit 

"..-..." and a keyboard. In addition, a variety of options are offered including 

one or two 5-1/4" Diskette Drives with adapter which can be housed 

inside the System Unit, an IBM Monochrome Display, an 80 CPS 

Matrix Printer, two display adapters, storage increments to 256 KB, an 

Asynchronous Communications Adapter, Printer Adapter and a 

Game Control Adapter. 

The System Unit is the heart of your IBM Personal Computer system. 

The System Unit houses the microprocessor, Read-Only Memory 

(ROM), Read/Write Memory, Power Supply, and System Expansion 

Slots for the attachment of up to five options. One or two 5-1/4" 

Diskette Drives can also be mounted in the system Unit providing 

160KB of storage each. 

The System Board is a large board which fits horizontally in the base 

of the System Unit and includes the microprocessor, 40KB ROM and 

16KB memory. The memory can be expanded in 16KB increments to 

64KB. The System Board also includes an enhanced version of the 

Microsoft BASIC-80 Interpreter without diskette functions. The 

BASIC Interpreter is included in the ROM. The System Board also 

permits the attachment of an audio cassette recorder for loading or 

saving programs and data. 

The System Unit power system is a 63.5 watt, 4 level DC and 120 AC 

unit. It is a switching regulator design" allowing for light weight and 

high efficiency. The DC power capacity is designed to support an 

expanded system. 

The 5-1/4" Diskette Drive Adapter fits into one of the five System 

Expansion Slots. This attachment supports two internal drives. The 

5-1/4" Diskette Drive Adapter uses write precompensation and a 

phase lock loop for clock and data recovery. 

The 5-1/4" Diskette Drive permits the IBM Personal Computer to 

read, write and store data on 5-1/4" diskettes. Each diskette stores 

approximately 160KB of data. Two of these drives may be installed 

internally in the System Unit. 

The keyboard is attached to the System Unit with a light-weight, coiled 

cable. The keyboard features 83 keys, and offers commonly used data 

and word processing functions in a design combining the familiar 

typewriter and calculator pad layouts. 

1-1

A base system requires one of two different display adapters, either a 

Color/Graphics medium resolution Monitor adapter or a high 

resolution monochrome alphanumeric adapter with a parallel printer 

adapter. 

The Color/Graphics adapter operates at standard television frequencies 

(15,750Hz), allowing attachment to a variety of industry ~ 

standard monitors, including home TVs with a user supplied RF 

modulator. 

The Color/Graphic Monitor adapter supports a variety of modes 

selected by program control. The adapter supports color or black and 

white alphanumeric modes with line width of 40 or 80 characters and 

25 lines. In the alphanumeric mode there are 256 characters. 

This adapter provides both a standard composite video and direct 

drive outputs. In addition, a light pen feature input port is provided. 

The IBM Monochrome Display is a high resolution green phosphor 

display offering the personal computer user quality usually found on 

larger computer systems. The display features an 11-1/2" screen with 

an anti-glare surface and a variety of highlighting choices. The screen 

displays 25 lines of 80 characters. It supports 256 different letters, 

numbers and special characters that are formed in a nine by 14 dot 

matrU. ~ 

The IBM Monochrome Display requires the Monochrome Display and 

Printer Adapter Option. This option installs in one ofthe System Unit's 

five System Expansion Slots. The display is powered from the System 

Unit. 

The 80 CPS Matrix Printer is a versatile, low cost, quality printer for 

the IBM Personal Computer. It prints in both directions at a nominal 

horizontal speed of 80 characters per second on continuous-feed, single 

or multi-part paper. The printer features four character sizes ( 40,66,80 

or 132 characters per line), Power-on Self-test and simple paper 

loading and ribbon cartridge uppercase and lower case ASCII character 

set and 64 special graphic characters. 

The 80 CPS Matrix Printer requires either the Monochrome Display 

and Printer Adapter or the Printer Adapter. These options install in one 

of the Systems Unit's five System Expansion Slots. The Printer 

requires standard 120 volt, 60 Hz power through its own power cord. ~ 

The printer requires the Printer Cable Option for attachment to the 

System Unit. 

1-2

The 16KB Memory Expansion Kits allow you to increase the memory 

size ofyour IBM p.ersonal Computer. The base system comes standard 

with 16KB of memory. Up to three 16KB Memory Expansion Kits 

may be installed to increase the memory size to 64KB. Memory can be 

further increased to 256KB with additional memory options once these 

three Expansion Kits are installed. 

~e Expansion Kits plug into the System Board and must be installed 

sequentially. They do not occupy any of the five System Expansion 

Slots. 

The 32KB and 64KB Memory Expansion Options permit you to 

increase memory capacity beyond 64KB. Multiple 32KB and 64KB 

Memory Expansion Options may be installed as long as System 

Expansion Slots are available. A maximum of three 64KB memory 

options may be installed for a total of 256KB of memory. 

The 32KB and 64KB Memory Expansion Options require a System 

Expansion Slot in the System Unit. The first 64KB on the System 

Board is required before 32KB and 64KB Memory Expansion Options 

can be installed. 

The Asynchronous Communications Adapter provides a channel to 

data processing or input/output devices outside of your immediate 

~system. These can be connected by telephone using a plug-in modem, 

qr directly by cable when the device is nearby. 

This option utilizes the RS232C asynchronous (start-stop) interface 

permitting attachment to a variety of devices including a large "host" 

computer or another IBM p.ersonal Computer. 

This option supports 50 to 9600 BPS transmission speeds. One 25 pin 

"D" shell, male type connector is provided to attach various peripheral 

devices. A "current loop" interface is located in the same connector, 

and a jumper block is provided to manually select either the voltage or 

the current loop interface. 

The Asynchronous Communications Adapter requires a System 

Expansion Slot in the System Unit. An external modem is required for 

telephone line transmission. 

The Game Control Adapter permits the attachment of user-supplied 

joysticks or paddles. Two joysticks and up to four paddles may be 

~. attached. IBM does not manufacture either the joysticks or the paddles. 

This option provides connectors for joysticks or paddles and requires a 

System Expansion Slot in the System Unit. 

A block diagram of the system is on the following page (1-4). 

1-3

System Block Diagram 

• OSC 

• elK 

• CNTRL 

8088 

MAIN 

PROCESSING 

UNIT 

20 81T 

4 CH 

DMA 

3 CH 

16 BIT 

TIC 

8 LEV. 

INTR 

SYSTEM 80ARD 

KEYBOARO 

ATTACHMENT 

ROS ROS 

8K x 8 8K x 8 

ROS ROS 

8K x 8 BK x 8 

ROS ROS 

8Kx 8 BK x 8 

110 CHANNEL 

16 x 9 READ! 

WRITE MEMORY 

16KB MEMORY 

EXPANSION 

16KB MEMORY 

EXPANSION 

16KB MEMORY 

EXPANSION 

Figure 1. SYSTEM BLOCK DIAGRAM 

1-4

SECTION 2. HARDWARE 

~ Contents: 

System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 

Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33 

IBM Monochrome Display And Printer Adapter... 2-37 

IBM Monochrome Display. . . . . . . . . . . . . . . . . . . . . . . 2-43 

Color/Graphics Monitor Adapter. . . . . .. . . . . . . . . . . 2-45 

Printer Adapter and Printer. . . . . . . . . . . . . . . . . . . . . . . 2-65 

5-1/4" Diskette Drive Adapter. . . . . . . . . . . . . . . . . . . . 2-89 

5-1/4" Diskette Drive............................ 2-110 

Memory Expansion Options 32KB and 64KB. . . . . . 2-113 

Game Control Adapter. . . . . . . . . . . . . . . . . . . . . . . . . . . 2-117 

Asynchronous Communications Adapter . . . . . . . . . . 2-123 

2-1

2-2 

NOTES

SYSTEM BOARD 

The System Board fits horizontally in the base of the System Unit 

and has dimensions of approximately 8-1/2 inches by 11 inches. The 

System Board isa multilayer single land-per-channel design, with 

ground and power internal planes provided. DC power and a signal 

from the power supply enter the board through two six pin connectors. 

Other connectors on the board are for attaching the keyboard, audio 

cassette, and the speaker. Five 62-pin card edge sockets are also 

mounted on the System Board. The system I/O channel is bussed 

across these five I/O slots. 

There are 16 (13 used) Dual In-line Package (DIP) switches mounted 

on the card which can be read under program control. These switches 

are used to indicate to the system software what options are installed. 

They are used to indicate amounts of installed storage, both on the 

System Board and in the System Expansion slots, type of display 

adapter installed, and desired operation modes upon power-up; ie, 

coloror black and white and 80- or 40 character lines. Switches are also 

used to identify when the operating system is to be loaded from 

diskette, and how many diskette drives are attached. 

The major elements of the System Board are divided into five major 

functional areas. They are, the processor subsystem and its support 

elements, the Read-Only Memory (ROM) subsystem, the Read/Write 

(RlW) Memory subsystem, integrated I/O adapters, and the I/O 

channel. All functions are described in detail in this section, except for 

the I/O channel, which has its own section. Figure 2.0 "System Board 

Data Flow" page 2-6, illustrates these functional areas. 

The heart of the System Board is the Intel 8088 microprocessor. 

This processor is an 8-bit bus version of the 16-bit 8086 processor by 

Intel. Itis software compatible with the 8086 and, thus, supports 16-bit 

operations including multiply and divide. The processor supports 20 

bits of addressing (1 megabyte of storage). The processor is 

implemented in maximum mode so a co-processor can be added as a 

feature. The processor is operated at 4.77 Mhz. This frequency is 

derived from a 14.31818 Mhz crystal which is divided by three for. the 

processor clock and by four to obtain the 3.58 Mhz color burst signal 

required for color televisions. 

At the 4.77 Mhz clock rate, the 8088 bus cycles are four clocks of 

210 ns or 840 ns. I/O cycles take five 210 ns clocks or 1.05 microsec 

(m sec). 

2-3

The processor is supported by a set of high function support devices 

providing four channels of 20-bit Direct Memory Access (DMA), 

three 16-bit timer counter channels, and eight prioritized 

interrupt levels. 

Three of the four DMA channels are available on the I/O bus and are 

provided to support high speed data transfers between I/O devices and 

memory without processor intervention. The fourth DMA channel is 

programmed to refresh the system dynamic memory. This is done by 

programming a channel of the timer counter device to periodically 

request a dummy DMA transfer. This creates a memory read cycle 

which is available to refresh dynamic storage both on the System Board 

and in the System Expansion slots. All DMA data transfers, except the 

refresh channel, take five processor clocks of 210 ns or 1.05 ns if the 

processor ready line is not deactivated. Refresh DMA cycles take four 

clocks or 840 ns. 

The three timer/counters are used by the system as follows: Channel 0 

is used to time and request refresh cycles from the DMA channel, 

Channel 2 is used to support the tone generation for the audio speaker, 

and Channel 1 is used by the system as a general purpose timer 

providing a constant time base for implementing a time-of-day clock. 

Each channel has a minimum timing resolution of 1.05 f.Lsec. 

Ofthe eight prioritized levels ofinterrupt, six are bussed to the I/O slots 

for use by feature cards. Two levels are used on the System Board. 

Level 0, the highest priority, is attached to Channell of the timer 

counter and provides a periodic interrupt. Level 1 is attached to the 

keyboard adapter circuits and receives an interrupt for each scan code 

sent by the keyboard. The Non-Maskable Interrupt (NMI) ofthe 8088 

is used to report memory parity errors. 

The System Board is designed to support both ROM and Read/Write 

Memory. The System Board contains space for 48K x 8 of ROM or 

EPROM. Six module sockets are provided, each capable of accepting 

an 8K x 8 device. Five of the sockets are populated with 40 KB of 

ROM. This ROM contains the Cassette BASIC interpreter, cassette 

operating system, Power-on Self-test, I/O drivers, dot patterns for 128 

characters inn graphics mode, and a diskette bootstrap loader. The 

ROM is packaged in 24-pin modules and has an access time of 250 ns 

and a cycle time of 375 ns. 

The System Board also contains from 16K x 9 to 64K x 9 of Read/ 

Write Memory. A minimum system would have 16 KB ofmemory with 

module sockets for an additional 48 KB. In a cassette version of the 

system, approximately 4 KB is used by the system leaving approxi 

mately 12 KB of user's space for BASIC programs. Additional 

memory beyond the System Board's maximum of64 KB, is obtained by 

adding memory cards in the System Expansion slots. 

2-4

The memory is dynamic 16K x 1 chips with an access time of 250 ns 

and a cycle time of 410 ns. All R/W memory is parity checked. 

The System Board contains circuits for attaching an audio cassette, 

the serial keyboard, and the speaker. The cassette adapter allows the 

attachment ofany good quality audio cassette via either the microphone 

1"""""\ or auxiliary inputs. The board has a jumper for either input. This 

interface also provides a cassette motor control line for transport 

starting and stopping under program control. This interface reads and 

writes the audio cassette at a data rate of between 1,000 and 2,000 

baud. The baud rate is variable and dependent on data content since a 

different bit-cell time is used for O's and 1 'so For diagnostic purposes, 

the tape interface can loop read to write to test the board's circuits. 

The system software blocks cassette data, generates and checks data 

with a Cyclic Redundancy Check (CRC). 

.~ 

The processor also contains the adapter circuits for attaching the 

serial interface from the keyboard. This generates an interrupt to the 

processor when a complete scan code is received. This interface can 

request execution of a diagnostic in the keyboard. 

Both the keyboard and cassette interfaces are provided via 5-pin 

DIN connectors, which are right angle mounts on the System Board 

and extend through the rear panel of the System Unit. 

The system is provided with a 2-1/4-inch audio speaker mounted inside 

the System Unit. The System Board contains the control circuits and 

driver for the speaker. The speaker connects through a 2-wire interface 

which attaches to a 4-pin header on the System Board. 

The speaker drive circuit is capable of approximately a 1/2 watt of 

power. The control circuits allow the speaker to be driven several 

different ways. First, a direct program control register bit may be 

toggled to generate a pulse train; second, the output ofChannel 2 ofthe 

timer counter may be programmed to generate a waveform to the 

speaker. Third, the clock input to the timer/counter can be modulated 

with a program controlled I/O Register Bit. All three forms of control 

may be performed simultaneously. 

2-5

System Board Data Flow 

PC< 

I 

I-- 

8259A 

INT{RRUPT 

CNTRLR 

o I 2 3 4 5 6 7 

lOCAL ADDRESS. 

DATA STATUS, 

A.NDCONTROL 

ClKJRESET 

WAIT 

CONTROl 

LINES 

£XTtRNAL ADOAES$ 

'US(XAI 

Figure 2. SYSTEM BOARD DATA flOW (SHEET 1 OF 2) 

2-6

System Board Data Flow 

Figure 2. SYSTEM BOARD DATA FLOW (SHEET 2) 

2·7

I/O Channel 

The I/O channel is an extension of the 8088 microprocessor bus. 

Itis, however, demultiplexed, repowered, and enhanced by the addition 

of interrupts and Direct Memory Access (DMA) functions. 

The I/O channel contains an 8-bit bidirectional data bus, 20 address ~ 

lines, 6 levels of interrupt, control lines for memory and I/O read or 

write, clock and timing lines, 3 channels ofDMA control lines, memory 

refresh timing control lines, a channel check line, and power and ground 

for the adapters. Four voltage levels are provided for I/O card +5 V dc, 

5 V dc, +12 V dc, and -12 V dc. These functions are provided in a 62-pin 

connector with 100 mil card tab spacing. 

A ready line is available on the I/O channel to allow operation with 

slow I/O or memory devices. If the channel's Ready line is not 

activated by an addressed device, all processor generated memory 

read and write cycles take four 210 ns clock or 840 ns/byte. All 

processor-generated I/O read and write cycles require five 210 ns 

clocks or 1.05 m sec/byte. All DMA transfers require five clocks for a 

cycle time of 1.05 m sec/byte. Refresh cycles are present once every 72 

clocks or approximately 15 m sec and require five clocks or approximately 

7% of the bus bandwidth. 

I/O devices are addressed using I/O mapped address space. The ,,--......, 

channel is designed so that 512 I/O device addresses are available to 

the I/O channel cards. 

A channel check line exists for reporting error conditions to the 

processor. Activating this line results in a NMI to the 8088 processor. 

Memory Expansion Options use this line to report parity errors. 

The I/O channel is repowered so there is sufficient drive to power 

all five System Expansion Slots, assuming two loads per slot. The 

IBM Option I/O adapters typically use only one load. A graphic 

illustration of the System I/O Channel and its descriptions are on the 

following pages. 

2-8

1/0 Channel Diagram 

REAR PANEl 

SIGNAL NAME 

- - 

1\ SIGN AL NAME 

GND - 

-81 Al- ~ -I/O CH CK 

+RESET DRV +07 

+5V - - +06 

+IRU2 r- - +05 

-5VDC 

'- 

+04 

 

 

 

+ORU2 

' - +03 

-12V I- +02 

RESERVED I- +01 

+12V 

'- +00 

GND I- 810 Al0- +1/0 CH ROY 

-MEMW I- +AEN 

-MEMR I- +A19 

-lOW I- - +A18 

-lOR f- 

+A17 

-DACK3 f- 

+A16 

+ORU3 

'- - +A15 

- 

- 

-DACKl ~ - +A14 

+ORUl I- 

+A13 

-OACKO 

f- 

+A12 

CLOCK I- 820 A20 - +All 

+IRQ7 f- +Al0 

+IRQ6 ~ - +AS 

- 

+IRQ5 ~ - +A8 

+IRQ4 I- 

+A7 

f- 

+IRQ3 +A6 

-DACK2 ~ - +A5 

+T/C f- - +A4 

+ALE- ~ 

+A3 

+5V I- 

+A2 

+OSC ~ +Al 

+GNO I- 831 A31 - +AO 

L....- 

L..- 

NOTE: 

A description of each signal 

is on the following pages. '\ \ COMPONENT SIDE 

- 

Figure 3. I/O CHANNEL DIAGRAM 

2-9

System Board I/O Channel Description 

The following is a description of the IBM Personal Computer System 

Board I/O Channel. All signal lines are TTL compatible. 

Signal 

I/O Description 

OSC 0 Oscillator: This signal is a high speed clock r"\ 

with a 70 nsec. period (14.31818 MHz.) It hat 

a 50% duty cycle. 

CLK 0 Clock: This is the system clock. It is a divide 

by - three of the oscillator and has a period of 

210 nsec. (4.77 Mhz.) The clock has a 33% 

duty cycle. 

RESET DRV 

AO-AI9 

o Reset Driver: This line is used to reset or 

initialize system logic upon power-up or during 

a low line voltage outage. This signal is synchronized 

to the falling edge of clock and is active 

HIGH. 

o Address Bits 0 to 19: These lines are used to 

address memory and I/O devices within the 

system. The 20 address lines allow access ofup 

to 1 megabyte of memory. AO is the Least 

Significant Bit (LSB) while A19 is the Most r"\ 

Significant Bit (MSB). These lines are generated 

by either the processor or the DMA 

Controller. They are active HIGH. 

DO-D7 

I/O Data Bits 0 to 7: These lines provide data bus 

bits 0 to 7 for the processor, memory, and I/O 

Devices. DO is the Least Significant Bit (LSB) 

and D7 is the Most Significant Bit (MSB). 

These lines are active HIGH. 

ALE o Address Latch Enable: This is provided by the 

8288 Bus Controller and is used on the System 

Board to latch valid addresses from the processor. 

It is available to the I/O Channel as an 

indicator of a valid processor address (When 

used in conjunction with AEN). Processor 

addresses are latched with the falling edge of 

ALE. 

I/O CH CK I -I/O Channei Check: This line provides the 

CPU with parity (error) information on memory 

or devices in the I/O Channel. When this 

signal is active LOW, a parity error is 

indicated. 

2-10 

r"\

I/O CHRDY I I/O Channel Ready: This line (nonnally high 

or "READY") is pulled low ("NOT 

READY") by a memory or I/O device to 

lengthen I/O or memory cycles. It allows 

slower devices to attach to the I/O Channel 

with a minimum of difficulty. Any slow device 

using this line should drive it low immediately 

upon detecting a valid address and a Read or 

write command. This line should never be held 

low for any period in excess of 10 clock cycles 

(2.1 usec.) Machine cycles (I/O or memory) 

are extended by an integral number of CLK 

cycles (210 ns). 

IRQ2-IRQ7 I Interrupt Request 2 to 7: These lines are used to 

signal the processor that an I/O device requires 

attention. They are prioritized with IRQ2 as 

the highest priority and IRQ7 as the lowest. An 

Interrupt Request is generated by raising an 

IRQ line (Low to High) and holding it high until 

it is acknowledged by the processor (Interrupt 

Service Routine). 

~ lOR 0 -I/O Read Command: This command line instructs 

an I/O device to drive its data onto the 

data bus. It may be driven by the processor or 

the DMA Controller. This signal is active 

LOW. 

lOW 0 -I/O Write Command: This command line 

instructs an I/O device to read the data on the 


the DMA controller. This signal is active LOW. 

MEMR 

-Memory Read Command: This command line 

instructs the memory to drive its data onto the 


the DMA Controller. This signal is active LOW. 

MEMW 0 -Memory Write Command: This command 

line instructs the memory to store the data 

~ present on the data bus. It may be driven by 

the processor or the DMA Controller. This 

signal is active LOW. 

2-11

DRQI-DRQ3 I DMA Request 1 to 3: These lines are asynchronous 

channel requests used by peripheral devices 

to gain DMA service. They are prioritized 

with DRQ1 having highest priority and 

DRQ3 the lowest. A request is generated by 

bringing a DRQ line to an active level (HIGH). 

A DRQ line must be held high until the 1"""""\ 

corresponding DACK line goes active. 

DACKO o -DMA Acknowledge 0 to 3: These lines are 

DACK3 

AEN 

T/C 

used to acknowledge DMA requests (DRQ1 

DRQ3) and to refresh system dynamic memory 

(DACKO). They are active LOW. 

o Address Enable: This line is used to degate the 

processor and other devices from the I/O 

Channel to allow Direct Memory Access 

(DMA) transfers to take place. When this line 

is active (HIGH), the DMA Controller has 

control of the address bus, data bus, read 

command lines, (memory and I/O), and the 

write command lines, (memory and I/O. 

o Terminal Count: This line provides a pulse 

when the terminal count for any DMA channel 1"""""\ 

is reached. This signal is active HIGH. 

The following voltages are available on the System Board 1/0 Channel: 

+5 Vdc + 5%, Located on 2 connector pins. 

-5 V dc + 10%, Located on 1 connector pin. 

+12 Vdc + 5%, Located on 1 connector pin. 

-12 Vdc + 10%, Located on 1 connector pin. 

GND (Ground), Located on 3 connector pins. 

2-12

System Board Component Diagram 

READ 

ONLY 

MEMORY 

SYSTEM 

EXPANSION 

110 SLOTS 

r -Jl-J-2~-:--J4-~ 

rJ 

I I 

: 

," I 

I 

I 

CASSETTE 110 KEYBOARD 110 

:: 

, b 

, Q 

0 

SYSTEM 

P2 'Q 

I : ~ CLOCK CHIP 

I ,. TRIMMER 

I~AUX 

BOARD 

PROCESSOR 

SOCKET 

=1 =2 

m 1 - INTEL 80S8 

0~ n~ n n :w.~- :::::~SOR 

U U U 

CONFIGURATION 

16-64 KB o 

READ/WRITE 

MEMORY '\ 

o00000 00 ""~""" 

00000000 0000000 

o DOODDDDDDDDOODD 

o 00000000 0000000 

o D~~DD~,,~,~ DOD 00 

SPEAKER OUTPUT 

MIC OR AUX 

SelECT 

Figure 4. SYSTEM BOARD COMPONENT DIAGRAM 

2-13

Keyboard 

The Keyboard is a device separate from the System Unit. Itis attached 

via a serial interface cable approximately 6 feet in length which plugs 

into the rear ofthe System Unit. The attaching cable is coiled, like that 

of a telephone headset, and is a shielded four-wire wire connection. The 

interface contains power ( +5 Vdc), ground and two bidirectional signal 

lines. The cable is permanently attached at the keyboard end and plugs 

into the System Unit via a DIN connector. 

The keyboard' uses a capacitive technology with a microcomputer 

(Intel 8048) performing the keyboard scan function. The keyboard is 

packaged in a low-profile enclosure with a tilt adjustment for 5 degree or 

15 degree orientations. 

The keyboard contains 83 keys laid out in three major groupings. 

The central portion of the keyboard contains a standard typewriter 

keyboard layout. On the left side, arranged as a 2x5 block, are 10 

function keys. These keys are user-defined by software. On the right is 

a l6-key, key pad area. This areais, defined by the software but 

contains legends for the functions of numeric entry, cursor control 

calculator pad screen edit. 

The keyboard interface is defined so system software has the maximum 

flexibility in defining keyboard operations such as shift states of keys, 

make/break keys, and typematic operation. This is accomplished by 

having the keyboard return scan codes rather than American National 

Standard Control Characters (ASCII) codes. In addition, all keys 

except control keys are typematic and generates both a make and a 

break-scan code. For example, key 1 produces scan code 01 on make, 

and code 81 on break. Break codes are formed by adding X'80' to make 

codes. The keyboard I/O driver can define keyboard keys as shift keys 

or typematic as required by the application. 

The microcomputer (Intel 8048) in the keyboard performs several 

functions including a Power-on Self-test and when requested by the 

System Unit This diagnostic CRC checks the microcomputer ROM, 

tests memory and checks for stuck keys. Additional functions 

are: keyboard scanning, key debounce, buffering of up to 20 key scan 

codes, maintaining bidirectional serial communications with the 

System Unit, and executing the hand shake protocol required by each 

scan code transfer. A keyboard diagram and table of scan codes are on 

the following pages. Figure (5) is a block diagram of the keyboard 

interface on the System Board. 

2-14

Keyboard Interface B lock Diagram 

74LS322 

74S74 

PAO QH QH 0 

PAl OG 0 IRQ] 

r"\ PA2 OF CLOCK 

PA3 OE ~ -CLR -0 

1'- 

PM 00 +5V-O -PR 

PAS 

OC 

PA6 

OB 

PA7 

OA 

PB7 

L 

-OE 

LSl25 

-CLR 

-6 

+5V - DO DRV 

-SE GND- 0 

OS 

~ S/-P 

4 -6 

r--- 01 

¢+5V 

4.1K OHM 

KEYBOARD 

DATA 

;-- ~ 0 """ 10 

CLOCK 0 

CLOCK ICLOCK :J 

LATCH 

1 

PB6 

,. 

PCL K 

LS04 

GND- 0 KEYBOARD CLOCK 

I j.-- 

9 

DRV 

l -6 4.1K OHM 

LSl25 

+5V 

Figure 5. KEYBOARD INTERFACE BLOCK DIAGRAM 

2-15

t;-J 

-0'1 

TEJIEfj llEJIDjl[]i[]I[]J1(]JlD1D~Dl(Jl[]J[]J[]lDEJDOEJCO~U ~ 

'i EJID IGJ[j[EJjEJI[JiEJI[]I[JrtJT[ jIEJr[lrDlil[]~b1~r[]r~jUI 3 

TEJrEJI 'OEJ[JEJIllY[JrDrE:lyEJIEJyEJyDrUl[JIDS[J I[jY[]T~ 

6[EJ1EJ j 4~8urDI[JJ[JI[]y[JI[]J[EJIBl[JI[JrDllED(BI~1[Dli~ [] 

TEJIEJj 50EJuJ[ 57 lID§DO~DObJu 

~ 

~ 

~ 

o 

~ 

"'"t 

Q.. 

o_. 

~ 

NOTE 

1 NOMENCLATURE IS ON BOTH TOP ANO FRONT FACE OF KEYBUTTON AS SHOWN. 

THE NUMBER TO THE UPPER LEFT OESIGNATES THE BUTTON POSITION. 

Figure 6. KEYBOARD DIAGRAM 

) ) )

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

Table 1. Keyboard Scan Codes 

Key Position 

Scan Code in Hex 

01 

02 

03 

04 

05 

06 

07 

08 

09 

OA 

OB 

OC 

00 

OE 

OF 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

1A 

1B 

1C 

10 

1E 

1F 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

2A 

Key Position 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

66 

67 

68 

69 

70 

71 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

82 

83 

Scan Code in Hex 

2B 

2C 

20 

2E 

2F 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

3A 

3B 

3C 

3D 

3E 

3F 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

4A 

4B 

4C 

40 

4E 

4F 

50 

51 

52 

53 

2-17

Keyboard Interface Connector Specifications 

REAR PANEL 

5 PIN DIN CONNECTOR 

PIN 

SIGNAL 

1 + Keyboard Clock 

2 + Keyboard Data 

3 - Keyboard Reset (Not used by keyboard) 

4 Ground 

5 +5 Volts 

2-18

Cassette User Interface 

The cassette interface control is implemented in software. (See FIRM 

WARE Section). An 825 3 timer output is used to control the data to the 

cassette recorder. This output exits the System Board, at the rear, 

through pin 5 of a DIN connector. The cassette input data is read by 

an 8255A-5 Programmable Peripheral Interface (PPI) input port bit. 

This signal is received through pin 4 of the cassette connector. Software 

algorithms are used to generate and read cassette data. The casette 

drive motor is controlled through pins 1 & 3 of the cassette connector. 

The motor on/off is controlled by an 8255A-PPI output port bit. 

(Port '61 H', bit 3). The 8255 A address and bit assignments are defined 

in the I/O Address Map page. On the following pages are read, write, 

and motor control block diagrams. 

Cassette Jumpers 

A 2x2 Berg Pin and Jumper are used on the cassette Data Out line. 

The jumper will allow the Data Out line to be used as a microphone 

input (75 mv.) when the jumper is placed across M and C pins. An 

auxiliary input is available when the jumper is placed across the A and 

C pins. The auxiliary input provides a .68 volt input to the recorder. 

Refer to System Board Component Diagram page (2-13) for cassette 

jumper location. 

JUMPER DIAGRAM 

M A M A 

Mike· 75 Mv. 

Aux·O.68V 

Circuit Block Diagrams 

GND 

+5V 

CASSETTE 

DATA IN 

RECORDER 

EARPHONE 

JACK 

SILICON 

GND DIODE 

VIR=,4V CATHODE 

GND 

Figure 7. CASSETTE INTERFACE READ HARDWARE 

2-19

+5V 

8253TIMER#2 to 

OUTPUT 

o 

74LS38 

OR 

3.9K OHM 

R 

0--------- 

.S78V 

TO AUX 

INPUT 

O------------------~• 

.075V 

TO MIC 

INPUT 

GND 

Figure 8. CASSETTE INTERFACE WRITE HARDWARE 

+5V 

I 

I +5V 

4.7 

KOHM SN75475 RELAY 

I 

+5V- CLAMP 

COIL 

S 

N/O 

74LS38 C~. CASSETTE 

VCC - 

MOTOR 

OR IN OUT COIL CONTROL 

MOTO~O 

ON 

o .---- VSS COM 

GNO 

Figure 9. CASSETTE MOTOR CONTROL 

2-20

Cassette Interface Connector Specifications 

REAR PANEL 

o 

5 PIN DIN CONNECTOR 

PIN SIGNAL ELECTRI CAL CHARACTE RISTICS* 

1 Motor Control Common from Relay 

2 Ground 

3 Motor Control 6 VDC; lA (Relay N.O.) 

4 Data In 500nA at ±13V - at 1,000 - 2,000 Baud 

5 Data Out (Mic or Aux) 250 JiA at 

} .68V 

or ** 

75mv 

*All voltages and currents are maximum ratings and should not be exceeded_ 

**Data out can be chosen using a jumper located on planar 

(AUX -+ _68V or MIC -+ 75 mV). 

Interchange of these voltages on the cassette recorder could lead to damage 

of recorder inputs. 

2-21

Speaker Interface 

The sound system contains a small permanent magnet 2-1/4" speaker. 

The speaker can be driven from one or both of two sources. The 

sources are: 

1. An 8255A-5 PPI output bit. The address and bit are defined in 

the I/O Address Map pages 2-23 and 2-24. ~ 

2. A timer Channel Clock out where the output is programmable 

within the functions ofthe 8253-5 timer with a 1.19 Mhz clock 

input. The timer gate is also controlled by an 8255A-5 PPloutput 

port bit. Address and bit assignment are in the I/O Address 

Map pages 2-23 and 2-24. 

PPI BIT 1,1/0 ADDR x'0061' 

1.19 MHz LOW 

TO 

,..--------, AND DRV PASS 

CLOCK 

SPEAKER 

TIMER CLKOUT 2 

FILTER 

IN 2 

PPI BIT 0, I/O ADDRESS X'0061' 

Figure 10. SPEAKER DRIVE SYSTEM BLOCK DIAGRAM 

Channel 2 

ITone generation for Speaker! 

GATE 2 - Controlled by 8255A-5 PPI Bit 

(See I/O Map) 

CLKIN2 -1.19318MhzOSC 

CLK OUT 2 - Used to drive Speaker 

- Used to write data on the Audio 

Cassette 

Speaker Connection - 4 Pin Berg Connector, Refer to 

System Board Diagram page 2-13 for speaker connection. 

PIN 

FUNCTION 

1 DATA 

2 KEY 

3 GROUND 

4 +5 VOLTS 

2-22

I/O Address Map 

HEX RANGE 9 8 7 6 5 4 3 2 1 0 DEVICE 

~O-OF 0 0 0 0 0 Z A3 A2 Al AO DMA CHIf' 8237-2 

20-21 0 0 0 0 1 Z Z Z Z AO INTERRUPT 8259A 

40-43 0 0 0 1 0 Z Z Z Al AO TtME R 8253-5 

60-63 0 0 0 1 1 Z Z Z Al AO PP18255A-5 

80-83 0 0 1 0 0 Z Z Z Al AO DMA PAGE REGS 

• AX 0 0 1 0 1 NMt MASK REG 

CX 0 0 1 1 0 RESERVED 

EX 0 0 1 1 1 RESERVED 

3F8-3FF 1 1 1 1 1 1 1 A2 Al AO TP RS-232-C CD 

3FO-3F7 1 1 1 1 1 1 0 A2 Al AD 51/4" DRV ADAPTER 

2F8-2FF 1 0 1 1 1 1 1 A2 Al AO RESERVED 

378-37F 1 1 0 1 1 1 1 Z Al AO PARALLEL PRTR PRT 

3DO-3DF 1 1 1 1 0 1 A3 A2 Al AO COLOR/GRAPHICS ADAPTER 

278-27F 1 0 0 1 1 1 1 Z Al AO RESERVED 

200-20F 1 0 0 0 0 0 A3 A2 Al AO GAME rio ADAPTER 

3BO-3BF 1 1 1 o 1 1 A3 A2 Al AO IBM MONOCHROME DISPLAY 

PARALLEL PRINTER ADAPTER 

Z =Don't Care, i.e., Not in Decode 

* At power on time, the Non Mask Interrupt NMI into the 8088 is masked off. This 

mask bit can be set and reset via system software as follows: 

Set mask: write X'80' to I/O Address X'AO' (enable NMI) 

Clear mask: wfite X'OO' to I/O Address X'AO' (disable NMI) 

2-23

I/O Address Map 

PAO +KBD SCAN CODE IPL 51/4 DISKETTE DRIVE (SW1-1) 

I 1 RESERVED (SW1-2) 

N 2 SYS. BD. READ/WRITE MEMORY SIZE • (SW1-3) 

X'OOSO' P 3 3 SYS. BD. READ/WRITE MEMORY SIZE • (SW1--4) 

U 4 4 OR +DISPLAY TYPE 1 (SW1-5) 

T 5 5 +DISPLAY TYPE 2 (SW1-6) 

6 6 NO. OF 5 1/4 0 RVS (SW1-7) 

7 7 NO. OF 51/4 DRVS (SW1-8) 

PBO +TIMER 2 GATE SPEAKER 

0 1 +SPEAKER DATA 

U 2 +(READ READ/WRITE MEMORY SIZE) OR (READ SPARE KEY) 

X'OOSJ' T 3 +CASSETTE MOTOR OFF 

P 4 -ENABLE READ/WRITE MEMORY 

U 5 -ENABLE I/O CH CK 

T S -HOLD KBD CLK LOW 

7 -(ENABLE KBD) OR + (CLR KBD & ENABLE SENSE SW'S) 

PCO I/O READiWRITE MEMORY (SW2-n]- ] [ SPARE KEY (SW2-5) 

I 1 I/O READiWRITE MEMORY (SW2-2) BINARY OR 

N 2 I/O READiWRITE MEMORY (SW2-3) VALUE 

X'0062' P 3 I/O REAOiWRITE MEMORY (SW2-4) X 32KB 

U 4 +CASSETTE DATA IN 

T 5 +TIMER CHANNEL 2 OUT 

6 +1/0 CHANNEL CHECK 

7 +READiWRITE MEMORY PCK 

X'0063' 

CMD/MODE REGISTER 

MODE REG VALUE 7 6 4 3 o 

1 0 1 1 o 1 

X'99' 

PA3 PA2 AMOUNT OF MEMORY 

SW1-4 SW1-3 LOCATED ON SYS. BD. 

o o 16K BYTES 

o 1 32K BYTES 

1 o 48K BYTES 

1 1 64K BYTES 

PA5 PA4 TYPE OF DISPLAY 

SW1-S SW1-5 

o o RESERVEO 

o 1 COLOR CARD 40X25 (BW MODE) 

o 

COLOR CARD 80X25 (BW MODE) 

1 IBM MONOCHROME DISPLAY (80 X 25) 

PA7 PAS NUMBER OF 5-1/4" DRIVES 

SW1-8 SW1-7 IN SYSTEM 

o o 1 

o 

8255A - I/O BIT MAP 

2 

3 

4 

NOTE: PA bit=O implies switch "ON". 

PA bit=1 implies switch "OFF". 

2-24

System Memory Map 

X'OOOOO' 

16 TO 64KB 

ON SYSTEM 

BOARD 

I/O CHANNEL 

ADDED MEM 

MAX 192KB 

384K MEMORY 

FUTURE 

EXPANSION 

265KB R/W MEMORY 

PRESENT 

SYSTEM 

MAX MEMORY 

FUTURE 

EXPANSION 

3/4 MEG 

MEMORY 

ADDRESS 

SPACE 

128KB 

128KB RESERVED 

GRAPHIC/DISPLAY 

BUFFER 

EXPANSION 

MEMORY 

216KB 

256KB ROM 

AD 0 R ESS 

SPACE 

X'FFFFF' 

40KB 

BASE SYSTEM 

ROM 

Figure 11. SYSTEM MEMORY MAP 

2-25

System Memory Map (Increments of 16KB) 

START ADDRESS: 

DECIMAL HEX 

0 00000 

16K 04000 

32K 08000 

48K OCOOO 

64K 

80K 

96K 

l12K 

128K 

144K 

160K 

178K 

192K 

208K 

224K 

240K 

256K 

272K 

288K 

304K 

320K 

336K 

352K 

368K 

384K 

400K 

416K 

432K 

448K 

464K 

480K 

496K 

512K 

528K 

544K 

560K 

576K 

592K 

608K 

624K 

10000 

14000 

18000 

lCOOO 

20000 

24000 

28000 

2COOO 

30000 

34000 

38000 

3COOO 

40000 

44000 

48000 

4COOO 

50000 

54000 

58000 

5COOO 

60000 

64000 

68000 

6COOO 

70000 

74000 

78000 

7COOO 

80000 

84000 

88000 

8COOO 

90000 

94000 

98000 

geooo 

FUNCTION: 

16-64 KB READIWRITE MEMORY 

ON SYSTEM BOARD 

UP TO 192 KB 

MEMORY IN I/O 

CHANNEL 

384 KB FUTURE 

R/W MEMORY EXPANSION 

IN I/O CHANNEL 

Figure 12. SYSTEM MEMORY MAP (INCREMENTS OF 16KB) (SHEET 1 OF 2) 

2-26

System Memory Map Cont. 

START ADDRESS: 

DECIMAL HEX 

FUNCTION: 

640K AOOOO RESERVED 

656K MOOO 

672K A8000 

688K ACOOO 112 KB 

704K BOOOO MONOCHROME GRAPHICS/DISPLAY 

VIDEO BUFFER 

720K B4000 

736K B8000 COLOR/GRAPHICS 

752K 

768K 

784K 

800K 

816K 

BCOOO 

COOOO 

C4000 

C8000 

CCOOO 

832K 00000 

848K 04000 192 KB MEMORY 

864K 08000 EXPANSION AREA 

880K OCOOO 

896K 

912K 

928K 

944K 

EOOOO 

E4000 

E8000 

ECOOO 

960K FOOOO RESERVED 

976K 

992K 

1.008M 

F4000 

F8000 

FCOOO 

48 KB BASE 

SYSTEM ROM 

Figure 12. SYSTEM MEMORY MAP (16KB) (SHEET 2) 

2-27

System Board and Memory 

Expansion Switch Settings 

On the following four pages are graphic illustrations of switch settings. 

These are necesary for the system to address components attached, ~ 

and to specify the amount of memory installed both on the System 

Board and in the System Expansion Slots. Refer to the System Board 

Component Diagram (page 13) for DIP switch locations. 

SWITCH 1 

o 1 2 3 4 5 6 7 8 1'\ 

rD~DDDDDD 

POSITION 

FUNCTION 

1-7-8 NUMBER OF 5%" DISKETTE DRIVES INSTALLED; PAGE 2-29 

2 UNUSED-MUST BE ON (RESERVED FOR CO-PROCESSOR) 

3-4 AMOUNT OF MEMORY ON SYSTEM BOARD; PAGE 2-30 

5-6 TYPE OF MONITOR YOU ARE USING; PAGE 2-29 

SWITCH 2 

o 1 2 3 4 5 6 7 8 1\ 

fDDDD~~~~ 

2-28 

POSITION 

FUNCTION 

1-2-3-4 AMOUNT OF MEMORY OPTIONS INSTALLED; PAGE 2-30 

5-6-7-8 ALWAYS IN THE OFF POSITION 

\

5-1/4" Diskette Drives Switch Settings 

SWITCH 1 

1-0RIVE fwnnnOD[jrJ 

12345678 

2-0RIVES 

12345678 

f ~DDDDD~u 

'"'''' t~OODnO~~ 

Monitor Type Switch Settings 

NONE 

SWITCH 1 

f nOOD~~OO 

COLOR/GRAPHICS 

MONITOR 

ADAPTER 

i 

2 8 

(40 x 251-TELEVISION ~ 0'003 04 

nril070 

OR MONITOR ~U 

NOTE: SOME TELEVISIONS AND MONITORS OPERATED 

IN (80 x 251 MOOE MAY HAVE CHARACTER LOSS_ 

2-29

System Board Memory Switch Settings 

SWITCH 1 SWITCH 2 

12345678 12345678 

32KB tDOWLJDDDD tu[j[j~DDDD 

'"'" tOO~DODDO t~~~~oom 

64KB tODW~OOOO 

r~~~~OOOD 

96 KB 

rDDW~DDDD 

12345678 12345678 

t~ulj[jDDDD 

12345678 12345678 

128 KB tDO~~DDDD t[j~[j[jDDDlJ 

160 KB tOD~WOOUO 

t~a~~OODU 

"'" tmw~oouo 

t~~w~mm 

224 KB tnD~WOOOO 

256KB tDU~OOOOC 

r~~W~ODOO 

~~ "------.--------" 

t~~~~DOOD 

2-30

32/64KB Memory Expansion Option 

Switch Settings 

Note: Positions 6-7-8 must always be ON. The sequence shown 

below must be followed to allow the system to address the 

~ memory properly. 

32 KB 

12345678 

96 KB t~LJu~LJDDD 

128 KB t~~~~~ooo 

64 KB 

32 KB 32 KB 

64KB 

32KB 

32 KB 32 KB 32 KB 

12345678 12345678 12345678 

160 KB 

t[j[j[j~[jDDD t [j[j[j~~DDD t[j[j~[1uDDD 

64 KB 64 KB 

12345678 12345678 

192 K8 t[jLJLJ~[jDDD t [jLJ~LJ[jDDD 

64 KB 32 KB 32 KB 

12345678 12345678 12345678 

192 KB 

tLJ[j~~[jDOD t[j[j~~[jDDD t[j~~[j~DDO 

64 KB 64 KB 32 KB 

12345678 12345678 12345678 

224 KB 

tu~[j~[jDDD t[j~~~~DDD t~~~~uDDD 

64 KB 64 KB 64 KB 

2-31

2-32 

NOTES

Power Supply 

The system DC power supply is a 63.5 watt, 4 voltage level switching 

regulator. It is integrated into the System Unit and supplies power for 

the System Unit, its options, and the keyboard. The supply provides 7 

amps of+5 Vdc, +5% 2 amps of +12Vdc, +5% 300 rna of -5Vdc, 

~+IO% and 250 rna of-12 Vdc, +10%. All power levels are regulated 

with overvoltage and over current protection. The input is 120 Vac and 

fused. DC over-load or over-voltage conditions exist, the supply will 

automatically shut down until the condition is corrected. The supply is 

designed for continuous operation at 63.5 watts. 

The System Board takes approximately 3 amps of +5 V dc thus 

allowing approximately 4 amps of 5 V dc for the adapters in the System 

Expansion Slots. The + 12 V dc power level is designed to power the 

two internal 5-1/4" Diskette Drives and the system's dynamic 

memory. Itis assumed that only one drive motor is active at a time. The 

- 5 V dc level is used for memory bias voltage and analog circuits in 

the diskette adapter phase lock loop. The +12 V dc and -12 V dc are 

used for powering the serial interface card EIA drivers and receivers 

for the Asynchronous Communications Adapter. All four power levels 

are bussed across the five System Expansion Slots and available 

for option adapter. 

~ 

The IBM Monochrome Display is self-powered. However, the high 

resolution display receives its AC power from the System Unit power 

system. It is switched on and off with the power switch, which saves a 

wall outlet. The AC output for the display is a nonstandard connector, 

so only the AC high resolution Display can use this AC port. 

2-33

Power Supply Location 

The Power Supply is located at the right rear area ofthe System Unit. It 

supplies operating voltages to the System Board, IBM Monochrome 

Display, annd provides two seperate connections for power to the 5 

1/4" Diskette Drives (if installed). The nominal power requirements 

and output voltages are listed on the following tables: 

r"\ 

Input Requirements 

Voltage 

VOLTAGE @ 60 Hz 

NOMINAL MINIMUM MAXIMUM 

Vac Vac Vac 

120 104 127 

Frequency 

60 Hz +/- .5 Hz 

Current 

DC Output 

2.5 AMPS MAX @ LOW LINE INPUT 

VOLTAGE OF 120 VAC 60 HZ 

VOLTAGE CURRENT REGULATION 

Vdc AMPS TOLERANCE 

NOMINAL MIN MAX ±% -% 

+ 5.0 2.3 7.0 5 4 

- 5.0 0.0 0.3 10 8 

+12.0 0.0 2.0 5 4 

-12.0 0.0 0.25 10 9 

AC Output 

VOLTAGE CURRENT VOLTAGE 

Vac AMPS LIMITS Vac 

NOMINAL MIN I 

MAX MIN I MAX 

120.0 0.0 I .75 101.0 I 130.0 

2-34

N 

I 

~ 

VI 

) 

§ 

I • 

\. 

~ 

o el 

so. 

0.. 

'"I -. 

00 00 ~ 

. .... 

~ 

..., 

::s 

::T'N 

CD "0 :> 

"0 -. r.n 

-.::s r.n .... 

~ 8 OQ 

o ~ 

::scr ::s 

l:li o 9 

~§ 

~ 

~ ::s ::s 

g.~ 

::s S 

00 '"I 

~ 

Important Operating Characteristics 

Over Voltage/Current Protection 

PRIMARY (INPUT) 

VOLTAGE 

NOMINAL 

VAC 

TYPE PROTECTION 

RATING 

AMPS 

120 60 Hz FUSE TYPE 2 SOC SD4 2AMPS 

Power On/Off Cycle: When the supply is turned off for a maximum of 

5 seconds, and then turned on, the power good signal will be 

regenerated. 

Signal Requirements 

The power good signal indicated that there is adequate power to 

continue processing. If the power goes below the specified levels, 

the power good signal triggers a system shut-down. 

The Power Supply. Provides a power good signal out, to indicate the 

presence ofthe +/-5V and +/-12Voutputs are above the sense level 

defined in the chart below, the power good signal is an up level (2.4V to 

5 .5V), TTL compatible and capable of sourcing 60 VA. When any of 

the four sensed output voltages is below its sense level voltage as 

defined in the chart below, the power good signal is down level (OV to 

O.4V), TTL compatible and capable of sinking 500 VA. The power 

good signal (after all levels of the output voltage are good) has a turn 

on delay of 100 MS, but no greater than 500 MS. 

The sense levels of the +/-5V and +/-12V outputs are: 

"'" 

OUTPUT 

MIN 

SENSE VOLTAGE 

NOMINAL 

MAX 

+5V +3.7 +4.0 +4.3 

-5V -3.7 -4.0 -4.3 

+12V +8.5 +9.6 +10.5 

-12V -8.5 -9.6 -10.5 

2-36

IBM Monochrome Display and Parallel 

Printer Adapter 

This adapter has dual functions. The first is to provide the interface to 

the IBM Monochrome Display. The second function is a parallel 

,~interface for the IBM 80 CPS Matrix Printer. 

The monitor interface is designed around the Motorola 6845 CRT 

Controller module. There are 4K bytes of static memory on the card 

which are used for the display buffer. The memory is dual ported and 

may be accessed directly by the CPU. No parity is provided on the 

display buffer. A block diagram of the Monochrome Display function 

in on page 2-38. 

The characteristics of the design are listed below: 

• 80x25 Screen 

• Direct Drive Output 

• 9x14 Character Box 

• 7x9 Character 

• 18 Khz Monitor 

• Character Attributes 

~ The adapter supports 256 character codes. An 8K byte character 

generator contains the fonts for the character codes. The characters, 

values, keystrokes and screen characteristics are tabled in Appendix 

C. Of Characters, Keystrokes and Color. 

Note: This Adapter when used with a display containing P39 

Phospor, will not support a light pen! 

Parallel Interface Description 

This topic is discussed in full on pages 2-65 through page 2-69. 

2-37

IBM Monochrome Display Adapter Block Diagram 

- 

(10) (10) • 

(12) 

CPUADDR MEMORY 2K MEMORY 

(11) ADDRESS ,...- CHARACTER 

,--. MUX CODE 

2KMEMORY 

ATTRIBUTE 

CPUDATA 

BDO-7 

DATA 

BUS 

GATING 

- 

(8) 

(8) 

, 

CHARACTER 

(8) ~LOCI 

OCTAL 

r 

.Ir 

OCTAL 

MA LATCH LATCH 

1 ~ ~ 

RA CHARACTER 

ATTRIBUTE 

~ GENERATOR DECODE 

AD ~ MC6845 

CHIP 

~ CRTC 

(4) 

SELECT DOTCLK , 

TIMING ~ 

SIGNALS 

SHIFT 

REGISTER 

I 1 

SDOTS 

r 

HSYNC, VSYNC, CURSOR, DISPEN 

. 

CHARACTER 

CLOCK 

I 

VIDEO 

PROCESS 

LOGIC 

~ 

MONITOR 

DIRECT DRIVE 

OUTPUTS 

Figure 14. IBM MONOCHROME DISPLAY ADAPTER BLOCK DIAGRAM 

2-38

System Channel Interface 

Lines Used 

This card uses the address and data bus, memory and I/O read/write 

signals, reset, I/O Ready, I/O Clock, and IRQ7. 

"...-....., Loads 

Where possible, only one "LS" load is on the signals present at the 

I/O slot. Some of the address bus lines have two "LS" loads. No 

signal has more than two "LS" loads. 

Special Timing 

At least one wait state will be inserted on all memory and I/O accesses 

from the CPU. The duration of the wait-state will vary because the 

CPU/monitor access is synchronized with the character clock on 

this adapter. 

To insure proper initialization of the attachment, the first instruction 

issued to the card must be to set the high resolution bit of the monitor 

output Port 1. (OUT PORT 3B8 = OlR). A CPU access to this 

adapter must never occur if the high resolution bit is not set. 

"...-....., System configurations which have two display adapter cards must 

insure that both adapters are properly initialized after a power on 

reset. Damage to either display may occur if not properly initialized. 

Data Rates 

For the IBM Monochrome Display Adapter, two bytes are fetched 

from the display buffer in 553 ns providing a data rate of 1.8M 

bytes/second. 

Interrupt and DMA Response Requirements 

• The display buffer can be written into, or read from using DMA. 

• The parallel interface uses the +IRQ7 line. Interrupt becomes 

active when the acknowledge input is low, and interrupts are 

enabled via the control port. 

2-39

Modes of Operation 

The IBM Monochrome Display and Printer Adapter supports 256 

character codes. In the character set are alphanumerics and block 

graphics. Each character in the display buffer has a corresponding 

character attribute. The character code must be an even address and the 

attribute code must be an odd address in the display buffer. ,............., 

7 6 5 4 3 2 o 

7 6 5 4 3 2 0 

BL R I R B 

CHARACTER CODE 

EVEN ADDRESS (M) 

ATTRIBUTE CODE 

I G I B I I G ODD ADDRESS (M+l) 

I 

I .. 

FOREGROUND 

~ 

: INTENSITY 

BACKGROUND 

~ 

... BLINK 

The adapter decodes the character attribute byte as defined above. The ,............., 

BLINK and INTENSITY bits may be combined with the FORE 

GROUND and BACKGROUND bits to further enhance the character 

attribute functions listed below. 

BACKGROUND FOREGROUND FUNCTION 

R G B 

R G B 

0 0 0 0 0 0 NON DISPLAY 

0 0 0 0 0 1 UNDERLINE 

0 0 0 1 1 1 WHITE CHARACTER/ 

BLACK BACKGROUND 

1 1 1 000 REVERSE VIDEO 

2-40

Programming Considerations 

Programming the 6845 CRT Controller 

The following table summarizes the 6845 Internal Data Registers and 

their functions and parameters. For the IBM Monochrome Display, 

r--.., the values in the table must be programmed into the 6845 to insure 

proper initialization of the device. 

Table 2. 6845 INITIALIZATION PARAMETERS 

REGISTER REGISTER PROGRAM 80x25 

# FILE UNIT MONOCHROME 

RO HORIZONTAL TOTAL CHARACTERS 61H 

Rl HORIZONTAL OISPLAYED CHARACTERS 50H 

R2 HSYNC POSITION CHARACTERS 52H 

R3 HSYNC WIDTH CHARACTERS FH 

R4 VERTICAL TOTAL CHAR ROWS 19H 

R5 VTOTAL ADJUST SCAN LINE 6H 

R6 VERTICAL DISPLAYED CHAR ROW 19H 

R7 VSYNC POSITION CHAR ROW 19H 

RS INTERLACE MODE --- 02 

R9 MAX SCAN LINE ADDRESS SCAN LINE DH 

R10 CURSOR START SCAN LINE BH 

Rll CURSOR END SCAN LINE CH 

R12 START ADDRESS (H) --- DOH 

R13 START ADDRESS (L) --- DOH 

R14 CURSOR (H) --- DOH 

R15 CURSOR (L) --- DOH 

R16 RESERVED --- -- 

R17 RESERVED --- -- 

Sequence of Events 

The first command issued to this attachment must be to output to 

PORT 3B8, hex 01, to set high resolution mode. Ifthe high resolution 

mode is not set, an infinite CPU wait-state will occur! 

Memory Requirements 

The attachment has 4K bytes of memory which is used for the display 

buffer. The memory supports one screen of 25 rows of 80 characters, 

plus a character attribute for each display character. No parity is 

provided on the memory. No system Read/Write memory is required 

for the monochrome adapter portion. The display buffer starts at 

address 'BOOOO'. 

2-41

DMA Channels 

The display buffer will support a DMA operation, however CPU 

wait-states will be inserted during DMA. 

Interrupt Levels 

Interrupt Level 7 is used on the parallel interface. Interrupts can be 

enabled or disabled via the Printer Control Port. The interrupt is a high 

level active signal. 

I/O Address and Bit Map 

The table below breaks down the functions ofthe I/O Address decode 

for the card. The I/O address decode is from '3BO' through '3BF'. 

The bit assignment for each I/O address follows: 

I/O Address Function 

3BO Not Used 

3Bl Not Used 

3B2 Not Used 

3B3 Not Used 

3B4 6845 Index Register 

3B5 6845 Data Register -. 

3B6 Not Used r , 

3B7 Not Used 

3B8 CRT Control Port 1 

3B9 Reserved 

3BA CRT Status Port 

3BB Reserved 

3BC Parallel Data Port 

3BD Printer Status Port 

3BE Printer Control Port 

3BF Not Used 

The 6845 Index and Data Registers are used to program the CRT 

controller to interface to the high resolution Monochrome Display. 

• CRT Output Port 1 (I/O Address '3B8') 

Bit :#= Function 

+high resolution mode 

2-42 

o 

1 Not used 

2 Not used 

3 + video enable 

4 Not used 

5 + enable blink 

6,7 Not used

• CRT Status Port (I/O Address '3BA') 

Bit Function 

o + Horizontal Drive 

1 Reserved 

2 Reserved 

3 +B/W Video 

IBM Monochrome Display 

The high resolution IBM Monochrome Display unit attaches to the 

System Unit via two cables of approximately 3' (914 mm) in length. 

One cable is a signal cable which contains direct drive interface from 

the IBM Monochrome Display and Printer Adapter. 

The second cable provides AC power to the display from the System 

Unit. This allows the System Unit power ON/OFF switch to also 

control the display unit. An additional benefit is a reduction in the 

requirements for wall outlets to power the system. The monitor 

contains an 12" (305 mm) diagonal 90° deflection CRT. The CRT and 

analog circuits are packaged in an enclosure so the display may either 

sit on top ofthe System Unit or on a nearby table top or desk. The unit 

has both brightness and contrast adjustment controls on the front 

~ available to the operator. 

Operating Characteristics 

Screen 

High persistance green phosphor (P 39) with an etched surface to 

reduce glare. Unit displays an 80 character by 25 line screen with a 

9 dot wide by 14 dot tall character box. 

Video Signal 

Maximum video bandwidth of 16.27 Mhz. 

Vertical Drive 

Screen refreshed at 50 Hz with 350 vertical lines of resolution and 

720 lines of horizontal resolution. 

~ Horizontal Drive 

Positive level TTL compatible frequency, 18.432 Khz. 

2-43

IBM Monochrome Direct Drive Interface 

and Pin Assignment 

REAR PANEL 

9 PIN "0" 

SHELL CONNECTOR~ 

o 

1 • • 6 

· e·C3lW-~~ o 

~ 0~ 

PARALLEL 

PRINTER 

ADAPTER 

• • 

: • 9 

IBM 

Monochrome 

At Standard TTL Levels 

Ground 1 

Ground - 2 

Not Used 3 

Not Used 4 

Not Used 5 

IBM 

Monochrome 

Display and 

Display .... + Intensity 6 Parallel Printe 

., 

.... + Video 7 

"" 

"" 

"" 

.... + Horizontal 8 

.... - Vertical 9 

NOTE: Signal voltages are 0 - .6 Vdc at down level 

+5 Vdc at high level 

Adapter 

2-44

Color/Graphics Monitor Adapter 

The Color/Graphics Monitor Adapter is designed to attach a wide 

variety of TV frequency monitors and TV sets (user-supplied RF 

modulator required for TVs). It is capable of operating in black and 

~ white or color, and provides three video interfaces; a composite video 

port, a direct drive port, and connection interface for driving a user 

supplied RF modulator. In addition, a light pen interface is provided. 

The adapter has two basic modes of operation; alphanumeric (A/N) 

and all points addressable graphics (APA). Additional modes are 

available within NN and APA modes. In NN mode, the display can 

be operated in a 40x25 mode for low resolution monitor and TV s or 

80x25 mode for high resolution monitors. In both modes, characters 

are defined in an 8x8 box and are 5x7 with one line of descender for 

lowercase (both uppercase and lowercase characters are supported in 

all modes). In black and white mode, the character attributes ofReverse 

Video, Blinking and Highlighting are available. Incolor mode, there are 

16 foreground colors and 8 background colors available per character. 

In addition, blinking on a per character basis is available. 

The adapter card contains 16KB of storage; thus, for a 40x25 screen, 

1000 bytes are used to store character information and 1000 bytes are 

~ used for attribute/color information. This means that up to 8 pages of 

screens can be stored in the adapter memory. Similarly, in an 80x25 

mode, 4 pages of display screen may be stored in the adapter. The full 

16KB storage on the display adapter is directly addressable by the 

processor allowing maximum software flexibility in managing the 

screen. In NN color modes, it is also possible to select the screen 

border color. One of 16 colors may be selected. 

2-45

In APA mode, there are two resolutions available; 320x200 and 

640x200. In the 320x200, each (picture element) pel may have one of 

four colors. The background color (color 0) may be any of the 16 

possible colors. The remaining 3 colors come from one of the two 

software selectable palettes. One palette contains red/green/brown, 

the other contains cyan/magenta/white. ~ 

The 640x200 mode is only available in black and white since the full 

16KB of storage is used to define the on or off state of the pel. 

The adapter operates in noninterlace mode at either 7 or 14 megahertz 

(Mhz) video bandwidth depending on the mode of operation selected. 

In NNmode, characters are formed from a ROM character generator. 

The character generator contains dot patterns for 256 characters. 

The character set contains the following major grouping of characters. 

Sixteen special characters for game support, 15 characters for support 

of word processing editing functions, the standard 96 ASCII graphic 

set, 48 characters to support foreign languages, 48 characters for 

business block graphics allowing drawing of charts, boxes and tables 

using single and double lines, 16 of the most often used Greek 

characters, and 15 ofthe most often used scientific notation characters. 

The Color/Graphics Monitor Adapter function is packaged on a single 

card which fits into one of the five System Expansions Slots on the 

System Board. The direct drive and composite video ports are rightangle 

mounted connectors at the rear ofthe adapter and extend through 

the rear panel of the System Unit. 

The display adapter is implemented using a Motorola 6845 CRT 

controller device. This adapter is highly programmable with respect to 

raster and character parameters. Thus, many additional modes are 

possible with clever programming of the adapter. A block diagram of 

the Color/Graphics Adapter is on the following page. 

r"'\ 

2-46

CPU 

.. r-- 

) ) ) 

DISPLAY 

ADDRESS BUFFER INPUT 

CPU DATA ~ 

ADDRESS LATCH (16K BUFFER 

BYTES) 

0 

""i 

l ~ 

"'0 

OUTPUT 

::r' 

CPU 6845 

DATA ~ CRTC 

ADDRESS DATA DATA 

~ LATCH I-- 

LATCH LATCH 

4 I-- -. 

LATCH (") 

rIl 

a: 

0 

=-. 

i 

GRAPHICS 

f---. 

SERIALIZER 

CHARACTER 

GEN. I 

SERIALIZER 

n 

- 

f---. ...... 

f----. '"1 

f----. 

COLOR 

,---t ENCODER 0 

r-t 

> 

ALPHA Q.. 

f-----. 

ROS ~ 

"'0 

...... 

~ 

PALETTEi ~ OVERSCAN '"1 

--" 

HORIZ. 

t:D 

L 

VERT. 

-0 

(") 

COMPOSITE 

COLOR ~ 

TIMING f--+ 

MODEl GENERATOR 

4 GENERATOR 

CONTROL 

& CONTROL ~ _. 

N Figure 15. COLOR/GRAPHICS MONITOR ADAPTER BLOCK DIAGRAM 

I 3 

.....,J 

"'" 

3Y"MOY"H 

~ 

(JQ 

'"1 

~ 

0 

0

Major Components Definitions 

Motorola 6845 CRT Controller 

This device provides the necessary interface to drive a raster scan 

CRT. 

Mode Set And Status Registers 

This is a general purpose programmable I/O register. Ithas I/O points 

which may be individually programmed. Its function in this attachment 

is to provide mode selection (page 2-49 and 2-50) and color selection in 

the medium resolution color graphics mode (page 2-51.) 

Display Buffer 

The Display Buffer resides in the CPU address space starting at 

address X'B8000'. It provides 16K bytes of dynamic read/write 

memory. A dual-ported implementation allows the CPU and the 

graphics control unit to access this buffer. The CPU and the CRT 

control unit have equal access to this buffer during all modes of 

operation except in high resolution alphanumeric mode. In this mode 

the CPU should access this buffer during the horizontal retrace 

intervals. The CPU may however, write to the required buffer at any 

time, but a small amount of display fetches will result if not during 

retrace intervals. 

Character Generator 

This attachment utilizes a ROM character generator. It consists of 8K 

bytes of storage which cannot be read/written under software control. 

This is a general purpose ROM character generator with three different 

character fonts. Two character fonts are used on this card (a 7x7 double 

dot and 5x7 single dot), selected by a card jumper. No jumper gives a 

7x7 double dot, with a jumper a single'dot font is selected. 

Timing Generator 

This block generates the timing signals used by the 6845 CRT 

controller and by the dynamic memory. It also resolves the CPU/ 

graphic controller contentions for accessing the Display Buffer. 

Composite Color Generator 

The logic in this block generates base band video color information. 

2-48


There are two basic modes of operation, 'Alphanumeric' and 

'Graphics'. Each of these modes provide further options in both color 

and black-and-white. The following text describes each mode of 

operation. 

~ 

Alphanumeric Mode 

Alphanumeric Display Architecture 

Every display character position is defined by two bytes in the regen 

buffer (part ofdisplay adapter, not system memory). Both the color and 

the black and white display adapter use this 2 byte character/attribute 

format. 

DISPLAY CHAR CODE BYTE 

ATTRIBUTE BYTE 

6 5 4 3 6 4 

Attribute Byte Definition 

ATTRIBUTE BYTE 

765 4 3 2 o 

B R G B I R G B 

ATTRIBUTE FUNCTION FG BACKGROUND FOREGROUND 

NORMAL B 0 0 0 I 1 1 1 

REVERSE VIDEO B 1 1 1 I 0 0 0 

NON DISPLAY (BLK) B 0 0 0 I 0 0 0 

NON DISPLAY (WHITE) B 1 1 1 I 1 1 1 

I = HIGH LIGHT FOREGROUND (CHAR) 

B= BLINK FOREGROUND (CHAR) 

Color TV 

• Display up to 25 rows of 40 characters each 

• Maximum of 256 characters 

• Requires 2000 bytes of Read/Write Memory (on the adapter) 

• 8x8 character box 

• 7x7 double dotted characters (one descender) 

• Character attributes (one for each character) 

2-49

7 6 543 2 1 0 76543210 

CHARACTER CODE 

I 

ATTRIBUTE CODE 

EVEN ADDRESS (M) ODD ADDRESS (M+1) 

ATTRIBUTE BYTE DEFINITIONS 

R: Red 7 6 5 4 3 2 o 

G: Green 

B: Blue 

I: Intensity 

B I I R G BI 

I 

Foreground Color 

Background Color 

Blinking 

Note: The starting address of the display buffer must be an 

even location. 

Color Monitor (with Direct Drive input capability) 

Display up to 25 rows of 80 characters each 

Requires 4000 bytes of Read/Write Memory (on the adapter) 

Maximum of 256 character set 

8x8 character box 

7x7 character with one descender 

Same format for attributes as for color TV 

Note: The starting address of the display buffer must be an 

even location. 

r"'\ 

2-50

IBM Monochrome Display Adapter V s. Color/ 

Graphics Adapter Attribute Relationship 

Table 3. Monochrome Vs Color/Graphics Attributes 

ON THE 

ON THE 

MONOCHROME COLOR/GRAPHIC 

7 6 5 4 3 Z 1 0 DISPLAY ADAPTER DISPLAY ADAPTER 

B R G B I R G B CHAR. ! BKGD. CHAR. BKGD. 

COLOR I COLOR COLOR COLOR 

FG BACKGROUND FOREGROUND 

NORMAL B 0 0 0 I 1 1 1 WHITE BLACK WHITE BLACK 

RVV B 1 1 1 I 0 0 0 BLACK WHITE BLACK WHITE 

NON DISP (BLKI B 0 0 0 I 0 0 0 BLACK BLACK BLACK BLACK 

NON DISP (WHTI B 1 1 1 I 1 1 1 WHITE WHITE WHITE WHITE 

ALL OTHER CODES ALL OTHER ALL OTHER 

DEFINE FOREGROUND CODES RESULT CODES CHANGE 

BACKGROUND COLOR IN WHITE FOREGROUND 

COMBINATIONS CHAR ON BLACK BACKGROUND 

BACKGROUND COLOR TO 

SELECTED 

VALUE 

G * CODE WRITTEN WITH AN UNDERLINE 

ATTRIBUTE FOR THE IBM MONOCHROME DISPLAY 

BLACK WHEN EXECUTED ON A COLOR/GRAPHICS ADAPTER 

1 BLUE WILL RESULT IN A BLUE CHARACTER 

0 GREEN WHERE THE UNDERLINE ATTRIBUTES 

1 CYAN ARE ENCOUNTERED. 

0 REO 

1 MAGENTA CODE WRITTEN ON A COLOR/GRAPHICS ADAPTER 

0 YELLOW WITH BLUE CHARACTERS, WILL BE 

WHITE DISPLAYED AS WHITE CHARACTERS 

ON BLACK BACKGROUND WITH A 

* AN ADDITIONAL WHITE UNDERLINE ON THE MOI~OCHROME DISPLAY 

8 COLOR (ACTUAL) 

DIFFERENT SHADES 

OF THE ABOVE) 

ARE SELECTED BY 

SETTING THE 

(II BIT 

Note: Not all Monitors Recognize the (1) Bit 

Table 4. Color/Graphics Modes 

HORIZONTAL VERTICAL NO OF COLORS 

(lNCl. BACKGROUND COLOR) 

LOW RES 160 100 16 (INCLUDES BLACK AND 

WHITE) 

MED RES 320 200 4 COLORS: 1 OF 16 FOR 

BACKGROUND PLUS GREEN, 

REO, YELLOW OR CYAN, 

MAGENTA, WHITE 

HIGH RES 640 200 B&WONLY 

2-51

1. Low resolution color graphics (TV or monitor). (Note: This 

mode is not supported in ROM). 

• Up to 100 rows of 160 pels each (2x2) 

• 1 of 16 colors each pel specified by I, R, G and B 

• Requires 8000 byte of Read/Write Memory (on the adapter) ,,-..... 

• Memory mapped graphics (requires special memory map 

and set up to be defined later) 

2. Medium resolution color graphics (TV or monitor) 

• Up to 200 rows of 320 pels each (lxl) 

• 1 out of 4 preselected colors in each box 

• Requires 16000 bytes of Read/Write Memory 

(on the adapter) 

• Memory mapped graphics 

4 pels/byte 

FORMAT: 7 6 5 4 3 2 0 

C1 CO C1 CO C1 CO C1 CO I 

First display 

pel 

• Graphics storage is organized in two banks of 

8000 bytes each. 

Graphics Storage Map 

Memory Address 

#0000 

even scans (0,2,4, " " "' 198) 

(8000 bytes) 

#1 F3F 

#2000 

odd scans (1,3,5, " " "' 199) 

(8000 bytes) 

#3F3F 

Address #0000 contains pel information for upper left comer of 

display area. 

2-52

Color selection is determined by the following logic: 

C 1 and CO will select 4 of 16 preselected colors. 

This color selection (palette) is preloaded in an I/O port. 

CI CO CODE SELECT COLOR FOR DISPLAY 

o 0 

POSITION 

DOT TAKES ON COLOR OF 1 OF 16 

o 1 

PRESELECTED BACKGROUND COLORS. 

SELECT 1ST COLOR OF PRESELECT COLOR 

SET"I" OR "2" 

1 0 SELECT 2ND COLOR OF PRESELECT COLOR 

SET "I" OR "2" 

1 1 SELECT 3RD COLOR OF PRESELECT COLOR 

SET"1" OR "2" 

The two color sets are: 

SET ONE 

COLOR 1 - CYAN 

COLOR 2 - MAGENTA 

COLOR 3 - WHITE 

SET TWO 

COLOR I - GREEN 

COLOR 2 - RED 

COLOR 3- BROWN 

The background colors are the same basic 8 color as defined for 

low resolution graphic plus 8 alternate intensities defined by the 

intensity bit for a total of 16 color including black and white. 

3. Black and white high resolution graphics (monitor) 

• Up to 200 rows of 640 pels each (IxI) 

• Black and white only 

• Requires 16000 bytes of Read/Write Memory 

(on the adapter) 

• Addressing and mapping is the same as for medium resolution 

color graphics, but the data format is different. In this 

mode each bit in memory is mapped to a pelon the screen. 

• 8 pels/byte 

76543210 

I I I I I I I I 

L H"t d',pl,y p,' " , by" 

2-53

Description of Basic Operations 

In the alphanumeric mode the adapter fetches character and attribute 

information from its display buffer. The starting address of the display 

buffer is programmable through the 6845, but it must be an even 

address. The character codes and attributes are then displayed 

according to their relative position in the buffer. 

(EVEN) Starting Address 

DISPLAY BUFFER 

CHAR CODE 'A' 

ATTRIBUTE 

CHAR CODE 'B' 

A 

(Example of a 40x25 screen) 

B 

ATTRIBUTE 

Video Screen 

X 

Last Address 1000 

CHAR CODE 'X' 

ATTRIBUTE 

The CPU and the display control unit have equal access to the display 

buffer during all the operating modes except high resolution alphanumeric. 

During this mode, the CPU should access the display buffer 

during the vertical retrace time (if not, then the display will be affected 

with random patterns as the CPU is using the display buffer). The 

characters are displayed from a prestored "character generator" which 

contains the dot patterns of all the displayable characters. 

In the graphics mode the displayed dots and colors are also fetched 

from the display buffer (up to 16K bytes). In the Color/Graphics Mode 

Section, the bit configuration for each graphics mode is explained. 

2-54

1"'"""""\ 

Table 5. 

I 

R G B 

Summary of Available Colors 

COLOR 

0 0 0 0 Black 

0 0 0 1 Blue 

0 0 1 0 Green 

0 0 1 1 Cyan 

0 1 0 0 Red 

0 1 0 1 Magenta 

0 1 1 0 Brown 

0 1 1 1 Light Gray 

1 0 0 0 Dark Gray 

1 0 0 1 Light Blue 

1 0 1 0 Light Green 

1 0 1 1 Light Cyan 

1 1 0 0 Light Red 

1 1 0 1 Light Magenta 

1 1 1 0 Yellow 

1 1 1 1 White 

Note: "I" provides extra luminance (brightness) to each shade 

available. Resulting in the light colors listed above, except 

where the "I" bit is not recognized by some monitors. 


Programming the 6845 CRT Controller 

The 6845 has 19 internal registers which are used to define and control 

a raster scanned CRT display. One of these registers, the Address 

Register, is actually used as a pointer to the other 18 registers. It is a 

write only register which is loaded from the CPU by executing an OUT 

instruction to I/O address 3D4. The five least significant bits ofthe I/O 

bus are loaded into the Address Register. 

In order to load any of the other 18 registers, the Address Register is 

first loaded with the necessary pointer and then the CPU may output a 

value to I/O address 3D5 in order to load the information in the 

preselected register. 

The following table defines the values which must be loaded in 6845 

1"'"""""\ Registers in order to control the different modes ofoperation supported 

by the attachment. 

2-55

Table 6. 6845 Register Description 

ADDR REG. REGISTER 40x25 80x25 GRAPHIC 

REG. # TYPE UNITS I/O ALPHA ALPHA MODES 

0 RO Horizontal Char. Write 38 71 38 

Total 

Only 

1 R1 Horizontal Char. Write 28 50 28 

Displayed 

Only 

2 R2 Horiz. Sync Char. Write 20 5A 20 

Position 

Only 

3 R3 Horiz. Sync Char. Write OA OA OA 

Width 

Only 

4 R4 Vertical Total Char. Write 1F 1F 7F 

Row Only 

5 R5 Vertical Total Scan Write 06 06 06 

Adjust Line Only 

6 R6 Vertical Char. Write 19 19 64 

Displayed Row Only 

7 R7 Vert. Sync Char. Write 1C 1C 70 

Position Row Only 

8 R8 I nterlace Mode - Write 02 02 02 

Only 

9 R9 Max Scan Scan Write 07 07 01 

Line Addr. Line Only 

A R10 Cursor Start Scan Write 06 06 06 

Line Only 

B R11 Cursor End Scan Write 07 07 07 

Line Only 

C R12 Start Addr. (HI - Write 00 00 00 

Only 

0 R13 Start Addr. (Ll - Write 00 00 00 

E R14 

Only 

Cursor - Read/ XX XX XX 

Addr. (HI 

Write 

F R15 Cursor - Read/ XX XX XX 

Addr. (Ll 

Write 

10 R16 Light Pen (HI - Read XX XX XX 

Only 

11 R17 Light Pen (Ll - Read XX XX XX 

Only 

Note: All register values are given in hexadecimal. 

2-56

Programming the Mode Control and Status Register 

The following I/O devices are defined on the Color/Graphics Adapter. 

HEX AOOR. A9 A8 A7 A6 A5 A4 A3 A2 Al AD FUNCTION OF REGISTER 

X'308' 1 1 1 1 0 1 1 0 0 0 DO REG (MODE CONTROL) 

X'309' 1 1 1 1 0 1 1 0 0 1 DO REG (COLOR SELECT) 

X'30A' 1 1 1 1 0 1 1 0 1 0 01 REG (STATUS) 

X'30B' 1 1 1 1 0 1 1 0 1 1 CLEAR LIGHT PEN LATCH 

X'30C' 1 1 1 1 0 1 1 1 0 0 PRE SET LIGHT PEN LATCH 

X'300' 1 1 1 1 0 1 0 Z Z 0 6845 REGISTERS 

X'301' 1 1 1 1 0 1 0 Z Z 1 6845 REGISTERS 

X'300' 1 1 1 1 0 1 0 Z Z 0 6845 REGISTERS 

X'301' 1 1 1 1 0 1 0 Z Z 1 6845 REGISTERS 

Z = don't care condition 

Color Select Register 

This is a 6 bit output only, register, it can not be read, its address is 

X'3D9' and can be written using the 8088 I/O OUT command. 

The following is a description of the Register functions. 

~ 

Bit 0 B (BLUE) Border Color Select ALPHA/BACKGROUND 

Bit 1 G (G REEN) Border Color Select ALPHA/BACKG RO UNO 

Bit 2 R (RED) Border Color Select ALPHA/BACKGROUND 

Bit 3 I Intensifies Border Color Select ALPHA/BACKGROUND IN 320 X 200 

Bit 4 Select Alt Back Color Set For Alpha Color Modes 

Bit 5 320 x 200 Color Set Select 

Bit 6 Not Used 

Bit 7 Not Used 

Bits 0, 1, 2, 3. Select the screens border color in 40x25 alpha mode. In 

graphics mode (medium resolution) 320 x 200 color, the screen 

background color (CO-Cl) is selected by these bit settings. 

Bit 4. This bit when set will select on alternate, intensified, set of background 

colors in the alpha mode. 

Bit 5 is only used in the medium resolution color mode (320 x 200). 

It is used to select the active set of screen colors for the display. 

2-57

When bit 5 is set to a "1" colors are determined as follows. 

The C 1 CO Set selected are: 

0 Background as defined by Bit 0-3 of Port '3D9' 

o 1 Cyan 

1 0 ~agenta 

1 1 White 

When bit 5 is set to a "0" Colors are determined as follows. 

The CO Cl Set selected are: 

0 Background as dermed by Bit 0-3 of Port '3D9' 

o 1 Green 

1 0 Red 

1 0 Yellow 

Mode Select Register 

This is a 6 bit output only register, it can not be read. Its address is 

X'3D8'. It can be written using the 8088 I/O OUT command. 

The following is a description of the registers functions. 

Bit 0 

Bit 0 

Bit 1 

Bit 2 

Bit 3 

Bit 4 

Bit 5 

Bit 6 

Bit 7 

80 x 25 mode 

Graphic Select 

B & W Select 

Enable Video Signal 

High Res 640 x 200 B & W ~ode 

Change BACKGROUND INTENSITY 

to Blink Bit 

Not Used 

Not Used 

Bit 0 Selects between 40 x 25 and 80 x 25 alpha mode, a "1" 

sets it to 80 x 25 mode. 

Bit 1 

Selects between ALPHA mode and 320 x 200 graphics 

mode, a "I" select 3 20 x 200 graphics mode. 

Bit 2 Selects color or B & W mode, a "1" selects B & W. 

Bit 3 

Bit 4 

2-58 

Enables the video signal at certain times when modes are 

Oeing changed. The video signal should be disabled when 

changing modes. A "1" enables the video signal. 

When on, this bit selects the 640 x 200 B & W graphics 

mode. One color of 8 can be selected on direct drive sets in 

this mode by using register 3D9.

Bit 5 

When on, this bit will change the character background 

intensity to the blinking attribute function for ALPHA 

modes. When the high order attribute bit is not selected, 16 

background colors (or intensified colors) are available. For 

normal operation, this bit should be set to "1" to allow the 

blinking function. 

Mode Register Summary 

Bits 

0 1 2 3 4 5 

0 0 1 1 0 1 40 x 25 ALPHA B & W 

0 0 0 1 0 1 40 x 25 ALPHA COLOR 

1 0 1 1 0 1 80 x 25 ALPHA B & W 

1 0 0 1 0 1 80 x 25 ALPHA COLOR 

0 1 1 1 0 z 320 x 200 B & W GRAPHICS 

0 1 0 1 0 z 320 x 200 COLOR GRAPHICS 

0 1 1 1 1 z 640 x 200 B & W GRAPHICS 

'1' 4" l" ~ .~ '1' 

Z = don't care condition 

ENABLE BLINK ATTRIBUTE 

640 x 200 B& W 

ENABLE VIDEO 

SELECT B & W MODE 

SELECT 320 x 200 GRAPHICS 

80 x 25 ALPHA SELECT 

* THE LOW RESOLUTION 160 x 100 MODE REQUIRES SPECIAL PROGRAMMING 

AND IS SET UP AS ALPHA MODE 40 x 25 

Status Register 

~ The status register is a 4 bit read only register. Its address is X'3DA'. 

It can be read using the 8088 I/O IN instruction. 

2-59

The following is a description of the register functions. 

Bit 0 

Bit 1 

Bit 2 

Bit 3 

Bit 4 

Bit 5 

Bit 6 

Bit 7 

Display Enable 

Light Pen Trigger Set 

Light Pen SW Made 

Alpha Dots 

Not Used 

Not Used 

Not Used 

Not Used 

Bit 0 This input bit, when active, indicates that a regen buffer 

memory access can be made without interfering with the 

Display. 

Bit 1 This bit, when active, indicates that a positive going edge 

from the light pen input has set the light pen trigger. This 

trigger is reset on power on and may also be cleared by doing 

an I/O OUT command to address X'3DB'. No specific data 

setting is required, the action is address activated. 

Bit 2 The light pen switch status is reflected in this status bit. 

The switch is not latched or debounced. A "0" indicates 

the switch is on. 

Bit 3 The ALPHA video output signal is readable in this status bit. ,.,.,......... 

Its purpose is to verify that video information is being 

generated for RAS purposes. 

Sequence of Events 

1. Determine mode of operation 

2. Reset Video Enable bit 

3. Program 6845 to select mode 

4. Program mode/color select registers 

Memory Requirements 

The memory used by this adapter is self-contained. It consists of 

16k bytes of memory without parity. This memory is used as both a 

display buffer for alphanumeric data and as a bit map for graphics data. 

The Regen Buffers address starts at X'B8000'. 

Interrupt Level (Vertical Retrace) 

Level 2 

2-60

I/O Address and Bit Map 

Read/Write Memory Address Space 

01000 

System ReadIWrite Memory 

B8000 

BBFFF 

Display Buffer (16K Bytes) 

128K RESERVED 

REGEN AREA 

Display Buffer (16 K Bytes) 

C8FFF 

2-61

Color/Graphics Monitor Adapter Direct Drive, and 

Composite Interface Pin Assignment 

REAR PANEL 

0 

· 

0 

e·~ • • 6 

• 9 

~ 0~ • 

AT STANDARD TTL LEVELS 

0 

COLOR DIRECT 

DRIVE 9 PIN "0" 

SHELL CONNECTOR 

Ground 1 

Ground 2 

... Red 3 

.... 

.... Green 4 

Direct .... Color/Graph ics 

Drive .... Blue 5 Direct Drive 

Monitor ~ 

Adapter 

.... Intensity 6 

" 

.... 

... Reserved - 7 

.... 

.... Horizontal Drive 8 

.... 

.... Vertical Drive 9 

"'" 

COMPOSITE PHONO JACK 

HOOK-UP TO MONITORS 

Composite Video Signal of approximately 1.5 Volts 

Video .... Peak to Peak Amplitude 1 Color/Graphics 

Monitor 

.... Chassis Ground 2 

Composite Jack 

2-62


Auxiliary Video Connectors 

PIJI PIN BERG STRIP 

FOR RF 

MODULATOR 

P2-6 PIN BERG STRIP 

FOR LIGHT PEN 


ADAPTER 

RF 

Modulator 

... 

..... 

t.... 

+12 Volts 

(key) Not Used 

Composite Video Output 

Logic Ground 

1 

2 

3 

4 

Color/Graphics 

Adapter 

R F Modulator Interface 

- Light Pen Input 

(key) Not Used 

1., 

2" 

Light 

Pen 

... 

..... 

... 

.. 

- Light Pen Switch 

Chassis Ground 

+ 5 Volts 

+ 12 Volts 

Light Pen Interface 

3 .. 

4" 

5 

6 

Color/Graphics 

Adapter 

2-63

2-64 

NOTES

Parallel Printer Adapter 

The Printer Adapter is specifically designed to attach printers with a 

parallel port interface, but it can be used as a general input/output port 

for any device or application which matches its input/output capabilities. 

It has 12 TTL buffer output points which are latched and can be 

written and read under program control using the processor IN or OUT 

instructions. The adapter also has five steady state input points that 

may be read using the processor's IN instructions. 

In addition, one input can also be used to create a processor interrupt. 

This interrupt can be enabled and disabled under program control. 

Reset from the power-on circuit is also "ORed" with a program output 

point allowing a device to receive a power-on reset when the processor 

is reset. 

This function is packaged on an adapter which fits into any of the five 

System Expansion slots on the System Board. The input/output signals 

are made available at the back of the adapter via a right angle PCB 

mounted 25 PIN "D" type connector. This connector protrudes 

through the rear panel ofthe System Unit where a cable and shield may 

be attached. 

"..-..., When this adapter is used to attach a printer, data, or printer, 

commands are loaded into an 8-bit latched output port, and the strobe 

line is activated writing data to the printer. The program then may read 

the input ports for printer status indicating when the next character can 

be written or it may use the interrupt line to indicate "not busy" to 

the software. 

The output ports may also be read at the card's interface for diagnostic 

loop functions. This allows fault isolation determination between the 

adapter and the attaching device. 

This same function is also part of the combination IBM Monochrome 

Display and Printer Adapter. A block diagram ofthe printer adapter is 

on the following page. 

2-65

Parallel Printer Adapter Block Diagram 

,.. ENABLE 

25 PIN "0" SHE LL 

BUS BUFFER DATA LATCH CONNECTOR 

r- 

8 8 

~ ... 

~ CLOCK 

I 

TRANS- 8 

~ 

r 

CEIVER 

DIR 

C 

~O 

AEN 

M 

M 

obJ 

E 

READ 

DATA 

C 

a 

A 0 

WRITE DATA 

WRITE CONTROL 

N 

D 

READ STATUS 

E 

READ 

R ~ONTROL 

RESET 

BUS CONTROL o.c. 

BUFFERS 

DRIVERS 

~ SLCT IN 

4 ENABLE 4 CLOCK 

STROBE 

~,.. AUTO 

~ 

f---t 

FO XT 

5 INIT 

ENABLE 

f-+ 

,.... CLR 

I 

ERROR 

SLCT 

PE 

ACK 

BUSY 

Figure 16. PARALLEL PRINTER ADAPTER BLOCK DIAGRAM 

2-66


The Printer Adapter responds to 5 I/O instructions - 2 output and 3 

input. The output instructions transfer data into 2 latches whose outputs 

~ are presented on pins of a 25 Pin "D" shell connector. 

Two of the three input instructions allow the CPU to read back the 

contents of the two latches. The third allows the CPU to -read the real 

time status of a group of pins on the connector. 

A description of each instruction follows. 

IBM Monochrome Display & Printer Adapter 


Output to address 3BCH Output to address 378H 

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 

Pin 9 Pin 8 Pin 7 Pin 6 Pin 5 Pin 4 Pin 3 Pin 2 

This instruction captures data from the data bus and is present on the 

respective pins. These pins are each capable of sourcing 2.6 rna and 

sinking 24 rna. 

It is essential that the external device not try to pull these lines to 

~ ground. 



Output to address 3BEH Output to address 37AH 

Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 

IRQ Pin 17 Pin 16 Pin 14 Pin 1 

Enable 

This instruction causes this latch to capture the five least significant 

bits of data bus. The four least significant bits present their outputs, or 

inverted versions oftheir outputs to the respective pins shown above. If 

bit 4 is written I, the card will interrupt the CPU on the condition that 

Pin 10 transitions high to low. 

These pins are driven by open collector drivers pulled to +5V through 

4.7K OHM resistors. They can each sink approximately 7 rna and 

maintain 0.8 volts down level. 

~ Note: For pin references, see Parallel Interface Connector 

Specifications, page 2-69. 

2-67

IBM Monochrome Display &Printer Adapter 


Input from address x' '3BC' Input from address 378H 

This command presents the CPU with data present on the pins 

associated with the out to x' '3BC'. This should nonnally reflect the 

exact value that was last written to x '3BC'.1fan external device should 

be driving data on these pins (in violation ofusage ground rules) at the 

time of an input, this data will be 'or' ed with the latch contents. 



Input from address 3BDH Input from address 379H 

This command presents real time status to the CPU from the pins 

as follows. 

Bit 1 Bit 0 



Input from address 3BEH Input from address 37AH 

This instruction causes the data present on pins 1, 14, 16, 17 and IRQ 

bit to be read by the CPU. In the absence of external drive applied to 

these pins, data read by the CPU will exactly match data last written to r""'\ 

x' '3BE' in the same bit positions. Note that data bits 0-2 are not 

included. Ifexternal drivers are dotted to these pins, that data will be 

'or'ed with data applied to the pins by the x' '3BE' latch. 

Bit 7 Bit 6 Bit 5 Bit4 Bit 3 Bit 2 Bit 1 Bit 0 

-- -- 

IRQ Pin 17 Pin 16 Pin 14 Pin 1 

Enable 

Por={) Por=1 Por={) Por=1 Por=1 

These pins assume the states shown after a reset from the CPU. 

Note: For pin references see Parallel Printer Adapter Interface 

Connector Specifications page 2-69. 

2-68

Parallel Printer Adapter 

Interface Connector Specifications 

REAR PANEL 

25 PIN "0" 


~ 0 

14· 

• • 

• • 

• • 

NOTE: 

All outputs are software !lenerated, 

and all inputs are real time si!lnals 

(not latched). 


Signal 

AMP 

Name 

Pin No 

- Strobe 1 ... 

..... + Data Bit 0 2 

.... 

, 

- 

..... + Data Bit 1 3 

+ Data Bit 2 4 

... 


r-. - 

I ... + Data Bit 4 6 

I"'" 

... 

..... 


I .... + Data Bit 6 8 

... 

I ... + Data Bit 7 9 

Printer .....- Parallel Printe 

- Acknowledae 10 Adapter 

-.... + Busy 11 

I..... + P. End (out of Paper) 12 

.... - 

+ Select 13 

- Auto Feed 14 ... 

- Error 15 ... 

- Initialize Printer 16 .. 

... 

- Select Input 17 ... 

Ground 18·25 ... 

.. 

.. 

2-69

IBM 80 CPS Matrix Printer 

The printer is a self powered, standalone table top unit. Itattaches to the 

System Unit via a parallel signal cable which is 6 feet in length. The unit 

obtains its A C power from a standard wall outlet (120 Vac). The printer 

is an 80 Character Per Second (CPS) bidirectional wire matrix device. 

Ithas a 9 wire head, allowing it to print characters in a 9x9 dot matrix. 

Itcan print in compressed mode 132 characters per line and in standard 

font, 80 characters per line. A large font also prints in 66 characters per 

line mode. The printer can print double size characters and double 

dotted characters. The printer prints the standard ASCII 96 character 

uppercase and lowercase character sets. In addition, a set of64 special 

block graphic characters are available. 

The printer can also accept commands setting the feed control desired 

for the application. Setting of 1 to 66 lines per page can be programmed 

and the lines per inch may be set to 5,8, or 10. This printer attaches to 

the System Unit via the Parallel Printer Adapter or the combination 

Monochrome Display Adapter and Parallel Printer Adapter. The cable 

is a 25 lead shielded cable with a 25 pin "0" type connector at the 

System Unit end, and a 36 pin connector on the printer end. 

Note: You may lose data anytime you are running a program with the 

printer off and attached to the System Unit. 

/""""'\ 

r--.. 

2-70

Table 7. 

Printer Specifications 

(1 ) PRINT METHOD: 

(2) PRINT SPEED: 

/~ (3) 

(4) 

PRINT DIRECTION: 

NUMBER OF PINS IN HEAD: 

(5) LINE SPACING: 

(6) PRINTING CHARACTERISTICS 

Matrix: 

Character Set: 

Graphic Character: 

(7) PRINTING SIZES 

Normal: 

Enlarged: 

Condensed: 

Condensed Enlarged: 

(8) MEDIA HANDLING 

Paper Feed: 

Paper Width Range: 

~ Copies: 

Paper Path: 

(9) INTERFACES 

Standard: 

(10) INKED RIBBON 

Color: 

Type: 

Life Expectancy: 

(11 ) ENVIRONMENTAL CONDITIONS 

Operating Temperature Range: 

Operating Humidity: 

(12) POWER REQUIREMENT 

Voltage: 

Current: 

Power Consumption: 

(13) PHYSICAL CHARACTERISTICS 

Height: 

~ Width: 

Depth: 

Weight: 

Serial impact dot matrix 

80 CPS 

Bidirectional with logical seeking 

9 

4.23 mm 0/6") or programmable 

9x9 

Full 96·character ASCII with decoders, 

plus 9 international characters/symbols 

64 block characters 

Maximum 

Characters characters 

per inch 

per line 

10 80 

5 40 

16.5 132 

8.25 66 

Adjustable sprocket pin feed 

101.6 mm Wlto 254 mm (10") 

One original plus two carbon copies (total 

thickness not to exceed 0.3 mm (0.012") 

Rear 

Parallel 8-bit 

Data & Control lines 

Black 

Cartridge 

3 million characters 

5 to 350 C (41 to 950 F) 

10 to 80% non·condensing 

120VAC, 60 Hz 

1 Amp maximum 

100 VA maximum 

107 mm (4.2") 

374 mm (14.7") 

305 mm (12.0") 

5.5 kg (12Ibs.) 

2-71

Setting The DIP Switches 

There are two DIP switches on the control circuit board. In order to suit 

the user's specific requirements, desired control modes are selectable 

by the DIP switches. The functions of the switches and their preset 

conditions at the time of shipment are as shown in Table 8 (DIP 

Switch 1) and Table 9 (DIP Switch 2). ~. 

" ,;;::; .,.);'PJ,'rr:on,o,.,/' "d(~ 

HMTP BOARD ... ll....M'''·_ •• M,'~' ••' ,0 

~~N::~'9.0:~I~~::: 

.. - ';', eo '0'D"D·' 

>0" - '" ..., 

... Q,~l,.n:: : ,~c ' ~ no 

• .,; g...". ' n.. 

'·~... ' .. '·_.n.. ,I ,;-0- D.. 

•• ' .,[]~f 

.' i;', nO 

C~8)j"~u 

~:: .7C.,U!oO.Z' U: ., • ~ cuU ~n 

. : ,; 0 5' 'C~··"l'" ,'C 00 't5 • M'_+ I 

;,~.., f., ~()' , :, ' c, • '.. J 1= + ~' 

~, Q 'D'D":""D""~" .q~ .. ~'~ll 0 0 ,."r·D ::::: ..: II 

.," II .. ,. ," ., v. ", ~ J ~ 

~ =:= ::~ --.so.' ~. f 

. :O-.B~, ,'[D': :~,\ 1111;' D~o: I'0: :·6~MITij;I~'r·1 ~ 

l[ 

'JIUO. "',"-sol .200:) -+~ :: as;" I.' ,. "~ I 

c,. 11: .... '"' 2 -Q".'" I 

Figure 17. LOCATION OF PRINTER DIP SWITCHES 

Table 8. Functions and Conditions of DIP Switch 1 

2-72 

Pin No. Function ON OFF Factory·set 

Condition 

1 Not applicable - - ON 

2 CR { Print & Line Feed Print only Print & ON 

Print only 

line feed 

3 Buffer full { Print & Line Feed Print only Print & ON 

Print only 

line feed 

4 Cancel code {Valid Invalid Valid OFF 

Invalid 

5 Delete code { Valid Invalid Valid ON 

Invalid 

6 Error Buzzer Sounds Does not ON 

sound 

7 Character generator N.A. Graphic OFF 

(Graphic pattern select) 

patterns 

select 

8 SLCT I N signal Fixed Not fixed ON 

Fixed internally 

Not fixed internally

Table 9. Functions and Conditions of DIP Switch 2 

Pin No. Function ON OFF Factory-set 

Condition 

1 

Not applicable - - ON 

2 - - ON 

3 AUTO FEED ~ Fixed internally Fixed Not fixed OFF 

XT signal Not fixed internally 

4 Coding table select N.A. Standard OFF 

Parallel Interface Description 

(1) Specifications 

(a) Data transfer rate: 1000 CPS (max.) 

(b) Synchronization: By externally supplied STROBE 

pulses. 

(c) Handshaking: ACKNLG or BUSY signals. 

(d) Logic level: Input data and all interface control signals 

are compatible with the TTL level. 

~ (2) Connector 

Plug: 57-30360 (AMPHENOL) 

(3) Connector pin assignment and descriptions of signals. 

Connector pin assignment and descriptions of respective 

interface signals are provided in Table (10) page 2-74. 

2-73

Table 10. Connector Pin Assignment and Descriptions 

ofInterface Signals 

Signal Return 

Pin No. Pin No. 

1 19 

2 20 

3 21 

4 22 

5 23 

6 24 

7 25 

8 26 

9 27 

10 28 

11 29 

Signal 

STROBE 

DATA 1 

DATA 2 

DATA 3 

DATA 4 

DATA 5 

DATA 6 

DATA 7 

DATA 8 

ACKNLG 

BUSY 

Direction 

In 

In 

In 

In 

In 

In 

In 

In 

In 

Out 

Out 

Description 

STROBE pulse to read 

data in. Pulse width 

must be more than 

O.5J.1S at receiving 

terminal. 

The signal level is 

normally "HIGH"; 

read·in of data is per· 

formed at the "LOW" 

level of this signal. 

These signals represent 

information of the 

1st to 8th bits of 

parallel data respectively. 

Each signal is 

at "HIGH" level when 

data is logical "1" and 

"LOW" when logical 

"0". 

Approx .. 5J.1S pulse. 

"LOW" indicates that 

data has been received 

and that the printer 

is ready to accept 

other data. 

A "HIGH" signal 

indicates that the 

printer cannot receive 

data. The signal 

becomes "High" in 

the following cases: 

1. During data entry 

2. During printing 

operation 

3. In OFF·LlNE state 

4. During printer error 

status. 

2-74


of Interface Signals (cont.) 

Signal Return 

Pin No. Pin No. Signal Direction Description 

12 30 PE Out A "HIGH" signal 

indicates that the 

printer is out of paper. 

13 - SLCT Out This signal indicates 

that the printer is in 

the selected state. 

14 - AUTO In With this signal being 

FEED XT 

at "LOW" level, the 

paper is automatically 

fed one line after 

printing. 

(The signal level can 

be fixed to "LOW" 

with DIP SW pin 2·3 

provided on the 

control circuit board.) 

15 - NC Not used. 

16 - OV Logic GN D level. 

17 - CHASSIS·GND - Printer chassis GN D. 

In the printer, the 

chassis GN D and the 

logic GN D are isolated 

from each other. 

18 - NC - Not used. 

19-30 - GND - TWISTED·PAI R 

RETU RN signal 

GN D level. 

31 - INIT In When the level of this 

signal becomes" LOW" 

the printer controller 

is reset to its initial 

state and the print 

buffer is cleared. This 

signal is normally at 

"HIGH"level, and 

its pulse width must 

be more than 50!1S at 

the receiving 

terminal. 

2-75


of Interface Signals (cont.) 

Signal Return 

Pin No. Pin No. Signal Direction Description 

32 ERROR Out The level of this signal 

becomes "LOW" 

when the printer is 

in 

1. PAPER END state 

2. OFF·LINE state 

3. Error state 

33 - GND - Same as with Pin No. 

19t030. 

34 - NC - Not used. 

35 Pulled up to +5V 

through 4.7 Kn 

resistance. 

36 - SLCTIN In Data entry to the 

printer is possible 

only when the level 

of th is signal is 

"LOW". (Internal 

fixing can be carried 

out with DIP SW 1-8. 

The condition at the 

time of shipment is 

set" LOW" for this 

signal.) 

NOTES 

1: "Direction" refers to the direction of signal flow as viewed from the printer. 

2: "Return" denotes "TWISTED PAl R RETU RN" and is to be connected 

at signal ground level. 

As to the wiring for the interface, be sure to use a twisted-pair cable for 

each signal and never fail to complete connection on the Return side. To 

prevent noise effectively, these cables should be shielded and connected 

to the chassis of the System Unit and the printer, respectively_ 

3: All interface conditions are based on TTL level. Both the rise and fall times 

of each signal must be less than O.2.us. 

4: Data transfer must not be carried out by ignoring the ACKN LG or BUSY 

signal. (Data transfer to this printer can be carried out only after confirming 

the AC KN LG signal or when the level of the BUSY signal is "LOW".) 

2-76

(4) Data transfer sequence 

Fig. 17 shows the sequence for data transmission. 

BUSY--"" 

r""'\ ACKNLG 

0.51'

~ 

ASCII Coding Table 

Table 11 shows all available codes when the Printer is set for 

operation with standard coding by setting the DIP switch pin 2-4 to 

the OFF position. This DIP switch pin is factory-set to the OFF 

position. 

Table 11. ASCII Coding Table 

-Q- 

'"- 

u.. 

::: 

Ṉ 

::: 

W 

0 

(.) 

'" 

Q- 

....., 

"'" 

- 

~ 

. 

+ 

~ 

~ 

- 0 

- 

u.. 

u.. 

.. 

- 

./ 

....J 

V' 

u.. 

0 

Q- 

CC 

(.) 

-- 

E 

:;: 

" 

I 

~ 

0- 

0 

en 

ASCII Control Codes 

Control Codes 

Various kinds ofcontrol codes are contained in Table 11. These control 

codes are recognized by the printer and perform specified functions 

~upon receipt of these codes. The following are descriptions of respective 

control codes. 

(1) CR (Carriage Return) 

When the CR code is transmitted to the print buffer, all data 

stored in the print buffer is printed. 

(When AUTO FEED XT (Pin No. 14) is at "LOW" level or 

DIP switch pin 2-2 is ON, the paper is advanced one line 

automatically after printing.) 

~ When 80 columns of print data (including spaces) are 

continuously received and the following data is valid and 

printable, the Printer automatically begins to print the 

data stored in the print buffer. In this case, if AUTO 

FEED XT is at "LOW" level or DIP switch pin 2-3 is 

ON, the paper is advanced one line after printing. 

(2) LF (Line Feed) 

When the LF code is input, all data in the print buffer is printed 

~ and the paper is advanced one line. 

Note: If no data precedes the LF code, or if all preceding data 

is "SPACE", only paper feeding is performed. 

For example, if the data is transferred in the order of 

DATA-+CR-+LF, DATA will be printed by the CR 

code, and when the Printer receives the LF code, it only 

carries out one line feed. 

(3) VT (Vertical Tab) 

When the VT code is input, all data preceding this code is 

printed. And the paper is advanced to the line position set by 

"ESC B" (described later). If no vertical tab position is set by 

ESC B, the VT code behaves like the LF code. Therefore, the 

paper is advanced one line after printing. 

(4) FF (Form Feed) 

The FF code carries out the printing of all data stored in the 

print buffer and advances the paper to the next predetermined 

Top ofForm position. The Top ofForm is determined when the 

POWR switch is turned on or the INIT signal is applied. Ifthe 

form length per page is not set by "ESC C+n", it is regarded 

as 66 or 72 lines. 

2-79

Note: The form length of72 lines per page is applicable to only 

the version marked with identifier code "M72" on the 

rear side of the lower case of the Printer. 

This code always initializes the printing of the data stored in 

the print buffer. 

(5) SO (Shift Out) 

Whell the SO code is input, all data that follows it in the same 

line will be printed out in enlarged (double width) characters. 

This code is cancelled by the printing operation or the input of 

"DC 4" code and can be input at any column position on a line. 

Therefore, normal size and enlarged characters can be mixed 

on the same line. 

1. [DATA] ABC 1so 1 DEF 1DC41 GHI ~ [!;£J 

[PRINT] 

ABCDEFGHI 

2. [DATA ABCD ~ EFGH ~ ~ IJLK 1SO 1 MNOP ~ ~ 

[PRINT 

ABCDEFGH 

IJKLMNOP 

(6) SI (Shift In) 

When the SI code is input, all data that follows it will be printed 

out in condensed characters. This code is cancelled by the input 1""""\ 

of "DC 2" code. The SI code can be input at any column 

position on a line, but all characters/symbols on the line 

containing SI code are printed out in condensed characters. 

When printing condensed characters, the data capacity of the 

print buffer will become 132 columns per line. 

When the SO code is received after the input of the SI code, 

condensed enlarged characters (double width of condensed 

characters) can be printed. This condition is cancelled by 

"DC 4" code, and the character size returns to "condensed". 

1. [DATA] ~ ABCDEFGHIJKL ~ ~ 

[PRINT] 

ABCDEFGHIJKL 

2. [DATA] ABC @] DEF ~ GHIJKL ~ ~ 

[PRINT] 

ABCDEFGHIJKL 

(7) DC 4 (Device Control 4) 

The DC 4 code cancels the SO mode. 

[DATA] ~ ABCDEF ~ GHI 1DC 41 JKL ~ ~ 

[PRINT] ABCDEFGHIJKL 

2-80

(8) DC 2 (Device Control 2) 

The DC 2 code cancels the SI mode. 

[DATA] ~ ABCDEF ~ GHI ~ ~ ~ JKLMN ICR I~ 

[PRINT] ABCDEFGHI 

JKLMN 

(9) HT (Horizontal Tab) 

The HT code carries out the horizontal tabulation. Ifthere is no 

tab position set, this code is ignored. The tab stop positions are 

set by "ESC D+n" (described later). 

(10) CAN (Cancel) 

Upon the input of the CAN code, all data previously stored in 

the print buffer is cancelled. Therefore, this code is regarded as 

the print buffer clear command. This code clears the print 

buffer, but control codes (Excluding the SO code) are still valid 

even ifthe CAN code is transferred. The validity or invalidity of 

the CAN code is selectable by the DIP switch pin 1-4 on the 

control circuit board. 

(11) DEL (Delete) 

This code functions the same as the CAN code. The validity or 

invalidity of the DEL code is selectable by the DIP switch pin 

1-5 on the control circuit board. 


The DC 1 code places the Printer in the Selected state. With the 

Printer in the Selected state, if the DC 1 code is input during 

data transfer, all data stored before the DC 1 code is ignored. 


The DC 3 code places the Printer in the Deselected state. In 

other words, it disables the Printer to receive data. Once the 

Printer is put in the Deselected state by the DC 3 code, the 

Printer will not revert to the Selected state unless the DC 1 code 

is input again. 

Note: When the DC 1 and DC 3 codes are used, DIP switch 

pin 1-8 should be in the "OFF" position. 

r'"'\, 1. [DATA] [Q[!J AAAAA 1DC 31 BBBBB @DJ CCCCC ~ [ill 

[PRINT] 

AAAAACCCCC 

2. [DATA] AAAAA @fJ] BBBBB IDC 31 CCCCC ~ @BJ [ill 

[PRINT] 

BBBBB 

2-81

Relations among the ON LINE switch, SLCT IN signal, 

DC1/DC3 code and interface signals are shown in Table 

12 below. 

Table 12. DCl/DC3 And Data Entry 

ON LINE 

SWITCH 

SLCTIN DC llDC 3 ERROR BUSY ACKNLG SLCT DATA ENTRY 

OFF-LINE HIGHILOW DC llDC 3 LOW HIGH Not LOW Impossible 

Generated 

DC I HIGH LOWI Generated HIGH Possible 

HIGH 

(Normal entry) 

HIGH 

DC 3 HIGH LOWI Generated LOW Possible 

HIGH 

(See Note 1.) 

ON-LINE LOW DC llDC 3 HIGH LOW/ Generated HIGH Possible 

HIGH 

(N ormal entry) 

NOTES 

1: In Table 12, it is assumed that as soon as the Printer receives data, it sends back the ACKNLG signal, 

though this data is not stored in the print buffer_ In this status, the Printer is waiting for the DC I 

code for normal entry_ 

2: The DC I/OC 3 code is valid under the condition that the DIP switch pin 1-8 is OFF, namely, the 

level of SLCT IN at the pin No_ 36 of the interface connector is "HIGH"_ When SLCT IN is "LOW", 

the DC I/DC 3 code is not valid. 

(14) NUL (Null) 

The NUL code is regarded as the termination for tabulation 

setting sequence (described in detail later). 

(15) BEL (Bell) ~ 

When the BEL code is input, the buzzer sounds for about 3 

seconds. 

(16) Escape (ESC) control 

(a) Escape numerical control 

Input ofan "ESC" code followed by an ASCII numeric 

code permits each of the following functions to be 

performed. 

1) ESC 0 (Escape 0) 

Receipt of an "ESC" followed by ASCII code 

"0" causes the line spacing to be set at 1/8 inch. 

Input of the ESC 2 code or INIT signal to the 

interface connector or turning the power off and on 

again causes the line spacing to return to 1/6 inch. 



"1" causes the line spacing to be set at 7 /72 inch. ~ 

Input of the ESC 2 code or INIT signal to the 

interface connector or turning the power off and on 

again causes the line spacing to return to 1/6 inch. 

2-82

(b) 



"2" causes the line spacing to be set at 1/6 inch. 

When the POWER switch is turned on, the line 

spacing is set at initia11/6 inch. The ESC 2 code is 

also a command to execute "ESC A+n" modes 

(described later). 


The ESC 8 code makes it possible to transmit data 

even if there is no paper in the Printer. This code 

should be transmitted before the Printer runs out 

of paper. After transmitting this code, when the 

Printer runs out of paper, the PE signal of the 

interface connector turns to High level; the 

ERROR signal remains at High level. 


This code cancels the ESC 8 condition. When the 

power is turned on, the Printer is initialized into 

ESC 9 status. Therefore, the Printer cannot 

receive data when there is no paper. 

6) ESC SI 

This code functions the same as "SI". 

7) ESC SO 

This code functions the same as "SO". 

ESC alphabetic control 

Receipt of an "ESC" code followed by ASCII code 

"X"(alphabetic code) permits each of the following 

functions to be performed. 

Note: "n" represents a 7-bit binary number, and the 

most significant bit is not treated as data. "+" is 

inserted for the purpose of legibility only, and 

should not be input in actual operation. 

1) ESC A+n 

This code specifies the amount of line spacing in 

the Line Feed 1 «n>10

The ESC A code is the command only to store 

spacing data into the memory. In other words, 

even if spacing data was transferred into the 

memory, the Printer does not actually carry out 

the line spacing in accordance with the spacing 

data. To execute the line spacing in accordance 

with the stored data, the ESC 2 code should be 

followed. Namely, the ESC 2 code is considered 

as the execution command for the line spacing. 

[DATA] AAAAAAA ICRI [LFl BBBBBBB ICRI !!£] IESC A+24 I 

CCCCCCC ICR 1 I1I] DDDDDDD I ESC 21 ICR 1 [ill 

[PRINT] 

EEEEEEE ICRI ITIJ FFFFFFF ICRI ILFI 

AAAAAAA} 

BBBBBBB 

CCCCCCC 

DDDDDDD} 

EEEEEEE 

1/6 inch = 12 steps/72 

1/3 inch = 24 steps/72 

FFFFFFF 

Note: 

When "n" is actually transferred to the 

Printer as data, it is transferred in the form 

of a 7-bit binary number. 

In case of "ESC A+24", actual output to 

the Printer is performed as 

HHH in hexadecimal 

code. 

2) ESC B+nl +n2+nk+NUL 

(1«n>1O

ehaves like the LF code. Therefore, the paper is 

advanced one line after printing. 

Receipt of "ESC B" code causes the Printer to 

accept the following codes as tab stop line num 

bers until the NUL code is input. The lack of the 

NUL code will cause incorrect data printout. 

The form length must be set by "ESC C+n" code 

prior to setting tab stops. 

Input of"ESC B" code followed by only the NUL 

code cancels predetermined tab stops. 

[DATA] IEseBI H H H INULI 

AAAAAAA IVTI BBBBBBB IVTI eeeeeee IVTI DDDDDDD 

[PRINT] AAAAAAA .... 1st line 

BBBBBBB ... ,4th lines 

eeeeeee .... 6th lines 

DDDDDDD .... 10th lines 

3) ESC C+n (1 «n>1010< 127,Ie::; 112) 

This code specifies the horizontal tab stop positions. 

The first 112 tab stops per line are 

recognized in the Printer, and subsequent tab 

stops are ignored. Tab stop numbers must be 

received in incremental numerical order. 

If a tab stop position of higher value than 80 is 

received in normal character printing mode, all 

horizontal tab functions after 80 columns are 

ignored. 

To execute tab stop positions, the HT code should 

be input. The HT code is ignored when the horizontal 

tab position has not been programmed. 

2-85

The NUL code should be input as the command 

for the termination ofthe tab set sequence, and the 

lack ofthis code will cause incorrect data printout. 

1. In case of 5th, 10th and 21st columns. 

[DATA] IESCDI H H H INUll ABC l8Il DEF [BIJ GHI [8IJ JKl 

@j]1lli 

[PRINT] ABC DEF GHI JKl 

2. In case of lack of stop position. 

[DATA] I ESC DI H H INULI ABC lEIl DEF [!ill GHI [8] JKL @ID [IT] 

[PRINT] ABC DEF GHIJKL 

3. In case of character data transferring over next tab stop. 

[DATA] IESCDI H H H INUll ABCDEF [8II GHI OITJ JKL @ID lIT) 

[PRINT] ABCDEF GHI JKl 

4. In case of transferring two HT codes at a time. 

[DATA] IESC DI H H H I NULl ABCD [8II I SPACE I IT!:!] EFGH [gjJ [];£J 

[PRINT] ABCD EFGH 

5) ESC E 

The ESC E code causes the Printer to print 

emphasized characters. Emphasized printing 

gives the character a stronger impression on the 

paper. 

This code can be input in any column position on a 

line. 

The speed ofthe head carriage reduces to 40 CPS 

while printing emphasized characters. 

1. [DATA] IESC E I ABCDEFGHI ICR I [ill 

[PRINT] 

ABCDEFGHI 

2. [DATA] Isol IESC E I ABCDEFGHI ICR I (ill 

[PRINT] 

ABCDEFGHI 

6) ESC F 

The ESC F code cancels the emphasized printing 

mode. 

7) ESCG 

The ESC G code causes the Printer to perform the 

double printing. Double printing is carried out in 

the following manner: 

a) A character is printed. 

b) The paper is advanced by 1/216 inch. 

c) The print head prints the same character 

again. 

In this way, the character becomes bold. 

2-86

[DATA] IESCGI ABCDEFGHI 

[PRINT] 

ABCDEFGHI 

ICRI ILFI 

8) ESC H 

The ESC H code cancels the double printing 

mode. 

2-87

2-88 

NOTES

5 1/4-Inch Diskette Drive Adapter 

The System Unit has space and power for one or two 5-1/4" Diskette 

Drives. The drives are soft sectored, single sided, with 40 tracks. They 

are Modified Frequency Modulation (MFM) coded in 512 byte 

~ sectors, giving a formatted capacity of 163,840 bytes per drive. They 

have a track to track access time of 8 ms and a motor start time 

of 500 ms. 

The 5-1/4" Diskette Drive Adapter fits in one of the System Board's 

five System Expansion Slots. It attaches to the two drives via an 

internal daisy chained flat cable which connects to one end ofthe drive 

adapter. The adapter has a second connector on the other end which 

extends through the rear panel of the System Unit. This connector 

contains the signals for two additional external drives, thus the 5-1/4" 

Diskette Drive Adapter is capable of attaching four 5-1/4" drives, two 

internal, and two external. 

The adapter is designed for double density MFM coded drives and uses 

write precompensation with an analog phase locked loop for clock and 

data recovery. The adapter is a general purpose device using the NEe 

IlPD765 compatible controller. Thus the drive parameters are 

programmable. In addition, the attachment supports the drive's write 

~ protect feature. 

The adapter is buffered on the I/O bus and uses the System Board direct 

memory access (DMA) for record data transfers. An interrupt level is 

also used to indicate operation complete and status condition requiring 

processor attention. 

In general, the 5-1/4" Diskette Drive Adapter presents a high-level 

command interface to software I/O drivers. A block diagram of the 

5-1/4" Diskette Drive Adapter is on the following page. 

2-89

N I'-" 

~ 

~ 

r-- 

BUFFER 

I-- 

...... ' 

INTR. 

) 

.. 

I'v- rv' 

~ 

I 

CLOCK & 

TIMING CKT 

WRITE WRITt DATA 

PRECOMP. 

f-- CKT ~ ~ 

• 

1 --- 

... 

L-4 o_. 

~ 

WRITE fI) 

DATA i'--- / I-- li'i;'" 

...... RODATA 

n> 

OATA f-----, 

VCO SYNC SEPARATOR 

STD.OATA 

I"'" 

DATA WINDOW 

r-:' .... _. o 

I"'" 

-< 

T 

NEC STEP n> 

HOPPY 

DISK 

DIRECTION 

CONTROLLER :> 

WRITE ENABLE Q.. 

~ 

HEAD SHECT 

"0 

INDEX n> 

f" 

-'"1 

WRITE PROTECT 

f" 

"-J t::d 

TRACT a 

L. -1'0. 

I"'" -o 

JRESET DRIVE A MOTOR ON 

DIGITAL 

I 

o _. 

L I---B 

I--C ~ 

CONTRD L ... 

-0 

OQ 

l I---c 

e 

PORT OHDOER DRIVE A SELECT '"1 

~ 

-B 

1---0 

UI 

'" 

(") 

li'i;'" 

Figure 19. 5%" DISKETTE DRIVE ADAPTER BLOCK DIAGRAM 

) )

~ 

Functional Description 

From a programming point ofview, this attachment consists of an 8-bit 

digital output register in parallel with a NEC ,uPD765 or equivalent 

Floppy Disk Controller (FDC). 

In the following description, drives numbers 0-3 are equivalent to drives 

A-D respectively. 

~ 

~ 

Digital Output Register (DOR) 

The Digital Output Register (DOR) is an output only register used to 

control drive motors, drive selection, and feature enable. All bits are 

cleared by the I/O interface reset line. The bits have the following 

functions: 

Bits 0 and 1 

Bit 2 

Bit 3 

Bits 4,5,6, and 7 

Floppy Disk Controller (FDC) 

These bits are decoded by the hardware to select 

one drive if its motor is on: 

Bit 1 0 Drive 

0 0 A 

o liB 

1 0 2 C 

1 1 3 D 

The FDC is held reset when this bit is clear. It 

must be set by the program to enable the FDC. 

This bit allows the FDC interrupt and DMA 

requests to be gated onto the I/O interface. Ifthis 

bit is cleared, the interrupt and DMA request I/O 

interface drivers are disabled. 

These bits control respectively the motors of 

drives 0,1,2,A,B,C, and 3,D. If a bit is clear, 

the associated motor is off, and the drive 

cannot be selected. 

The following is a brief summary ofthe registers and commands implemented 

by the FDC. 

The FDC contains two registers which may be accessed by the main 

system processor; a Status Register and a Data Register. The 8-bit 

Main Status Register contains the status information of the FDC, and 

may be accessed at any time. The 8-bit Data Register (actually 

consisting ofseveral registers in a stack with only one register presented 

to the data bus at a time) stores data, commands, parameters, and FDD 

status information. Data bytes are read out of, or written into, the Data 

2-91

Register in order to program or obtain the results after a particular 

command. The Main Status Register may only be read and is used to 

facilitate the transfer of data between the processor and FDC. 

The bits in the Main Status Register are defmed as follows: 

Bit 

Number 

Name Symbol Description 

DBOFDD FDDABusy DAB FDD number is in the 

Seek mode. 

DBI FDD B Busy DBB FDD number I is in the 

Seek mode. 

DB2 FDD C Busy DCB FDD number 2 is in the 

Seek mode. 

DB3 FDDDBusy DDB FDD number 3 is in the 

Seek mode. 

DB4 FDC Busy CB A read or write command 

is in process. 

DB5 Non-DMA NDM The FDC is in the non- 

Mode 

DMAmode. 

DB6 Data Input! DIO Indicates direction of data 

transfer between FDC 

and Processor. If 

D I 0 = "I", then transfer 

is from FDC Data Regis 

- ter to the Processor, If 

DIO = "0", then transfer 

is from the Processor to 

FDC Data Register. 

DB7 Request for RQM Indicates Data Register is 

Master 

ready to send or receive 

data to or from the Processor. 

Both bits DIO and 

RQM should be used to 

perform the handshaking 

functions of "ready" and 

"direction" to the 

processor. 

2-92

The FOe is capable of performing 15 different commands. Each 

command is initiated by a multi-byte transfer from the processor, and 

the result after execution of the command may also be a multi-byte 

transfer back to the processor. Because ofthis multi-byte interchange of 

information between the FOe and the processor, it is convenient to 

~ consider each command as consisting of three phases: 

Command Phase 

The FDC receives all information required to perform a particular operation 

from the processor. 

Execution Phase 

The FOe performs the operation it was instructed to do. 

Result Phase 

After completion of the operation, status and other housekeeping 

information are made available to the processor. 

2-93


Table 13. Symbol Descriptions 

The following tables define the symbols used in the command summary 

which follows. 

SYMBOL 

NAME 

AO Address Une 0 

C 

0 Data 

Cylinder Number 

07-00 Data Bus 

OTL 

EDT 

GPl 

H 

HO 

HlT 

HUT 

MF 

MT 

N 

NCN 

Data length 

End of Track 

Gap length 

Head Address 

Head 

Head load Time 

Head Unload Time 

FM or MFM Mode 

Multi-Track 

Number 

New Cylinder 

Number 

OESCRIPTION 

AO controls selection of Main Status Register 

(AO = 0) or Data Register (AO = 1). 

Cstands for the current/selected Cylinder 

(track) number of the medium. 

ostands for the data pattern which is going to 

be written into a Sector. 

8-bit Data Bus, where 07 stands for a most 

significant bit, and DO stands for a least 

significant bit. 

When N is defined as 00, OTl stands for the 

data length which users are going to read out 

or write into the Sector. 

EDT stands for the final Sector number on a 

Cylinder. 

GPl stands for the length of Gap 3 (spacing 

between Sectors excluding VCD Sync. Field). 

Hstands for head number 0 or 1, as specified 

in 10 field. 

HO stands for a selected head number 0 or 1. 

(H = H 0 in all command words.) 

H l T stands for the head load time in the F 0 0 

(4 to 512 ms in 4 ms increments). 

HUT stands for the head unload time after a 

read or write operation has occurred (0 to 

480 ms in 32 ms increments.) 

If M F is low, FM mode is selected, and if it is high, 

MFM mode is selected only if MFM is implemented. 

If MT is high, a multi-track operation is to 

be performed. (A cylinder under both HOO 

and H D 1 will be read or written.) 

Nstands for the number of data bytes written 

in a Sector. 

NCN stands for a new Cylinder number, which 

is going to be reached as a result of the Seek 

operation. Desired position of Head. 

2-94

Table 13. Symbol Descriptions (continued) 

SYMBOL 

NO 

PCN 

R 

R/W 

SC 

SK 

SRT 

NAME 

Non-DMA Mode 

Present Cylinder 

Number 

Record 

Read/Write 

Sector 

Skip 

Step Rate Time 

ST 0 Status 0 

ST 1 Status 1 

ST 2 Status 2 

ST3 Status 3 

STP 

USO, 

US1 

Scan Test 

Unit Select 

DESCRIPTION 

ND stands for operation in the Non-DMA Mode. 

PCN stands for Cylinder number at the completion 

of SENSE INTER RUPT STATUS Command, 

indicating the position of the Head at present 

time. 

Rstands for the Sector number, which will 

be read or written. 

R!W stands for either Read (R) or Write (W) 

signal. 

SC indicates the number of Sectors per Cylinder. 

SK stands for Skip Deleted Data Address Mark. 

SRT stands for the Stepping Rate for the FDD. 

(2 to 32 ms in 2 ms increments'! 

ST 0-3 stand for one of four registers which 

store the status information after a command 

has been executed. This information is available 

during the result phase after command execution. 

These registers should not be confused 

with the main status register (selected by AO =0). 

ST 0-3 may be read only after a command has 

been executed and contain information 

relevant to that particular command. 

During a Scan operation, if STP = 1, the data in 

contiguous sectors is compared byte by byte 

with data sent from the processor (or DMA), 

and if STP = 2, then alternate sectors are 

read and compared. 

US stands for a selected drive number 

encoded the same as bits 0 and 1 

of the digital register (DOR) p 2-91 

2-95

Command Summary 

oindicates 'logical 0' for that bit, 1 means 'logical 1', 

X means 'don't care'. 

DATA BUS 

PHASE RIW D7 D6 D5 D4 D3 D2 Dl DO REMARKS 

READ DATA 

Command W MT MF SK 0 0 1 1 0 Com mand Codes 

W X X X X X HD US1 usn 

W C Sector 10 

W H information prior 

W R to Command execution 

W 

N 

W 

EDT 

W 

GPl 

W 

DlL 

Exec"tion 

Data-transfer between 

the FDD and main-system 

Result R ST 0 Status information after 

R ST 1 Command execution 

R ST 2 

R C Sector 10 information 

R H after Command execution 

R 

R 

R 

N 

READ DELETED DATA 

Command W MT MF SK 0 1 1 0 0 Command Codes 


w C Sector I D information 

W H prior to Command 

W R execution 

W 

N 

W 

EDT 

W 

GPl 

W 

DlL 

Execution 




R ST 1 command execution 

R ST 2 


R H after command execution 

R 

R 

R 

N 

WRITE DATA 

Command W MT MF 0 0 0 1 0 1 Command Codes 


w C Sector I D information 

Execution 

W H to command execution 

W 

R 

W 

N 

W 

EDT 

W 

GPl 

W 

DTl 


the main-system and FDD 

Result R STO Status information after 


R ST 2 



2-96 

R 

R 

R 

N

Command Summary (continued) 

DATA BUS 

PHASE RIW 07 06 05 04 03 02 01 DO REMARKS 

WRITE DELETED DATA 

Command W MT MF 0 0 1 0 0 1 Command Codes 

W X X X X X HO US1 usn 

W C Sector 10 information 

W H prior to command 

W R execution 

W 

N 

Execution 

Result 

W 

W 

W 

EDT 

GPL 

DTL 


FDD and main-system 

Status 10 information 

after common execution 

R 

R 

ST 0 

ST 1 

R ST 2 



R 

R 

R 

N 

READ A TRACK 

Command W 0 MF SK 0 0 0 1 0 Command Codes 




W R execution 

W 

N 

W 

EDT 

W 

GPL 

W 

DTL 

Execution 


the FDO and main-system. 

FDC reads all of cylinders 

contents from index hole 

to EDT. 



R ST 2 



R 

R 

R 

N 

READID 

Command W 0 MF 0 0 1 0 1 0 Command Codes 


Execution 

The first correct ID 

information on the 

cylinder is stored in 

data register. 

Result R STO Status information 

R ST 1 after command execution 

R ST 2 


R H during execution phase 

R 

R 

R 

N 

f: 

f; 

f: 

~ 

I=.: 

2-97


OATA BUS 

PHASE R/W 07 06 05 04 03 02 01 00 REMARKS 

FORMAT A TRACK 

Command W 0 MF 0 0 1 1 0 0 Command Codes 


w N Bytes/Sector 

W SC Sector/Track 

W GPL Gap 3 

W 0 filler byte 

Execution 

FOe formats an entire 

cylinder 

Result R ST 0 Status information 

R ST 1 after command 

R ST 2 execution 

R C Iil this case, the ID 

R H information has no 

R R meaning 

R 

N 

SCAN EQUAL 



W C Sector lDinformatio n 


W R execution 

W 

N 

W 

EDT 

W 

GPL 

W 

STP 

Execution 

Data compared between 

the FOD and main-system 



R ST 2 

R e Sector ID information 

R 

H 

R 

R 

R 

N 

SCAN LOW OR EQUAL 





W R execution 

W 

N 

W 

EDT 

W 

GPL 

W 

STP 

Execution 

Oata compared between 

the FOO and main-system 

Result R STU Status information after 


R 

ST2 



R 

R 

R 

N 

2-98


DATA BUS 

PHASE RIW 07 06 05 04 03 02 01 DO REMARKS 

SCAN HIGH OR EQUAL 


W X X X X X HD US1 usa 

w C Sector 10 information 


W R execution 

W 

N 

W 

EDT 

W 

GPL 

W 

STP 

Execution 

Data compared between 




R ST 2 



R 

R 

R 

N 

RECALIBRATE 

Command W 0 0 0 0 0 1 1 1 Command Codes 

W X X X X X 0 US1 usa 

Execution Head retracted to track 0 

No Result 

Phase 

SENSE INTERRUPT STATUS 


Result R ST 0 Status information at 

R PCN the end of seek operati 

on about the F 0 C 

SPECIFY 


W -SRT HUT 

W --HLT NO 

No Result 

Phase 

SENSE DRIVE STATUS 



Result R ST 3 Status information 

about FDD 

SEEK 


Execution 

No Result 

Phase 


w 

NCN 

Head is positioned 

over proper cylinder 

on diskette 

INVALID 

Command W Invalid Codes Invalid command codes 

(NoDp - FDC goes into 

standby state) 

Result R ST 0 STO=80 

2-99

Command Status Registers 

Table 14. Status Register 0 

NO. 

07 

06 

NAME 

Interrupt 

Code 

05 Seek End 

BIT 

04 Equipment 

Check 

03 Not Ready 

02 Head Address 

01 Unit Select 1 

DO Unit Select 0 

SYMBOL 

IC 

SE 

EC 

NR 

HO 

US 1 

US 0 

DESCRIPTION 

07 = 0 and 06 = 0 

Normal termination of command, (NT), 

Command was completed and properly 

executed. 

07 = 0 and 06 =1 

Abnormal termination of command, 

(AT). Execution of command was 

started, but was not successfully 

completed. 

07 =1 and 06 = 0 

Invalid command issue (lC). Command 

wh ich was issued was never started. 

07 = 1 and 06 =1 

Abnormal termination because during 

command execution the ready signal 

from FOO changed state. 

When the FOC completes the Seek 

command, this flag is set to 1 (high). 

If a fault signal is received from the 

FOO, or if the track 0 signal fails to 

occur after 77 step pulses (recalibrate 

command) then this flag is set. 

When the F 0 0 is in the not·ready state 

and a read or write command is issued, 

this flag is set. If a read or write command 

is issued to side 1 of a single sided drive, 

then this flag is set. 

This flag is used to indicate the state 

of the head at interrupt. 

These flags are used to indicate a Drive 

unit Number at interrupt. 

2-100

Table 15. Status Register I 

BIT 

NO. NAME SYMBOL 

D7 End of Cylinder EN 

D6 - 

D5 Data Error DE 

D4 Over Run OR 

D3 - 

D2 No Data ND 

Dl Not Writable NW 

DO Missing Address MA 

Mark 

DESCRIPTION 

When the FD Ctries to access a sector 

beyond the final sector of a cylinder, 

this flag is set. 

Not used. This bit is always 0 (low). 

When the FDC detects a CRC error in 

either the I D field or the data field, ~ 

this flag is set. t; 

~ 

If the FDC is not serviced by the main· t; 

systems during data transfers within a f- 

certain time interval, this flag is set. 

Not used. This bit is always 0 (low). 

During Execution of a Read Data, Write 

Deleted Data, or Scan command, if the 

FDC cannot find the sector specified 

in the I D register, this flag is set. 

During execution of the Read I D 

command, if the FDC cannot read 

the I D field without an error, then 


During the execution of the Read-a- 

Cylinder command, if the starting 

sector cannot be found, then this 

flag is set. 

During Execution of a Write Data, Write 

Deleted Data, or Format aCyl inder 

command, if the FDC detects a write 

protect signal from the F DO, then this 

flag is set. 

If the FDC cannot detect the I D Address 

Mark, this flag is set. Also at the same 

time, the MD (Missing Address Mark in 

Data Field) of Status Register 2 is set. 

2-101


BIT 

NO. NAME SYMBOL 

07 - 

06 Control Mark CM 

05 Data Error in DO 

Data Field 

04 Wrong Cylinder WC 

03 Scan Equal Hit SH 

02 Scan Not SN 

Satisifed 

01 Bad Cylinder BC 

00 Missing Address MD 

Mark in Data 

Field 

DESCRIPTION 

Not Used. This bit is always 0 (low). 

During execution of the Read Data or 

Scan command, if the FDC encounters 

a sector which contains a Deleted Data 

Address Mark, this flag is set. 

If the FOC detects a CRC error in the 

data then this flag is set. 

This bit is related with the NO bit, and 

when the contents of Con the medium 

are different from that stored in the 

ID Register, this flag is set. 

During execution of the Scan command, 

if the condition of "equal" is satisfied, 


During execution of the Scan command, 

if the FDC cannot find a sector on the 

cylinder which meets the condition, then 


This bit is related with the NO bit, and 

when the contents of C on the medium 

are different from that stored in the ID 

Register, and the content of C is FF, then 


When data is read from the medium, if 

the FDC cannot find a Data Address 

Mark or Deleted Data Address Mark, 

then this flag is set. 

2-102


BIT 

NO. NAME SYMBOL DESCRIPTION 

07 Fault FT This bit is used to indicate the status of 

the Fault signal from the FOO. 

OS Write Protected WP 

05 Ready RY 

04 Track 0 TO 

03 Two Side TS 

02 Head Address HO 

01 Unit Select 1 US 1 

DO Unit Select 0 US 0 

This bit is used to indicate the status of 

the Write Protected signal from the FOD. 


the Ready signal from the FDD. 

I 

This bit is used to indicate the status of f: 

the Track 0 signal from the FOO. ~ 


the Two Side signal from the FDD. 


Side Select signal to the FOD. 


the Unit Select 1 signal to the FOO. 


the Unit Select 0 signal to the FOD. 

~ 

I 

Programming Summary 

DPe Registers (Ports) 

FDC Data Reg 

FDe Main, Status Reg 

Digital Output Reg 

I/O Address 3F5 

110 Address 3F4 

I/O Address 3F2 

Bit 0 Drive OO:DR#A 10: DR #C 

1 Select 01: DR #B 11: DR #D 

2 Not FDC Reset 

3 Enable INT & DMA Requests 

4 Drive A Motor Enable 

5 Drive B Motor Enable 

6 Drive . C Motor Enable 

7 Dnve D Motor Enable 

All bits cleared with channel reset. 

2-103

Interrupt 6 

DMA 2 

100 Disk Format 

1 Head, 45 cylinders, 8 sectors/TRK, 512 bytes/sector,MFM. 

FDC Constants 

N: H'02', SC: 08, HUT: F, SRT: C, GPL FORMAT: H'05', 

GPL RD/WR: 2A, HLT: 01, (8ms track-track) 

Drive Constants 

HD Load 35 ms 

HD Settle 25 ms 

Motor Start 500 ms 

Comments 

1. Head loads with drive select, wait HD Load time before RD/WR 

2. Following access, wait HD Settle time before RD/WR 

3. Drive motors should be off when not in use. Only A or B and C or D 

may run simultaneously. Wait Motor Start time before RD/WR ,..-....., 

4. Motor must be on for drive to be selected. 

5. Data Errors can occur while using a Home Television as the 

system display. Locating the TV too close to the diskette area can 

cause this to occur. To correct the problem, move the TV away 

from, or to the opposite side of the System Unit. 

System I/O Channel Interface 

All signals are TTL compatible: 

MPUL 5.5 Vdc 

LPUL 2.7 Vdc 

MPDLO.5 Vdc 

LPDL -0.5 Vdc 

The following lines are used by this adapter. 

+DO-7 (Bidirectional, Load: 1 74LS; Driver: 74LS 3-state) ~ 

These eight lines form a bus by which all commands, 

status, and data are transferred. Bit 0 is the loworder 

bit. 

2-104

~ 

~ 

+AO-9 

+AEN 

-lOW 

-lOR 

-DACK2 

+T/C 

+RESET 

+DRQ2 

~ +IRQ6 

(Adapter Input, Load: 1 74LS) 

These ten lines form an address bus by which a 

register is selected to receive or supply the byte 

transferred via lines DO-7. Bit 0 is the low-order bit. 


The content of lines AO-9 is ignored if this line is 

active. 

(Adapter Input, Load: 1 74 LS) 

The content of lines DO-7 is stored in the register 

addressed by lines AO-9 or DACK2 at the trailing 

edge of this signal. 


The content of the register addressed by lines AO-9 

or DACK2 is gated onto lines DO-7 when this line 

is active. 


This line active degates output DRQ2, selects the 

FDC data register as the source/destination of bus 

DO-7, and indirectly gates T / C to IRQ6. 

(Adapter Input, Load: 4 74 LS) 

This line and DACK2 active indicates that the byte 

of data for which the DMA count was initialized is 

now being transferred. 


An up level aborts any operation in process and 

clears the Digital Output Register (DOR). 

(Adapter Output, Driver: 74LS 3-state) 

This line is made active when the attachment is ready 

to transfer a byte ofdata to or from main storage. The 

line is made inactive by DACK2 becoming active or 

an I/O read of the FDC data register. 

(Adapter Output, Driver: 74LS 3-state) 

This line is made active when the FDC has completed 

an operation. It results in an interrupt to a 

routine which should examine the FDC result bytes 

to reset the line and determine the ending condition. 

2-105

Drive A and B Interface 

All signals are TTL compatible: 

MPUL 5.5 Vdc 

LPUL 2.4 Vdc 

MPDLO.4 Vdc 

LPDL -0.5 Vdc 

All adapter outputs are driven by open-collector gates. The drive(s) 

must provide termination networks to Vcc (except Motor Enable 1 

which has a two kohm resistor to Vcc). 

Each adapter input is terminated with a 150 ohm resistor to V cc. 

Adapter Outputs 

-Drive Select A&B (Driver: 7438) 

These two lines are used by drives A&B to 

de gate all drivers to the adapter and 

receivers from the attachment (except Motor 

Enable) when the line associated with a drive is 

not active. 

-Motor Enable A&B (Driver: 7438) 

The drive associated with each of these lines r"\ 

must control its spindle motor such that it starts 

when the line becomes active and stops when 

the line becomes not active. 

-Step (Driver: 7438) 

The selected drive moves the read/write head 

one cylinder in or out per the direction line 

for each pulse present on this line. 

-Direction (Driver: 7438) 

For each recognized pulse of the step line the 

read/write head moves one cylinder toward 

the spindle if this line is active, and away 

from the spindle if not-active. 

-Write Data (Driver: 7438) 

For each not-active to active transition of this 

line while Write Enable is active, the selected 

drive causes a flux change to be stored on 

the disk. 

-Write Enable (Driver: 7438) 

The drive disables write current in the head 

unless this line is active. 

2-106

Adapter Inputs 

-Index 

-Write Protect 

r"\ 

-Track 0 

-Read Data 

The selected drive supplies one pulse per 

disk revolution on this line. 

The selected drive makes this line active if 

a write protected diskette is mounted in the 

drive. 

The selected drive makes this line active if 

the read/write head is over track O. 

The selected drive supplies a pulse on this 

line for each flux change encountered on the 

disk. 

2-107

5-1/4" Diskette Drive Adapter 

Internal Interface Specifications 

34 PIN KEYED 

EDGE CONNECTOR 

NOTE: LANDS 1-33 ARE ON THE BACKSIDE 

OF THE BOARD, LANDS 2-34 ARE ON THE 

FRONT, OR COMPONENT SIDE. 

COMPONENT 

SIDE 


Land No. 

..... 

"'" 

... 

... 

... 

"'" ..... 

... 

..... 

..... 

IBM 5 1/4" "'" 

Diskette 

Drives ... 

... 

"'" 

Ground-Odd Numbers 

Unused 

Index 

Motor Enable A 

Drive Select B 

Drive Select A 

Write Data 

Write Enable 

Track 0 

Write Protect 

Read Data 

Select Head 1 

Unused 

1-33 

2,4,6 

8 ---.. ... 

10 

Motor Enable B 

16 5 1/4" Diskette 

Direction (Stepper Motor! 18 

Drive 

Adapter 

Step Pulse 

20 

12 

14 

22 

24 

26 .. 

... 

28 ... 

 

30 ... 

32 

34 

2-108

5-1/4" Diskette Drive Adapter 

External Interface Specifications 

REAR PANEL 

37 PIN '0' SHELL 

CONNECTOR 

o 

1 • • 20 

• • 

• • 

• • 

• • 37 

o 


Pin no. 

Unused 

1 ·5 

Index 6 .. 

I... Motor Enable C 7 

1""1" 

I... 

.... 

Drive Select 0 8 

... Drive Select C 9 

I""'" 

- 

..... 

Motor Enable 0 10 

I... Direction (Stepper Motod 11 

External ..... 

5%" Diskette 

Drives ... Step Pulse 12 Drive 

.... 

Adapter 

... Select Head 1 13 

~ 

Write Enable 14 

... 

- 

.... 

Track 0 15 Write Protect 16 Read Data 17 .. 

~-.. 

Write Data 18 

Ground 20·37 

.. 

2-109

5-1/4" Diskette Drive 

The IBM 5-1/4" Diskette Drive is a single sided, double density, 40 

track unit. The Diskette Drive has a formatted capacity of 163,840 

bytes, and is capable of reading and recording digital data using 

Modified Frequency Modulation (MFM) methods. User access for 

diskette loading is provided by way of a slot located at the front ~ 

of the unit. 

The Diskette Drive is fully self-contained and requires no operator 

intervention during normal operation. The Drive consists of a spindle 

drive system, a head positioning system, and read/write/erase system. 

When the front latch is opened, access is provided for the insertion of a 

diskette. The diskette is positioned in place by plastic guides, and the 

front latch. In!out location is ensured when the diskette is inserted until 

a back stop is encountered. 

Closing the front latch activates the cone/clamp system resulting in 

centering of the diskette and clamping of the diskette to the drive hub. 

The drive hub is driven at a constant speed of 300 rpm by a servo 

controlled DC motor. In operation, the magnetic head is loaded into 

contact with the recording medium whenever the front latch is closed. 

The magnetic head is positioned over the desired track by means of a 

4-phase stepper motor/band assembly and its associated electronics. 

This positioner employs a one-step rotation to cause a I-track linear 

movement. When a write-protected diskette is inserted into the Drive, 

the write-protect sensor disables the write electronics of the Drive and 

an appropriate signal is applied to the interface. 

When performing a write operation, a 0.33 mm (0.013-in.) data track 

is recorded. This track is then tunnel erased to 0.30 mm (0.012 in.). 

Data recovery electronics include a low-level read amplifier, differentiator, 

zero-crossing detector, and digitizing circuits. All data decoding 

is provided by the adapter card. 

The Drive is also supplied with the following sensor systems: 

(I) 

A track 00 switch which senses when the Head/Carriage 

assembly is positioned at Track 00. 

(2) The index sensor, which consists of a LED light source and 

phototransistor, is positioned such that when an index hole is ,.-......, 

detected, a sigital signal is generated. 

2-110

(3) The write-protect sensor disables the Diskette Drive electronics 

whenever a write-protect tab is applied to the diskette. 

For Interface Information, refer to the Diskette Drive Adapter 

section. 

~ Diskettes 

The IBM 5-1/4" Diskette Drive uses a standard 133.4 mm (5.25 in.) 

diskette. For programming considerations, single sided, double density 

soft sectored diskettes are used. The figure below is a simplified 

drawing of the diskette used with the Diskette Drive. This recording 

medium is a flexible magnetic disk enclosed in a protective jacket. The 

protected disk, free to rotate within the jacket, is continuously cleaned 

by the soft fabric lining of the jacket during normal operation. 

Read/Write erase head access is made through an opening in the jacket. 

Openings for the drive hub and diskette index hole are also provided. 

_____ m 

11-- 

3.S6 mm 

(D.140 INCH) 630 + 0.25 mm 133.4 mm 

I - I~Fr{025+ 0.01 INCH) j- (5.251NCH) 

I 1 ~~~~~~TlVE~ /' -- - - ---- "-.. 

I - JACKET I -, / 

1 to IOXIDECOATED \\ 

SPINDLE 

~ 9) E~ 133.4mm I MYLARDIS~. 

~ @ ~~ {5025j1NCHI ( \0) 

m gf LINER Ir~ ~ ~g~~ss / 

1 

___ '33.4mm -j- - ~.'-.... ·O~~~/:~TU/RE / 

1... (5.25 INCH) 

---- 

 

I 

----- 

RECORDING MEDIUM 

2-111

Table 18. 

Mechanical and Electrical Specifications 

Media 

Tracks per inch 

Number of Tracks 

Dimensions 

Height 

Width 

Depth 

Weight 

Temperature 

(Exclusive of Media) 

Operating 

Non-operating 

Relative Humidity 

(Exclusive of Media) 

Operating 

Non-operating 

Seek Time 

Head Setting Time 

Error Rate 

Head Life 

Media Life 

Disk Speed 

Instantaneous Speed Variation 

Start/Stop Time 

Transfer Rate 

Recording Mode 

Power 

Industry-compatible 5%-inch diskette 

48 

(4·0) 

85.85 mm (3_38 inches) 

149.10 mm (5.87 inches) 

203.2 mm (8.0 inches) 

2.04 Kg (4.5 Ibs.) 

100eto 440 C (500 F to 1120 F) 

-400eto 600 C(-400 Fto 1400 F) 

20% to 80% (Non-condensing) 

5% to 95% (Non-condensing) 

8 msec track to track 

25 msec !last track addressed) 

1 per 10 9 (recoverable) 

1 per 10 12 (non-recoverable) 

1 per 10 6 (seeks) 

20,000 hours (normal use) 

3.0 x 10 6 passes per trac k 

300 rpm ± 1.5% (long term) 

±3.0% 

500 msec (maximum) 

250 Kbits/sec 

MFM 

+12 dc ± 0.6v 900 rna AVE. 

+5v de ± 0.25 v, 600 rna AVE. 

2-112

Memory Expansion Options 

Two Memory Expansion Options offered for the IBM Personal 

Computer are the 32K x 9 and the 64K x 9 Memory Expansion 

Options. These options plug into any ofthe five System Expansion slots 

on the System Board. These options are used to extend system memory 

beyond 64KB. A maximum of 64KB of memory may be installed on 

the System Board as modules without using any System Expansion 

Slots or Expansion Options. 

An expansion option must be configured to reside at sequential32K or 

64K memory address boundary within the system address space. This 

is done by setting dip switches on the option. 

The expansion options are designed with 250 ns access 16K x 1 

dynamic memory chips. On the 32KB card, 16-pin industry standard 

parts are used. On the 64 KB card, stacked modules are used resulting 

in a 32K xI 18-pin module. This allows the 32KB and 64KB to have 

approximately the same packaging densities. 

Both expansion options are parity checked and if a parity error is 

detected, a latch is set and an I/O channel check line is activated, 

indicating an error to the processor. 

".-,., In addition to the memory modules, the expansion options contain the 

following circuits: bus buffering, dynamic memory timing generation, 

address multiplexing, and card select decode logic. 

Dynamic memory refresh timing and address generation are functions 

which are not performed on the expansion options but are done once on 

the System Board and made available in the I/O channel for all devices. 

To allow the System to address 32KB and 64KB Memory Expansion 

Options, refer to the system configuration switch settings page 2-28. 

Operating Characteristics 

The System Board operates at a frequency of 4.77 Mhz, which results 

in a clock frequency of 210 ns. 

Normally, four clock cycles are required for a bus cycle so that an 

840 nsec memory cycle time is achieved. Memory write and memory 

".-,., read cycles both take four clock cycles, or 840 ns. 

2-113

General specifications for memory used on both cards are: 

Access - 250 ns 

Cycle - 410 ns 

Memory Module Description 

Each option contains 18 dynamic memory modules. The 32KB 

Memory Expansion Option utilizes 16K x 1 bit modules and the 

64KB Memory Expansion Options utilizes 32K x 1 bit modules. 

Both memory modules require three voltage levels (+5Vdc, -5Vdc, 

+ 12V dc) and 128 refresh cycles every 2 msec. Absolute maximum 

access times are: 

From RAS: 250 ns 

From CAS: 165 ns 

Table 19. Memory Module Pin Configuration 

PIN 

NO. 

16K X 1 BIT MODULE 

(Used on 32KB Card) 

1 - 5V 

2 Data In ** 

3 - Write 

4 - RAS 

5 AO 

6 A2 

7 Al 

8 +12V 

9 +5V 

10 A5 

11 A4 

12 A3 

13 A6 

14 Data Out ** 

15 - CAS 

16 GND 

17 - * 

18 - * 

32K X 1 BIT MODULE 

(Used on 64KB Card) 

- 5V 

Data In ** 

- Write 

- RAS 0 

- RAS 1 

AO 

A2 

A1 

+12V 

+ 5V 

A5 

A4 

A3 

A6 

Data Out ** 

- CAS 1 

- CASO 

GND 

* 16K X 1 bit m.odule has only 16 pins. 

** Data In and Data Out are tied together (three state bus). 

2-114

Switch - Configurable Start Address 

Each card has a small DIP Module which contains eight switches. The 

switches are used to set the card start address as follows: 

Table 20. DIP Module Start Address 

NO. 

DESCRIPTION 

1 ON: A19=O; OFF: A19=1 

2 ON: A18=O; OFF: A18=1 

3 ON: A17=O; OFF: A17=1 

4 ON: A16=O; OFF: A16=1 

5 ON: A15=O; OFF: A15=1 * 

6 Not Used 

7 Not Used 

8 Used Only In 64KB RAM Card * 

* Switch No.8 may be set on the 64KB Memory Expansion Option to use only half the 

memory on the card (i.e., 32KB). If Switch No.8 is ON, all 64KB is accessible. If Switch 

No.8 is 0 F F, address bit A15 (as set by Switch No.5) is used to determine wh ich 32KB 

are accessible and the 64KB option behaves exactly like a 32KB option. 

2-115

2-116 

NOTES

 

Game Control Adapter 

The Game Control Adapter allows the system to attach paddles and 

joysticks. Up to four paddles or two joysticks may be attached. In 

addition, four input for switches are provided. Paddle and joystick 

positions are determined by changing resistive values sent to the 

adapter. The adapter plus system software converts the present 

resistive value to a relative paddle orjoystick position. On receipt ofan 

output signal, four timing circuits are started. By determining the time 

required for the circuit to time out (a function of the resistance), the 

paddle position can be determined. This card could be used as a general 

purpose I/O card with four analog (resistive) inputs plus four digital 

input points. This card fits into any ofthe five System Board I/O slots. 

The game control interface cable attaches to the rear ofthe card which 

protrudes through the rear panel of the System Unit. 

Game Control Adapter Block Diagram 

A9 - AO 

'\ .. 

../ 

CONVERT A RESISTIVE INPUT 

I 10 ... 

... 

DECODE TO K 

4 I 

AEN .. INSTRUCTION RESISTANCE 

lOW .. DIGITAL " 

PU LSE 

lOR .. 

.-- 

.....- TYPICAL FREQUENCY 

07·00 OF 833 Ht 

A 

DATA BUS A 

,r 

8 BUFFER/ 4 

... DRIVER " " 

DIGITAL INPUTS 

A 

" 

.... 

4 I 

Figure 20. GAME CONTROL ADAPTER BLOCK DIAGRAM 

2-117


Address Decode 

The select on the Game Control Adapter is generated by two 

74LS138's as an address decoder. AEN must be inactive while the 

address is 201 in order to generate the select. The select allows a write r-., 

to fire the one-shots or a read to give the values ofthe trigger buttons and 

one-shot outputs. 

Data Bus Buffer/Driver 

The data bus is buffered by a 74LS244 buffer/driver. For an IN from 

address X'20 1', the Game Control Adapter will drive the data bus; at 

all other times the buffer is left in the high impedance state. 

Trigger Buttons 

The trigger button inputs are read via an IN from address X'20 I'. A 

trigger button is on each joystick/paddle. These values are seen on 

data bits 7 through 4 (see Software Interface sub-section). These 

buttons default to an open state and are read as "1". When a button is 

depressed, it is read as "0". Software should be aware that these 

buttons are NOT debounced in hardware. 

Joystick Positions 

The joystick position is indicated by a potentiometer for each 

coordinate. Each potentiometer has a range from 0 to 100 K ohms that 

varies the time constant for each of the four one-shots. As this time 

constant is set at different values, the output of the one-shot will be of 

varying durations. 

All four one-shots are fired at once by an OUT to address X'201'. All 

four one-shot outputs will go true after the fire pulse and will remain 

high for varying times depending on where each potentiometer is set. 

These four one-shot outputs are read via an IN from address X'201 ' 

and are seen on data bits 3 through O. 

2-118

I/O Channel Description 

A9-AO: 

D7-DO: 

1""""'\ lOR, lOW: 

AEN: 

+SV: 

GND: 

AI9-AlO: 

MEMR,MEMW: 

DACKO-DACK3: 

IRQ7-IRQ2 

DRQ3-DRQ1: 

ALE, TIC: 

I""""'\CLK, OSC: 

Address lines 9 through 0 are used to 

address the Game Control Adapter. 

Data lines 7 through 0 are the data bus. 

I/O Read and I/O Write are used when reading 

from or writing to an adapter (IN, OUT). 

When active, the adapter must be inactive 

and the data bus driver inactive. 

Power for the Game Control Adapter. 

Common ground. 

Unused 

Unused 

Unused 

Unused 

Unused 

Unused 

Unused 

1/0 CHCK: Unused 

I/O CH RDY: 

HRQI/O CH: 

RESETDRV: 

-Sv, + 12v, -12v: 

Interface Description 

Unused 

Unused 

Unused 

Unused 

The Game Control Adapter has 8 input lines, 4 of which are digital 

inputs and 4 of which are resistive inputs. The inputs are read with one 

IN from address x'20 1'. 

The 4 digital inputs each have a lK ohm pullup resistor to +SV. With 

~ no drive on these inputs, a' l' is read. For a '0' reading, the inputs must 

be pulled to ground. 

The 4 resistive inputs, measured to +SV, will be converted to a digital 

pulse with a duration proportional to the resistive load, acccording to 

the following equation: 

Time = 24.2 fJ-sec + 0.011 (r) fJ-sec 

2-119

The user must first begin the conversion by an OUT to address x'201 '. 

An IN from address x'201' will show the digital pulse go high and 

remain high for the duration according to the resistance value. All four 

bits (Bit 3-Bit 0) function in the same manner, their digital pulse will all 

go high simultaneously and will reset independently according to the 

input resistance value. 

Input from address x'201' 

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 

, I 

J 

\ I 

Digital '" Inputs 

Resistive --Inputs 

The typical input to the Game Control Adapter is a set ofjoysticks or 

game paddles. 

The joysticks will typically have a set of two joysticks (A&B). These 

will have one or two buttons each with two variable resistances each, 

with a range from 0 to 100 K ohms. One variable resistance will 

indicate the X coordinate and the other variable resistance will indicate 

the Y coordinate. This should be attached to give the following 

input data: 

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 

B-#}. B-#l A-#2 A-#l B-Y B-X A-Y A-X 

Button Button Button Button Coord. Coord. Coord. Coord. 

The game paddles will have a set of two (A&B) or four (A,B,C, & D) 

paddles. These will have one button each and one variable resistance 

each, with a range from 0 to 100 K ohms. This should be attached to 

give the following input data: 

Bit 7 Bit 6 Bit 5 Bit4 Bit 3 Bit 2 Bit 1 Bit 0 

D C B A D C B A 

Button Button Button Button Coord. Coord. Coord. Coord. 

A schematic diagram for attaching a set of game controllers is on 

page 2-121. 

2-120

) ) ) 

15 PIN MALE '0' SHELL c....t 

o 

'< 

CONNECTOR 

-f) 

__ -, JOYSTICK A ~ 

JOYSTICK B 

~------------, _--- 1~ r-------------~ I I /-- • I I til 

f) 

I I 2 I I t:r' 

~ 

: X COORDINATE : 9 • : 6 X COORDINATE : 

I • 3 I 

3 

L- BUTTON I 

: '1'~ ;: 

't' 

~ 

..... 

-f) 

, BUTTON,.! : ,0 I 

i ~ ; : : 

Y COORDINATE : 12 • : : 

~ I I • 6 : I Y COO RDIN ATE 

I I 13 • I I ~ 

(I) 

..... 

: : • 7 I : 

I I 14 • : I 

I I • 8 I I 

I L _____________J" I J 15 • I I L _____________ ...1 

--- 

_--"",,' I 

-~ 

NOTE: POTENTIOMETER FOR X & Y COORDINATES HAS A RANGE OF 0 TO 100KQ. 

BUTTON IS NORMALLY OPEN; CLOSED WHEN DEPRESSED. 

-tv Figure 21. JOYSTICK SCHEMATIC 

3YVMOYVH

Game Controller Adapter (Analog Input) 

Connector Specifications 

REAR PANEL 

· .·SS • 

15 PIN "0" SHELl~ 

CONNECTOR 

0 

1 9 

• • 

~ 0e • ••• 

«;) 

• • 15 

0 

•• 

AT STANDARD TIL LEVELS 

Voltage 

AMP 

Pin No. 

... + 5 Volts 1 

.... 

Button 4 2 .... 

Position 0 3 

... 

.. 

Ground 4 

Ground 5 

Position 1 6 .... 

External Button 5 7 .... Game Control 

Devices 

... 

Adapter 

... + 5 Volts 8 

... 

"" + 5 Volts 9 

"" Button 6 10 "" 

... 

Position 2 11 ..... 

Ground 12 

Position 3 13 .... 

Button 7 14 ... 

... + 5 Volts 15 

.... 

.. 

2-122

Asynchronous Communications Adapter 

The Asynchronous Communications Adapter is a 4"H x 5"W card 

that plugs into a System Expansion Slot. All system control signals and 

voltage requirements are provided through a 2 x 31 position card edge 

~ tab. Ajumper module is provided to select either RS-232-C or current 

loop operation. 

The adapter is fully programmable and supports asynchronous 

communications only. It will add and remove start bits, stop bits, and 

parity bits. A programmable baud rate generator allows operation from 

50 baud to 9600 baud. Five, six, seven or eight bit characters with 1, 

1-1/2, or 2 stop bits are supported. A fully prioritized interrupt system 

controls transmit, receive, error, line status and data set interrupts. 

Diagnostic capabilities provide loopback functions oftransmit/receive 

and input! output signals. 

Figure (22) is a block diagram ofthe Asynchronous Communications 

Adapter. 

The heart of the adapter is a INS8250 LSI chip or functional equivalent. 

The following is a summary of the 8250's key features: 

• Adds or Delete Standard Asynchronous Communication Bits 

(Start, Stop, and Parity) to or from Serial Data Stream. 

• Full Double Buffering Eliminates Need for Precise 

Synchronization. 

• Independently Controlled Transmit, Receive, Line Status, and 

Data Set Interrupts. 

• Programmable Baud Rate Generator Allows Division of Any 

Input Clock by 1 to (2 16 -1) and Generates the Intemal16x Clock. 

• Independent Receiver Clock Input. 

• MODEM Control Functions Clear to Send (CTS), Request to 

Send (RTS), Data Set Ready (DSR), Data Terminal Ready 

(DTR), Ring Indicator (RI), and Carrier Detect. 

• Fully Programmable Serial-Interface Characteristics 

5-, 6-, 7-, or 8-Bit Characters 

Even, Odd, or No-Parity Bit Generation and Detection 

1-, 1 1/2-, or 2-Stop Bit Generation 

Baud Rate Generation (DC to 9600 Baud) 

2-123

• False Start Bit Detection. 

• Complete Status Reporting Capabilities. 

• Line Break Generation and Detection. 

• Internal Diagnostic Capabilities. 

Loopback Controls for Communications Link Fault 

Isolation. 

Break, Parity, Overrun, Framing Error Simulation. 

• Full Prioritized Interrupt System Controls. 

All communications protocol is a function of the system microcode 

and must be loaded before the adapter is operational. All pacing ofthe 

interface and control signal status must be handled by the system 

software. 

Asynchronous Communications Block Diagram 

ADDRESS BUSS 

ADDRESS 

DECODE 

CHIP SELECT 

DATA BUS 

INTERRUPT 

OSCILLATOR 

1.8432 Mhz 

--" 

8250 

ASYNCH RONOUS 

COMMUNICATIONS 

ELEMENT 

EIA 

RECEIVERS 

EIA 

DRIVERS 

A 

CURRENT LOOP 

Y ~ 

J 

A 

L 

L. 

25 PIN 

"D"SHELLCONNECTOR 

Figure 22. ASYNCHRONOUS COMMUNICATIONS ADAPTER 

BLOCK DIAGRAM 

2-124


The different modes of operation are selected by programming the 

8250 Asynchronous Communications Element. This is done by 

selecting the I/O address (3F8 to 3FF) and writing data out to the card. 

Address bit AO, Al and A2 select the different registers which define 

r"'\ the modes of operation. Also, the Divisor Latch Access Bit (Bit 7) of 

the line control register is used to select certain registers. 

I/O Decode for Communications Adapter 

Table 21. I/O Decodes (3F8 to 3FF) 

I/O 

DECODE REGISTER SELECTED DLABSTATE 

3FB TX BUFFER DLAB=O (WRITE) 

3FB RX BUFFER DLAB=O (READ) 

3FB DIVISOR LATCH LSB DLAB=l 

3F9 DIVISOR LATCH MSB DLAB=l 

3F9 INTERRUPT ENABLE REGISTER DLAB=O 

3FA 

3FB 

3FC 

3FD 

3FE 

INTERRUPT IDENTIFICATION 

REGISTERS 

LINE CONTROL REGISTER 

MODEM CONTROL REGISTER 

LINE STATUS REGISTER 

MODEM STATUS REGISTER 

ADDRESS BITS 

A9 A8 A7 A6 A5 A4 A3 A2 A1 AD DLAB REGISTER 

3F8 to 3FF 1 1 1 1 1 1 1 X X X 

0 0 0 0 Receive Buffer 

(read), Transmit 

Holding Reg. 

(write) 

0 0 1 0 Interrupt Enable 

0 1 a x Interrupt Identification 

0 1 1 X Li ne Control 

1 a 0 X Modem Control 

1 0 1 X Line Status 

1 1 a X Modem Status 

1 1 1 X None 

0 a 0 1 Divisor Latch (LSB) 

0 0 1 1 Divisor Latch (MSB) 

A2, Al and AO bits are "Don't Cares" and are used to select the 

different register of the communications chip. 

2-125

Interrupts 

One interrupt line is provided to the system. This interrupt is IRQ4 and 

will be positive active. To allow the communications card to send 

interrupts to the system, Bit 3 of the Modem Control Register must be 

set = 0 (low). At this point, any interrupts allowed by the Interrupt 

Enable Register will cause an interrupt. ,...-....... 

The data format will be as follows: 

TRANSMITTER OUTPUT AND RECEIVER INPUT 

00 01 02 03 04 05 06 07 

Transmit 

Oata Marking 

Data Bit 0 is the ftrst bit to be transmitted or received. The adapter 

automatically inserts the start bit, the correct parity bit if programmed 

to do so, and the stop bit ( 1, 1-1/2 or 2 depending on the comm.and in 

the Line Control Register). 

Interface Description 

The communications adapter provides an EIA RS-232-C like interface. 

One 25 pin "D" shell, male type connector is provided to attach 

various peripheral devices. In addition, a current loop interface is also 

located in this same connector. Ajumper block is provided to manually 

select either the voltage interface, or the current loop interface. 

The current loop interface is provided to attach certain printers 

provided by IBM Corporation that use this particular type ofinterface. 

Pin 18 + receive current loop data (20Ma) 

Pin 25 - receive current loop return (20Ma) 

Pin 9 + transmit current loop return (20Ma) 

Pin 11 - transmit current loop data (20Ma) 

2-126

I TRANSMIT 'IACUIT I 

+5V 

~ 4S-"l 

Tx DATA ----I~.,..-----------.,:~ :11::1 

+5V 

RECEIVE CIRCUIT 

PIN 18 4---t-., 

OPTO ISOLATOR 

5.SK.I1 

:>0--- Rx DATA 

PIN 25 "'__+--J 

+5V 

Figure 23. CURRENT LOOP INTERFACE 

~ 

The voltage interface is a serial interface. It supports certain data and 

control signals as listed below. 

Pin 2 

Pin 3 

Pin 4 

Pin 5 

Pin 6 

Pin 7 

Pin 8 

Pin 20 

Pin 22 

Transmit Data 

Receive Data 

Request to Send 

Clear to Send 

Data Set Ready 

Signal Ground 

Carrier Detect 

Data Terminal Ready 

Ring Indicate 

The adapter converts these signals to/from TTL levels to EIA voltage 

levels. These signals are sampled or generated by the communication 

control chip. These signals can then be sensed by the system software 

to determine the state of the interface or peripheral device. 

2-127

Voltage Interchange Information 

Interface 

Interchange Voltage Binary State Signal Condition Control Function 

Positive Voltage = Binary (0) = Spacing =On 

Negative Voltage = Binary (1) = Marking =Off 

Invalid Levels 

+15V---------- 

On Function 

+3V ---------- 

0\1 Invalid Levels 

-3V ---------- 

Off Function 

-15V---------- 

Invalid Levels 

The signal will be considered in the "marking" condition when the 

voltage on the interchange circuit, measured at the interface point, is 

more negative than minus three volts with respect to signal ground. The 

signal will be considered in the "spacing" condition when the voltage is 

more positive than plus three volts with respect to signal ground. The 

region between plus three volts and minus three volts is defined as the 

transition region, will be considered in invalid levels. The voltage which 

is more negative than -15V or more positive than +15V will be 

considered in invalid levels. 

During the transmission of data, the "marking" condition will be used 

to denote the binary state "one" and "spacing" condition will be used to 

denote the binary state "zero". 

For interface control circuits, the function is "on" when the voltage 

is more positive than +3V with respect to signal ground and is "off" 

when the voltage is more negative than -3V with respect to signal 

ground. 

2-128

INS8250 Functional Pin Description 

The following describes the function of all INS8250 input/output pins. 

Some of these descriptions reference internal circuits. 

Note: In the following descriptions, a low represents a logic 0 (0 volt 

,.-......, nominal) and a high represents a logic 1 (+2.4 volts nominal). 

Input Signals 

Chip Select (SCO, CS1, CS2), Pins 12-14: When CSO and CSI are high 

and CS2 is low, the chip is selected. Chip selection is complete when 

the decoded chip select signal is latched with an active (low) Address 

Strobe (ADS) input. This enable comunication between the INS8250 

and the CPU. 

Data Input Strobe (DISTRDISTR) Pins 22 and 21: When DISTR is 

high or DISTR is low while the chip is selected, allows the CPU to read 

status information or data from a selected register of the INS8250. 

Note: Only an active DISTR or DISTR input is required to transfer 

data from the INS8250 during a read operation. Therefore, tie either 

the DISTR input permanently low or the DISTR input permanently 

high, if not used. 

,.-......, Data Output Strobe (DOSTR, DOSTR), Pins 19 and 18: When 

DOSTR is high or DOSTR is low while the chip is selected, allows the 

CPU to write data or control words into a selected register of the 

INS8250. 

Note: Only an active DOSTR or DOSTR input is required to transfer 

data to the INS8250 during a write operation. Therefore, tie either the 

DPSTR input permanently low or the DOSTR input permanently high, 

if not used. 

Address Strobe (ADS), Pin 25: When low, provides latching for the 

Register Select (AO, AI, A2) and Chip Select (SOC, CSl, CS2) 

signals. 

Note: An active ADS input is required when the Register Select 

(AO, AI, A2) signals are not stable for the duration of a read or write 

operation. If not required, the ADS input permanently low. 

2-129

Register Select (AO, AI, A2), Pins 26-28: These three inputs are used 

during a read or write operation to select an INS8250 register to read 

from or write into as indicated in the table below. Note that the state of 

the Divisor Latch Access Bit (DLAB), which is the most significant bit 

of the Line Control Register, affects the selection of certain INS8250 

registers. The DLAB must be set high by the system software to access 

the Baud Generator Divisor Latches. 

DLAB A2 A1 AD Register 

0 0 0 0 Receiver Buffer (read), Transmitter Holding 

Register (write) 

0 0 0 1 Interrupt Enable 

X 0 1 0 Interrupt Identification (read only) 

X 0 1 1 Li ne Co ntrol 

X 1 0 0 MODEM Control 

X 1 0 1 line Status 

X 1 1 0 MODEM Status 

X 1 1 1 None 

1 D 0 0 Divisor Latch (least significant byte) 

1 D D 1 Divisor Latch (most significant byte) 

Master Reset (MR), Pin 35: When high, clears all the registers 

(except the Receiver Buffer, Transmitter Holding, and Divisor 

Latches), and the control logic of the INS8250. Also, the state of 

various output signals (SOUT, INTRPT, OUT 1, OUT 2, RTS, 

DTR) are affected by an active MR input. (Refer to Table 1.) 

Receiver Clock (RCLK), Pin 9: This input is the I6x baud rate 

clock for the receiver section of the chip. 

Serial Input (SIN), PintO: Serial data input from the communications 

link (peripheral device, MODEM, or data set). 

Clear to Send (CTS), Pin 36: The CTS signal is a MODEM control 

function input whose condition can be tested by the CPU by reading 

Bit 4 (CTS) of the MODEM Status Register. Bit 0 (DCTS) of the 

MODEM Status Register indicates whether the CTS input has 

changed state since the previous reading of the MODEM Status 

Register. 

Note: Whenever the CTS bit ofthe MODEM Status Register changes 

state, an interrupt is generated if the MODEM Status Interrupt 

is enabled. 

2-130

Data Set Ready (DSR), Pin 37: When low, indicates that the 

MODEM or data set is ready to establish the communications link and 

transfer data with the INS8250. The DSR signal is a MODEM-control 

function input whose condition can be tested by the CPU by reading Bit 

5 (DSR) of the MODEM Status Register. Bit 1 (DDSR) of the 

MODEM Status Register indicates whether the DSR input has 

r""\ changed state since the previous reading of the MODEM Status 

Register. 

~ Whenever the DSR bit ofthe MODEM Status Register changes 

state, an interrupt is generated if the MODEM Status Interrupt 

is enabled. 

Received Line Signal Detect (RLSD), Pin 38: When low, indicates 

that the data carrier has been detected by the MODEM or data set. 

The RLSD signal is a MODEM-Control function input whose 

condition can be tested by the CPU by reading Bit 7 (RLSD) of the 

MODEM Status Register. Bit 3 (DRLSD) of the MODEM Status 

Register indicates whether the RLSD input has changed state since the 

previous readingof the MODEM Status Register. 

Note: Whenever the RLSD bit of the MODEM Status Register 

changes state, an interrupt is generated ifthe MODEM Status Interrupt 

is enabled. 

~ Ring Indicator (RI), Pin 39: When low, indicates that a telephone 

ringing signal has been received by the MODEM or data set. The RI 

signal is a MODEM-control function input whose condition can be 

tested by the CPU by reading Bit 6 (RI) of the MODEM Status 

Register. Bit 2 (TERI) of the MODEM Status Register indicates 

whether the RI input has changed from a low to a high state since the 

previous reading of the MODEM Status Register. 

Note: Whenever the RI bit of the MODEM Status Register changes 

from a high to a low state, an interrupt is generated if the MODEM 

Status Interrupt is enabled. 

vce, Pin 40: +5 volt supply. 

VSS, Pin 20: Ground (O-volt) reference. 

2-131

Output Signals 

Data Terminal Ready (DTR), Pin 33: When low, informs the 

MODEM or data set that the INS8250 is ready to communicate. The 

DTR output signal can be set to an active low by programming Bit 0 

(DTR) of the MODEM Control Register to a high level. The DTR 

signal is set high upon a Master Reset operation. 

Request to Send(RTS), Pin 32: When low, informs the MODEM or 

data set that the INS8250 is ready to transmit data. the RTS output 

signal can be set to an active low by programming Bit 1 (RTS) of the 

MODEM Control Register. The RTS signal is set high upon a Master 

Reset operation. 

Output 1 (OUT 1), Pin 34: User-designated output that can be set to 

an active low by programming Bit 2 (OUT 1) ofthe MODEM Control 

Register to a high level. The OUT 1 signal is set high upon a Master 

Reset operation. 

Output 2 (OUT 2), Pin 31: User-designated output that can be set 

to an active low by programming Bit 3 (OUT 2) of the MODEM 

Control Register to a high level. The OUT 2 signal is set high upon a 

Master Reset operation. 

Chip Select Out (CSOUT), Pin 24: When high, indicates that the 

chip has been selected by active CSO, CSl, and CS2 inputs. No data 

transfer can be initiated until the CSOUT signal is a logic 1. 

Driver Disable (DDIS), Pin 23: Goes low whenever the CPU is 

reading data from the INS8250. A high-level DDIS output can be 

used to disable an external transceiver (if used between the CPU and 

INS8250 on the D7-DO Data Bus) at all times, except when the CPU 

is reading data. 

Baud Out (BAUDOUT), Pin 15: 16x clock signal for the transmitter 

section of the INS8250. The clock rate is equal to the main reference 

oscillator frequency divided by the specified divisor in the Baud 

Generator Divisor Latches. The BAUDOUT may also be used for the 

receiver section by typing this output to the RCLK input of the chip. 

Interrupt (INTRPT), Pin 30: Goes high whenever anyone of the 

following interrupt types has an active high condition and is enabled via 

the IER: Receiver Error Flag; Received Data Available; Transmitter 

Holding Register Empty; and MODEM Status. The INTRPT Signal is 

reset low upon the appropriate interrupt service or a Master Reset 

operation. 

Serial Output (SOUT), Pin 11: Composite serial data output to the 

communications link (peripheral, MODEM or data set). The SOUT 

signal is set to the Marking (Logic 1) state upon a Master Reset 

operation. 

2-132

Input/Output Signals 

Data (D7-DO) Bus, Pins 1-8: This bus comprises eight TRI-STATE 

input/output lines. The bus provides bidirectional communications 

between the INS8250 and the CPU. Data, control words, and status 

information are transferred via the D7-DO Data Bus. 

r"\ External Clock Input/Output (XTAL1, XTAL2, Pins 16 and 17: 

These two pins connect the main timing reference (crystal or signal 

clock) to the INS8250. 


Table 22. Asynchronous Communications Reset Functions 

Register/Signal 

Interrupt Enable Register 

Interrupt Identification 

Register 

Line Control Register 

MODEM Control Register 

Line Status Register 

MODEM Status Register 

SOUT 

INTRPT (RCVR Errs) 

INTRPT (RCVR Data 

Ready) 

INTRPT (RCVR Data 

Ready) 

INTRPT (MODEM 

Status Changes) 

OUT 2 

RTS 

DTR 

OUT 1 

Reset Control 

Master Reset 

Master Reset 

Master Reset 

Master Reset 

Master Reset 

Master Reset 

Master Reset 

Read LSR/MR 

Read RBR/MR 

Read II R/Write 

THR/MR 

Read MSR/MR 

Master Reset 

Master Reset 

Master Reset 

Master Reset 

Reset State 

All Bits Low 

(0-3 Forced and 4-7 

Permanent) 

Bit 0 is High, 

Bits 1 and 2 Low 

Bits 3-7 are 

Permanently Low 

All Bits Low 

All Bits Low 

Except Bits 5 & 6 are High 

Bits 0-3 Low 

Bits 4-7 - Input Signal 

High 

Low 

Low 

Low 

Low 

High 

High 

High 

High 

2-133

INS8250 Accessible Registers 

The system programmer may access or control any of the INS8250 

registers via the CPU. These registers are used to control INS8250 

operations and to transmit and receive data. 

INS8250 Line Control Register 

The system programmer specifies the format of the asynchronous data 

communications exchange via the Line Control Register. In addition to 

controlling the format, the programmer may retrieve the contents ofthe 

Line Control Register for inspection. This feature simplifies system 

programming and eliminates the need for separate storage in system 

memory ofthe line characteristics. The contents of the Line Control 

Register are indicated and described below. 

Line Control Register (LCR) 

3FB 

BIT 7 6 5 4 3 2 1 0 

I' I : Word L,"gth SoI,01 Bit DIW LSD) 

Word Length Select Bit 1 (WLS1) 

Number of Stop Bits (STB) 

~--~Parity Enable (PEN) 

'------~Even Parity Select (EPS) 

'-------~Stick Parity 

L--_____~ Set Break 

L--______.... Divisor Latch Access Bit (DLAB) 

Bit 0 and 1: These two bits specify the number of bits in each 

transmitted or received serial character. The encoding of bits 0 and 1 

is as follows: 

Bit 1 Bit 0 Word Length 

0 0 5 Bits 

0 1 6 Bits 

1 0 7 Bits 

1 1 8 Bits 

Bit 2: This bit specifies the number of Stop bits in each transmitted or 

received serial character. If bit 2 is a logic 0, 1 Stop bit is generated or 

checked in the transmit or receive data, respectively. Ifbit 2 is logic 1 

when a 5-bit word length is selected via bits 0 and 1, 1-1/2 Stop bits are 

generated or checked. Ifbit 2 is logic 1 when either a 6-, 7-, or 8-bit word 

length is selected, 2 Stop bits are generated or checked. 

2-134

Bit 3: This bit is the Parity Enable bit. When bit 3 is a logic 1, a Parity 

bit is generated (transmit data) or checked (receive data) between the 

last data word bit and Stop bit ofthe serial data. (The Parity bit is used 

to produce an even or odd number of 1's when the data word bits and the 

Parity bit are summed.) 

~ Bit 4: This bIt is the Even Parity Select bit. When bit 3 is a logic 1 and 

bit 4 is a logic 0, an odd number oflogic 1 's is transmitted or checked in 

the data word bits and Parity bit. When bit 3 is a logic 1 and bit 4 is a 

logic 1, an even number of bits is transmitted or checked. 

Bit 5: This bit is the Stick Parity bit. When bit 3 is a logic 1 and bit 5 is a 

logic 1, the Parity bit is transmitted and then detected by the receiver as 

a logic 0 if bit 4 is a logic 1 or as a logic 1 if bit 4 is a logic O. 

Bit 6: This bit is the Set Break Control bit. When bit 6 is a logic 1, the 

serial output (SOUT) is forced to the Spacing (logic 0) state and 

remains there regardless of other transmitter activity. The set break is 

disabled by setting bit 6 to a logic O. This feature enables the CPU to 

alert a terminal in a computer communications system. 

Bit 7:This bit is the Divisor Latch Access Bit (DLAB). It must be set 

high (logic 1) to access the Divisor Latches ofthe Baud Rate Generator 

during a Read or Write operation. Itmust be set low (logic 0) to access 

~ the Receiver Buffer, the Transmitter Holding Register, or the Interrupt 

Enable Register. 

INS8250 Programmable Baud Rate Generator 

The INS8250 contains a programmable Baud Rate Generator that is 

capable oftaking the clock input (1.8432 MHz) and dividing it by any 

divisor from 1 to (21 6 -1). The output frequency ofthe Baud Generator 

is 16x the Baud rate [divisor #= (frequency input) / (baud rate x 16)]. 

Two 8-bit latches store the divisor in a 16-bit binary format. These 

Divisor Latches must be loaded during initialization in order to ensure 

desired operation of the Baud Rate Generator. Upon loading either of 

the Divisor Latches, a 16-bit Baud counter is immediately loaded. This 

prevents long counts on initial load. 

2-135

Divisor Latch Least Significant Bit (DLL) 

3F8 

DLAB=l 

BIT 7 6 5 4 3 2 o 

LS 

BIT 

0 

BIT 1 

BIT 2 

BIT 3 

BIT4 

'--------------- BIT 5 

Divisor Latch Most Significant Bit (DLM) 

3F9 

DLAB=l 

BIT 7 6 5 4 3 2 1 0 

I L... BIT8 

BIT 6 

BIT 7 

~BIT9 

'----------t~ BIT 10 

'---------. BIT 11 

L..-___________ BIT 12 

'-------------__ BIT 13 

'---------------__ BIT 14 

"-----------------__ BIT 15 

Table 23 illustrates the use of the Baud Rate Generator with a 

frequency of 1.8432 Mhz. For baud rates of 9600 and below, the error 

obtained is minimal. 

Note: The maximum operating frequency of the Baud Generator is 

3.1 Mhz. In no case should the data rate be greater than 9600 Baud. 

2-136

Table 23. BAUD RATE AT 1.843 Mhz 

Desired Divisor Used Percent Error 

Baud to Generate Difference Between 

Rate 16x Clock Desired & Actual 

Decimal Hex 

50 2304 '900' - 

75 1536 '600' - 

110 1047 '417' 0.026 

134.5 857 '359' 0.058 

150 768 '300' - 

300 384 '180' - 

600 192 'OCO' - 

1200 96 '060' - 

1800 64 '040' - 

2000 58 '03A' 0.69 

2400 48 '030' - 

3600 32 '020' - 

4800 24 '018' - 

7200 16 '010' - 

9600 12 'OOC' - 

~ Line Status Register 

This 8-bit register provides status information to the CPU concerning 

the data transfer. The contents ofthe Line Status Register are indicated 

and described below. 

Line Status Register (LSR) 

3FD 

BIT 6 4 3 2 1 0 

DATA READY (DR) 

OVERRUN ERROR (OR) 

I Li=: 

PARITY ERROR (PE) 

... FRAMING ERROR (FE) 

!: 

:. 

BREAK INTERRUPT (BI) 

TRANSMITTER HOLDING 

REGISTER EMPTY (TH RE) 

... 

po TX SHIFT REGISTER 

EMPTY (TSRE) 

=0 

- 

2-137

Bit 0: This bit is the receiver Data Ready (DR) indicator. Bit 0 is set to a 

logic 1 whenever a complete incoming character has been received and 

transferred into the Receiver Buffer Register. Bit 0 may be reset to a 

logic 0 either by the CPU reading the data in the Receiver Buffer 

Register or by writing a logic 0 into it from the CPU. 

Bit 1: This bit is the Overrun Error (OE) indicator. Bit 1 indicates that r--... 

data in the Receiver Buffer Register was not read by the CPU before the 

next character was transferred into the Receiver Buffer Register, 

thereby destroying the previous character. The OE indicator is reset 

whenever the CPU reads the contents of the Line Status Register. 

Bit 2: This bit is the Parity Error (PE) indicator. Bit 2 indicates that 

the received data character does not have the correct even or odd parity, 

as selected by the even parity-select bit. the PE bit is set to a logic 1 

upon detection of a parity error and is reset to a logic 0 whenever the 

CPU reads the contents of the Line Status Register. 

Bit 3:This bit is the Framing Error (FE) indicator. Bit 3 indicates that 

the received character did not have a valid Stop bit. Bit 3 is set to a logic 

1 whenever the Stop bit following the last data bit or parity bit is 

detected as a zero bit (Spacing level). 

Bit 4: This bit is the Break Interrupt (BI) indicator. Bit 4 is set to a logic 

1 whenever the received data input is held in the Spacing (logic 0) state r--... 

for longer than a full word transmission time (that is, the total time of 

Start bit + data bits + Parity + Stop bits). 

Note: Bits 1 through 4 are the error conditions that produce a Receiver 

Line Status interrupt whenever any of the corresponding conditions 

are detected. 

Bit 5: This bit is the Transmitter Holding Register Empty (THRE) 

indicator. Bit 5 indicates that the INS8250 is ready to accept a new 

character for transmission. In addition, this bit causes the INS8250 to 

issue an interrupt to the CPU when the Transmit Holding Register 

Empty Interrupt enable is set high. The THRE bit is set to a logic 1 

when a character is transferred from the Transmitter Holding Register 

into the Transmitter Shift Register. The bit is reset to logic 0 

concurrently with the loading of the Transmitter Holding Register by 

the CPU. 

Bit 6: This bit is the Transmitter Shift Register Empty (TSRE) 

indicator. Bit 6 is set to a logic 1 whenever the Transmitter Shift 

Register is idle. It is reset to logic 0 upon a data transfer from the 

Tranmitter Holding Register to the Transmitter Shift Register. Bit 6 

is a read-only bit. 

Bit 7: This bit is permanently set to logic O. 

2-138

Interrupt Identification Register 

The INS8250 has an on-chip interrupt capability that allows for 

complete flexibility in interfacing to all the popular microprocessors 

presently available. In order to provide minimum software overhead 

during data character transfers, the INS8250 prioritizes interrupts into 

r"\ four levels. The four levels of interrupt conditions are as follows: 

Receiver Line Status (priority 1); Received Data Ready (priority 2); 

Transmitter Holding Register Empty (priority 3); and MODEM 

Status (priority 4). 

Information indicating that a prioritized interrupt is pending and the 

type of that interrupt are stored in the Interrupt Identification Register 

(refer to Table 5). The Interrupt Identification Register (IIR), when 

addressed during chip-select time, freezes the highest priority interrupt 

pending and no other interrupts are acknowledged until that particular 

interrupt is serviced by the CPU. The contents ofthe IIR are indicated 

and described below. 

Interrupt Identification Register (IIR) 

3FA 

BIT 6 5 4 3 2 1 0 

I L: 0 If INTERRUPTPENDING 

I I ~~ INTERRUPT 10 BIT (0) 

I INTER RUPT 10 BIT (1) 

'--------~ ~ 0 

'-----------.... ~ 0 

'-------------~ ~O 

L-____________~ ~O 

'-----------------.... ~O 

Bit 0: This bit can be used in either a hardwired prioritized or polled 

environment to indicate whether an interrupt is pending. When bit 0 is a 

logic 0, an interrupt is pending and the IIR contents may be used as a 

pointer to the appropriate interrupt service routine. When bit 0 is a logic 

1, no interrupt is pending and polling (if used) continued. 

Bits 1 and 2: These two bits ofthe IIR are used to identify the highest 

priority interrupt pending as indicated in Table 5. 

,.,-...., Bits 3 through 7:These five bits of the IIR are always logic O. 

2-139

Table 24. Interrupt Control Functions 

Interrupt I D 

Register 

Bit 2 Bit 1 Bit 0 

0 0 1 

1 1 0 

1 0 0 

0 1 0 

0 0 0 

Priority 

Level 

- 

Highest 

Second 

Third 

Fourth 

Interrupt Set and Reset Functions 

Interrupt 

Type 

None 

Receiver 

Line Status 

Received 

Data Available 

Transmitter 

Holding Register 

Empty 

MODEM Status 

Interrupt 

Source 

None 

Overrun Error 

or 

Parity Error 

or 

Framing Error 

or 

Break Interrupt 

Receiver 

Data Available 

Transmitter 

Holding Register 

Empty 

Clear to Send 

or 

Data Set Ready 

or 

Ring Indicator 

or 

Received Line 

Si gna I 0 etect 

Interrupt 

Reset Control 

Reading the 

Line Status 

Register 

Reading the 

Receiver 

Buffer 

Register 

Reading the 

II R Register 

(if source of 

interrupt) 

or 

Writing into 

the Transmitter 

Holding 

Register 

Reading the 

MODEM Status 

Register 

2-140

Interrupt Enable Register 

This 8-bit register enables the four types of interrupt of the INS8250 

to separately activate the chip Interrupt (INTRPT) output signal. It is 

possible to totally disable the interrupt system by resetting bits 0 

through 3 of the Interrupt Enable Register. Similarly, by setting the 

r'\ appropriate bits of this register to a logic 1, selected interrupts can be 

enabled. Disabling the interrupt system inhibits the Interrupt Identification 

Register and the active (high) INTRPT output from the chip. 

All other system functions operate in their normal manner, including 

the setting of the Line Status and MODEM Status Registers. The 

contents of the Interrupt Enable Register are indicated and 

described below. 

Interrupt Enable Register (IER) 

3F9 

DLAB=O 

BIT 7 6 4 3 1 0 

L:: 

p =0 

~------------------__• =0 

=0 

~----------------__________~. =0 

1= ENABLE DATA 

AVAILABLE INTERRUPT 

I=ENABLE TX HOLDING REG 

EMPTY INTERRUPT 

1= ENABLE RECEIVE LINE 

STATUS INTERRUPT 

I=ENABLE MODEM STATUS 

INTERRUPT 

Bit 0: This bit enables the Received Data Available Interrupt when set 

to logic 1. 

Bit 1: This bit enables the Transmitter Holding Register Empty 

Interrupt when set to logic 1. 

Bit 2: This bit enables the Receiver Line Status Interrupt when set to 

logic 1. 

Bit 3: This bit enables the MODEM Status Interrupt when set to 

logic 1. 

r-"\ Bits 4 through 7: These four bits are alway logic O. 

2-141

MODEM Control Register 

This 8-bit register controls the interface with the MODEM or data set 

(or a peripheral device emulating a MODEM). The contents of the 

MODEM Control Register are indicated and described below. 

MODEM Control Register (MCR) 

3FC 

BIT 6 5 43210 

~: 

. L=;~ ~~~~ESTTOSEND(RTS) 

_III~IL 

I. 

I 

- OUT2 

'---------.. LOOP 

~------------------~ 

L-______________________• 

DATA TERMINAL READY IOTR! 

;0 ;0 

~------------------------__. ;0 

Bit 0: This bit controls the Data Terminal Ready (DTR) output. When 

bit 0 is set to a logic 1, the DTR output is forced to a logic O. When bit 0 

is reset to a logic 0, the DTR output is forced to a logic 1. 

Note: The DTR output of the INS8250 may be applied to an EIA 

inverting line driver (such as the DS1488) to obtain the proper polarity 

input at the succeeding MODEM or data set. 

Bit 1: This bit controls the Request to Send (RTS) output. Bit 1 affects 

the RTS output in a manner identical to that described above for bit O. 

Bit 2: This bit controls the Output 1 (OUT 1) signal, which is an 

auxiliary user-designated output. Bit 2 affects the OUT 1 output in a 

manner identical to that described above for bit O. 

Bit 3: This bit controls the Output 2 (OUT 2) signal, which is an 

auxiliary user-designated output. Bit 3 affects the OUT 2 output in a 

manner identical to that described above for bit O. 

Bit 4: This bit provides a loopback feature for diagnostic testing of the 

INS8250. When bit 4 is set to logic 1, the following occur: the 

transmitter Serial Output (SOUT) is set to the Marking (logic 1) state; 

the receiver Serial Input (SIN) is disconnected; the output of the 

Transmitter Shift Register is "looped back" into the Receiver Shift 

Register input; the four MODEM Control inputs (CTS,DSR, RLSD, 

and RI) are disconnected; and the four MODEM Control outputs 

(DTR, RTS, OUT 1, and OUT 2) are internally connected to the four 

MODEM Control inputs. In the diagnostic mode, data that is 

transmitted is immediately received. This feature allows the processor 

to verify the transmit- and receive-data paths of the INS8250. 

r"\ 

r"\ 

2-142

In the diagnostic mode, the receiver and transmitter interrupts are fully 

operational. The MODEM Control Interrupts are also operational but 

the interrupts' sources are now the lower four bits of the MODEM 

Control Register instead of the four MODEM Control inputs. The 

interrupts are still controlled by the Interrupt Enable Register. 

r--... The INS8250 interrupt system can be tested by writing into the lower 

four bits ofthe MODEM Status Register. Setting any ofthese bits to a 

logic 1 generates the appropriate interrupt (if enabled). The resetting of 

these interrupts is the same as in normal INS8250 operation. To return 

to normal operation, the registers must be reprogrammed for normal 

operation and then bit 4 ofthe MODEM Control Register must be reset 

to logic O. 

Bits 5 through 7: These bits are permanently set to logic O. 

MODEM StMus Register 

This 8-bit register provides the current state ofthe control lines from the 

MODEM (or peripheral device) to the CPU. In addition to this currentstate 

information, four bits of the MODEM Status Register provide 

change information. These bits are set to a logic 1 whenever a control 

input from the MODEM changes state. They are reset to logic 0 

whenever the CPU reads the MODEM Status Register. 

~ The content of the MODEM Status Register are indicated and 

described below. 

MODEM Status Register (MSR) 

3FE 

BIT 6 5 4 3 2 1 0 

L:: 

DELTA CLEAR TO 

I 

SEND WCTS) 

DELTA DATASET 

READY WDSR) 

L----____• TRAILING EDGE RING 

INDICATOR (TERI) 

DELTA RX LINE SIGNAL 

OETECT WRLSD) 

CLEAR TO SEND (CTS) 

~------------;.~ DATA SET READY (oSD) 

'---------------. RING INDICATOR (RI) 

'-----------------. RECEIVE LINE SIGNAL 

DETECT (RLSD) 

2-143

Bit 0: This bit is the Delta Clear to Send (DCTS) indicator. Bit 0 

indicates that the CTS input to the chip has changed state since the last 

time it was read by the CPU. 

Bit 1: This bit is the Delta Data Set Ready (DDSR) indicator. Bit 1 

indicates that the DSR input to the chip has changed state since the last 

~~~re~~~~ll ~ 

Bit 2: This bit is the Trailing Edge of Ring Indicator (TERI) detector. 

Bit 2 indicates that the RI input to the chip has changed from an On 

(logic 1) to an Off (logic 0) condition. 

Bit 3: This bit is the Delta Received Line Signal Detector (DRLSD) 

indicator. Bit 3 indicates that the RLSD input to the chip has changed 

state. 

Note: Whenever bit 0, 1, 2, or 3 is set to a logic 1, a MODEM Status 

interrupt is generated. 

Bit4: This bit is the complement ofthe Clear to Send (CTS) input. Ifbit 

4 (loop) of the MCR is set to a 1, this bit is equivalent to RTS in the 

MCR 

Bit 5: This bit is the complement ofthe Data Set Ready (DSR) input. If 

bit 4 ofthe MCR is set to ai, this bit is equivalent to DTR in the MCR 

Bit6: This bit is the complement ofthe Ring Indicator (RI) input. Ifbit 4 r-... 

of the M CR is set to aI, this bit is equivalent to OUT 1 in the M CR 

Bit 7: This bit is the complement of the Received Line Signal Detect 

(RLSD) input. If bit 4 ofthe MCR is set to ai, this bit is equivalent to 

OUT 2 of the MCR 

Receiver Buffer Register 

The Receiver Buffer Register contains the received character as 

defined below. 

Receiver Buffer Register (RBR) 

3F8 DLAB;O READ ONLY 

BIT 4 3 2 1 0 

I 

~~ m~ml 

1,----1________ 

'---.--------:. DATABIT4 

'-----------. DATABIT5 

'-----------------. DATA BIT 6 

'-----------------.. DATA BIT 7 

Bit 0 is the least significant bit and is the first bit serially received. 

2-144

Transmitter Holding Register 

The Transmitter Holding Register contains the character to be serially 

transmitted and is defined below: 

Transmitter Holding Register (THR) 

r'"'\ 

3F8 DLAB=O WRITE ONLY 

BIT 7 6 5 4 3 2 1 0 

I I • DATA BIT 0 

L----==; DATA BIT 1 

'---------1. DATA BIT 2 

'---------.. DATABIT3 

'-------------1. DATA BIT 4 

L--------------a DATA BIT 5 

'---------------____ DATA BIT 6 

L-_______________----I~ DATA BIT 7 

Bit 0 is the least significant bit and is the first bit serially transmitted. 

2-145

Selecting The Interface Format 

The Voltage or Current loop interface is selected by plugging the 

programmed shunt module, with the locator dot up or down. See the 

figure below for the two configurations. 

D 

o 

D 

D 

o 

ASYNCHRONOUS 

COMMU N ICATI 0 NS 1....I...I...L..J..I....L...L.J~t..L.L.JL...L...L..L..L.J.J..L.L~II-'-I-.................. 

ADAPTER 

CURRENT LOOP 

INTERFACE 

DOT DOWN 

VOLTAGE INTERFACE 

DOT UP 

Figure 23. SELECTING THE INTERFACE FORMAT 

2-146

Asynchronous Communications Adapter Connector 

Interface Specifications 

REAR PANEL 

/""\ \\ 

External 

Device 

_OCZ5 

o 

~ 0~ 


Description 

... 

.... 

... , 

NC 

Transmit Data 

Receive Data 

Request to send 

Clear to send 

Data set ready 

Signal ground 

Carrier detect 

... +Transmit current loop return (20 rna) 

~ 

NC 

....L 

.... 

-Transmit current loop data (20 rna) 

NC 

NC 

NC 

NC 

NC 

NC 

+Receive current loop data (20 rna) 

NC 

Data Terminal Ready 

NC 

Ring Indicate 

NC 

NC 

- Receive current loop return (20 rna) 

Pin 

1 

2 

3 .. 

4 

5 

.. 

r' 

6 

.. 

7 

8 

.. 

9 

0 

• 25 

• • 

• 

• 

• • 14 

• 

0 

10 

11 

Asynchronous 

12 

Communications 

13 Adapter 

14 (RS232C) 

15 

16 

17 

18 ... 

19 

20 

21 

22 

23 • 

24 

25 .. 

.. 

NOTE: 

To avoid inducing voltage surges on interchange circuits, signals from interchange 

circuits shall not be used to drive inductive devices, such as relay coils. 

2-147

2-148 

NOTES

SECTION 3. ROM and SYSTEM 

r", USAGE 

Contents: 

ROM BIOS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

BIOS Cassette Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Keyboard Encoding and Usage . . . . . . . . . . . . . . . . . . . 

Low Memory Maps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

3-2 

3-8 

3-11 

3-21 

3-1

ROM BIOS 

The ROM resident Basic I/O System (BIOS) provides the device 

level control of the major I/O devices in the System Unit. The 

BIOS routines allow the assembly language programmer to 

perform block (diskette and cassette) or character (Video, ~ 

communications, keyboard and printer) level I/O operations 

without any concern for device address and operating characteristics. 

Additionally, system services such as time of day and 

memory size determination are provided. The goal is to provide 

an operational interface to the system and relieve the programmer from 

concern over hardware device characteristics. 

Finally the BIOS interface· insulates the user from the hardware 

allowing new devices to be added to the System Unit, yet 

retaining the BIOS level interface to the device. In this manner, 

user programs become transparent to hardware modifications 

and enhancements. A complete listing of the BIOS is provided 

in Appendix "A". 

Use of BIOS 

Access to the BIOS function is through the 8088 software 

interrupts. Each BIOS entry point is available through its own 

interrupt, which can be found in the interrupt vector listing. 

The software interrupts lOH through lAH each access a 

different BIOS routine. For example, to determine the amount 

of memory available in the system, 

INT 12H 

will invoke the memory size determination routine in BIOS 

and return the value to the caller. 

Parameter Passing 

All parameters passed to and from the BIOS routines go through 

the 8088 registers. The prologue of each BIOS function indicate 

the registers used on the call and the return. For the memory 

size example above, no parameters are passed, and the result, 

memory size in 1 K Byte increments is returned in the 

AX register. 

Where a BIOS function has several possible operations, the AH 

register is used on input to indicate the desired operation. For 

example, to set the time of day, the following code is required. 

3-2

MOV AH,l ;function is to set time of 

day. 

MOV CX,HIGH_COUNT ;establish the current time. 

MOV DX, Low_COUNT 

INT lAH ;Set the time. 

~ While to read the time of day: 

MOV AH,O ;function is to read the time 

of day. 

INT lAH ;read the timer. 

As a general rule, the BIOS routines preserve all registers except 

for AX and the flags. Other registers are modified on return 

only if they are returning a value to the caller. The exact register 

usage can be seen in the prologue of each BIOS function. 

Interrupt Vector Listing 

Interrullt Number Name BIOS Initialization 

0 Divide by Zero None 

1 Single Step None 

2 Non Maskable NMLlNT (FOOO:E2C3) 

3 Breakpoint None 

4 Overflow None 

5 Print Screen PRINLSCREEN (FOOO:FF54) 

6 Unused 

7 Unused 

8 Time of Day TIMER-INT (FOOO:FEA5) 

9 Keyboard KLINT (FOOO:E987) 

A 

Unused 

B 

8259 

Unused 

C 

Interrupt 

Unused (Reserved Communications) 

D 

Vectors 

Unused 

E Diskette DISK_I NT (FOOO:EF57) 

F 

Unused (Reserved Printer) 

10 Video VIDEO_I 0 (FOOO:F065) 

11 Equipment Check EQUIPMENT (FOOO:F84D) 

12 Memory MEMORY_SIZE_DETERMINE (FOOO:F841) 

13 Diskette DISKETTE_I 0 (FOOO:EC59) 

14 BIOS Communications RS2.3LI 0 (FOOO:E739) 

15 Entry Cassette CASSETTE_I 0 (FOOO:F859) 

16 Points Keyboard KEYBOARD_I 0 (FOOO:E82E) 

17 Printer PRINTER_I 0 (FOOO:EF02) 

18 Cassette BASI C (F600:0000) 

19 Bootstrap BOOLSTRAP (FOOO:E6F2) 

lA Time of Day TIME_OF_DAY (FOOO:FE6E) 

lB User Supplied Keyboard Break DUMMY_RETURN (FOOO:FF53) 

lC Routines Timer T\ick , DUMMY RETU RN (FOOO: FF53) 

lD Video Initialization VIDEO_PARMS (FOOO:FOA4) 

IE 

BIOS 

Diskette Parameters DISK_BASE (FOOO:EFC7) 

IF 

Parameters 

Video Graphics Chars None 

3-3

3-4 

NOTES

Vectors With Special Meanings 

Interrupt 1 BH - Keyboard Break Address 

This vector points to the code to be exercised when the CTRL 

BREAK keys are depressed on the keyboard. The vector is 

r-"\ invoked while responding to the keyboard interrupt, and control 

should be returned via an lRET instruction. The power on routines 

initialize this vector to point to an lRET instruction, so that nothing 

happens when CTRL BREAK keys are depressed unless 

the application program sets a different value. 

Control may be retained by this routine, with the following 

problems. The BREAK may have occurred during interrupt 

processing, so that one or mor End of Interrupt commands must 

be set to the 8259 controller. Also, all I/O devices should be reset in 

case an operation was underway at that time. 

Interrupt 1 CH - Timer Tick 

This vector points to the code to be executed on every tick of the 

system clock. This vector is invoked while responding to the 

timer interrupt, and control should be returned via an lRET 

~ instruction. The power on routines initialize this vector to point 

. to an lRET instruction, so that nothing happens unless the 

application modifies the pointer. It is the responsibility of the 

application to save and restore all registers that will be modified. 

Interrupt IDH - Video Parameters 

This vector points to a data region containing the parameters 

required for the initialization of the 6845 on the video card. Note 

that there are four separate tables, and all four must be 

reproduced if all modes of operation are to be supported. The 

power on routines initialize this vector to point to the parameters 

contained in the ROM video routine. 

Interrupt 1 EH - Diskette Parameters 

This vector points to a data region containing the parameters 

required for the diskette drive. The power on routines initialize 

the vector to point to the parameters contained in the ROM 

diskette routine. These default parameters represent the 

specified values for any IBM drives attached to the machine. 

Changing this parameter block to reflect the specifications of 

the other drives attached may be necessary. 

3-5

Interrupt 1 FH - Graphics Character Extensions 

When operating in the graphics modes ofthe Color/Graphics Monitor 

Adapter (320 x 200 or 640 x 200), the read/write character interface 

will form the character from the ASCII code point, using a set of dot 

patterns. The dot patterns for the first 128 code points are 

contained in ROM. To access the other 128 code points, this ~ 

vector must be established to point at a table of up to I K bytes, 

where each code point is represented by 8 bytes of graphic 

information. At power on this vector is initialized to 0:0, and it is 

the responsibility of the user to change this vector if the 

additional code points are required. 

Other Read/Write Memory Usage 

The IBM ROM BIOS routines use 256 bytes of memory starting 

at absolute 400 to 4FF. Locations 400-407 contain the base 

addresses of any RS232 cards attached to the system, O's ifnone 

attached. These locations, in order, represent the 0 to 3 values used as 

the parameter to the RS232 BIOS routine. Locations 

408-40F provide the same function, but for the PRINTER. 

Memory locations 300-3FF are used as a stack area during the 

power on initialization, and the bootstrap, when control passed 

to it from power on. If the user desires the stack in a different area, ~ 

it must be set by the application. 

Note: Use the Interrupt Vector Listing as an aid to locate these topics 

in the ROM BIOS listing, Appendix "A". 

BIOS Programming Tip 

When programming with BIOS you should keep in mind that if an error 

is reported by the diskette code, to reset the diskette adapter and retry 

the operation. A specified number of retrys should be required on reads 

to ensure the problem is not due to motor start-up. 

3-6

BIOS Memory Map 

STARTING ADDRESS HEX 

00000 

00080 

BIOS 

INTERRUPT 

VECTORS 

AVAILABLE 

INTERRUPT 

VECTORS 

00400 

BIOS 

DATA 

AREA 

00500 

USER 

READ/ 

WRITE 

MEMORY 

,. L". 

.... L". 

,.~ 

,..~ 

F4000 

F6000 

USER 

READ ONLY 

MEMORY 

CASSETTE 

BASIC 

INTERPRETER 

FEOOO 

BIOS 

PROGRAM 

AREA 

Figure 24. BIOS MEMORY MAP 

3-7

BIOS Cassette Logic 

Software Algorithms 

Interrupt 15 

The cassette routine will be called with the request type in AH and ~ 

the address of the bytes to be read or written will be specified by 

(ES):(BX) and the number of bytes to read/write will be specified by 

(CX). The actual number of bytes read will be returned in (DX). 

Read block and write block will automatically tum the motor on at the 

start and off at the end. The requests are as follows: 

(AH) = 0 Tum the cassette motor on. 

(AH) = 1 

(AH) = 2 

(AH) = 3 

STATUS: 

AH=OO 

AH=Ol 

AH=02 

AH=04 

AH=80 

Note: 

Cassette Write 

Tum the cassette motor off. 

(Read Block ) Read (CX) bytes into 

memory beginning at address (ES):(BX) 

and return actual number of bytes read in 

(DX). Return the cassette status in (AH). 

(Write Block) Write (CX) bytes onto the 

cassette beginning at address (DS):(BX). 

Return the cassette status in (AH). 

No errors 

CRC-Error (Read Block) 

No data transitions 

No leader 

Invalid command 

The carry flag will be set on any error. 

The WRITE BLOCK routine writes a tape block on the cassette. The 

tape block is described in Data Record Architecture page (3-10). 

The WRITE BLOCK routine turns on the cassette motor and a syn 

chronization bit (0) and then writes 256 bytes of all ones, the leader, 

to the tape. Next, one or more data blocks are written (depends on 

number in CX). After each data block of 256 bytes, a two byte 

CRC is written. The data bytes are taken from the memory location 

pointed at by ES. 

The WRITE BYTE routine disassembles the byte and writes it a 

bit at a time to the cassette. The method used is to set TIMER 2 to 

the period of the desired data bit. The timer is set to a period of 

1.0 millisecond for a one bit and 0.5 millisecond for a zero bit. 

3-8

The timer is set mode 3 which means it will output a square wave 

with period given by its count register. The timer's period is changed on 

the fly for each data bit to be written to the cassette. Ifthe number of 

data bytes to be written is not an integral multiple off 25 6, then after the 

last desired data byte from memory has been written, the data block will 

~ be extended to 256 bytes by writing multiples ofthe last data byte. The 

last block will be closed with two CRC bytes as usual. After the last 

data block, a trailer consisting of four bytes of all one bits will be 

written. Finally, the motor will be turned off. There are no errors 

reported by this routine. 

\.-- 250 USEC ----.j 

I 

r 

500 USEe 

·1 

ZERO BIT 

lONE BIT 

~ 

1000 USEC 

I~ 

·1 

Cassette Read 

The READ BLOCK routine turns on the cassette motor and then 

delays for approximately 0.5 secs for it to come up to speed. 

The READ BLOCK routine then searches for leader and must 

detect all one bits for approximately 1/4 ofleader length before it 

can look for the sync byte. If a correct sync byte (X '16') is not 

found, the routine goes back and searches for leader again. 

The data is read a bit a a time and assembled into bytes. After 

each byte is assembled it is written into memory at location 

ES:BX and then BX is incremented by one. 

After each multiple of 256 data bytes are read, the CRe is read 

and compared to the eRe generated. If a eRe error is detected, 

the routine will exit with the carry flag set to indicate an error 

and status (AH) - 01 for eRe error. DX will contain the number 

of bytes written into memory. 

Note: The Time of Day Interrupt (IRQO) is disabled during the 

cassette read operation. 

3-9

Data Record Architecture 

MOTOR 

ON 

MOTOR 

OFF 

1. Leader 256 bytes (of ones) 

2. Sync byte ASCII Sync Char (X'16') 

3. Sync byte (X '16') 

4. Data Blocks 256 bytes 

5. CRC -- 2 bytes - for each data block 

Error Recovery 

Error recovery is handled by software. A cyclic redundancy 

check (CRC) is used to detect errors. The polynomial used is: 

G(X) - X16 «X12 « X5 X 1 

Which is the polynomial used by the SDLC interface. Essentially, 

as bits are written/read from tape, they are passed through 

the CRC-register in software. After a block of data is written, the 

complemented value of the calculated CRC-register is written on 

tape. On reading the cassette data, the CRC bytes are read and 

compared to the generated CRC value. If the read CRC does not 

equal the generated one, the processor's carry flag is set and 

status (AH) is set to X'Ol' to indicate a CRC error has occurred. 

Also, the routine is exited on CRC error. 

3-10

Keyboard Encoding and Usage 

Encoding 

The keyboard routine provided by IBM in ROM BIOS is 

responsible for converting the keyboard scan codes into what 

~ill be termed "Extended ASCII". 

Extended ASCII encompasses one byte character codes with 

possible values of 0-255, an extended code for certain extended 

keyboard functions and functions that are handled within the 

keyboard routine or through interrupts. 

Character Codes 

The following character codes are passed through the BIOS 

keyboard routine to the system or application program. A 

"-1" means the combination is suppressed in the keyboard 

routine. The codes are returned in AL. See Appendix C for exact 

codes. Use keyboard Scan Code diagram for reference page 2-17. 

Table 25. Character Codes 

KEY# BASE CASE UPPER CASE CTRL ALT 

1 ESC ESC ESC -1 

2 1 Y2 -1 Note 1 

3 2 @ NU L (000) Note 1 Note 1 

4 3 # -1 Note 1 

5 4 $ -1 Note 1 

6 5 % -1 Note 1 

7 6 1\ RS (030) Note 1 

8 7 & -1 Note 1 

9 8 * -1 Note 1 

10 9 ( -1 Note 1 

11 0 ) -1 Note 1 

12 - - 

US (031) Note 1 

13 = + -1 Note 1 

14 Backspace (008) Backspace (OOS) DEL(127) -1 

15 ---+t (009) I+- (Note 1) -1 -1 

16 q 0 DCl (017) Note 1 

17 w W ETB (023) Note 1 

18 a E ENQ (005) Note 1 

19 r R DC2 (018) Note 1 

20 t T DC4 (020) Note 1 

21 Y 

Y EM (025) Note 1 

22 u U NAK (O21) Note 1 

23 i I HT (O09) Nota 1 

24 0 0 SI (O15) Note 1 

25 p P OLE (O16) Note 1 

26 [ ! ESC (O27) -1 

27 ] I GS (029) -1 

3-11

Table 25. Character Codes (cont.) 

KEY # BASE CASE UPPER CASE 

CTRL 

ALT 

28 CR CR 

29CTRL -1 -1 

30 a A 

31 s S 

32 d D 

33 f F 

34 g G 

35 h H 

36 j J 

37 k K 

38 I L 

39 : 

, 

40 " 

\ 

~ 

41 

42SHIFT -1 -1 

43 

I 

\ I 

44 z Z 

45 x X 

46 c C 

47 v V 

48 b B 

49 n N 

50 m M 

51 < 

, 

52 > 

53 / ? 

54SHIFT -1 -1 

55 * (Note 2) 

56ALT -1 -1 

57 SP SP 

58 CAPS -1 -1 

LOCK 

59 NUL (Note 1) NUL (Note 11 

60 NUL (Note 1) NUL(Notel) 

61 NUL (Note 1) NU L (Note 1) 

62 NUL(Notel) NUL (Note 1) 

63 NUL (Note 1) NUL (Note 1) 






69NUM -1 -1 

LOCK 

70SCROLL -1 -1 

LOCK 

LF (010) -1 

-1 -1 

SOH (001) Note 1 

DC3 (019) Note 1 

EOT (004) Note 1 

ACK (006) Note 1 

BEL (007) Note 1 

BS (008) Note 1 

LF (010) Note 1 

VT(Ol1) Note 1 

FF(012) Note 1 

-1 -1 

-1 -1 

-1 -1 

-1 -1 

FS (028) -1 

SUB (026) Note 1 

CAN (024) Note 1 

ETX (003) Note 1 

SYN (022) Note 1 

STX (002) Note 1 

SO (014) Note 1 

CR (013) Note 1 

-1 -1 

-1 -1 

-1 -1 

-1 -1 

(Note 1) -1 

-1 -1 

SP 

SP 

-1 -1 

NUL (Note 1) NUL (Note 1) 


NUL (Note 1) NU L (Note 1) 






NU L (Note 1) NUL (Note 1) 


Pause -1 

(Note 2) 

Break -1 

(Note 2) 

Note 1: Refer to Extended Codes Page (3-13). 

Note 2: Refer to Special Handling Page (3-15). 

3-12

Keys 71-83 have meaning only in base case, in NUMLOCK (or 

shifted) states, or in CTRL state. It should be noted that the shift 

key temporarily reverses the current NUMLOCK state. 

KEY # NUM LOCK BASE CASE ALl ClRL 

71 7 Home (Note 1) Note 1 Clear Screen 

72 8 of' (Note 1) Note 1 -1 

73 9 PageUp (Note 1) Note 1 Top of Text & Home 

74 - - -1 -1 

75 4 ~ (Note 1) Note 1 Reverse Word 

(Note 1) 

76 5 -1 Note 1 -1 

77 6 ~ (Note 1) Note 1 Adv Word 

(Note 1) 

78 + + -1 -1 

79 1 End (Note 1) Note 1 Erase to EO L 

(Note 1) 

80 

81 

2 

3 

..v 

(Note 1) 

PageDown (Note 1) 

Note 1 

Note 1 

-1 

Erase to EOS 

(Note 1) 

82 0 INS Note 1 -1 

83 DEL (Notes 1,2) Note 2 Note 2 

Note 1: Refer to Extended Codes Page (3-13). 

Note 2: Refer to Special Handling Page (3-15). 

Extended Codes 

A. Extended Functions 

For certain functions that can not be represented in the 

standard ASCII code, an extended code is used. A character 

code of 000 (NUL) is returned in AL. This indicates that the 

system or application program should examine a second 

code that will indicate the actual function. Usually, but not 

always, this second code is the scan code of the primary key 

that was pressed. This code is returned in AH. 

3-13

Table 26. Keyboard Extended Functions 

SECOND CODE 

FUNCTION 

3 NUL Character 

15 

16-25 ALTn, W, E, R, T, Y, U, I, 0, P 

30-38 ALT A, S, 0, F, G, H, J, K, L 

44-50 ALT Z, X, C, V, B, N, M 

59-68 Fl-Fl0 Function Keys Base Case 

71 Home 

72 t 

73 Page Up & Home Cursor 

75

ALT - Temporarily shifts keys 2-13, 16-25, 30-38,44-50, and 

59-68 to ALT state. Used with CTRL and DEL to cause 

system reset function described in Section 1.3. 

ALT has a special use to allow the user to enter any character 

code (0-255) into the system from the keyboard. The user 

holds down the ALT key and types the decimal value of 

characters using the numeric keyboard (keys 71-73, 75-77, 

79-82). The ALT key is then released. If more than three 

digits are typed, a modulo 256 result is created. These three 

keys are interpreted as a character code (000-255) and are 

transmitted through the keyboard routine to the system or 

application program. ALT is handled internal to keyboard 

routine. 

CAPS LOCK - Shifts keys 16-25, 30-38, 44-50 to upper case 

A second depression of CAPS LOCK reverses the action. 

Handled internal to keyboard routine. 

NUM LOCK - Shifts keys 71-73, 75-77, 79-83 to numeric 

state. A second depression of NUM LOCK reverses the 

action. Handled internal to keyboard routine. 

SCROLL LOCK - Interpreted by appropriate application 

programs as indicating that the use of the cursor control 

keys should cause windowing over the text rather than 

cursor movement. A second depression of SCROLL LOCK 

reverses the action. The keyboard routine simply records 

the current shift state of SCROLL LOCK. It is up to the 

system or application program to perform the function. 

C. Shift Key Priorities and Combinations 

If combinations of ALT, CTRL and SHIFT are pressed and 

only one is valid, the precedence is as follows: Highest is 

ALT, then CTRL, then SHIFT. The only valid combination 

is ALT CTRL, which is used in system reset. 

Special Handling 

A. System Reset 

The combination of ALT CTRL DEL (Key 83) will result in 

the keyboard routine initiating the equivalent of a system 

reset/reboot. Handled internal to keyboard routine. 

3-15

B. Break 

The combination CTRL BREAK will result in the keyboard 

routine signaling interrupt -lAo Also, the extended characters 

(AL =DOH, AH = DOH) will be returned. 

Power up initialization, this interrupt is set up to cause the 

break sequence to be ignored. It is up to the system or 

application initialization code to change the interrupt 

vector in order to support an actual "break" function. 

C. Pause 

The combination CTRL NUM-LOCK will cause the keyboard 

interrupt routine to loop, waiting for any key except 

NUM-LOCK to be pressed. This provides a system/ 

application transparent method of suspending list/print/ 

etc. temporarily, and then resuming. The "Unpause" key 

is thrown away. Handled internal to keyboard routine. 

D. The following keys will have their typematic action 

suppressed by the keyboard routine: CTRL, SHIFT, ALT, 

NUM-LOCK, SCROLL-LOCK, CAPS LOCK, INS. 

E. Print Screen 

The combination SHIFT-PRINT SCREEN (Key 55) will 

result in an interrupt invoking the print screen routine. 

This routine works in alpha/graphics mode, with unrecognizable 

characters printing as blanks. 

The keyboard routine does its own buffering. The buffer is big 

enough to support a fast typist. If a key is entered when the 

buffer is full, the key will be ignored and the "bell" will 

be sounded. 

r'" 

3-16

Keyboard Usage 

This section is intended to outline a set ofguidelines for key usage when 

performing commonly used functions. 

~ Table 27. Keyboard - Commonly Used Functions 

FUNCTION 

Home Cursor 

Return to outermost menu 

Move cursor up 

Page up, scroll backwards 

25 lines & home 

Move cursor left 

Move cursor right 

Scroll to end of text 

Place cursor at end of line 

Move cursor down 

Page down, scroll forwards 

25 lines & home 

Start/Stop insert text at 

cursor, shift text right 

in buffer 

Delete character at cursor 

Destructive bac kspace 

Tab forward 

Tab reverse 

Clear screen and home 

Scroll up 

Scroll down 

Scroll left 

Scroll right 

Delete from cursor to 

EOL 

Exit/Escape 

Start/Stop Echo screen 

to printer 

Delete from cursor to 

EOS 

KEY(S) 

HOME 

HOME 

i 

PG UP 

...- Key 75 

~ 

END 

! 

PGON 

INS 

DEL 

...- Key 14 

--./ 

I+ 

CTRL HOME 

i 

! 

... 

~ 

CTRLEND 

ESC 

PRTSC 

CTRL K55 

GTRL PG 

ON 

COMMENT 

Editors; word processors 

Menu driven applications 

Full screen editor, word 

processor 


Text, command entry 



Full screen editor, word 

processor 





Text entry 

Text entry 

Command entry 

In scroll lock mode 





Editor, 1 level of menu, etc 

Any time 


3-17

Table 27. Keyboard - Commonly Used Functions (cont.) 

FUNCTION 

Advance word 

Reverse word 

Window Right 

Window Left 

Enter insert mode 

Exit insert mode 

Cancel current line 

Suspend system (pause) 

Break interrupt 

System reset 

Top of document and 

home cursor 

Standard Function Keys 

Secondary function keys 

Extra function keys 

Extra function keys 

KEY(S) 

CTRL -+ 

CTRL ~ 

CTRL -+ 

CTRL ~ 

INS 

INS 

ESC 

CTRL 

NUMLOCK 

CTRL 

BREAK 

ALTCTRL 

DEL 

CTRL PG UP 

F1-F10 

SHIFT F1-F10 

CTRL F1-F10 

ALTF1-F10 

ALT Keys 

2-13 

(1-9,0,-,=) 

ALT A-Z 

COMMENT 

Text entry 

Text entry 

When text is too wide to fit 

screen 

When text is too wide to fit 

screen 

Line editor 

Line editor 

Command entry, text entry 

Stop list, stop program, etc. 

Resumes on any key 

Interrupt current process 

Reboot 

Editors, word processors 

Primary function keys 

Extra function keys if 10 

are not sufficient 

Used when stickers are 

put along top of keyboard 

Used when function starts 

with same letter as one of 

the alpha keys 

3-18

Table 28. BASIC Screen Editor Special Functions 

FUNCTION 

Carriage return 

Line feed 

Bell 

Home 

Cursor up 

Cursor down 

Cursor left 

Cu rsor right 

Advance one word 

Reverse one word 

Insert 

Delete 

Clear screen 

Freeze output 

Tab advance 

Stop execution (break) 

Delete current line 

Delete to end of line 

Position cursor to end of line 

KEY 

~ 

CTRl -.J 

CTRl G 

HOME 

\ 

+ 

--+- 

CTRl--+- 

CTRl + 

INS 

DEl 

CTRl HOME 

CTRl NUMlOCK 

--., 

CTRl BREAK 

ESC 

CTRl END 

END 

".-..." Table 29. DOS Special Functions 

FUNCTION 

Suspend 

Echo to printer 

Stop echo to printer 

Exit cllrrent function 

(break) 

Backspace 

Line feed 

Cancel line 

Copy character 

Copy till match 

Copy remaining 

Skip character 

Skip until match 

Enter insert mode 

Exit insert mode 

Make new line the template 

String separator in REPLACE 

End of file in keyboard input 

KEY 

CTRl NUMlOCK 

CTRL-PRTSC 

(Key 55 any case) 

CTRl·PRTSe 

(Key 5!J any case) 

CTRL 

BREAK 

+- Key 14 

CTRl -.J 

ESC 

Flor --+ 

F2 

F3 

DEl 

F4 

INS 

INS 

F5 

F6 

F6 

3-19

3-20 

NOTES

Low Memory Maps (O-'0600'x) 

Table 30. Interrupt Vectors (O-7F) 

ADDRESS INTERRUPT 

HEX HEX FUNCTION 

0-3 0 Divide by Zero 

4-7 1 Single step 

8-B 2 Non-Maskable Interrupt (NMI) 

C-F 3 Break Point Instruction ('CC'x) 

10-13 4 Overflow 

14-17 5 Print Screen 

18-1 F 6,7 Reserved 

20-23 8 Timer (18.2 per second) 

24-27 9 Keyboard Interrupt 

28-37 A,B,C,D Reserved 

38-3B E Diskette Interrupt 

3C-3F F Reserved 

40-43 10 Video I/O Call 

44-47 11 Equipment Check Call 

48-4B 12 Memory Check Call 

4C-4F 13 Diskette I/O Call 

50-53 14 RS232 I/O Call 

54-57 15 Cassette I/O Call 

58-5B 16 Keyboard I/O Call 

5C-5F 17 Printer I/O Call 

60-63 18 ROM Basic Entry Code 

64-67 19 Boot Strap Loader 

68-6B 1A Time of Day Call 

6C-6F 1B Get Control on Keyboard Break: Note 1 

70-73 1C Get Control on timer interrupt: Note 1 

74-77 10 Pointer to video initialization table: Note 2 

78-7B 1E Pointer to diskette parameter table: Note 2 

7C-7F 1F Pointer to table (1 KB) for graphics character 

Generator for ASCII 128-255. Defaults to 0:0 

Notes: 

(1 ) Initialized at power up to point to an IRET Instruction. 

(2) Initialized at power up to point to tables in ROM. 

3-21

Table 31. BASIC and DOS Reserved Interrupts 

(80-3FF) 

ADDRESS 

HEX 

INTERRUPT 

HEX 

80-83 20 

84-87 21 

88-8B 22 

8C-SF 23 

90-93 24 

94-97 25 

98-9B 26 

9C-9F 27 

AO-FF 28-3F 

100-1 FF 40-7F 

200-217 80-85 

218-3C3 86-FO 

3C4-3FF F1-FF 

FUNCTION 

DOS Program Terminate 

ODS Function Call 

ODS Terminate Address 

ODS CTRL-BRK Exit Address 

ODS Fatal Error Vector 

DOS Absolute Disk read 

ODS Absolute Disk write 

ODS Terminate, Fix in Storage 

Reserved for 0 OS 

Not Used 

Reserved By BASIC 

Used by BASIC Interpreter while BASIC is Running. 

Not Used 

Table 32. Reserved Memory Locations (400-SFF) 

ADDRESS 

HEX 

MODE 

400-48F ROM BIOS 

490-4CF ODS 

400-4EF 

4FO-4FF 

500-5FF 

500 ODS 

504 ODS 

510-511 BASIC 

512-515 BASIC 

516-519 BASIC 

51A-51O BASIC 

FUNCTION 

See BIOS Listing 

Used by ODS Mode Command 

Reserved 

Reserved as Intra·Application Communication 

area for any application. 

Reserved for ODS and BASIC 

Print Screen status flag store. 

O-Print screen not active or successful print 

screen operation. 

1-Print screen in progress. 

255-Error encountered during print screen 

operation. 

Single drive mode status byte. 

BASIC's segment address store. 

Clock interrupt vector segment: offset store. 

Break key interrupt vector segment: 'offset store. 

Disk error interrupt vector segment: ·offset store. 

3-22

BASIC Workspace Variables 

If you do DEF SEG (Default workspace segment) 

OFFSET 

LENGTH 

Line number of current line being executed X '2E' 2 

Line number of last error X '347' 2 

Offset into segment of start of program text X '30' 2 

Offset into of start of variables X '358' 2 

(end of program text 1-1) 

Keyboard buffer contents X'SA' 1 

if O-no characters in buffer 

if l-characters in buffer 

if you POKE & H6A, 0 you 

flush any characters in buffer 

Example: 

100 Print PEEK (&H2E) + 256*PEEK (&H2F) 

) L H 

100 

I 

X'S4' 

I 

X '00' 

I 

3-23

3-24 

NOTES

APPENDICES 

Contents: 

Appendix A: ROM BIOS Listing ............................ . 

Appendix B: Assembly Instruction Set Reference .............. . 

Appendix C: OfCharacters, Keystrokes and Color .............. . 

Appendix D: Logic Diagrams ................................ . 

Appendix E: Unit Specifications ............................. . 

A-O

APPENDIX A 

~ ROM BIOS LISTINGS 

CONTENTS 

ITEM 

Equates and Data Areas 

Power-on Self-test 

Boot Strap Loader 

r""\ I/O Support 

Asynchronous 

Communications 

(RS 232) I/O 

Keyboard I/O 

Diskette I/O 

Printer I/O 

Display (VIDEO) I/O 

Cassette I/O 

System Configuration Analysis 

Memory-Size- 

Determination 

Equipment- 

Determination 

(Options) 

~ 

Graphics-Character Generator 

Time-of-day 

Print Screen 

Notes for the BIOS Listing 

LINE 

NUMBER 

1 

198 

1355 

1410 

1640 

2255 

3007 

3119 

4977 

4903 

4933 

5503 

5642 

5817 

ADDRESS PAGE 

A-2 

E016 A-4 

E6F2 A-20 

E729 A-20 

E82E A-23 

EC59 A-32 

EFD2 A-42 

F045 A-43 

F859 A-68 

F841 A-67 

F84D A-67 

FA6E A-75 

FE6E A-77 

FF53 A-79 

. A-81 

A-I

lOC OBJ LINE SOURCE 

STITlE( ROM BIOS FOR IBM PERSONAL COMPUTER) 

; ----------------------- 

; EQUATES 

; ------------------------ 

0060 PORT_A EQU 60H i 8255 PORT A ADDR 

0061 PORT_B EQU 61H j 8255 PORT B ADDR 

0062 PORT.C EQU 62H ;8255 PORT C ADDR 

0063 CMO]ORT EQU 63H 

0020 9 INTAOO EQU 20H ;8259 PORT 

0021 10 INTAOl EQU 21H ;8259 PORT 

0020 11 EOI EQU 20H 

0040 12 TIMER EQU 'OK 

0043 13 TIM.tTl EQU '3H ;8253 TINER CONTROL PORT ADDR 

0040 14 TINERO EQU 'OH ;8253 TIMER/CNTER a PORT ADDR 

0001 15 THIHT EQU 01 ITIHER a INTR RECVD MASK 

0008 16 OMAoa EQU 06 ;oNA STATUS REG PORT ADDR 

0000 17 DHA EQU 00 JDMA CHANNEL a ADDRESS REG PORT ADoR 

0540 18 MAX.PERIOD EQU 540H 

0410 I. MIN.PERIOD EQU 410H 

0060 20 KBD.IN EQU 60H IKEYBDARD DATA IN AOOR PORT 

0002 21 KBDINT EQU 02 ;KEYBOARD INTR I1A.SK 

0060 22 KB.DATA EQU 60H ; KEYBOARD SCAN CODE PORT 

0061 23 

24 

KB.CTL EQU 61H ; CONTROL BITS FOR KEYBOARD SENSE DATA 

1------------------------------------------- 

25 j 8088 INTERRUPT LOCATIONS 

26 ;----------------------------------------- 

0000 27 ABSO SEGMENT AT 0 

0000 2. LABEL BYTE 

0008 2. ORG 2*' 

0008 30 LABEL WORD 

0014 31 ORG 5*' 

0014 

LABEL 

0020 

0020 

33 

3. 

O.G 

.*. 

LABEL 

WORD 

WORD 

0020 35 LABEl DWORD 

0040 36 O.G 10H*4 

0040 37 LABEl WORD 

0074 38 ORG IDH*4 

0074 39 LABEL DWORD I POINTER TO VIDEO PARHS 

0078 .0 ORG 01EH*4 I INTERRUPT IEH 

0078 .1 OISK]OINTER LABEl DWORD 

D07C .2 DRG 01 FH*4 ; LOCATION OF POINTER 

DO?C 43 EXT_PTR LABEL DWORD I POINTER TO EXTENSION 

7COO 

•• 

ORG 7COOH 

7COO .s BOOT_LOCN LABEl FAR 

46 ABSO ENDS 

47 

48 j-------------------- 

49 ; STACK - USED DURING INITIALIZATION ONLY 

50 ;--------------------- 

51 STACK SEGHEUT AT 30H 

0000 (128 ???? I 52 DW 128 DUPf?) 

0100 53 TOS LABEl WORD 

54 STACK ENOS 

55 

56 ;------------------------------------------ 

57 ; RON BIOS DATA AREAS 

58 j --------------------------------------- 

0040 59 DATA SEGHENT AT 40H 

0000 (4 ????) 60 RS232_BASE OW 4 DUPf?) ; ADDRESSES OF RS232 ADAPTERS 

0008 (4 !???) 61 PRWTER_BASE DW 4 DUP(? I ; ADDRESSES OF PRINTERS 

0010 ???? 62 EQUIPJLAG DW ; nlSTALLED HARDWARE 

0012 ?? 63 MFG_TST DB ; INITIALIZATION FLAG 

0013 ???? 64 MEMeRY.SIZE DW ; MEMORY SIZE IN K BYTES 

0015 ???? 65 IO.RAM_SIZE DW ; MEMORY IN I/O CHANNEL 

0017 ?? 69 KBJLAG DB 

66 ; - ---------------------------------------- 

67 ; KEYBOARD DATA AREAS 

68 ; ---------- - -.---------------------------- 

70 

71 ;-----. SHIFT flAG EQUATES WITHIN KB_FlAG 

72 

0080 73 INS_STATE EQU 80K ; INSERT STATE IS ACTIVE 

0040 7. CAPS_STATE EQU 40H j CAPS LOCK STATE HAS BEEN TOGGLED 

0020 75 HUJ'CSTATE EQU 20K j HUM LOCK STATE HAS BEEN TOGGLED 

0010 76 SCROLL_STATE EQU 10H ; SCROll LOCK STATE HAS BEEN TOGGLED 

0008 77 All_SHIFT EQU 08H i ALTERNATE SHIfT KEY DEPRESSED 

A-2

LaC OBJ LINE SOURCE 

0004 

0002: 

0001 

0018 11 

0080 

0040 

OOZO 

0010 

0008 

0019 ?? 

OOlA ???? 

ODIC ???? 

ODIE (16 ???'?) 

003E 

0045 

0046 

0038 

0010 

003A 

002A 

0036 

0052 

0053 

003E ?? 

0080 

003f ?? 

0040 ?? 

0025 

0041 ?? 

0080 

0040 

0020 

0010 

0009 

0008 

0004 

0003 

0002 

0001 

0042 (7 ?? J 

78 eTL_SHIFT EOU 04H ; CONTROL SHIFT KEY DEPRESSED 

79 lEfT_SHIFT EOU 02H ; lEFT SHIFT KEY DEPRESSED 

80 RIGHT_SHIFT EOU O1H ; RIGHT SHIFT KEY DEPRESSED 

81 

82 DB ; SECOND BYTE OF KEYBOARD STATUS 

83 

INS_SHIFT 84 EOU 80H ; INSERT KEY IS DEPRESSED 

85 CAPS_SHIFT EOU 40H ; CAPS LOCK KEY IS DEPRESSED 

8. HUH_SHIFT EOU 20H ; NUN LOCK KEY IS DEPRESSED 

87 SCROLL_SHIFT EOU IOH SCROLL LOCK KEY IS DEPRESSEO 

88 HOLD_STATE EOU 08H SUSPEND KEY HAS BEEN TOGGLED 

89 

90 ALT_INPUT DB STORAGE fOR ALTERNATE KEYPAD ENTRY 

91 BUFFER_HEAD OW POINTER TO HEAD Of KEYBOARD BUFFER 

.2 BUFFER_TAIL OW POINTER TO TAIL OF KEYBOARD BUFFER 

93 KB_BUFFER OW 16 Dupe? I j ROOM FOR 15 ENTRIES 

94 KB_BUFFER_EHO LABEL WORD 

.5 

96 j------ HEAD = TAIL INDICATES THAT THE BUFFER IS EMPTY 

.7 

•• 

•• 

98 NUMJEY EOU SCAN CODE FOR NUMBER LOCK 

SCROLL_KEY EOU 70 SCROLL LOCK KEY 

100 ALTJEY EOU 5. ALTERNATE SHIFT KEY SCAN COOE 

101 CTL_KEY EOU 2. SCAN CODE FOR CONTROL KEY 

102 CAPS_KEY EOU 58 SCAN CODE FOR SHIFT LOCK 

103 LEFT_KEY EOU 42 SCAN CODE FOR LEFT SHIFT 

104 RIGHTJEY EOU 54 SCAN COOE FOR RIGHT SHIFT 

105 INS_KEY EOU 82 SCAN CODE FOR UlSERT KEY 

10. DEL_KEY EOU 83 SCAN CODE FOR DELETE KEY 

107 

108 j ------------------------------------------- 

109 j DISKETTE DATA AREAS 

110 j ------------------------------------------- 

111 DB ; DRIVE RECALIBRATION STATUS 

112 BIT 3-0 = DRIVE 3-0 NEEDS RECAL BEFORE 

113 NEXT SEEK IF BIT IS = 0 

114 INTJLAG EOU oaOH ; INTERRUPT OCCURRt:NCE FLAG 

115 MOTOR_STATUS DB ; MOTOR STATUS 

11. BIT 3-0 = DRIVE 3-0 IS CURRENTLY R\..INI'IIHG 

117 I BIT 7 = CURRENT OPERATION IS A WRITE. REQUIRES DEU.Y 

118 ttOTOR_COUNT DB ; TIME OUT COUNTER fOR DRIVE TURN OFF 

MOTOR_WAIT EQU 37 ; TWO SECONDS OF COUNTS FOR I1OTOR TURN OFF 

"' 120 

121 

122 DISKETTE_STATUS DB j SINGLE BYTE OF RETURN CooE INFO FOR STATUS 

123 TIME_OUT EQU 80H ; ATTACHMENl rAILED TO RESPOND 

124 BAD_SEEK EQU 40H ; SEEK OPERATION FAILED 

125 BAD_NEC EQU 20H ; NEe CONTROLLER HAS FAILED 

12' BAD_CRC EQU IOH j BAD CRC ON DISKETTE READ 

127 DMA_BOUNDARY EqU 09H ; ATTEMPT TO DMA ACROSS 64K BOUNDARY 

128 BAD_DMA EQU 08H ; DMA OVERRUN ON OPERATION 

12' RECORD_NOTJND EQU 04H I REQUESTED SECTOR NOT FOUND 

130 WRITE_PROTECT EQU OJH I WRITE ATTEMPTED ON WRITE PROT DISK 

131 BAO ADDR_HARK EQU 02H ADDRESS MARK HOT FOUND 

132 BAD_CHO EQU O1H BAD COMNAND PASSED TO DISKETTE I/O 

133 

134 DB 7 DUP(?) ; STATUS BYTES FROM NEC 

135 

0049 ?? 

004A ???? 

004C ???? 

004E ???? 

~ 0050 (8 ????I 

0060 ???? 

0062 ?? 

0063 ?1?1 

0065 ?? 

0066 ?? 

0067 '???? 

0069 ???? 

136 j ------------------------------------------- 

137 ; VIDEO DISPLAY DATA AREA 

138 ; ------------------------------------------- 

139 CRT_MODE DB ; CURRENT CRT HOOE 

140 CRT_COLS OW ; HUMBER OF COLUMNS ON SCREEN 

141 CRT_LEN ow j LENGTH OF REGEN IN BYTES 

142 CRT_START OW STARTING ADDRESS IN REGEN BUFFER 

143 CURSOR_POSN ow 8 DUP{?) ; CURSOR FOR EACH OF UP TO a PAGES 

144 CURSOR MODE OW CURRENT CURSOR MODE SETTING 

145 ACTIVE_PAGE DB CURRENT PAGE BEING DISPLAYED 

14. ADDR_684S OW BASE ADDRESS FOR ACTIVE DISPLAY CARD 

147 CRT_MODE SET DB CURRENT SETTING Of 1liE 3X8 REGISTER 

14B CRT_PALLETTE DB ; CURRENT PALLETTE SETTING COLOR CARD 

14, 

150 ; ------------------------------------------- 

151 ; CASSETTE DATA AREA 

152 j------------------------------------------- 

153 OW ;TIME COUNT AT DATA EDGE 

154 ow JCRC REGISTER 

A-3

LOC OBJ LINE SOURCE 

0068 ?! 155 De ;LAST INPUT VALUE 

156 

157 1----------------------------________________ 

158 ; TIMER DATA AR€A 

159 -----------------___________________________ 

Ot6C ?1!'! 160 TlI1ER_LOW 

0" j lOW WORD OF TIMER COUHT 

006£ ???? 161 TIMER_HIGH ow ; HIGH WORD OF TIMER COUNT 

0070 ?! 162 TINER_OFL De ; TIMER HAS ROllED OVER SINCE LAST READ 

163 ;COUNTS.SEC lOU 18 

16' ,COUNTS.NIH EQU 1092: 

165 iCOUtlTS_HOUR lOU 65543 

166 ; COUNTS_DA.Y EOU 1513040 = 1800BOH 

167 

168 i -------------------------________________• __ 

169 ; SYSTEM DATA AREA 

170 ; ---- - ----------_____________________________ 

0071 ?? 171 BIOS_BREAK DB ; BIT 7 = 1 IF BREAK HY HAS BEEN DEPRESSED 

0072 ???? 172 RESET_FLAG OW ; WORD = 1234H IF KEYBOARD RESET UNDERWAY 

173 OATA WOS 

174 

175 ; -----~-':' _:.•.---._____________________________ 

176 J EXTRA DATA AREA 

177 1------------------------------------------- 

'0050 178 XXDATA SEGMENT AT 50H 

O~OO 11 179 STATUS_BYTE DB 

18. XXOATA ENDS 

181 

18Z ; ------------------------------------------- 

183 J VIDEO DISPUY BUFFER 

184 ; ----------- --- - - - - - - - ---------------------- 

8800 18S VIDEO_RAM SEGMENT AT OBaOOH 

'0000 186 REGEN LABEL BYTt 

0000 187 REGENW LABEL WORD 

(1000 (16}84 ??) 188 DB 1638't DUPl?) 

189 ENIlS 

190 i ----------------------------------------- 

191 ; ROM RESIDENT CODE 

19' ; ---------------------- ------------------- - 

fOOD 193 CODE SEGMENT AT OFOOOH 

0000 (51344 111 19. DB 57344 DUP(?) j FI LL LOWEST 56K 

, 195 

:EOOO 35373030303531 196 08 '5700051 CDPR. IBM 1981' I COPYRIGHT NOTICE 

20434F50522E20 

49424020313938 

31 

197 

198 ; ------------------------------------------- 

199 j INITIAL RELIA8ILITY TESTS -- PHASE 1 

200 ; --- - - - - - - --- - ------- -- - - - -- - --------------- 

201 ASSUME CS:COOE,SS:COOE,ES:ABSO,OS:DATA 

202 ; ------------------------------------------- 

203 DATA DEfINITIONS 

2.04 J - - ------------------ -------- ------------- -- 

E016 D8EO 205 Cl 0" Cll • RETURN ADDRESS 

E016 EDEI '06 C' 0" C" 

i PETlmtl ADDRESS FOR DUMMY STACK 

207 ; ----------------------- ---------------- - --- 

lOS 

209 OF STORGAGE. 

THIS SUBROUTINE PERFORMS A READ/WRITE STOOAGE TEST ON A 16K 8LOCK 

210 ;ENTRY REQUIREMEtHS: 

211 ES = ADDPESS OF STORAGE SEGt!EHT eEING TESTED 

21Z 

Z13 

OS = ADDRESS OF STORAGE SEGMENT BEING TESTED 

\oIHEH EHlERltIG AT STGTST_CHT. CX MUST BE LOADED WITH THE BYTE COUNT. 

Z14 .EXIT PARAtlETERS: 

ZIS ZERO HAG =


E02.4. 

"9 

C3: i STG01 

E02;,4, 4F 23. DEC 01 I POnH TO LAST BYTE JUST WR ITTEN 

E026 FO 231 STO ;SET OIR fLAG TO GO- tACKl~flROS 

EOZC BBF7 23' C4: MOV SI,OI 

E02E 88tB 233 MOV CX,BX ; SETUP BYTE CHT 

,,, 

f030 At 23. C5: LODSB ;READ CHAR FROH STORAGE 

E031 32C4 XO. Al,AH JDATA READ As ExPECTED? 

E033 75Z5 23. JNE C7 ; NO - GO TO ERROR ROUTINE 

E035 £462 237 IN AL,PORT_C JDIO A. PARITY ERROR OCCUR? 

E037 24CO 

AL,OCOH 

E039 BODO "9 

MOV AL,O jAL=O DHA COMPARE OK 

e038 751D 24. JNZ C7 

f03D 80FCOO '41 eMP AH,O iREADING ZERO PATTERN? 

"B .., 

,4' 

C' 

E040 7403 JE iCONTINUE READING TILL END 

E042 BACZ '43 MOV Al,Dl ,GET NEXT DATA PATTERN TO WRITE 

E044 AA 244 STOSB iWRITE IN BYTE LOC WE JUST READ 

£045 24S C6: j WRITE_HO_MORE 

'4' 

£047 80FCOO '47 CMP AH.O ,ZERO PATTERN WRITTEN TO ~T6 

[045 £2£9 LOOP C5 ,CONTINUE TILL 16K/4K BLOCK TESTED 

£04,4, 740£ 248 JE C7 ;. YES - RETURN TO CALLER 

E04t: BAED 24, MaY AH.AL ;SETUP TO NEW YALUE TO COMPARE 

E04E 86FZ 25. XCIiG OH.OL .HOYE ZERO DATA PATIERN TO OL 

E050 Fe 251 CLO ; SET OIR FLAG TO GO FORWARD 

E051 47 252 WC 01 ; SET POINTER TO BEG LOCAnON 

E052. 7408 253 JZ C4 jREAD/URITE FORWARD IN STG 

E054 4F 2S4 OEC 01 

E055 8AOI00 255 MOV DX,l ;SETUP 01 AND ao PATIERNS 

E058 EBDO 25' JMP SIiORT C3 ;READ/WRITE BACKWARD IN STG 

E05A 257 C7: 

E05.4. C3 258 RET 

259 STGTST ENDP 

260 ;----------------- -------------------------- 

261 ,TEST .01 

262 80B8 PROCESSOR TEST 

263 ,DESCRIPTION 

264 VERIFY 8088 FLAGS, REGISTERS AND CONDITIONAL JUHPS 

265 

E.58 266 RESET LABEL NEAR 

Eosa FA 267 START: CLI ;DISABLE INTERRUPTS 

Eose 84D5 268 HOV AH.OD5H ;.SET SF, CF, IF, AND AF fLAGS ON 

EOSE 9E 269 SAHF 

E05f 734£ 270 JNC ERROl ;GO TO ERR ROUTINE IF CF NOT SET 

f061 754C 271 JI~Z ERROl ;GO TO ERR RourmE IF ZF HOT SET 

f063 784.4. 272 JNP ERROl ; GO TO ERR ROUTH.jE IF PF NOT SET 

f065 7946 273 JNS ERROl ;GO TO ERR ROUTINE IF SF NOT SET 

27' 

f067 9F LAHF ,LOAD F LAG IMAGE TO AH 

f068 8105 275 NOV CL.5 ILOAD CNT REG WITH SHIFT CNT 

f06A DZEC 27. SHR AH,CL ;SHIFT AF INTO CARRY BIT POS 

E06C 7341 277 Jnc ERROl ;GO TO ERR ROUTINE IF AF NOT SET 

f06E B040 27. HOV AL,40H .SET THE Of nAG ON 

f070 ODED 279 SHL AL, I ;SETUP FOR TESTING 

E072 713B 2BO JIIO ERROl ;GO TO ERR ROUTINE IF OF NOT SET 

£074 32£4 2Bl XOR AH.AH ,SET AH :: 0 

f076 9E 282 SAHF JCLEAR SF. CF, ZF, AND PF 

E077 7236 2.3 JC ERPOI .GO TO ERR ROUTINE IF CF ON 

E079 7434 2B4 JZ ERIlO 1 lGO TO ERR ROUTINE IF ZF ON 

EOlB 7832 285 JS ERROl ;GO TO ERR ROUTINE IF SF ON 

E070 7A30 2•• JP ERROl ;.60 TO ERR ROUTINE IF PF ON 

Ea7F 9F 287 LAHF ,LOAD FLAG IHAGE TO /lH 

E080 BIOS 288 HOV CL.S ; LOAD CNT REG WITH SHIFT CNT 

e082 02EC 289 SHR AH.CL ; SHIFT t.F' INTO CARRY BIT POS 

£064 7229 290 JC ERRO 1 ; GO TO ERR ROUTINE IF ON 

£086 00£4 291 SHL AH,! ;CHECK THAT OF' IS CLEAR 

E066 7025 292 JO ERROl ;GO TO ERR ROUTINE IF ON 

293 

294 READ/WRITE THE 8088 GENERAL AND SEGMENTATION REGISTERS 

29S 

". 

W.ITH AlL ONE'S AND ZEROES'S. 

EDBA B8FFFF 297 HOY AX.OFFFFH ;SETUP ONE'S PATTERN IN AX 

E080 f9 298 STC 

E08E 8E08 29. CB: HOY OS,AX ;WRITE PATTERN TO ALL REGS 

3., 

£090 8C08 30. NOV BX,DS 

Eon 8EC3 HOY ES.BX 

E094 6CCl 3.2 MOV CX,ES 

E096 8EOl 303 MOV SS,CX 

E098 6C02 304 MOY OX.SS 

£09,4, BSE2 3.5 NOV SP,DX 

E09C 86Et 3•• MOV BP,SP 

A-5

LOC OBJ 

LINE 

SOURCE 

E09E BBf5 

EOAO BBFE 

EOA2 7307 

EOM 33C7 

[DAb 7507 

EOA8 Fa 

EOA9 730 

EDAB 

EDAB DBC7 

EOAD 740 I 

EOAF F4 

EOBO 

ECBD BODO 

EOB2 E6AO 

EOB4 E683 

EDBb 6099 

E068 E663 

EOBA BOFe 

ECSt E661 

EDbE 2ACO 

EoeD BA0803 

Eon EE 

EOC4 FEeD 

EOC6 5/..6803 

Eoe9 EE 

EOCA BBOOFD 

EOCD 6EOO 

EOCF 8600EO 

ED02 8C16EO 

EODS E93301 

E008 7505 

EOoA 8004 

EOoC E608 

EODE 6054 

fOEO E643 

EOE2 2BC9 

EOE4 SAD9 

EOE6 8ACl 

EOE8 E641 

EDEA 

EOEA 8040 

EOEC E643 

EOEE 

E441 

EOFO OAD8 

EOF2 60fBFF 

EDFS 7404 

EOF7 ElF1 

EOF9 EBB4 

EOFB 

EoFB BAC3 

EOFO 28e9 

EOFF E641 

EI01 

E101 8040 

EI03 E643 

nos E441 

EI07 2208 

EI09 7404 

EIOB E2F4 

A-6 

"7 

"8 

30. 

310 

311 

3" 

313 

3" (9: 

315 

316 

317 ERROl: 

318 ; - - - - - - ------------------------------------- 

319 ;TEST.02 

HOY 

MOV 

JNC 

XQR 

JNZ 

eLe 

J~~C 

OR 

JZ 

HLT 

SI,BP 

OI.SI 

C9 

AX ,01 

EPROI 

C8 

AX.DI 

CI0 

320 ROS CHECKSUM TEST I 

3~1 jOESCRIPTIOtl 

-------------------------------- 

I TSTIA 

;PATTER~~ 

MAKE IT THRU ALL REGS 

;NO - GO TO ERR ROUTINE 

; TSTlA 

;ZERO PATTERN MAKE IT THRU? 

;YES - GO TO tlEXT TEST 

;HALT SYSTEM 

322 A CHECKSUM IS OCNE FOR THE 8K ROS NODULE CQlHAI!HNG POD AND BIOS. 

323 ; ----------- 

324 CIO: 

325 HOV 

326 OUT 

327 OUT 

"8 

". 

HOV 

OUT 

3" tlOV 

331 OUT 

332 SUB 

333 HOV 

334 OUT 

335 mc 

336 f18V 

337 CUT 

338 flOV 

33. MOV 

340 MOV 

341 MOV 

342 JI1P 

343 Cll; JI ~ E 

Al,O 

OAOII,AL 

83H.Al 

Al.99H 

CND_PORT ,AL 

Al,orCH 

popr_B.AL 

AL,AL 

DX,3DeH 

OX,AL 

" ox, '368" 

OX,Al 

AX,COOE 

55,AX 

ElX,OEOOOH 

SP,OFFSET Cl 

ROS_CHECKSUM 

ERROL 

34"+ • - - - ----- - - --------------------------------- 

3(6 iTESr.03 

346 8237 ONA INITIALIZATION CHM1NEL R[GISTE.R TEST 

347 iDESCRIPTIOH 

lDISABlE HMI INTERRUPTS 

; INITIALZE DMA PAGE REG 

iSET 8255 A,C-INPUT,B-OUTPUT 

;WRITE 8255 CMD/MOOE PEG 

iOISABlE PARITY CI-IECKEPS ANO 

; GATE S!


E100 EBAO 38. JNP SHORT ERROl 

386 

387 INITIALIZE TINER 1 TO REFRESH MEMORY 

388 

EIOF 38. C15: ; WRAP_OMA_REG 

flOF 8054 3.0 MOV Al.54H ;SEl TIM I. LSB. MODE 2 

Ell1 E643 391 OUT TIMER+3.AL ;WRITE TIMER MODE REG 

E113 B012 392 MOV AL.IS ;SETUP DIVISOR FOR REFRESH 

EllS E641 393 OUT TIMER+l.Al iL-:RITE TIMER 1 CNT REG 

E1l7 E600 394 OUT OMA+ODH,Al iSH/O MASTER CLEAR TO DMA 

395 

396 WRAP oMA CHANNELS ADDRESS AND COUNT REGISTERS 

397 

E119 BOFF 3.8 MOV AL,OFFH ;WRITE PATTERN FFH TO ALL REGS 

EllB 8A08 39. C16: MOV BL,AL ;SAVE PATTERN FOR COMPARE 

EllD 8AF8 400 MOV BH,AL 

EllF 890800 401 MOV CX,B ;SETUP LOOP CNT 

E122 BAOOOO 402 MOV OX,DMA ; SETUP I/O PORT AD DR OF REG 

E125 EE 403 t17: O'JT DX,Al IWRITE PATTERN TO REG, LSB 

E126 EE 404 OUT OX,AL ;t1SB OF 16 BIT REG 

E127 B80101 405 110V AX,OIOIH ;AX TO ANOTHER PAT BEFORE RO 

E12A EC 406 

'" 

AL,oX 

;READ 16-BIT DMA eH REG, LSB 

E128 8AEO 407 tIDY AH,AL ;SAYE lSB OF 16~BIT REG 

E120 EC 408 IN AL,oX ;READ MSB OF DMA CH REG 

f12E 3808 40. CtlP 8X,AX ;PATTERN READ AS WRITTEN? 

EnD 7403 410 J' C18 ; YES - CHECK NEXT REG 

E 132 E97AFF 411 JMP ERROl ;NO - HALT THE SYSTEM 

E135 41. C18: I NXT_DI1A_CH 

E135 42 413 INC OX ;SET I/O PORT TO NEXT CH REG 

E136 ElED 414 LOOP CI7 iWRITE PATTERN TO NEXT REG 

E136 F6DO 41. NOT AL iSET PATTERN TO ZERO 

E13A 74DF 416 JZ C16 ;WRITE TO CHANNEL REGS 

417 

418 INITIALIZE AND START DMA FOR MEMORY REFRESH. 

419 

EBe BOFF 420 MOV At,OFFH ; SET CNT OF 64K FOR RAM REFRESH 

E13E E601 421 OUT DMA+l,Al 

E140 E601 422 OUT QMA+l,Al 

El42 B058 423 tlOV Al,058H ,SET OMA MODE.CH O,READ,AUOTIHT 

E144 E608 424 OUT DHA+OBH,AL ,WRITE oMA MODE REG 

E146 8000 425 MOV Al,O ; ENABLE OMA CONTROLLER 

E148 E606 426 OUT OMA+8,Al ; SETUP OMA COMMAND REG 

E14A E60A 427 OUT DMA+I0 ,At ;ENABLE CHANNEL 0 FOR REFRESH 

E14C B041 42. MOV AL,41H ,SET MODE FOR CHANNEL 1 

E14E E608 4•• OUT OMA+OBH,AL 

E150 8042 43D MOV AL,42H ;SET MODE FOR CHANNEL 2 

E152 E608 431 OUT DMA+OBH,AL 

E154 8043 432 MOV AL,43H ;SET MODE FOR CHANNEl 3 

E156 E608 433 OUT OMA+OBH .AL 

434 ;------------------------------------------- 

435 ;TESr.04 

436 BASE 16K REAO/WRITE STORAGE TEST 

437 

438 ;DESCRIPTION 

439 WRITE/REAOIVERIFY DATA PATTERNS FF,55.AA.Ol, ANO 00 TO 1ST 16K OF 

440 STORAGE. VERIFY STORAGE AOORESSABIllTY. 

441 INITIALIZE THE 8259 INTERRUPT CONTROllER CHIP FOR CHECKING 

442 MANUFACTURING TEST 2 MODE. 

443 ; ---------------------------------- ---- 

444 DETERMINE MENORY SIZE AND FILL MEMORY Wlrn DATA 

445 

E158 884000 446 MOV AX,OATA jPOINT OS TO DATA SEG 

E158 8E08 447 MOV OS,AX I 

EISC 681E7200 448 HOV BX,RESETJLAG ;SAVE RESET_FLAG' IN ax 

E161 28CO 449 SUB AX,AX ;SET ES MID OS TO 0 

E163 8EtO 450 NOV ES,AX ; SETUP ES SEGMENT REG 

f165 6E08 451 MOV oS,AX 

El67 2BFF 452 SUB 01,01 

E169 E460 453 IN Al.PORT_A IDETERMINE BASE RAM SIZE 

E168 240C 454 AHO AL,OCH jISQlATE RAM SIZE SWS 

E160 0404 455 ADO AL, 4 I CALCULATE MEMORY SIZE 

E16F BlOC 456 MOV CL, 12 

E171 03EO 457 SHL AX, CL 

EI73 88C8 458 MOV CX, AX 

E175 8AEO 45. MOV AH. AL 

fI77 Fe 460 CLD ISET DIR FLAG TO INCR 

E178 AA 461 C19: STOSB ;FIlL BASE RAM WITH DATA 

A-7


£179 E2FD 462 LOOP C19 ; LOOP TIL All ZERO 

463 

464 DETERMINE 10 CHANNEl RAM SIZE 

465 

fI78 £462 466 IN Al,PORT_C 

E170 240F '67 AND Al,orH 

E17F 7418 'b. JZ CZl 

f161 BA0010 4., MOV DX.loaOH SEGMENT FOR 110 RAM 

£184 8AEO 47. MOV AH,Al 

El86 BODO .71 MOV AL.O 

ElB8 '7> C20: FIll_IO: 

ElM 8etZ 473 HOY ES.DX 

EISA 890080 .7• ttov CX.800OH ; FIll 3ZK BYTES 

El80 2:BFF • 75 SUB 01.01 

£18F f3 47b REP SIOSB 

£190 AA 

fl'9l 81C20008 477 ADD DX,800H i NEXT SEGMENT VALUE 

El'95 FEee '7. DEC AH 

£197 75EF .79 JtlZ C2 • ; FIll_IO 

••• 

; ------------------------------------------- 

INITIALIZE THE 8259 INTERRUPT CONTROLLER CHIP 

'8' 

.82 ; ------------------------------------------- 

El'99 483 C21: 

El'99 8013 .8. MOV Al.13H iICWl - EDGE, SHGL. ICW4 

El'9B £62:0 485 OUT INTAOD ,Al 

El'90 B008 48b MOV AL.8 iSETUP lewz - INT TYPE 8 IS-F J 

El9F £621 .87 OUT INTAOl,A1. 

ELl! 8009 MOV AL.'9 .SETUP ICW4 - 8UFFRO,8086 l100E 

..," 

ElA3 E621 .8. OUT HITAOI,AL 

EIA5 2BeO '.0 SUB AX,AX ,POINT OS AND ES TO BEGIN 

ElA7 8ECO 49. MOV ES,AX ; OF R/w STORAGE 

ElA9 BE4000 .92 HOV SI,DATA ;PQIHT as TO DATA SEG 

ElAc SEDE '93 MOV DS,SI 

EIAE 891E7,ZOO 

.,. 

HDV RESET_FLAG,BX ,RESTORE RESETJUG 

E182 813E72003412 '.5 CMP RESET_FUG,l234H .RESETJLAG SET? 

El88 7438 JE C25 ins - SKIP STG TEST 

••• 

ElBA 8E08 497 MOV OS,AX i FOltIT as TO 1ST 16K OF STG 

..8 i------------------------------------------- 

4" 

CHECK FOR MAHUFACTUIUNG TEST 2 TO LOAD TEST PROGRAMS FROM KEYBOARD. 

soo ;------------------------------------------- 

EISC BCF03F 501 MOV SP, lFFOH , ESTABLISH TEMPORARY STACK 

EI8F 8EDO 502 MOV S5, AX 

EICI 8BFe 50' NOV 01, AX 

EIC3 882400 5•• MOV 6X, 24H 

EIC6 C707B6E2 5.5 MOV WORD PTR tBX),OFFSET 011 ISET UP KB INTERRUPT 

EICA 43 50b INC BX 

ElCB 43 S07 INC BX 

Elce 8COF SOS MOV (BXJ,CS 

ElCE E88704 50. CAU KBD_RESET ; READ IN KB RESET CODE TO Bt 

EIDI 80FB65 ..0 CftP Bl,065H ; IS THIS MANUFACTURING TEST 2? 

EI04 750E 511 JNZ C23 ; JUMP IF NOT MAN. TEST 

EI06 B2FF ..2 MOV Dl,255 ; READ IN TEST PROGRAM 

Et06 E86A04 513 e22 : CAll SP _TEST 

EIOB 8AC3 514 MOV At.BL 

ElDD AA 515 STose 

ElOE FECA 51b DEC OL 

ElEO 75F6 5.7 JNZ C22 i JUMP IF NOT DONE YET 

EIE2 CD3E 5." ItIT 3EH ;SET INTERUPT TYPE 62 ADDRESS F8H 

EIE4 5.' e23: jCONTItlUE IN NORMAL t100E 

EIE4 DE 520 PUSH CS ; PUT SS B'.CK 

ElE5 17 521 POP 55 

ElE6 FA 

5" 

CLI 

E1E7 BC18EO 523 ~10V SP,OFFSET C2 ;SETUP REltrRN ADDRESS 

ElEA EnDFE JHP STGTST IGO TO RDIWRT STG SUBROUTINE 

EIED 7403 '" 525 C24: JE C25 .GO TO NEXT TEST IF OK 

EIEF E9BDFE 52' 

527 

JMP ERROl 

5Z8 

SHUP STACK SEt AtID S1' 

52~ 

EIF2 530 C25: 

E1F2 B83000 531 MOV AX.STA.CK ; GET STACK VALUE 

E1F5 8EDO 532 MOV SS,AX ; SET THE STACk UP 

EIF7 BCOOOI 533 ttoV SP ,OFFSET TOS ; STACK IS READY TO GO 

534 

535 SETUP THE HHI INTERRUPT VECTOR POINTER 

53. 

A-8


~ 

EIFA 26C7060800C3EZ R 537 MOV ES:NMI_PTR,OFFSET NI1I_INT 

E201 ZilC706QAQOOOfO A 538 MOV ES:Ht1I_PTRtZ .COOE 

E208 E920400 539 JMP T5T6 1GO TO NEXT TEST 

54. 

f208 S41 ROS_CHECKSUM PROC HEAR J NEXT_ROS_MODULE 

f2:0B 8900:1:0 542 tl0Y CX.8192 ;NUtI8ER- Of BYTES TO ADD 

f20E 32C;0 5" XCR Al,Al 

E210 544 C26: 

1;210 2E0207 545 ADO Al,cs:IBXl 

un 43 546 INC. BX ; POINT TO NEXT BYTE 

1:214 ElF. 547 lOOP C26 IADO ALL BYTES IN ROS t10DULE 

E216 OACO 548 OR AL,AL 150M = 07 

£2.18 C3 549 RET 

55. ROS_CHECKSUM E~mp 

551 ; --------.--.------------------------- 

552 I INITIAL RELIABILITY TEST -- PHASE 2 

553 1--------------------------------------- 

554 ASSUME CS:COOE,ES:ABSO 

555 

E219 504152,4954$920 556 01 OB 'PARITY CHECK 2' 

43484543482032 

OOOE 55.7 OIL EQU $-01 

E227 50415249545920 55. D2 08 'PARITY CHECK l' 

43484S43482031,/ 

DaDE 55. on 'QU $-02 

£235 568 T5T6: 

StoO ;------------------------------------------- 

561 ; TEST. 06 

562 8259 INTERRUPT CONTROLLER TEST 

563 IDESCRIPTION 

564 • READl'WRITE THE INTERRUPT MASK REGISTER (UIU WITH ALL ONES AHO ZEROES. 

565 ENABLE SYSTEM INTERRUPTS. MASt< DEVICE INTER.RUPTS OFF. CHECK FOR 

566 HOT INTERRUPTS (UNEXPECTED). 

567 ; - -----____________________________----.---- 

E235 Z8tO 569 SUB AX,AX ; SET UP ES REG 

E237 BEtD 57' MOV E5,AX 

571 

572 i--~--- SET UP THE INTERRUPT 5 POINTER TO A OUNNY 

573 

E239 26C706140054FF R 574 MOV ES-:INT5_PTR,OFFSET PRINT_SCREEN ;PRINT SCREEN 

E240 26C70"6160000FO R 575 MOV ES: It'fT5_PTR+2,CODE 

576 

577 TEST THE IMR REGISTER 

578 

E247 fA 579 eLI IOIABLE INTERRUPTS 

5., 

E248 BODO 58. MOV AL,O ; SET II1R TO ZERO 

E24A E62.l OUT INTA01.AL 

E24C E421 582 IN AL,IUTAOI IREAO IMR 

E24E OACO 5.3 OR Al.AL ;INR :::: 07 

E250 7528 5.' JIll 06 ;GO TO ERR ROUTINE IF HOT 0 

E252 BOFF 585 MOV AL,OFFH iDISABLE DEVICE INTERRUPTS 

E254 E621 ..6 OUT INTA01,AL iWRITE TO IMR: 

E256 £421 5.7 HI Al,INTAOl IREAD IMR 

E258 0401 5•• AOO AL,! IAlL 1t1R BIT OM? 

... 

E25A 7521 JHZ 06 iND· - GO TO 'ERR ROUTINE 

5'. 

591 CHECK FOR HOT INTERRUPTS 

592 

E'25C Fe 593 ClO ISET DIR flAG TO GO FORWARD 

E250 890800. 594 MOV CX.8 ; SETUP TEMP INT RTNE IN PRT TBL 

E260 8F2000 595 MOV DI,OFfSET INT_PTR ;GET ADDRESS OF INT PROC TABLE 

E263 596 03; ; VECTBLO: 

E261 8886£2: 597 NOV AX,OFFSET 011 ; HOVE ADDR Of INTR PROC TO TSl 

... 

£266 AS STOSW 

E267 8800"0 59. MOV AX,CODE IGET ADDR OF INTR PROC SEG 

ElU AB 6'0 STOSW 

H6B 83C]04 6.1 AOO BX.4 ;SET BX TO POINT TO NEXT VAL 

r"'\ f26E E2J1'3 6.. lOOP 03 ; VECTBLO 

603 

6.. INTERRUPTS ARe: MASKED OfF. CHECK THAT NO INTERRUPTS OCCUR. 

60S 

E270 32E4 6.6 XOR AH,AH ICLUR AH REG. 

E272 Fe 6.7 srr ; ENABL'E EXTERNAL INTERRUPTS 

E273 28C9 608 SUB eX,ex INAlT 1 SEC FOR ANY INTRS THAT 

E275 HFE 6.' 0'" LOOP 04 iHIGHl OCCUR 

£277 E2fE 61. DS: LOOP 05 

E279 04E4 611 OR AK.AH IDID ANY' IlfTERRUPTS OCCUR? 

A-9


E278 7408 612 JZ 07 i NO ~ GO TO NEXT TEST 

E270 BACIOl '13 06: tlDV OX,lOIH ;BEEP SPEAKER IF ERROR 

E280 £6ADO] 

61' CALL ERR_BEEP .GO TO BEEP SUBROUTINE 

£283 FA 615 eLI 

E284 F4 .16 HLT ;HALT THE SYSTEM 

617 ; ------------------------------------------- 

618 ; TEST • 7 

61' 8253 TIMER CHECKOUT 

62. .DESCRIPTION 

621 VERIFY THAT THE SYSTEM TIMER (0 J DOESN'T CDum TOO FAST NOR TOO 

6Z2 

SLOW • 

." ,------------------------------------------- 

E285 6•• 07: 

E285 8400 625 MOV AH.O ;RESET TIMER I»TR RECYO FLAG 

£287 32EO 6.. XDR CH,CH ,CLEAR THE CH REG 

£289 BOFE 627 MOV AL,OFEH lttASK ALL INTAS EXCEPT lVl 0 

E28B E6Z 1 628 OUT INTAOt.AL jlolRITE THE 6259 IMR 

£2:80 BOlO 

02' MOV Al,aODiacoae iSH TIM O. LSB, MODE O. BINARY 

E28F E643 63. OUT TIM.CTL,Al j~RITE TIMER CONTROL HODE REG 

E291 BU6 631 IfOV Cl.l6H j SET PGM LOOP tNT 

E293 8ACI 632 MOV AL.CL jSET TIMER 0 CNT REG 

E295 E640 633 OUT TIMERO.AL ;1o.'RITE TINER 0 CNT REG 

E297 F6C4FF 63. 08: TEST AH.OFFH ;010 TIMER 0 INTERRUPT OCCUR? 

E29A 7504 635 Jill O' ; YES - CHECK TIMER OP FOR SLOW TIME 

E29C E2F9 "6 LOOP 08 IWAIT FOR INTR FOR SPECIFIED TIME 

£29E EBOD 637 JMP 06 j TINER 0 INTR DION T OCCUR - ERR 

E2AO 6112 "8 09: HOV CL.18 ISET PGM LOOP CNT 

HA2 BOFF 63' MOV AL,OFFH jWRITE TIMER 0 CNT REG 

E2A4 E640 6•• OUT TIMEPO.AL 

E2A6 B400 641 MOV AH.O JRESET mTR RECEIVED FLAG 

E2A8 BOFE 64. HOV AL.OfEH jREENABLE TIMER 0 INTERRUTS 

E2AA E621 643 OUT IN7A01.AL 

E2AC F6C4FF 6•• 010: TEST AH.OfFH JDID TIMER 0 INTERRUPT OCCUR? 

E2AF 75CC "5 JllZ D. ;YES - TIMER CNTING TOO FAST. ERR 

E2Bl E2F9 646 LOOP 01. .WAIT FOP. INTR FOR SPECIFIED TIME 

£2B3 £93600 647 JMP TST6 ;GO TO NEXT TES r ROUTIU£ 

6.8 ;------------------------------------------- 

64. TEMPORARY INTERRUPT SERVICE ROurItfE 

65. J------------------------------------------- 

••66 651 011 PROC NEAR 

E286 8401 .5' H.V "',1 

E288 50 653 PUSH AX ;SAVE REG AX CONTENTS 

E289 eOFF 654 MOV AL.OFFH jHASK ALL INTERRUPTS OFF 

E2BD £621 655 OUT INTA01,AL 

f2BD 8020 6.. MOV AL,EOI 

E2BF £62:0 657 OUT INTAOQ,Al 

E2:Cl 56 658 POP AX ;RESTORE REG AX CONTENTS 

£2C2 CF 65. lRET 

... 011 ENDP 

661 

E2C] 662 NMI_INT PROC NEAR 

E2C3 50 ..3 PUSH AX ;SAVE DRIS CONTENTS Of AX 

Eleft Elt62: 66' IN AL.PORT_C 

E2C6 A640 665 TEST AL.40H ; 10 CH PARITY CHECK? 

E2C8 7408 66. Jl 01. I YES - FLAG IS SET TO 0 

E2CA BEI9E2: ..7 flOV SI,OFfSET 01 ; ADoR OF ERROR MSG 

E2Co B90EOO ..8 HOV CX.olL IMSG LENGTH 

E2:00 EBOA 66. JMP SHORT 013 jOISPLAY ERROR "SG 

E2:02 67. 012: 

E202 A880 671 TEST AL,80H jPLANAR RAM P-CHECK? 

EZ04 7410 672 JZ 01' INa - AUX INT 

£206 BE27E2 '73 HOV S1.OFFSET 02 ;ADOR OF ERROR MSG 

E209 B90EOO '7' 

MQV CX.02L iMSG LENGTH 

E20C 675 013: 

E2DC asoooo 676 MOV AX.O ; INIT Atm SET 110DE FOR VIDEO 

E20F COlO 677 INT 10H JCALL VIDEO_IO PROCEDURE 

E2El E8E603 678 CALL P_MSG ;PRINT ERROR I1SG 

E2E4 FA 6i9 eLI 

E2ES F4 6B. HLT ;HALT SYSTEM 

E2E6 'SI 014: 

E2E6 56 'S2 POP AX i RESlORE ORIG CONTENTS OF AX 

E2E7 CF 'S3 IRET 

6•• HMI_INT ENDP 

A-tO


685 ; -------------------------------- 

686 ; nUTIAL RELIABILITY TEST - PHASE 3 

687 ; - ------------------------------- 

688 ASSUHE CS:COOE,DS:DATA 

66. 

flE8 20323031 6.0 El DB 201 ' 

0004 691 ElL EQU $-El 

692 

693 ESTABLISH BIOS SUBROUTINE CALL INTERRUPT VECTORS 

694 

f2Ee 695 TST8: 

E2Ee Fe 696 eLO jSET OIR FLAG TO CO FORWARD 

EZEO BF4000 697 NOV DI,OFFSET VIDEO_INT ; SETUP ADDR TO INTR AREA 

EZFO DE 693 PUSH CS 

E2Fl IF 699 POP os jS[TUP AD DR OF VECTOR TABLE 

ElF2 BE13FF 700 r-:OV SI,OFF13H ; OFFSET YECTOR_TABLE+3Z 

E2:F5 892000 701 MOV CX,ZOH 

EZF8 F3 702 REP NOVSU iMOYE VECTOR TABLE TO RAM 

E2F9 AS 

703 

704 SETUP TINER 0 TO NODE 3 

705 

EZFA BOFF 706 MOV AL,OFFH ;DISABLE ALL DEVICE INTERRUPTS 

E2Fe E621 707 OUT INTAOt ,AL 

E2FE B036 708 MOV AL.36H ;SEl TIM O.LSB,MSB,MODE 3 

f300 E643 70. OUT TINER+3,AL ;WRITE TIMER MODE REG 

n02 BODO 710 MOV AL,O 

E304 E640 711 OUT TINER,AL ;WRITE LSB TO TIMER 0 REG 

f306 E640 71. OllT TINER.AL IWRITE MSB TO TIMER 0 REG 

713 

714 SETUP TItIER 0 TO BLINK LEO IF MANUFACTlJRING TEST MODE 

71S 

716 ASSUME OS:OATA 

f308 884000 717 MOV AX,DATA i POINT OS TO DATA SEG 

f30B BED8 716 MOV OS,AX 

E30D E87803 719 CALL KBD_RESET iSEND SOFTWARE RESET TO KEYBRO 

E3l0 60FBAA 720 eMP BL.OAAH iSCAN CODE AA' RETURNED? 

Ell3 7426 721 JE E3 ; YES - CONTINUE {UON MFG MODE I 

E3lS BOle 722 MOV AL.3CH ; EN KBO. SET KBD CLK. LINE LOW 

E317 E661 723 OUT PORT_B.AL jWRITE 8255 PORT B 

E319 90 724 NOP 

ellA 90 725 NOP 

ElIB E460 726 IN AL,PORT_A iWAS A BIT CLOCKED IN? 

ElID 24Ff 727 ANO AL,OFFH 

nIt 7516 726 JNZ E. iYES - CONTINUE {HON MFG MODE I 

ElZi FE061200 729 INC NFG_ TST i ELSE SET SW FOR MFG TEST MODE 

El2S 26C706200082E6 R 730 MOV ES: INT_AODR .OFFSET BLINK_INT ,SETUP TIMER INTR TO BLINK LEO 

ElZC 26C7062Z0000FO R 731 MOV ES: INT_AODR+2.. CODE 

El33 BOFE 73. MOV AL.OFEH ; ENABLE TINER INTERRUPT 

E33S E621 733 OUT INTAOl.AL 

E337 73. E2: ; JUMPER_NOT_IN: 

E337 Boce 735 MOV AL,OCCH ;RESET THE KEYBOARD 

039 E66l 736 OUT PORT_B,AL 

737 ; --------------- - - - ---------------.------ 

738 ; TEST. OS 

739 ROS CHECKSUM II 

740 .DESCRIPTION 

741 

A CHECKSUM IS DONE FOR THE 4 ROS NODULES CONTAINING BASIC CODE 

742. 

j -----_____________________________________ _ 

El3B 743 E3: 

El3S 82.04 744 MOV OL.4 iNO. OF ROS NODULES TO CHECK 

E330 B80060 745 MOV BX.6000H j5ETUP STARTWG POS ADDR 

E340 746 E4: ; CHECK_ROS: 

E340 747 EBC8fE CALL ROS.CHECKSUM 

E343 7507 748 JNE E5 jBEEP SPEAKER IF ERROR 

E345 FECA 749 DEC OL ,ANY MORE TO DO? 

!~ E3477SF7 730 JNZ E4 ; YES - cmnINUE 

El49 E80790 7>1 Jt1P E6 ;NO - GO TO NEXT TEST 

E34C 752 E5: j ROS_ERROR; 

E34C BAOIOl 753 MOV OX.lOIH 

E34F f80E02 754 CALL ERR.BEEP ;BEfP SPEAKER 

A-ll


755 ; ---------------- ----------.---------------- 

750 ;TEST .08 

757 INITlALIZE AH1) START CRT COUTROLLER (6845) 

758 TEST VID EO READ/WRITE STtmAGE. 

759 ;OESCIHPTIOU 

760 R£SET THE VID.fO EtlABlE SIGNAl~ 

7., SELECT ALPHANUMERIC troDt. 40 * 2:5. B & W. 

7.' READ/URITE DATA PATT~::flS TO 51G. CHECK SIG -ADDRESSABIlITY. 

763 ; ---------------------------------------.--- 

E352 764 E6: 

E352 f46D 765 AL.PORT_A ;RUO SENSE SWITCHES 

El54 8400 '" AH,C 

766 HOY 

E3S6 A31000 767 HOY EQUIPJUG,AX ;STORE SENSE SW INFO 

£359 2430 76a .NO Al.'30H ; ISOLATE VIDEO SWS 

Elsa 7503 7•• JHZ E7 I VIDEO SWS SET TO 01 

E3S0 £99800 77. JMP fl' 

;SKIP VIDEO TESTS FOR BURN-IN 

E36D 771 £7: ; TEST.VIDEO: 

£360 86£0 772 XCHG AIi.AL 

E362 Bort3o 773 C"" Alt,3DH ;B/W CARD ATTACHED'! 

£365 7409 774 JE Ea ,YES - SET MODE fOR 8/W CARD 

E367 FECO 775 rHe Al lS£T COLOR I'100E FOR COLOR CD 

E369 80fC20 77. tHP AH,20H 180X25 MODE SElECTED? 

E36C 7502 777 JNE Ea iNQ - SET MODE fOR 40X25 

£36£ B003 77a HOY AL.3 jSET MODE FOR eOX25 

E370 779 E8: I SET_HODE: 

£370 50 7a. PUSH AX ;SAVE VID'EO "'ODE ON STACK 

E371 2.1.[4 7a. SUB AH,AH lINITlALIZE TO ALPHANUMERIC I1D 

E373 COlO 7a2 IHT '.H ;CALl VIDEO_IO 

E375 S8 783 pop AX JRESTORE VIDEO SENSE SWS IN AH 

£376 SO 7a_ PUSH AX J RESAVE VALUE 

E377 8800BO 7a5 HOV 8X,OSOOOH IBEG VIDEO RAM ADDR BIW CO 

E37A BAB803 786 I10V DX.3B8H IMOOE REG fOR B/W 

El7a 890010 7a7 HOY CX,4096 iRAtI BYTE CNT FOR 8/W CD 

BSO 8001 788 MOV AL,1 ; SET MODE FOR BW CARD 

£382 SOFC30 7a. CHP AH .30H lB.IW VlDEO CARD ATTACHED! 

£3.55 740B 7•• JE EO I YES - GO TEST VIDEO STG 

E3S7 BMOBa 79l HOY BX.OB800H jBEG VIDEO RAM AODR COLOR CD 

ElBA BADS03 792 HOY oX,30aH ;NOOE REG FOR COLOR CD 

E36D 890040 7.3 HOY CX,4000H ;RAM BYTE tNT FOR COLOR CO 

E390 fEce 7•• DEC AL I SET f100E TO 0 FOR COLOR CO 

£392 7'5 £9: ; TEST_VIDEO_STG! 

E392 EE 79. OUT OX ,At. iQISABLE VIDEO FOR COlOR CD 

£393 S£C3 7.7 NOV Es,ax JPOINT ES TO VIDEO RAI'1 STS 

£395 884000 R 7.8 MOY AX ,DATA. IPOINT OS TO DATA SEGM'ENT 

E39S SEDS 799 HOY DS.. AX 

E39A 813E72.oo3412 a •• CHP RESETJLAG,1234H ; POD INITIATED BY KBO RESET! 

BAD 7400 8.1 JE flO I1ES - SKIP VIDEO RAM TEST 

E3A2 8EDB 802 HOY DS.BX ; POINT OS TO VIO'£O RAM STG 

E3A4 Ee76FC a03 CALL STGTST_CN'T ;GO TEST VIDEO R/w STC; 

BA7 7406 a04 JE flO ISTG OK - CONTINUE TESTING 

flA' BA020} 8.5 HOY OX ,l02H ; SHUP I Of BEEPS 

BAC E6810Z 8•• CALL ERR_BEEP ;GO BEEP SPEAKER 

807 ;------------------------------------------- 

80a ;TEST.09 

a •• 

SETUP VIDEO DATA ON SCREEN FOR VIDEO UNE TEST. 

alO 

8ll 

8l' 

;DESCRIPTION 

EtlABLE VIDEO SIGNAL AtID SET MODE. 

DISPLAY A HORIZONTAL f\AR ON SCREEt{. 

al3 i ----------------------------.-------.- - - --- 

E3AF 8l' ElO: 

E3AF 58 815 POP AX jGET VIDEO SENSE SWS (AM) 

nBO 50 al6 PUSH AX JSAVE IT 

UBI 5400 817 HOY AH ,0 ;EIIABLE VIDEO AND SET MODE 

E3Bl COlO ala INT lOH j VIDEO 

E3B5 SS2070 8" 

HOV AX.70Z0H ;W~T BLANKS IN PEVERSE V,IDEO 

E3B8 2BfF 8'. SUB DI,Dt ; SETUP STARTING LOC 

E38A B9'2600 8ll l10V CX,CiO ;NO. Of" BLANKS TO DISPLAY 

E38D Fe 0" 

CLO ;SET OIR flAG TO INCREMENT 

E3BE F3 821 REP 5T05101 iWRITf VIDEO STORAGE 

E3Bf AB 

A-12


~:~~:: 

82.4 ; ------------------------------------------- 

82.5 ;TE5T.10 

826 CRT INTERFACE lINES TEST 


62:8 SENSE ON/OFF TRANSITION OF THE VIDEO ENABLE AtIJ HORIZONTAL 

829 ; SYNC LINES. 

830 1------------------------------------------- 

8" 

pop AX ; GET VIDEO SENSE SW INFO 

8" 

PUSH AX 

i5AVE IT 

E3C2 80FC30 8ll CHP AH.30H iB/w CARD ATTACHED? 

E3C5 BABADl 81. MaV DX.038AH iSETUP AODR OF BW STATUS PORT 

nee 7403 815 JE Ell ;YES - GO TEST LINES 

f3eA BADA03 81. I10V DX,03DAH jCOLOR CARD IS ATTACHED 

1!!3CD 817 Ell: i LIHf_TST: 

nco 8408 818 MOV AH.8 

EXF 8.. EI2.: 

BeF 28C9 8.0 SUB CX,CX 

BOI EC 8.1 E13: IH AL,DX ;READ CRT STATUS PORT 

8., 

£302 22C4 AND AL,AH ;CHECK VIDEO/ttORZ LINE 

8., 

E3D8 [ell 8'5 JMP SHORT 'El7 I GO PRINT ERROR MSG 

nOA 28t9 8" El4: SUB CX,CX 

flOC EC 8.7 ElS: IN AL,DX ;READ CRT STATUS PORT 

ElOO 22:C4 8.8 AND AL,AH ;CHECK VIDEO/HORZ LINE 

8" JZ 

El' 

-£304 7504 8., JNZ EI4 ; ITS ON - CHECK IF IT GOES OfF 

ElOtt E2F9 LOOP EU ; LOOP TILL ON OR TIMEOUT 

nOF 7404- ; ITS ON - CHECK NEXT LINE 

ElEl £2F9 850 LOOP ElS ; LOOP IF OFF TILl: IT GOES ON 

E3E] EBO-S 851 JMP SHORT E17 

E3£5 8S> E16: I NXT_LINE: 

E3ES BI03 851 MOV CL,3 ; GET NEXT BIT TO CHECK 

E3E7 D2EC 85. SHO AH.CL 

ElE9 75£4 855 JHZ ElO ;GO CHECK HORIZONTAL LINE 

ElEB £B06 85. JMP SHORT El8 ;DISPLAY CURSOR ON SCREEN 

ElEO 857 E17: ; CRT_ERR: 

E3ED BADlOI 85. HOV DX.I02H 

£3FO E83D02 85. CALL ERR_BEEP ;GO BEEP SPEAKER 

~:~:~ 58 8.1 POP AX IGET VIOEO SENSE SWS UH) 

ElF4 8400 MOV AH.O iSET HOOE AND DISPLAY CURSOR 

8" 

'E3F6 COlO 8.. mT 10H ;CALL VIDEO liD PROCEDURE 

8'0 E18: ; DISPLAY_CURSOR: 

864 J-------- - ------- ----------- -------- -------- 

865 ;TEST. 11 

866 ADDITIONAL READ/WRITE STORAGE TEST 


868 WRITE/READ DATA PATTERNS TO ANY READ/WRITE STORAGE AFTER ntE BASIC 

869 16K. STORAGE ADDRESSABILITY IS CHECKED. 

870 ; --- ------ - ----------------------------- ---- 

871 ASSUME OS:DATA 

ElF8 870 £19: 

BF8 884000 8n MOV 

E3FB 8E08 87. MOV 

875 

87. DETERMINE RAM SIZE ON PLA~iAR BOARD 

877 

BFD 8A261000 8i8 MOV AH.BYTE PTR EQUIP_FLAG ; GET SENSE SIoIS INFO 

E401 80E40C 87. AND AH.OCH ; ISOLATE RAM SIZE SWS 

£404 8004 8.. MOV AL~4 

£406 F6E4 881 MUL AH 

£408 0410 8S;! ADO AL,I6 ;AOD BASIC 16K 

£40A 8BOO 881 MOV OX.AX ;SAVE PLANAR RAM SIZE IN ox 

E40C 8B08 88' MOV eX.AX ; AND IN ex 

M' 

8•• 

DETERMINE 10 CHAHNEL RAM SIZE 

U7 

E40£ £462 8U IN AL,PCRT_C ;READ 10 CH RAM SIZE SWS 

£410 240F 88. ANO AL.OFH I ISOLATE FROI1 OntER BITS 

~E412 842:0- 8.0 MOV AH,32 

£414 F6£4 891 M\JL AH 

£416 A31500 8., 

MOV IO_RAM_SIZE .AX ;SAVE 10 CHANNEL RAM SIZE 

£419 83F840 8" CMP 8X.40H ; P LAHAR RAM SIZE ::: 64K? 

E41C 7402: 8" JE EaO ;YES - ADD 10 CHN RAM SIZE 

E41E lacO 895 SUB AX,AX ;NO - 000 T ADD ANY 10 RAM 

8" 

£420 E20: ; ADD_IO_SIZE: 

£42:0 OX3 897 ADD Ax.ex ;SUM TOTAL RAM SIZE 

£422 A31300 898 MOV MEtfORY_SIZE,AX ;SETUP MEMORY SIZE PARM 

E425 813E72003412 8'9 CMP RESETJLAG.l2.34N ; POD INITIATED BY KBD RESET? 

A-13

LOC OSJ LINE SOU RCE 

E42B 7440 900 JE "2 iYES - SKIP MEMORY TEST 

901 

902 TEST ANY OTHER REAOIWRITE STORAGE AVAILABLE 

903 

E42D ee0004 90. MOV eX,400H 

E430 B91000 905 MOV CX,16 

E433 906 E21 : 

E433 3801 907 CHP oX,ex ,ANY HORE STG TO BE TESTED? 

E435 7646 908 JBE E23 iNO - GO TO NEXT TEST 

E437 SEDS 909 HOV OS,BX iSETUP STG ADDR IN OS AND ES 

E439 8EC3 910 MOV ES,BX 

E43B 83C110 911 ADO CX,16 ;ItlCREMENT STG BYTE COUNTER 

E43E 81C30004 912 ADD BX, 400H i SET POINTER TO NEXT 16K BLK 

E442 51 913 PUSH CX iSAVE REGS 

E443 53 91. PUSH BX 

E444 52 915 PUSH OX 

E445 E8DlFS 916 CALL STGTST iGO TEST A 16K BLK OF STG 

E448 SA 917 POP OX 

E449 5B 918 POP BX iRESTORE REGS 

E44A 59 919 POP CX 

E44B 74E6 920 JE E21 jCHECK IF MORE STG TO TEST 

921 

922 PRINT FAILING ADDRESS AND XOP'EO PATTERN IF DATA COMPARE EPROP 

923 

E440 eCOA 92. MOV OX.DS jCONVERT FAILING HIGH-ORDER 

E44F SAf8 925 MOV CH.AL iSAVE FAILING BIT PATTERN 

E451 8AC6 926 MOV AL.DH iGET FAILING ADDR (HIGH BYTE) 

E453 BI04 927 MOV CL,4 

E455 02E8 928 SHR AL.CL jRIGHT-JUSTIFY HIGH BYTE 

E4S7 E83EOO 929 CALL XLAT_PPINT_CODE ;CONVERT AND PRINT CODE 

E4SA BAC6 930 MOV AL,OH 

E45C 240F 931 AND AL,OFH 

E4Sf E83700 932 CALL XLAT_PRINT_CODE ; CONVERT AND PRINT CODE 

E461 8ACS 933 HOV AL,CH ;GET FAILING BIT PATTERN 

E463 BI04 93. HOV CL,4 i AND ISOLATE LEFTMOST NIBBLE 

E465 o2E8 935 SHR AL,CL 

E467 E82EOO 936 CALL XLAT_PRINT_CODE iCONVERT AND PRItlT CODE 

E46A 8ACS 937 HOV AL,C!~ ;GET FAILING BIT PATTERn AND 

E46e 2.40F 93. AND AL,OFH ; ISOLATE RIGHTMOST tHBBLE 

E46E f82700 939 CALL XLAT_PRWT_COOE ICONVERT AND PRINT CODE 

E471 BEESE! 940 HOV SI.OfFSET EI ;SETUP ADDRESS OF ERROR MSG 

E474 B90400 9'1 tlOV CX.EIL I GET MSG BYTE coum 

E477 E85002 9'2 CALL P_MSG ; FRINT ERROR MSG 

E47A 943 E22: ; GO_TST12! 

E47A E94AOO 94. JMP TST12 IGO TO NEXT TEST 

E470 945 E23: j STG_TEST.ODtIE: 

E410 884000 946 MOV AX,OATA jPOINT 05 TO DATA SEGMENT 

E480 8ED8 9.7 MOV OS,AX ; CHG MADE 3127161 

E482 8B161500 9.8 MOV OX , IO_PAM_SIZE lGET 10 CHANNEL RAM SIZE 

E486 OB02 9'9 OR OX,DX ; SET FLAG PESUL T 

E488 74FO 950 Jl En ;tlO 10 RAM. GO TO NEXT TEST 

E48A 890000 951 MOV CX,O 

E480 81FBOOIO 952 eMP eX,lOOOH jHAS ID RAM BEEN TESTED 

E491 77E7 953 JA E22 ; YES - GO TO ~lEXT TEST 

E493 BBOOIO 95. MOV BX,IOOOH ; SETUP BEG lOC FOR 10 RAM 

E496 EB9B 955 JMP SHORT E21 ;GO TEST 10 CHANNEL RAM 

956 ; ----------------••---------------------- 

957 CONVERT AND PRINT ASCII CODE 

958 

959 AL MUST CONTAIN NUMBER TO BE CONVERTED. 

960 AX AND BX DESTROYEO. 

961 i ------------------------------------------ 

E498 962 XLAT_PRINT_CODE PROC NEAR 

E498 IE 963 PUSH OS ;SAVE OS VALUE 

E499 DE 96. PUSH CS j POINT OS TO CODE SEG 

E49A IF 965 POP OS 

E498 [lBB7E4 %6 MOV 6X.OE4B7H ; OFFSET ASCII_T6l-XLAT TABLE 

E49E 07 967 XLATB 

E49F B40E 968 MOV AH,14 

E4Al B700 969 MOV CH,O 

E4A3 COlO 970 WT IDH ;CALL VIDEO_IO 

E4A5 IF 971 POP 05 ;RESTORE ORIG VALUE IN OS 

E4A6 C3 972 RET 

A-14


97. ;-------------------------------------- 

97. ; INITIAL RELIABILITY TEST -- PHASE 4 

97. ;-------------------------------------- 

977 ASSUME CS:COOE ,OS: DATA 

E4A7 20333031 97. '1 DB • 301' 

0004 97. EQU $-FI J KEYBOARD MESSAGE 

E4A8 313331 980 DB '131' 

"L EOU t-F2 i CASSETTE MESSAGE 

E4AE 363031 982 F3 O' '601 ' 

".......... 0003 9Bl " 

••• 

'IL 

00Q3 9B3 F3L EOU $-F3 ; DISKETTE MESSAGE 

98. 

E481 985 F. LABEL WORD ; PRINTER SOURCE TABLE 

E4Bl BC03 986 OW 38CH 

E483 7603 9B7 OW 378H 

E485 7602 9BB OW 278H 

E487 989 F'E LABEL WORD 

£487 30313233343536 9'0 ASCII.TBl DB '0123456789ABCDEF' 

37383941424344 

.546 

991 .------------------------------------------- 

9'2 HEST.12 

9.J KEYBOARD TEST 

99. ;DESCRIPTION 

E4C7 '.B TSTl2: 

99. PESET THE KE'tBOARD AND CHECK THAT SCAN CODE AA.' IS RETURNED 

99. TO THE CPU. CHECK FOR STUCK KEYS. 

9.7 i -----------------------------------------.- 

E4C7 884000 MOV AX,DATA ;POINT OS TO DATA SEG 

E4CA 8E08 1000 MOV OS,AX 

E4CC 803E120001 1001 eMP ~:FG_TST ,I ;MANUFACTURING TEST HODE? 

E401 7439 1002 JE F7 ; YES - SKIP KEYBOARD TEST 

E4D3 E8B201 1003 CAll K8D_RESET ; ISSUE SOFTWARE RESET TO KEYBRD 

E4D6 E32B 1004 JCXZ '6 

i PRINT ERR HSG IF NO INTERRUPT 

E4D8 B04D 1005 NOV AL,4DH ; ENABLE KEYBOARD 

E40A E661 1006 OUT PORT_B,Al 

E40C 80FBll 1007 CMP Bl,OAAH iSCAN CODE AS EXPECTED? 

".......... 

1009 

E40F 7522 1006 JHE F. iNO - DISPLAY ERROR HSG 

1010 CHECK FOR STUCK KEYS 

1011 

E4E1 BOCt 1012 tIOV Al,otCH ; e lR KBD. SET ClK lINE HIGH 

E4E3 E661 Ion OUT PORT_B,Al 

E4£5 B04C 1014 MOV Al.4CH IENABlE KBD,elK IN NEXT BYTE 

E4E7 E661 1015 OUT PORT_B,Al 

E4E9 2BC9 1016 SUB ex,cx 

E4EB 1017 F5: ; KBD_WAIT: 

E4EB E2FE 1018 lOOP '5 

;DELAY FOR A WHILE 

E4ED E460 1019 IN Al,KBD_IN ICHECK FOR STUCK KEYS 

E4EF 3COO 1020 CMP Al,o iSCAN CODE = O? 

E4Fl 7419 1021 JE '7 

J YES - CONTINUE TESTING 

E4F3 8AE8 1022 MOV eH,Al .SAVE SCAN CODE 

E4F5 BI04 1023 MOV Cl,4 

E4F7 02E8 1024 5H. Al,el iRIGHT-JUSTIFY HIGH BYTE 

E4F9 E89CFF 1025 CAll XlAT_PIHHT_CODE j CONVERT AND PRINT 

E4FC 8AC5 1026 MOV Al.CH JRECOVER SCAN CODE 

E4FE 240F 1027 AND Al.OFH iISOlATE LOW ORDER BYTE 

E500 E895FF 1028 CAll XlAT_PRINT_CODE I CONVERT ANO PRINT 

E503 BEA7E4 1029 F6: MDV 5I.OFFSET F 1 ;GET MSG AOOR 

E506 B90400 1030 MOV CX,F1l ;GET HSG BYTE COUNT 

E509 E86E01 1031 CAll P_HSG i PRINT MSG ON SCREEN 

1032 

1033 SETUP INTERRUPT VECTOR TABLE 

1034 

ESOC 1035 F7: ; SE1UP_lNT_TABlE: 

E50C 2BCO 1036 SUB AX,AX 

£50£ 8ECO 1037 MOV ES,AX 

".......... £510 B93000 1038 MOV CX,24*Z: ;GET VECTOR CNT 

E513 OE 1039 PUSH CS iSETUP OS SEG REG 

E514 IF 1040 POP OS 

£515 BEnF£ 1041 MOV SI.OFEF3H ; OFFSET VECTOR_TABLE 

E518 BF2000 1042 MOV OI.OFFSET INT_PTR 

E51B FC 1043 CLD 

E5lC F3 1044 .EP HOV5W 

E51D AS 

A-IS


ESIE 884000 

E521 8E08 

f523 B04t1 

£525 E661 

E527 BOFF 

E529 £621 

f5za B086 

£520 £643 

ESZ' 860304 

£532 (642 

!534 8AC4 

£536 £642 

E538 £462 

f53A 2410 

f5X 1.26800 

E53F E83E14 

ESifZ £83814 

ES45 E30C 

£547 81F84005 

E54B 7306 

£540 61F81004 

E551 7309 

E553 

E553 BEABE4 

E556 B90300 

£559 £86EOI 

ESSC 

ESSC 80Ft 

ESSE £621 

E560 1.01000 

E563 1.801 

E565 7503 

E567 E98900 

£56A 

E56A Boee 

E56C £621 

E56£ 8400 

£570 CDn 

f572 F6C4FF 

f575 7520 

£577 BAF201 

£57. eOIC 

f57C EE 

ES7D 28C9 

E57F 

E51F E2FE 

E581 

E581 ElFE 

E583 3302 

1045 J------------------------------------------- 

1046 ;TEST.Il 

1047 CASSETTE DATA WRAP TEST 

1048 .DESCRIPTION 

1049 , TURN CASSETTE MOTOR OFF. WRITE A BIT OUT TO THE CASSETTE DATA BUS. 

1050 VERIFY THAT CASSETTE DATA READ IS WITHIN A VALID RANGE. 

1051 ; ------------------------------------------- 

1052 

1053 TURN THE CASSETTE HOTOR OFf 

1054 

1055 NOV AX,DATA ;POINT OS REG TO DATA SEG 

1056 HOV OS,AX 

1057 HOV AL,04DH ; SET TIMER 2: SPK OUT, AND CASST 

1058 OUT PORT_B.U jOur BITS ON. CASSETTE MOT OFf 

1059 

lObO 

1061 

WRITE A BIT 

1062 I10V AL.OffH ;DISABLE TIHER INTERRUPTS 

1063 OUT nlTMI,AL 

1064 NOV AL.OB6H iSEL TIM 2, LSB, t1S8, l1D 3 

106S OUT TltIER+3,AL jWRlTE 8253 CMD/MODE REG 

1066 NOV AX, 1235 ;5ET TIMER 2 CNT fOR 1000 USEC 

1067 OUT TIMEFh2.Al ;WRITE TIMER 2 COUHTER REG 

106a HOV AL,AH ;WRITE HSB 

1069 OUT TIMER+2,AL 

1070 

1071 READ CASSETTE INPUT 

1072 

1073 IN AL,PORT_C ;READ VAWE OF CASS IN BIT 

1074 AND AL~ I OH ; ISOLATE FRctI OTHER BITS 

107$ NOV LAST_VAl,AL 

1076 CALL READ_HALF_BIT 

1077 CALL READ_HALF_BIT 

1078 JCXZ fa ; CAS_ERR 

1079 CN" BX.MAX_PERIOD 

1080 JNC fa i CAS_ERR 

1081 CHP BX,MIN_PERIOD 

1082 JNC f9 ;GO TO NEXT TEST IF OK 

1083 Fa: ) CAS_ERR: 

I ... HOV SI.OfFSET F2 iCASSETTE WRAP FAIlED 

lOSS NOV CX,f2L 

1086 CALL P_MSG ;GO PRINT ERROR MSG 

1087 ; ------------------------------------------- 

1088 iTEST.14 

1089 DISKEnE ATTACHMENT TEST 

1090 lDESCRIPTION 

1091 CHECK IF IPL DISKETTE DRIVE IS ATTACHED TO SYSTEM. IF ATTACHED. 

1092 VERIFY STATUS OF NEC FDC AFTER A RESET. ISSUE A RECAL AHD SEEK 

1093 CHO TO FDC AND CHECK STATUS. COI1PLETE SYSTEI1 INITIALIZATION THEN 

1094 PASS CONTROL TO THE BOOT LOADER PROGRAJ1. 

1095 l------------------------------------------- 

1096 F9: 

1097 MOV AL.OFCH ;ENABLE TIMeR AND KeD INTS 

1098 OUT INTAOI,Al 

1099 MOV AL.BYTE PTR EQUIPJLAG ;GET SENSE SWS INFO 

1100 TEST AL.OIH ;IPL DISKETTE DRI .... E AHCH? 

1101 JNZ fl. ;YES - TEST DISKETTE CONTR 

1102 JNP ,.. 

.NO - SKIP THIS TEST 

1103 FlO: ; DISK_TEST: 

1104 MeV AL,OSCH ; ENABLE DISKETTE I KEYBOARD, 

1105 OUT INTAOt,AL ; AND TINER INTERRUPTS 

1106 HOV AH ,0 ;RESET flEC FOC 

1107 INT BH iVERIfY STATUS AFTER RESET 

1108 TEST AH.OFFH ;STATUS OK? 

1109 JNZ fl' 

iNa - FDC FAILED 

1110 

1111 TURN DRIVE 0 MOTOR ON 

1112 

1113 NOV OX.OlF2H ; GET AODR OF FOC CARD 

1114 HOV AL.ICH ;TURN MOTOR ON, EN DHA/IHT 

1115 OUT DX,AL il,JRITE FOC CONTROL REG 

1116 sua CX,CX 

1117 F11: ; NOTOR_WAIT: 

1118 LOOP fll ;WAIT FOR 1 SECOND 

1119 F12: I HOTOICWAITl: 

1120 lOOP fl2 

1121 XOR DX,OX ;SELECT DRIVE 0 

A-16

lOC OBJ lJNE SOURCE 

E585 6501 

ES87 88163EOO 

ESBB EBF30S 

ES8E n07 

E590 8522 

E592 f8Ee08 

E595 7309 

E597 

E597 BEAEElt 

E59A 890300 

E590 fB2AOt 

E5AO 

[SAO BoDe 

E5A2 BAF20J 

E5A5 EE 

ESAO 

E5A6 C7061A001EOO 

ESAC C7061C001£00 

E582 8081E4 

E585 BEOOOO 

E588 

E588 2E885600 

E58C BOAA 

ESSE EE 

ESBF 2ACO 

E5Cl EC 

E5C2 leAA 

ESC4 7506 

E5e6 89940800 

ESCA 46 

EseB 46 

ESCC 

Esec 45 

EseD 45 

EseE BIFDB7E4 

E502 75E4 

E504 BBOOOO 

E507 BAFA03 

E50A EC 

E50B ABFa 

E50D 7508 

ESDF C7870000FS03 

E5E5 43 

E5E6 43 

ESE7 SAfAD2 

ESEA EC 

ESEB ABfa 

ESED 7506 

E5EF C7870000f802 

ESF5 43 

ESF6 43 

ESF7 

ESF7 8BC6 

ESF9 6103 

ESFB 02G8 

E5FO OAe3 

ESFF A21100 

~E602BAOI02 

f605 EC 

f606 AaOF 

E608 7505 

f60A 800E110010 

E60F 

E60F B080 

E611 E6AO 

1122 HOV 01,1 ; Sf lEeT TRACK 1 

1123 HOV SEEK_STATUS,OL 

112:4 CALL SEEK ;R"ECAlIBRATE DISKETTE 

112:5 JC F13 IGO TO EPA' SUBROUTINE IF ERR 

1126 HOV CH.34 I SELECT TRACK 34 

1127 CALL SEEK ,SEEK TO TRACK 34 

1128 JHC F14 10K. TURH HOTOR OFF 

112:9 F13: ; DSK_ERR! 

1130 MOV SI.OFFSET F3 IGET ADOR OF HSG 

1131 HOV CX.F3L IGET I1SG BYTE COUNT 

1132: CALL P _HSG IGO PRINT ERROR HSG 

1133 

1134 TURN DRIVE 0 MOTOR OFF 

1135 

1136 F14: 

1137 MOV AL,OCH ; TURN DRIVE 0 MOTOR OFF 

1138 MOV OX,03FZH ; FOC ClL ADDRESS 

1139 OUT DX,AL 

1140 

1141 SETUP PRINTER ANO RSZ3Z BASE ADDRESSES IF DEVICE ATTACHED 

114, 

1143 F15: 

1144 MOV SUFFER_HEAD, OFFSET KB_BUFFER ISETUP KEYBOARD PARAI1ETERS 

1145 MOV BUFFER_TAIL.OFFSET KB_BUFFER 

1146 MOV BP.OFFSET F4 

1147 MOV SI.O 

1148 Fl6: 

1149 MOV OX,CS: [BP] i6ET PRINTER BASE ADDR 

1150 MOV AL,OAAH iWRITE DATA TO PORT A 


1152: SUB AL.AL 

1153 IN AL,DX ;READ PORT A 

1154 CMP AL,OAAH iDATA PATTERN SAME 

1155 JNE Fl7 iNO - CHECK NEXT PRT CD 

1156 MOV PRINTER_BASEL SI J,OX iYES - STORE PRT BASE ADDR 

1157 INC SI ; INCREMENT TO NEXT WORO 

1158 INC 51 

U59 F17: 

1160 INC BP I POINT TO NEXT BASE ADDR 

1161 It~C BP 

116, CMP BP.OFFSET F4E IALL POSSIBLE AOORS CHECKED? 

1163 Jt1E FI6 

1264 HOV ex.o ;POINTER TO RS2:32: TABLE 

1265 HOV OX.3FAH ;CHECK IF RS2:32 co 1 ATTCH? 

1166 IN AL,OX iREAQ INTR 10 REG 

1167 TEST AL,OF8H 

1168 JNZ Fl8 

1169 MOV RS232_BASE[ BX 1, 3F6H iSETUP RS2:32 CD II ADOR 

1170 INC BX 

1171 WC BX 

1172 FIB: MOV DX,2FAH ;CHECK IF RSl32 CD 2: ATTCH 

1113 IN AL.OX ;READ INTERRUPT 10 REG 

1174 TEST AL.OF8H 

1175 JtlZ FI9 

1176 ; SETUP RS232 CD 12 

1177 INC BX 

1178 INC BX 

1179 

1180 j------ SET UP EQUIP FLJ.G TO INDICATE NUMBER OF PRINTERS AND RS2:32: CARDS 

1181 

Jl8, 

Fl9: 

1163 MOV AX,SI ; 51 HAS 2* N1.JM8E'R Of RS232 

1184 MOV Cl,3 ; SHIFT COlMT 

118S ROR Al,Cl ; ROTATE RIGHT 3 POSITIONS 

1186 OR AL,BL ; OR IN THE PRINTER COUNT 

1187 MOV BYTE PTR EQUIP_FLAG+l.Al ; STURE AS SECOND BYTE 

1188 HOV DX.20IH 

1189 IN AL,DX 

1190 TEST Al,OFH 

1191 JNZ f20 ; HO_GAME_CARD 

1192 OR BYTE PTR EQUIPJLAG+l,16 

1193 F20: 

1194 

1195 EHABLF NMI INTERRUPTS 

1196 

1197 MOV AL,80H ;ENABlE HMI nrrERRUPTS 

1198 OUT OAOH,AL 

A-I7


E613 803E120001 1199 CMP HFG_Tsr.l ;HFG MODE? 

E618 7406 1200 JE 

; LOAD_BOOT_STRAP 

E61A BAOI00 1201 MOV OX.! 

f610 f81000 1202 CAll ERR_BEEP ;BEEP 1 SHORT TONE 

'" 

E620 1203 F21 : I LOAD_BOOT_STRAP: 

E620 E9CfOO 1204 JMP ;60 TO THE BOOT lOAOER 

E623 1205 F22 : ; LOOP.POD: 

E623 B03El2:0001 120b CMP MfG.TST .1 ;MANUFACTURING TEST MODE? 

E628 7503 1207 JNE 

'" 

; NO - GO TO BOOT LOAD ER 

E62A enEFA 12:08 JMP START ;YES - LOOP POWER-aN-CrAGS 

E620 1209 F23: GO.TO.BOOT: 

f62:0 E976FF 1210 JMP Fl5 JMP.BOOT 

1211 ; - - ---------------------------------------. 

1212 j INITIAL RELIABILITY TEST - SUBROUTINES 

1213 j - - - - - -- - -----------.--------------------. 

1214 ASSU~'E CS:CODE,DS:DATA 

1215 1------ - ------------------------------- 

1216 SUBROUTINES fOR Po!~ER ON DIAGNOSTICS 

1217 ; -------------- - - - -- - ------------------- 

1218 THIS PROCEDURE WILL ISSUE otlE LONG TONE (3 SECS) AND ONE OR 

1219 MORE SHORT TONES (1 SECI TO INDICATE A FAILURE ON THE PLANAR 

1220 BOARD, A BAD RAN NODULE, OR A PROBLEM WITH THE CRT. 

1221 iENTRY PARAMETERS: 

1222 DH = NUMBER Of LONG TONES TO BEEP 

1223 DL = .ruMBER Of SHORT TarlES TO BEEP. 

1224 ; ------------- ---------------------- ---- 

f630 1225 ERR.BEEP PROC NEAR 

f630 ge 122b PUSHF ;SAVE FLAGS 

E631 FA 1227 CLI ;DISABLE SYSTEM INTERRUPTS 

E632 IE 1228 PUSH OS ,SAVE OS REG CONTENTS 

E633 884000 1229 HOV AX.DATA ; POINT OS TO DATA SEG 

E636 6ED8 1230 MOV OS,AX 

E636 OAF6 

E63A 7418 

1231 

1232 

OR 

JZ 

DH,DH 

G, 

;, ANY LONG ONES TO BEEP 

, ti~. 00 THE SHORT ONES 

E63e 1233 Gl: ; LONG.BEEP: 

E63e B30b 1234 MOV BL.b ; COUUTER FOR BEEPS 

E63E E82500 1235 CALL BEEP ; DO THE BEEP 

E641 ElFE 1236 G2: LOOP G2 ; DELAY BET~EEN BEEPS 

E643 FEee 1237 D!OC DH ; ANY MORE TO DO 

E645 7SFS 1238 JtlZ G1 ; DO IT 

E647 603E120001 1239 CMP MfG.TST.l ; MfG TEST tl0DE? 

E64C 7506 1240 JtlE 

G' 

; YES - CONTINUE BEEPING SPEAKER 

E64E BOCD 1241 MOV AL.. OCDH ; STOP BLINKING LED 

E650 E661 1242 OUT PORT_B.AL 

E652 fBE6 1243 JMP SHORT Gl 

E654 1244 ; SHORT_BEEP: 

E654 6301 1245 MOV BL.t ; COUNTER fOR .. SHORT BEEP 

E656 f60000 1246 CALL BEEP ; DO THE SOUND 

E659 ElFE 1247 G4: LOOP G4 ; DELAY BETl-:EEN BEEPS 

f656 FEeA 1248 DEC Dl i DONE iolITH SHORTS 

E650 75FS 1249 JNZ G3 ; DO SOME MORE 

E65F ElFE 1250 G5: LOOP G5 ; LONG DELAY BEFORE RETURN 

E661 ElFE 1251 G6: LOOP G6 

E663 IF 1252 POP os ;RESTORE ORIG CONTENTS OF OS 

E664 90 1253 POPF ;RESTORE fLAGS TO ORIG SETTINGS 

E665 C3 1254 RET ; RETURN TO CALLER 

1255 ERR_BEEP ENDP 

1256 

1257 ROUTINE TO SOUND BEEPER 

1258 

E666 1259 BEEP PROC NEAR 

f666 B066 1260 MOV AL.I0110110B ,SEL TIM ~.LSB.MSB.BINARY 

E668 E643 1261 OUT TIMER+3.AL ;WRITE THE TIMER MODE REG 

E66A 883305 1262 MOV AX.533H ;DIVISOR FOR 1000 HZ 

f66D E642 1263 OUT TIMER+2.AL ,WRITE TIMER Z CNT - LSB 

E66f 6AC4 1264 nov AL.AH 

E671 E642 1265 OUT TIMER+Z,AL ;WRITE TIMER 2 CNT - MSB 

E673 E461 1266 IN AL,FORT.B ;GET CURRENT SETTING OF PORT 

E675 6AEO 1267 HOV AH,AL ; SAVE THAT SETTINGH 

E677 oe03 1268 OR AL.03 ;TURN SPEAKER ON 

E679 E661 1269 OUT PORT.B.AL 

E67B 26C9 1270 SUB CX.CX ;SET CNT TO WAIT 500 HS 

f67D ElFE 1271 67: LOOP G7 ;DELAY BEFORE TURNING OfF 

E67F FEee 1272 DEC BL ;DELAY WT EXPIRED? 

E661 75FA 1273 JtlZ G7 ,NO - CONTINUE BEEPING SPK 

E683 6AC4 1274 MOV AL,AH ; RECOVER VALUE OF PORT 

A-I8


E6BS E661 1275 OUT 

E687 C3 1276 RET ;RETURN TO CALLER 

1277 BEEP EtlDP 

1278 1------------------------------------------- 

1279 THIS PROCEDURE WILL SEND A SOFTWARE RESET TO THE KEYBOARD. 

1280 SCAN CODE AA' SHOULD BE RETURNED TO THE CPU. 

1281 ; ------------------------------------------- 

E688 1282 PROC NEAR 

E688 BOOC 1283 AL,OCH ;SET KBD CLK LINE LOW 

£6810. E661 1284 PORT.B,AL ;WRITE 8255 PORT B 

f68t 695629 1285 MOY CX, 10582 ;HOLO KBD CLK LOW FOR 20 MS 

E6aF E2FE 1286 G8: LOOP G8 ,LOOP FOR 20 MS 

£691 Boce 1287 MOV AL.OCCH ,SET CLK, ENABLE LINES HIGH 

E693 E661 1288 OUT PORT.B.AL 

£695 1289 SP_TEST: I ENTRY FOR I1AHUFACTURING TEST 2 

£695 B04C 1290 HOV AL.4CH ,SET KBD CLK HIBH. ENABLE LOW 

£697 E661 1291 OUT PORT.B.AL 

E699 SOFO 1292 HOV AL,OFOH i ENABLE KEYBOARD INTERRUPTS 

E695 £62.1 1293 OUT INTAOl.AL ,WRITE 8259 IMR 

E690 FB 1294 STI iENABLE SYSTEM INTERRUPTS 

£69£ 6400 1295 HOV AH.O ,RESET INTERRUPT IUDICATOR 

£6AO 28C9 1296 sua CX.CX ,SETUP INTERRUPT TIMEOUT CNT 

f6A2 F6C4FF 1297 G9: TEST AH, OFFH iDID A KEYBOARD INTR OCCUR~ 

£610.5 750Z 1298 Jtll GI0 ;YES - READ SCAN COOE RETtmNED 

£6A7 E2F9 1299 LOOP G9 INa - LOOP TILL TIMEOUT 

£6A9 £460 1300 GI0: IN AL,PORT.A !READ KEYBOARD SCAN CODE 

E6AB 810.08 1301 HOV BL,AL ,SAVE SCAN CODE JUST READ 

E6AD Boce 1302 HOV AL,OCCH ,CLEAR KEYBOARD 

E6AF E661 1303 OUT PORT.B,AL 

E6Bl C3 1304 RET IRETURN TO CALLER 

1305 KBD.RESET ENDP 

1306 

1307 BLINK LED PROCEDURE FOR t1FG BURN-IN AND RUN-IN TESTS 

1308 (LED WILL BLINK APPROXIMATELY. 25 SECOND) 

1309 i - - - --- - - - - ---------------------- - - - - - 

f662 1310 BLIN'CINT PROC NEAR 

f682 FB 1311 STI 

E683 51 1312 PUSH ex I SAVE CX REG CONTENTS 

£684 50 1313 PUSH AX ;SAVE AX REG CONTENTS 

E685 £461 1314 IN AL,PORT_B ;READ CIJR'RENT VAL OF PORT 8 

E6B7 24BF 1315 AND AL.OBFH 

£689 E661 1316 OUT PORT_B,AL !BLINK LED 

EbBS 28C9 1317 SUB CX,CX 

E6BD E2FE 1318 Gl}: LOOP G11 

E68F OC40 1319 OR AL,40H ISTOP BLINKING LEO 

fbCl E661 1320 OUT PORT_B,AL 

£6C3 B020 1321 HOV AL,EOI 

f6C5 £62:0 1322 OUT INTAOO.AL 

f6C7 58 1323 POP AX ,RESTORE AX REG 

f6e8 59 1324 POP CX !RESTORE CX REG 

E6C9 CF 1325 IRET 

1326 

1327 ; ----------------------------------------- 

1328 THIS SUBROUTINE WILL PRINT A MESSAGE ON THE DISPLAY 

1329 

1330 !ENTRY REQUIREMENTS: 

1331 51 ::: OFFSETCADORESS) OF MESSAGE BUFFER 

1332 CX = MESSAGE BYTE COUNT 

1333 MAXIMUM MESSAGE LENGTH IS 36 CHARACTERS 

1334 ; ------------------------------------------- 

E6CA 1335 

E6CA 884000 1336 HOV AX,DATA I POINT OS TO DATA SEG 

E6eD 8E08 1337 HOV OS,AX 

E6CF 803£120001 1338 CHP MFG.TST .1 IMFG TEST MODE? 

£604 7505 1339 JNE G12 ;NO - DISPLAY ERROR M5G 

E6D6 B601 1340 HOV OH,1 ; YES - SETUP TO BEEP SPEAKER 

~ Eb08 E95SFF 1341 JMP ERR.BEEP ; YES - BEEP SPEAKER 

EbDB 1342 G12: ; WRITCMSG: 

E6DB 2E8A04 13l.3 NOV AL,CS:(SIl ; PUT CHAR IN AL 

E60E 46 1344 INC SI ; POINT TO NEXT CHAR 

E60F B700 1345 MOV FJ;H,O ;SET PAGE # TO ZERO 

f6E1 840£ 1346 MOV AH.14 ;~RITE CHAR {TTY-INTERFACE) 

E6El COlO 1347 HIT 10H iCALL VIDEO.IO 

f6E5 E2F4 1348 lOOP G12 ; CONTINUE TI lL "SG WRITTEN 

f6E7 B80DOE 1349 MOV AX, OEODH ; POSITION CURSOR TO NEXT LINE 

f6EA COlO 1350 INT 10H ;SeNO CARRIAGE RETURN AND 

A-19

LaC OSJ LINE SOURCE 

E6EC eSOAOE 

E6EF COlO 

£6fl Cl 

E6F2 

E6F2: FB 

E6F3 884000 

E6F6 8£08 

E6Fe All000 

E6F8 A801 

E6FD 7423 

E6FF 890400 

E702 

noz 51 

£703 8400 

E705 CDll 

n07 7214 

£109 8402 

£10& B80000 

E70E 8fC3 

E7l0 BB007C 

E713 BAOOOO 

E7l6 8901QO 

E7l9 B001 

E7lB CDl3 

E7lD 59 

E7lE 7304 

E720 £2£0 

£722: 

E72:O! C018 

E7Z4 

e724 EAOO7COOOO 

1351 MOV AX,OEOAH ; LINE FEED CHARS 

1352: ItH 10H 

1353 RET 

1354 P _HSG EHOP 

1355 ;--- INT 19 ---------------------------- 

1356 I BOOT STRAP LOADER 

1357 IF A 5 1/4" DISKETTE DRIVE IS AVAIlABLE 

1358 ON THE SYSTEM. TRACK 0, SECTOR 1 IS READ INTO THE 

1359 BOOT LOCATION (SEG~IENT O. OFFSET 7COO} 

1360 Aim CONTROL IS TRANSFERRED THERE. 

1361 

1362 IF TIiERE IS NO DISKETTE DRIVE. OR IF THERE IS 

1363 IS A HAROWARE ERROR CONTROL IS TRANSFERREO 

1364 TO THE CASSETTE BASIC E~Y POINT. 

1365 

1366 I IPl ASSUMPTIONS 

1367 8255 PORT bOH El:lT 0 

1368 = 1 IF IPL FROH DISKETTE 

1369 ; ------------------------------.-------- 

1370 ASSUME CS:CDDE.DS:DATA 

1371 BOOT.STRAP PROC NEAR 

1372 

1373 STI 1 ENABLE INTERRUPTS 

1374 HOV AX,DATA ; ESTABLISH ADDRESSING 


1376 HOV AX. EQUIPJUG ; GET THE EQUIPMENT SWITCKE' 

1377 TEST ALd J ISOLATE IPL SENSE SWITCH 

1378 JZ H3 ;, GO TO CASSETTE BASIC ENTRY POINT 

1379 

1380 ;------ MUST LOAD SYSTEM FROM DISKETTE - ex HAS RETRY COUHT 

1381 

1382 NOV CX.4 ; SET RETRY COUNT 

1383 HI: J IPL.SYSTEH 

1384 PUSH ex ; SAVE RETRY COl.mT 

1385 HOV AH,O ; RESET THE DISKETTE SYSTEM 

1386 INT 13ft j DISKETTE.IO 

1387 JC HZ I IF ERROR. TRY AGAIN 

1388 HOV AH,2 ; READ IN THE SINGLE SECTOR 

1389 MOV BX.O ; TO THE BOOT LOCATION 

1390 MOV ES,BX 

1391 HOV eX,oFFSET BOOT.LOCN 

139Z HOV OX,O I DRIVE 0, HEAD 0 

1393 MOV CX.! ; SECTOR I, TRACK 0 

1394 NOV AL,I ; READ ONE SECTOR 

n95 INT IlH i DISKETTE.IO 

1396 POP ex j RECOVER RETRY COUNT 

1397 JNe H4 ; CF SET BY UNSUCCESSFUL READ 

1398 LOOP HI j DO IT FOR RETRY TIMES 

1399 

1400 j------ UNABLE TO IPL FROM THE DISKETTE 

1401 

1402 H3: I CASSETTE_JUMP: 

1403 INT 18H ; USE INTERRUPT VECTOR TO GET TO BASIC 

1404 

1405 1------ IPL WAS SUCCESSFUL 

1406 

1407 H4: 

1406 

1409 

1410 ; -----INT 14------------------------------- 

1411 ;RS232_IO 

1412 THIS ROUTINE PROVIDES BYTE STREAM I/O TO THE: COf1MUNICATIOHS 

1413 PORT ACCORDING TO THE: PARAMETERS: 

1414 (AH )=0 INITIALIZE TItE COMMUNICATIONS PORT 

1415 j AL) HAS PARMS fOR INITIALIZATION 

1416 

1417 7 • 4 I 

1416 ---- BAUD RATE - -PARITY- STOPBIT --WORD lENGTH- 

1419 

1420 000 - 110 xo - NONE o 1 10 - 7 BITS 

1421 001 - 150 01 - COD 1 - Z 11 - 8 BITS 

1422 010 - 300 11 - EVEN 

1423 011 - 600 

1424 100 - 1200 

1425 101 - 24QO 

1426 110 - 4600 

1427 III - 9600 

A-20


~ 

E729 

E72' 1704 

E7lS 0003 

E72D eOOl 

E72:F CODO 

E731 6000 

£733 3000 

E735 1800 

E737 DeaD 

en9 

E739 Fa 

£73A IE 

E73S 52 

E73e 56 

E730 57 

E73£ 51 

E7l' 88f2 

n41 DlE6 

E743 8ol4000 

E746 eEDA 

E748 88940000 

E74e 0802: 

E74E 7416 

E7S0 OA£4 

E752 7418 

E7S4 FEee 

£756 744£ 

E758 FEte 

E7SA 7503 

E7St £96900 

1428 ON RETURN, CONDITIONS SET AS IN CALL TO como STATUS UH=3J 

1429 (AH'=1 SEND THE CHARACTER IN (AL) aVER THE cotI1O UHE 

1430 (AU REGISTER IS PRESERVED 

1431 ON EXIT. BIT 7 OF AH IS SET IF THE ROUTINE: WAS UNA6lE TO 

1432 TO TRANSMIT THE BYTE OF DATA OYER THE LINE. THE 

1431 REMAINDER Of AH IS SET AS IN A STATUS REquEST. 

1434 REFElECTING THE CURRENT STATUS Of THE LINE. 

1435 (AM)=! RECEIVE A CHARACTfR IN fAll FRon caMMO LINE BEFORE 

1436 RETURNING TO CA LLER 

1437 ON EXIT, AM HAS THE CURRENT LINE STATUS. AS SET BY THE 

1438 THE STATUS ROUTINE. EXCEPT THAT THE ONLY BITS 

1439 LEfT ON ARE THE ERROR BITS f7.4.3.2.1) 

1440 IN THIS CASE. THE TIME OUT BIT INDICATES DATA SET 

1441 READY WAS NOT RECEIVED. 

1442: THUS. AH IS HON ZERO ONLY WHEN AN ERROR OCctmRED. 

1443 UHl:3 RETURN THE COMMa PORT STATUS IN (AX) 

1444 AH CONTAINS THE LINE CONTROL STATUS 

1445 BIT 7 = TIME OUT 

1446 BIT 6 = TRANS SHIfT REGISTER EMPTY 

1447 BIT 5 = TRAN HOLOIHS REGISTER EMPTY 

14"'8 

BIT 4 = BREAK DETECT 

1449 BIT 3 = FRAMING ERROR 

1450 BIT 2: = PARITY ERROR 

1451 BIT 1 : OVERRUN ERROR 

1452: BIT 0 = DATA READY 

1453 AL CONTAIUS THE HOOE" STATUS 

1454 BIT 7 = RECEVEO LINE SIGNAL DETECT 

1455 BIT 6 = RING INDICATOR 

1456 Bn 5 = DATA SET READY 

1457 BIT 4 = CLEAR TO SEND 

14sa 

BIT 3 = DELTA RECEIVE LINE SIGNAL DETECT 

1459 BIT 2 = TRAILING EDGE RING DETECTOP 

1460 BIT 1 = DELTA DATA SET READY 

1461 BIT 0 = DELTA CLEAR TO SENO 

1462 

1463 COX) = PARAMETER INDICATING WHICH RSZ32 CARD fO,l ALLOWED) 

1464 ; DATA AREA RS232_BASE CONTAINS THE BASE ADDRESS OF THE 8"50 ON THE CARD 

1465 LOCATION 400H CONTAINS UP TO 4 RS232 ADDRESSES POSSIBLE 

1466 ~OVTPUT 

1467 AX MODIfIED ACCORDING TO PARNS OF CALL 

1468 ALL OTHERS UNCHANGED 

1469 1------------------------------------------- 

1470 ASSUHE CS:CODE.DS:DATA 

1471 Al LABEL WORD 

1472 DW 1047 110 BAUD ; TABLE Of INIT VALUE 

1471 OW 768 150 

1474 ow 384 300 

1475 OW 192 i 600 

1476 ow ,. i I~OO 

1477 ow 43 i 2400 

1476 ow Z4 i 4800 

1479 ow 12 i 9600 

1480 

llt81 RS232_IO PRDC FA. 

1482 

1483 1------ VECTOR TO API'


E7SF 1505 .402: 

E7SF FEee 1506 DEC AH ; TEST FOR (AH )=3 

£761 7503 1507 JHZ A3 

£763 £98900 1508 JMP A18 ; COMMUNICATION STATUS 

£766 1509 .403: , RETURN FROM RS232 

E766 59 1510 POP ex 

£767 SF 1511 POP 01 

E768 5E 1512 POP 51 

£769 SA 1513 POP DX 

E76A IF 1514 POP as 

E768 CF 1515 lRET I RETURN TO CAllER. NO ACTION 

1516 

1517 ;------ INITIALIZE THE COMM\.JHICATlONS PORT 

1518 

£76C 1519 A4: 

f76C 8AEO 1520 NOV AH.Al ; SAVE INIT PARMS IN AH 

£76E 83C203 1521 ADD OX,3 • POINT TO 8250 CONTROL REGISTER 

E771 B080 1522 ti0V .4.L,6QH 

E773 EE 1523 OUT OX.Al ; SET DLAS;1 

1524 

1525 ; ----- DETERMINE BAUD RATE DIVISOR 

1526 

£774 8A04 152:7 MaV OL.AH ; GET PARMS TO DL 

£776 00C2 1528 ROL OLd 

E778 00C2 1529 ROL OLd I GET BAUD RATE TERM TO LOW BITS 

E77A DOC2 1530 ROL OLd 

Ene ooe2 1531 ROL OL,} ; *2 FOR WORD TASlE ACCESS 

EnE 81E20EOO 1532 A,m OX.DEH ; ISOLATE THEM 

£782 SF29E7 1533 MOV 01.0FFSET Al I BASE OF TADlE 

E78S 03FA 1534 ADO OI.DX ; PUT INTO INDEX REGISTER 

E787 88940000 1535 MOV OX.RS232_BASE(SIl ; POINT TO HIGH ORDER OF DIVISOR 

E7BB 42 1536 INC OX 

E7SC 2E8A4501 1537 NOV Al,CS:[DI1+l ; GET HIGH ORDER OF DIVISOR 

£790 EE 1538 OUT OX.AL ; SET MS OF DIV TO 0 

E791 4" 1539 DEC OX 

E792 2£8A05 1540 HOV Al.CS:[OIl ; GET LOW ORDER OF DIVISOR 

E795 EE 1541 OUT OX.Al ; SET LOW OF DIVISOR 

£796 83C203 1542 ADO DX.3 

£799 8'&'C4 1543 MOV AL.AH ; GET PARMS BACK 

£798 241F 1544 'NO AL.OIFH ; STRIP OFF THE BAUD BITS 

£790 EE 1545 OUT DX,At ; LINE CONTROL TO 8 BITS 

£79£ 83£A02 1546 SUB DX,2 

f7Al BODO 1547 MOV Al,O 

£7A3 EE 1546 OUT DX,Al J INTERRUPT ENABLES ALL OFF 

£7A4 E879 1549 JMP SHORT .1.18 ; Cot'CSTATUS 

1550 

1551 ,------ SEND CHARACTER IN (ALI OVER COMMa LINE 

1552 

£7A6 1553 AS: 

E7A6 50 1554 PUSH AX I SAVE CHAR TO SEND 

£7A7 83C204 1555 ADD OX.4 ; MODEM CONTROL REGISTER 

E7AA 8003 1556 MOV AL.3 ; OTR AND RTS 

E7AC EE 1557 OUT OX.AL ; DATA TERMIN'AL READY, REQUEST TO SEND 

£7AO 33C9 1558 XOR cx.cx ; INITIALIZE TIME OUT COUNT 

E7AF 83C202 1559 ADD DX.2 ; MODEM STATUS REGISTER 

E7BZ 1560 .4.6: I WAIT_OATA_SET_READY 

£782 EC 1561 IN At.OX ; GET HOOEN STATUS 

E7B3 .l820 1562 TEST Al.20H ; DATA SET READY 

E7BS 7508 1563 Jt~Z A7 I TEST_CLEAR_TO_SEND 

£7B7 E2F9 1564 LOOP A6 ; WAIT_OATA_SET_READY 

E7B9 58 1565 POP AX 

E7BA 80CC50 1566 OR AH.80 ; INDICATE TINE OUT 

E7BD fBA7 1567 JMP A3 I RETURN 

E7SF 1568 A7: 

E7SF 28C9 1569 SUB cx.CX 

E7et 1570 A8: ; WAIT_CLEAR_TO_SEHO 

E7et EC 1571 IN Al.DX ; GET MODEM STATUS 

E7t2 A810 1572 TEST Al.IOH I TEST CLEAR TO SEND 

E7C4 7508 1573 JHZ A9 

£7&6 E2F9 1574 LOOP A6 ; W.6.IT_tlE.6.R_TO_SEND 

£7C8 58 1575 pop AX , TIME OUT HA.S OCCURRED 

£7C9 80ce80 1576 OR AH.80H 

E7ee £B98 1577 JMP A3 ; RETLlR~1 

f7eE 1578 .4.9: 

f7eE 4A 1579 DEC ox ; LINE STATUS REGISTER 

E7CF 2BC9 1580 SUB CX.CX ; ItUTIALIZE WAIT COUNT 

E701 1581 AlD: 

A-22


,,-..., 

,,-..., 

EiO! EC 

E7DZ A82:0 

E704 7508 

E706 E2F9 

E7D8 sa 

E7D9 80ce80 

E7ae Ee88 

E7DE 

E7Df 83EA05 

E7El 59 

E7EZ: 8ACl 

E7£4 EE 

E7E5 E97EFF 

E7E8 

E7E8 80Z671007F 

E7ED 83C204 

E7FO BOOI 

E7n EE 

E7F3 83C202 

E1F6 2BC9 

E7Fa 

E7F8 EC 

E7F9 AB20 

E7FB 7507 

E7FD E2F9 

E7fF 

E7FF 8480 

EaCI E962FF 

EB04 

Ea04 4A 

Eaos 

ESOS EC 

E806 A801 

Eece 7509 

EeCA F6067100eO 

E80F 74F4 

E811 EBEC 

E813 

EB13 241E 

EB15 8AED 

EBl7 88940000 

E81B EC 

E81C E947ff 

E8lF 

E81F 88940000 

E823 83C205 

E826 EC 

E827 8AEO 

E82:9 42 

E82:A EC 

E82B E938FF 

1582 IN AL,DX ; GET STATUS 

158l TEST AL,ZOH ; IS TRANSMITTER READY 

1584 JNZ All ; OUT_CHAR 

1585 LOOP AID ; GO BACK FOR MORE. AND TEST FOR TIME OUT 

1586 POP AX ; RECOVER ORIGINAL INPUT 

1587 OR AH.SOH ; SET THE TIME OUT BIT 

1"8 JMP Al ; RETUWN 

1589 All: ; OUT_CHAR 

1590 SUB OX,S " DATA PORT 

1591 POP ex ; RECOVER IN ex TEMPORARILY 

1592 MOV AL,Cl ; GET OUT CHAR TO Al FOR OUT. STATUS IN AH 

1593 OUT DX,Al ; OUTPUT CHARACTER 

1594 JMP Al ; RETURN 

1595 

1596 J------ RECEIVE CHARACTER FROM COMMO LINE 

1597 

1598 .1.12 : 

1599 ANO BIOS_BREAK. 07FH ; TURN OFF BREAK BIT IN BYTE 

1600 ADO DX,4 j MODEM CON1ROl REGISTER 

1601 MOV Al,! ; DATA TERMINAL READY 

1602 OUT OX,At 

1603 ADO DX,2 ; MODEM STATUS REGISTER 

1604 SUB CX,CX ; ESTABLISH TIME OUT COUNT 

1605 A13: ; WAIT_DSR 

1606 IN Al,OX ; MODEM STATUS 

1607 TEST Al,2OM ; DATA SET READY 

1608 JNZ A1S ; IS IT READY YET 

1609 LOOP All ; WAIT UNTIL IT IS 

1610 A14: ; TIME_OUT_ERR 

1611 MOV AH.80H ; SET TIME OUT ERROR 

1612 JMP Al J RETUPN WITH ERROR 

1611 AIS: ; WAIT_OSR_ENO 

1614 DEC OX ; LINE STATUS REGISTER 

1615 A16: ; WAIT_RECV 

1616 IN Al,OX ; GET STATUS 

1617 TEST Alol J RECEIVE BUFFER FUll 

)618 JNZ A17 ; GET CHAR 

1619 TEST BIOS_BREAK,BOH J TEST FOR BREAK KEY 

1620 JZ Alb I LOOP IF ~mT 

)621 JMP A14 i SET TIME OUT ERROR 

1622 A17: ; GET_CHAR 

)623 AND Al,OOOl1110B ; TEST FOR ERROR CONDITIONS ON RECV CHAR 

1624 MOV AH,Al ; SAVE THIS PART OF STATUS FOR LATER OPERATION 

1625 MOV DX,RS232_BASE[ SI J ; DATA PORT 

1626 Al,DX ; GET CHARACTER FROH LINE 

1627 '" JMP Al ; RETURN 

1628 

1629 ;------ COMMO PORT STATUS ROUTINE 

1630 

1631 A18: 

1632 MOV OX ,RS232_BASE[SI J 

1633 ADO OX.S J CONTROL PORT 

1634 IN AL,OX ; GET LINE COHTROL STATUS 

1635 MOV AH,Al I PUT IN AH FOR RETURN 

1636 INC OX ; POINT TO MODEM STATUS REGISTER 

1637 IN Al,OX ; GET MODEM CONTROL STATUS 

1638 JMP Al ; RETURN 

1639 RS232_IO ENOP 

1640 ; ---- INT 16 ------------------------------- 

1641 i KEYBOARD I/O 

1642: THESE ROUTINES PROVIDE KEYBOARD SUPPORT 

)643 ; INPUT 

1644 I AHJ=O READ THE NEXT ASCII CHARACTER STRUCK FROM THE KEYBOARD 

1645 RETURN THE RESULT IN I AU, SCAN CODE IN (AH I 

164& (AHJ=l SET THE Z FlAG TO INDICATE IF AN ASCII CHARACTER IS AVAIlABLE 

1641 TO BE READ. 

1648 (ZF )=1 -- NO COOE AVAILABLE 

1649 (IF )=0 -- CODE IS AVAILABLE 

1650 IF Zf = 0, THE NEXT CHARACTE~ IN THE BUFftR TO BE READ IS 

1651 IN AX, AtID THE ENTRY REMAINS IN THE BUFFER 

1652 (AHI=2 RETURN THE CURRENT SHIFT STATUS IN AL PEGISTER 

1653 THE BIT SETTINGS FOR THIS CODE ARE INDICATED IN THE 

1654 THE EQUATES FOR KBJLAG 

1655 ; OUTPUT 

1656 AS NOTED ABOVE, OIRY AX Atm FLAGS CHANGED 

1651 All REGISTERS RETAWED 

1658 1--------- ------- ----------------------- 

A-23


1659 ASSUME CS:CODE,DS!DAiA 

E8tE 1660 KEYBOARD_IO PROC "R 

E82E FB 1661 SH j INTERRUPTS BACK ON 

ESZ:F IE 1662 PUSH OS J SAVE CURRENT DS 

. E8lt 53 16.63 IJUSH 6X I SAVE BX TEMPORARILY 

E831 B84000 1664 I10V ex,OATA 

E8M SEDB 1665 MOV OS,BX I ESTABLISH POINTER TO DATA REGION 

£836 OAF. 1666 OR ....... ; AH=O 

E83& 740B 1667 JZ .1 ; ASCII_READ 

E63A fEee 

1666 

O'C A. 

I AH-=1 

E83C 7420 

1669 

JZ 

J ASCII_STATUS 

•• 

E83E FEet 

1670 

DEC AH 

; AH:::2 

E840 71\2D 1671 JZ Kl ; SHIFT_STATUS 

E842 5B 1672 POP BX J RECOVER REGISTER 

E843 IF 1673 POP OS 

E84lt CF 1674 IRET J INVALID COHt1AND 

1675 

1676 ;------ READ THE KEY TO FIGURE OUT WHAT TO DO 

1677 

1678 Kl: ; ASCII READ 

'84' 

E845 FB 1679 STt ; INTERRUPTS BACK ON DURING LOOP 

E846 90 1680 NOP J AlLOW AN INTERRUPT TO OCCUR 

EM7 FA 1681 eLI I INTERRUPTS BACK OFf 

E848 881ElAOO 1682 MaV ex.BUfFER_HEAD I GET POINTER TO HEAD OF BUFFER 

EMC 381EICOO 1683 eMP BX,BUFFER_TAIl I TEST END Of BUFfER 

E850 74F3 1684 JZ Kl I LOOP UNTIL SOMETHING IN BUFFER 

f652 8B07 1685 I10V AX,lBXl j GET SCAM CODE AND ASCII CODE 

E654 E81EOO 16.. CALL K' I MOVE POINTER TO NEXT POSITION 

E857 891E lAOO 1687 I10V eUfFER_HEAD,BX I STORE VALUE IN VARIABLE 

E858 58 1688 pop ex ; RECOVER REGISTER 

f85t IF 1689 POP os • RECOVER SEGMENT 

E8SD Cf 1690 IRET ~ RETURN TO C.A LLER 

1691 

1692 1------ .ASCII STATUS 

1693 

E85E 1694 

E85E FA 169S eLI ; INTERRUPTS Off 

E85F 881£1AOO 1696 I10V ax .SUFFER_HEAD ; GET HUD POINTER 

E86.3 381ElCOO 1697 CMP ex.BUFFER_TAIl ; IF EQUAL (Z=l) THEN NOTHIHG THERE 

E867 8807 1696 HOV AX.fex] 

[869 Fe 1699 SH ; INTERRUIJTS BACK ON 

E8~A 58 1700 POP BX J RECOVER REGISTER 

E86B IF 1701 POP OS o RECOVER SEGMENT 

E86C CA02O'O 1702 RET ; THROW AWAY fLAGS 

1703 

1704 1------ SHIfT SfArus 

1705 

E8bF 1706 K3: 

E86F A01700 1707 I10V Al ,KBJLAG 1 GET THE SHIFT STATUS FLAGS 

E872 58 1708 pop ex ; RECOVER REGISTER 

£873 IF 1709 POP DS ; RECOVER REGISTERS 

E874 CF 1710 IRET ; RETURN TO CALLER 

1711 

1712 

17U 

1714 

j------ INCREMENT A BUFfER POINTER 

E875 1715 K4 PROC NEAR 

E875 83C302 1716 ADD B)(,2 ; MOVE TO NEXT WORD IN LIST 

E878 81 F83EOO 1717 CHP BX,OfFSET KB_BUFFER_ENO ; AT END OF eUFFER? 

Ea7C 7503 1718 JNE .s j NO. CONTINUE 

E87E 881EOO J719 MOV ax ,OFfSET Ke_BUFFER t YES, RESET TO eUFFER BEGINNING 

'681 1720 KS: 

E881 C3 1721 RET 

1722 K4 ENDP 

1723 

1724 ~------ TABLE OF SHIfT KEYS AtI) tuSK VALUES 

Ins 

Eee! 1726 K6 LABEL eYTE 

E882 ;2 1727 DB INS_KEY ; INSERT KEY 

E8&3 3A45463&10 1728 06 CAPS_KEY ,NUN_KEY ,SCROL~KEY •AlT_KEY.eTl_KEY 

E888 2A36 1729 DB LEF-r_KEy,RIGHT_KEY 

0008 1130 .bL 'OU $-K6 

1731 

1732 ;------ SHIFT_H'\sK_TABLE 

1733 

..... 1734 K7 LABEL BYTE 

E88A 80 1735 DB ; INSERT MODE SHIFT 

A-24

LOC OBJ I.INf SOURCE 

,..-..." 

~ 

Eass 4020101:1804- 1736 

E890 020. 1737 

1738 

1739 

1740 

£892 IBFFOOFFFFFFI EFF 1741 

E89A fFFfFFIFfF7FFFll 1742 

f8A2 170512:141915090F 1743 

feAA lO181DOAFF01l3 1744 

E8B1 040b-C17080AOBOCFFff 1745 

EeBA FFFFICIA18031602 1746 

fBe2: OEODfFFfFfFFFfff 1747 

E8CA 20F-F 1748 

1749 

f8ce 1750 

fBce 'SESF606162636465 1751 

£8D4 6667FHF77Ff84fF 1752: 

ESDC 73F"F74FF75Ff76FF 1753 

£8£4 FF 17·54 

1755 

E8ES 1756 

£8£5 IB 1757 

feE6 31323334353637 

383930203DO&09 

£8F4 7177657274797S \758 

696F70SBSDODFF 

£902 61736466676864 

6B6C3B'27 

£900 bOFF5C 1759 

EnD 7A7863766Z6E6D 

2CZEZFFf2AFFZO 

-E.9lE FF 1760 

1761 

1762: 

£91F 1763 

E91F 18 ]764 

£920 214023242'55£ 

£92:6 262A28295F280800 

EnE 5157455254-5955 1765 

494F507B7DODFF 

E93C 4153444647484A 

4B4C3A22 

£947 7£FF 1766 

£949 7CSA584356424E 

4D3C3E3FFfO OF F2:0F F 

1767 

£959 1768 

£q59 S4555657S8S9SA 1769 

£960 515CSD 1710 

1771 

£963 177Z 

£963 68696A686C 1773 

£968 -606-(6F7071 1774 

1775 

1776 

E'96b 1777 

E96b 3738392£)343536 171a 

28311233302£ 

08 CAPS_SHIfT .NJI'LSHIFT.SCROLL_SHIFT ,AL T_SHIFT .CTl_SHIFT 

DB LEFT_SHIFT ,RIGHT_SHIFT 

;------ SCAN COOE TABLES 

K8 DB 27.-1.0,-1,-1,-1.10,-1 

DB -1.-1.-1,31.-1 ,]2:7.-1, 17 

DB 23.5.1-6.2:0.2:5.21,9.15 

DB 16.27,2:9,10. -1,1,19 

08 4,6,7.8.10.11,12:,-1,-1 

08 -1. -1.2:8.2:6 .24.3.22:.Z 

08 14.13.-1,-1,-1,-1,-1,-1 

DB',-1 

J-------- eTL TABLE SCAN 

K9 LABEL BYTE 

DB 94.95,96 ,97.98,99,100,101 

08 102:,103.-1, -1.119,-10132:.-1 

DB 115.-1.116,-1, ll7.-1.118.-.1 

DB -1 

i----..- LC TABLE 

KID LABEL BYTE 

DB 

o18H. '12:]4567890-=' ,08H,09H 

08 'lIw~rtyuiopt J' ,DOH, -1. I asdtfh;klJ' ,Q21H 

D8 

1------ UC TABLE 

KII LABEl BYTE 

DB -\ 

DB 

60H.-l ,5CH. 'z·xcvbIlJ!\ •. /' .-1, '.' .-1,' • 

DB 'QWERTYUIOP •• OOH ,-1.'ASDFGHJKL:'" 

DB 

;------ tIC TABLE SCAN 

K12 LABEL SYTE 

07EH,-I,' zxcWNr1?',-l.O.-I,' '.-1 

DB 84 ,85.a6 .87.88,e'9. 99 

DB 91,92.93 

;------ ALT TA8LE SCAN 

K13 LABEL BHE 

;------ HUM STATE TABLE 

K14 LABEl BYTE 

DB 

DB 1040105,106.107,108 

DB 1-09,110,111.112:,113 

'769-456.1230.' 

£97,\ 

£97A 474849F'F48f140 

E981 FF4FSOSISZSl 

~ 

E987 

£987 F8 

E988 50 

E989 53 

E98A 51 

E988 52: 

E9ee 56 

E980 ,57 

E98E IE 

£98F 06 

£990 Fe 

E991 884000 

KB_INT PROC fAR 

STI 

PUSH AX 

PUSH BX 

PUSH ex 

PUSH OX 

PUSH SI 

PUSH OI 

PUSH OS 

PUSH 

eLO 

HOV 

,5 

AX,O-ATA 

J FORWARD DIRECTION 

A-25


E994 8E08 1798 HOV DS,AX ; SET UP ADDRESSING 

E996 E460 1799 IN AL,KB_DATA j READ IN THE CHARACTER 

E998 50 1800 PUSH AX ; SAVE IT 

E999 E461 11301 m AL,KB_CTL j GET THE CONTROL PORT 

E998 8AEO 1802 MOV AH ,AL ; SAVE VALUE 

E990 DC8D 1803 OR AL,80H ; RESET BIT fOR KEYBOARD 

E99F E661 1804 OUT 

E9Al 66ED 1605 XCHG AH,AL j GET BACK ORIGINAL CONTROL 

E9A3 E661 1806 OUT KB_CTl,AL ; KB HAS BEEN RESET 

E9A5 58 1807 POP AX ; RECOVER SCAN CODE 

E9A6 8AEO 1808 HOV AH,Al ; SAVE SCAN CODE IN AH ALSO 

1809 

1810 ;------ TEST FOR OVERRUN SCAN CODE FROM KEYBOARD 

1811 

E9A8 3eFF 1812 CMP AL,OFFH ; IS THIS AN OVERRUN CHAR 

E9AA 7503 len JI~Z K16 ; NO, TEST fOR SHIfT 'KEY 

E9AC E97502: 1814 J~IP K62 I BUFFER_FULL_BEEP 

1815 

1816 ;------ TEST FOR SHIFT KEYS 

1817 

E9AF 1818 K16: I TEST_SHIFT 

E9AF 247F 1819 AHa AL,07FH ; TURN OFF THE BREAK BIT 

E9Bl DE 1820 PUSH OS 

E982 07 1821 POP ES I ESTABLISH ADDRESS OF SHIFT TABLE 

E9B3 BF8ZE8 1822 MOV DI,OFFSET K6 ; SHIFT KEY TABLE 

E9B6 890800 1823 MOV CX,K6L LENGTH 

E~9 F2 1824 PEPNE SCASB ; LOOK THROUGH THE TABLE FOR A MATCH 

E9SA AE 

E9B8 8A.C4 1825 HOY AL,AH j RECOVER SCAN COOE 

E9SD 7403 1826 JE K17 j JUMP IF MATCH FOUND 

E98F E9880D 1827 JtlP K2S ; IF NO MATCH, THEN SHIrT NOT FOUND 

1828 

1829 j------ SHIFT KEY FOUHD 

1830 

E9C2 81EF83E8 1831 K17: SUB DI,OFFSET K6.1 J ADJUST PTP TO SCAN CODE MTCH 

E9C6 2E8AA5BAfa 1832 MOV AH,CS:K7[DII I GET MASK INTO AH 

E9CD .1.680 1833 TEST AL,eOH ; TEST FOR BREAK KEY 

EQCD 7554 1834 JNZ K21 ; BREAK_SHIFT_FOUND 

1835 

1836 j------ SHIFT HAKE FOlR'ID, DETERMINE SET OR TOGGLE 

1837 

E9CF 80FCI0 1838 OHP AH ,SCROLL_SHIFT 

E902 7307 1839 JAE K18 IF SCROll SHIFT OR ABOVE, TOGGLE KEY 

1840 

1841 1------ PLAIN SHIFT KEY, SET SHIFT ON 

1842 

E9D4 08261700 1843 OR TURN ON SHIFT BIT 

E9D8 E98300 1844 JHP ; INTERRUPT_RETURN 

1845 

1646 1------ TOGGLED SHIFT KEY. TEST FOR 1ST MAKE OR NOT 

1847 

E9DB 1848 K18: ; SHIFT-TOGGLE 

E9DB F606170004 1849 TEST KBJLAG. CT,"-SHIFT ; CHECK CTL SHIFT STATE 

E9EO 7568 1850 JNZ K25 JUMP IF CTL STATE 

E9E2 3e52 1851 CMP Al, INS_KEY I CHECK FOR INSERT KEY 

E9E4 7525 1852 JHZ K22 1 JUMP IF NOT INSERT KEY 

E9E6 F60617DQ08 1653 TEST KBJLAG. ALT_SHIFT CHECK FOR ALTERNATE SHIFT 

E9E8 7403 1654 JZ K19 JUMP IF NOT ALTERNATE SHIFT 

E9ED E85890 1855 JHP K25 JUt1P IF ALTERNATE SHIFT 

E9FO F606170020 1856 K19: TEST KBJLAG, NUH_STATE ; CHECK FOR BASE STATE 

E9F5 750D 1857 JNZ KZl ; JUMP IF NUM LOCK IS ON 

E9F7 F606170003 1858 TEST 

E9Fe 7400 1859 JZ K22 ; JUMP IF BASE STATE 

1660 

E9FE 1861 K20: ; truMERIC ZERO. NOT INSERT KEY 

E9FE 883052 1862 "OV AX, 5230H ; PUT OUT AN ASCII ZERO 

EADI E90801 1863 JHP K57 ; BUFFER]ILL 

EA04 le64 ; MIGHT BE NUMERIC 

EA04 F606170003 1865 TEST KBJLAG, LEFT_SHIFT+ RIGHT_SHIFT 

EA09 74F3 1866 JZ K20 i JUMP NUHERIC, NOT INSERT 

1867 

EADs 1868 K22: ; SHIFT TOGGLE KEY HIT; PROCESS IT 

EADB 84261800 1869 ; IS KEY ALREADY DEPRESSED 

EAOF 7540 1870 JNZ K26 ; JUMP IF KEY ALREADY DEPRESSED 

EAll 08261800 1871 OR KBJLAG_l.AH INDICATE THAT THE KEY IS DEPRESSED 

EAtS 30261700 1872 XOR K8JLAG.AH TOGGLE THE SHIFT STATE 

EAi9 3C52 1873 Cf1P Al.INS_KEY TEST FOR 1ST MAKE OF INSERT KEY 

EAIB 7541 1874 JNE K26 JUMP IF NOT INSERT KEY 

A-26


EAID 680052 

EA20 E98901 

£.1.23 

EAll 80FCI0 

~EA26731A 

fAze F6D4 

EAZA 20261700 

EAZE XBa 

£.1.30 752C 

£A3l .1.01900 

EA35 8400 

EA37 88261900 

£AlB XOD 

£.1.30 741F 

EA3F £9.1.301 

EA42 

EA42 F604 

EA44 20261800 

EA46 E814 

EA4A 

EA4A 3eao 

EA4C 7310 

fA4E F606180008 

£.1.53 7417 

EA55 3C45 

EAS7 7405 

EA59 80261800F7 

EASE 

EASE FA 

EA5F 6020 

£.1.61 £620 

£.1.63 

EA63 01 

£.1.64 IF 

EA6S SF 

EA66 5£ 

EA67 5.1. 

EA66 59 

EA69 58 

EA6A 58 

EA66 CF 

EA6C 

EA6C F606170008 

fA71 7503 

EA73 £98FOO 

£.1.76 

£A76 F606170004 

EA78 7431 

EA70 3C53 

~ EA7F 7520 

EASt C70672003412 

£A87 £901F5 

fAaA 

EAaA 524F5051484C4O 

1875 MOV AX,INS_KEY*Z56 , SET SCAN CODE INTO AH. 0 INTO Al 

1876 JMP '57 ; PUT INTO OUTPUT BUFFER 

1877 

1878 1------ BREAK SHIFT fOUND 

1879 

le80 K23: f BREAK-SHIFT-FOUND 

1881 eMP AH,SCROLL_SHIFT ; IS THIS A TOGGLE KEY 

1682 JAE '24 ; YEs. HAtJOlE BREAK TOGGLE 

1883 UOT AH i INVERT MASK 

1684 AND KBJLAG,AH TlJ!

LOC 08J LINE SOURCE 

£"91 474849 

EA9tt 1011121314151&17 

EA9C 18191EIF20212223 

E:A.A4 24252b2C2D2:E2f30 

EAAC 3132 

1951 DB 71.72,73- ; 10 HUMBERS ON KEYPAD 

1952 ;------ SUPER-SHIFT-TABlE 

1953 DB 16,17,18,19,20,2:1,22,23 i A-Z TYPEWRITER CHARS 

l'954 DB 24.2S.30.31.32.33,~.35 

1955 DB 36.37,38,44,45,46,47.48 

1956 DB 49,,50 

1957 

1958 ;_.-••- IN ALTERNATE SHIFT, RESET NOT FOUtIJ 

fAAE 

EAAE X3V 

EA&'O ?SOS 

£A82 -B020 

EAM E92501 

fAS7 

EAB1 BF8AEA 

UBA 890100 

EABD F2 

EABE AE 

EASF 7SU 

'£Ac1 81EF8BEA 

fAtS .1.01900 

EAtS 840A 

EAtA F6£4 

flee Ole7 

EACE "21900 

EADl EB&8 

1959 

1960 K31: I NO-RESET 

1961 CNP AL,57 ; TEST FOR 'SPACE KEY 

I ... JNE K3< ; NOT THERE 

1963 HOV Al •• ; SET SPACE CHAR 

1964 JHP K57 ;: BUFF(R_FIll 

1965 

J------ LOOK 

1966 FOR KEY PAD ENTRY 

1967 

1966 K32 : J -All-KEY-PAD 

1969 I10V OI.OFFSET K30 I ALT-INPUT-TASlE 

1970 HOY CX.lO ; lOOK FOR ENTRY USING KEYPAD 

1971 REPNE seASB I tOOK FOR MATCH 

JNE 'l3 

I NO.AlT_KEYPA.D 

SUB DI,OFFSET K3D+l ; 01 NOW HAS ENTRY VALUE 

HOV AL.ALT_n~puT ; GET THE CURRENT BYTE 

HOV AH.ID ; MULTIPLY BY 10 

HUL 

ADO 

HOV 

IN" 

AH 

AX.OI 

••• 

ALT.INPUT ,Al 

1981 1------ L.()()I( fOR 'SUPERStlIFT ENTRY 

fAD3 

EA03 'C6G6'1 toOItO 

fAne 891AOO 

fA08 F2 

fADe AE 

EADD 7505 

U.OF 8000 

un £9F800 

1982 

1983 ; NO-AlT-KEYPAO 

1964 ; ZERO ANY PREVIOUS ENTRY INTO INPUT 

1985 NOV CX,26 ; DI,ES ALREADY POINTING 

1986 REPME SCASS ; LOOK FOR MATCH IN ALPHABET 

1987 JNE K34 i NOT FOUNO. FUNCTIOO KEY OR OTHER 

1988 MOV Al.a ; ASCII CODE OF ZERO 

1989 JM-P K57 ; PUT IT IN THE BUf.FER 

199'0 

1991 ;------ LOOK FOR TOP ROW OF ALTERNATE SHIFT 

UE4 

EAE4 3C02: 

EAE6 noe 

EAE8 3COE 

EAEA 7308 

EAft 80C476 

U,Ef BODO 

EAFI £9£800 

1992 

1993 K14: ; ALT-TOP-ROW 

1994 eM!' AL.2 ~ KEy.wITH 'I' OH IT 

1995 JB K35 ; NOT O"'E OF INTERESTING Kt'rs 

1996 eMP Al.14 i IS IT IN THE REGION 

1997 JAE K35 ; ALT-FUNCTION 

J11.198 ADO AH.118 ; COINERT PSUEDO SUN CODt: TO RANGE 

1999 MOV Al.O ; INDICATE AS SUCH 

2'00'0 JMP K57 ; BUFFER_FILL 

2~01 

2'002 ;------ TRANSlATt: ALTERNATE SHIFT PSEUDO stAN COMS 

2003 

EAF4 

EAt4 3ClB 

EAF6 7303 

EAFe 

EAF8 ·n63FF 

EAFB 

UFB lC47 

fAFO 73F9 

UFF 8863E9 

E80-2 E92501 

2'0'04 

I ALT-FUNCTION 

2005 ; TEST FOR IN TAGLE 

2006 1 All-CONTINUE 

2'0'07 

; CtOSE-RET\JIl'N 

2008 ; IGNORE THE KEY 

2009 I AlT-CONTINUE 

2'010 ; IN KEYPAD REGION 

2011 ; IF SO. IGNOR'E 

2'012 ; AL T SHIFT PSEUDO SCAN TABLE 

20ll 

; TRANSLATE THAT 

2'014 

2'015 1--"--- NOT IN ALTERNATE SHIFT 

fBOS 

£805 F6'06170004 ~ 

EBOA 7458 

£80C 3C46 

[BOE 7513 

2'016 

2'017 1


~EB.a 

£BI0 881EOO a2b MOV aX.OFFSET KB_BUFFER ; RESET BUFFER TO EMPTY 

EBll 891ElADO 2027 MOV BUFFER_HEAD .aX 

EB17 891E1COQ 2028 MOV BUFfER_TAIL,ex 

EBIS C6067l0060 202~ MOV BIOS_BREAK.SOH ; TURN ON BIOS_BREAK BIT 

EBZO CDIS 2030 INT lB. ; BREAK IUTERRUPT VECTm 

E822 B80000 2031 NOV AX. 0 ; PUT OUT Dut1HY CHARACTER 

E825 £98400 2032 JMP K57 ; BUFFERJIll 

201l 

2034 K39: I NO-BREAK 

EB28 3e45 203-5 CHP AL. HUH_KEY ; LOOK FOR PAUSE KEY 

E82A 7521 2036 .... K41 

; NO-PAUSE 

E5ze 800E180006 2037 O' KBJLAG_l,HOLD_STATE I TURN ON THE HOLD FLAG 

Ea31 B020 203a MOV AL.EO! ; ENO Of INTERRUPT TO CONTROL PORT 

E833 £620 2039- OUT 020H •.u .... 

; ALLOW FURTHER KEYSTROKE IHTS 

Z041 ; ------ DURING PAUSE INTERY.AL. TtmN CRT BACK ON 

2042: 

E835 803£49Q007 2043- CMP CRT_I100E.7 J IS THIS BLACK AND WHITE CARD 

EalA 7407 2044 JE K4. J YES, NOTHING TO DO 

EBle BAOSQl 2045 MOV DX,03DSH I PORT FOR COLOR CARD 

EB1F A06500 204ft AL.CRT_HOOE_SET , GET THE VALUE OF THE CLRRENT tlDDE 

""V 

EB4Z EE 2047 OUT DX.AL ; SET THE CRT MODE, SO TRAT CRT IS ON 

EB43 2048 K40: i PAUSE-lOOP 

••• 

EM3 F606180008 2049 TEST KBJLAG_l.H.OlO_STATE 

EM8 75f9 2050 JHZ ; lOOP UNTIL FLAG TURNED OfF 

eB4A E'H6FF 2Ul JMP .27 l INTERRUPT_RETURN_HD_EOI 

E840 2052 K41: j NO-PAUSE" 

2053 

2054 j ------ TEST SPECIAL CASE KEY 55 

2055 

EB40 3C37 2056 CHP AL.S5 

EB4f 7506 2057 JNE '4Z 

J HOT-KEY-55 

EBS1 8&4072 2058 MOV AX, 114*256 I START/STOP PRINTING SWITCH 

EB54 £98500 2059 JMP '57 ~ BUFFER_FILL 

z060 

2061 ; ------ SET UP TO TRANSLATE CONTROL SHIFT 

Z062 

~EB57 2063 K42: ; NOT-KEY-55 

f857 BB92ES 2064 NOV BX, OFFSET K8 ; SET UP TO TRANSLATE CTL 

EeSA 3C3B 2065 tMP Al.59 ; IS IT IN TABLE 

ES5C 7303 .... 

JAE K43 ; CTl-TABLE-TRANSLATE 

E8SE E87890 2067 JMP K56 ; YES. GO TRANSLATE CHAR 

.... 

'861 K43: J tTL-TABLE-TRANSLATE 

EB61 B8CCe8 2069 ""V BX,OFfSET 1


E890 E99700 

E893 

E693 BBlFE9 

E896 E840 

E898 

EMS F606170020 

EB9D 7520 

EB9F F606170003 

EBA4 7520 

EBA6 

EBA6 3C4A 

EBA8 7408 

EBAA 3C4E 

EBAC 740C 

EBAE 2C47 

Eeao BB7AE9 

EBBl EBn 

EBBS 882D4" 

EBB8 E822 

EBBA B82B4E 

EBBD E~lD 

EBBF 

EBBF F606170003 

EBC4 75EO 

EBC6 

EBC6 2C46 

EBce BB6DE9 

EBce EBOB 

EBCD 

EBCD 3e38 

EeCF 7204 

EBDI BODO 

EBD3 EB07 

E8DS 

EBDS BBE5E8 

EBD8 

EBDB FEee 

EBDA 2ED7 

EBDC 

EBDC 3eFF 

EBDE 741F 

EBED 80FCFF 

EeE3 

EBES 

741A 

EBES F606170040 

EBEA 7420 

EBEC F606170003 

2103 JMP K63 I TRANSLATE_SCAN 

2104 

2105 K47: ; NOT-UPPER-FUNCTION 

2106 MOV BX,OFFSET K11 ; POINT TO UPPER CASE TABLE 

2107 JMP SHORT K56 ; OK. TRANSLATE TlIE CHAR 

2108 

2109 ;------ KEYPAD KEYS, HUST TEST HUM LOCK FOR DETERMINATION 

2110 

2111 K48: ; KEYPAD-REGION 

2112 ; ARE WE IN ,,"'UH_LOCK 

2113 JNZ KS2 ; TEST FOR SURE 

2114 TEST KB_FLAG.LEFT_SHIFT+RIGHT_SHIFT; ARE WE IN SHIFT STATE 

2115 JHZ K53 j IF SHIFTED, REALLY HUM STATE 

2116 

2117 j ------ BASE CASE FOR KEYPAD 

2118 

2119 K49: j BASE-CASE 

2120 

2121 eHP AL,74 j SPECIAL CASE FOR A COUPLE OF KEYS 

l122 JE K50 ; MINUS 

2123 eMP AL,78 

2124 JE K51 

2125 SUB AL,71 j CONVERT ORIGIN 

2126 HOV BX.OFFSET K15 J BASE CASE TABLE 

2127 JMP SHORT K64 , CONVERT TO PSEUDO SCAN 

2128 

2129 K50: HOV AX. 74*256+ '-' j MINUS 

2130 JMP SHORT K57 J BUFFERJILl 

2131 

2132 K51: MOV AX. 781f256+' +' I PLUS 

2133 JMP SHORT K57 1 BUFFER_FILL 

2134 

tllS 1------ MIGHT BE N\.I1 LOCK, TEST SHIFT STATUS 

t136 

2137 K5t: ; ALMOST-NUt1-STATE 

2138 TEST KBJLAG.LEFT_SHIFT+RIGHT_SHIfT 

2119 JHZ K4. ; SHIFTED TEMP OUT OF NUt1 STATE 

2140 

2141 K53: j REALLY_NUr"LSTATE 

2142 SUB AL,70 I CONVERT ORIGIN 

2143 MOV BX,OFFSET K14 ; NUM STATE TABLE 

2144 JMP SHORT K56 , TRANSLATE_CHAR 

2145 

2146 j------ PLAIN OLD LOWER CASE 

2147 

2148 K54: ; NOT-SHIFT 

2149 eMP AL.59 j TEST FOR FUNCTION KEYS 

2150 JB K55 ; NOT-LOWER-FUNCTION 

2151 MOV AL.O ; SCAN CODE IN AH ALREADY 

2152 JHP SHORT K57 I BUFFER_FILL 

2153 

2154 K55: j NOT-LOWER-FUNCTION 

2155 MOV BX.OFFSET KID j LC TABLE 

2156 

2157 j------ TRANSLATE THE CHARAC-rER 

2158 

2159 K56: ; TRANSLATE-CHAR 

2160 DEC AL ; CONVERT ORIGIN 

2161 XLAT CS:K11 ; CONVERT THE SCAN CODE TO ASCII 

2162 

2163 ;------ PUT CHARACTER INTO BUFFER 

Z164 

2165 K57: ; BUFFER-FILL 

2166 eMP AL.-l IS THIS AN IGNORE CHAR 

2167 JE K5. j YES. DO NOTHING WITH IT 

2168 eMP ; LOOK FOR -1 PSEUDO SCAN 

2169 JE ; NEAR_INTERRUPT_RETURN 

2170 

2171 ;------ HANDLE THE CAPS LOCK PROBLEM 

2172 

2173 K58: I BUFFER-FILL-NOTEST 

2174 TEST KBJLAG.CAPS_STATE ; ARE WE IN CAPS LOCK STATE 

2175 JZ K61 ; SKIP IF NOT 

2176 

2177 ; ------ IN CAPS LOCK STATE 

2178 

2179 TEST KBJLAG. LEFT_SHIFT+RIGHT_SHIFT TEST FOR SHIFT STATE 

A-30

LOC OBJ LINE sou RCE 

ESFI 740F 2180 JZ K60 ; IF NOT SHIFT. CONVERT LOWER TO LIPPER 

2181 

2182 ;------ CONVERT ANY UPPER CASE TO LOWER CASE 

2183 

EBF3 3C41 2184 CMP AL, 'A' ; FIND OUT IF ALPHABETIC 

EBFS 7215 2185 JB K61 ; NOT_CAPS_STATE 

EBF7 3CSA 2:186 CMP AL. 'Z' 

EBF9 7711 2187 JA K61 ; NOT_CAPS_STATE 

EBFB 0420 2188 ADD Al, 'a '-'A' ; CONVERT TO LO~ER CASE 

fBFO EBOD 2189 JMP SHORT K61 ; NOT_CAPS_STATE 

2190 

EBFF 2191 K59: ; NEAR-INTERRUPT-RETURN 

EBFF E95CFE 2192 JMP KZ6 ; INTERRUPT_RETURN 

2193 

2194 i ----- CONVERT ANY LOWER CASE TO UPPER CASE 

2195 

EC02 2196 K60: ; LOWER-TO-UPPER 

EC02 3C61 2197 CMP AL. 'a' ; fINO OUT IF ALPHABETIC 

EC04 7206 2198 JB K61 ; NOT_CAPS_STATE 

fC06 3C7A 2199 CMP AL, 'z' 

EC08 7702 2200 JA 1-',61 ; NOT_CAPS_STATE 

EeOA 2e2:0 2201 SUB AL. 'n'-'A' ; CONVERT TO UPPER CASE 

2202 

Eeoc 2203 K61: ; NOT-CAPS-STATE 

Eeoc 2:::04 ; GET THE END POINTER 8BlEICOO MOV BX,BUFFER_TAIl TO THE BUfFER 

ECIO BaF3 2205 tiDV SI.eX SAVE THE VALUE 

fe12 E860FC 2206 CALL K4 ADVANCE THE TAll 

EClS 3BIEIAOO 2207 CIlP BX.BUFFER_HEAD HAS THE BUFFER WRAPPED AROUND 

ECl9 7409 2208 JE K62 BUFFER_FUll_BEEP 

ECIB 8904 2209 MOV [SI1,AX STORE THE VALUE 

ECID 891EICOO 2210 MOV BUFFER_TAIL,eX 1 MOVE THE POltHER UP 

Ee21 E93AFE 2211 JMP K26 INTERRUPT_RETURN 

2212 

2213 BUFFER IS FUll, somm THE ;------ BEEPER 

2214 

[C24 2215 K62: BUFFER-FUll-BEEP 

~ EC24 f80DOO 2216 CALL ERROR_BEEP 

Ee27 E934FE 2217 K'6 

2218 

2219 TRANSLATE SCAN FOR ;------ PSEUDO SCAN CODES 

2220 

Ee2A 2221 K63: j TRANSLATE-SCAN 

EC2A 2222 ; CONVERT ORIGIN 2C38 SUB AL,59 TO FUNCTION KEYS 

felt 2223 K64: I TRANSlATE-SCAtl-ORGD 

fe2t 2ED7 2224 XlAT CS:K9 ; CTL TABLE SCAN 

Eelf BAED 2225 MOV AH,AL ; PUT VALUE INTO AH 

EC30 BODO 2226 MOV AL.e ; ZERO ASCII CODE 

EC32 EBA8 2227 JHP KS7 ; PUT IT INTO THE BUFfER 

2228 

2229 EflOP 

I

LOC 08J LINE SOURCE 

2255 ;-- INT 13 ---------------------'------------ 

2256 ;DISKETTE 1/0 

2257 THIS INTERFACE PROVIDES ACCESS TO THE 5 1/4" DISKETTE DRIVES 

2.258 ; INPUT 

2259 (AH };;Q RESET DISKETTE SYSTEM 

2260 HARD RESET TO NEC, FREPARE COMMAND. RECAL REQD ON ALL DRIVES 

2261 (AHI=l READ THE STATUS OF THE SYSTEM INTO (All 

2262 DISKETTE_STATUS FROM LAST OP'" IS USIO 

2263 REGISTERS FOR P.EAO/WRITE/vERIFY/FORMAT 

2264 (OLI - DRIVE NUtlBER (0-3 ALLOWED, VALUE CHECKED) 

22:65 {DHI ~ HEAD ~ruMBER (0-1 ALLOWEn, I\'OT VALUE CHECKED) 

2266 (CH) - TRACK NUtlBER (0-39, t.'OT VALUE CHECKEO) 

22:67 (eL) - SECTOR truMBER f 1-8, NOT VALUE CHECKEO) 

2268 fAll - NUMBER OF SECTORS ( MAX ;; 8, NOT VALUE CHECK EO) 

2269 

2270 (ES:BX) - ADDRESS OF BUffER ( NOT REQUIRED FOR VERIFY) 

2:271 

2272 (AH )=2: READ THE DESIRED SECTOOS INTO MEMORY 

2273 «AH )=3 WRITE HlE DESIRED SECTORS FROM HEMORY 

2274 (AH 1=4 VERIFY THE DESIRED SECTORS 

22:75 (AH);:5 FORMAT THE DESIRED TRACK 

2276 FOR THE fORMAT OPERATlm" THE BUFFER POINTER (ES,BXI MUST 

2277 POINT TO THE COLLECTIOH OF DfSIRED ADDRESS FIElDS FOR THF.: 

22:78 TRACK. EACH FIELD IS CQtlPOSED OF 4 BYTES. (C,H,R,NI, WHERE 

2279 C ;; TRACK HUMBER, H=HEAD NUMBER, R ;; SECTOR NUMBER, N= NUMBER 

2280 OF BYTES PER SECTOR ("00=128, 01=256, 02=512. 03=1024,) 

2281 THERE MUST BE ONE ENTRY FOR EVERY SECTOR ON THE TRACK. 

USZ 

2:283 READ/WRITE ACCESS. 

2284 ; DATA VARIABLE - DISK_POINTER 

THIS INFORMATION IS USED TO Fum THE REQUESTED SECTOR DURING 

~28S DOUBLE WORD POINTER TO THE CURRENT SET OF DISKETTE PARAMETERS 

2286 ; OUTPUT 

2287 AH = STATUS OF OPERATION 

2288 STATUS BITS ARE DEfINED IN THE EQUATES fOR DISKETTE_STA,TUS 

2289 VARIABLE IN THE DATA SEGMENT OF THIS NODULE 

EC59 

EC59 fB 

ECSA 53 

Ee58 51 

ECSC IE 

Ee50 56 

ECSE 57 

ECSF 55 

EC60 52 

EC61 8BEt 

EC63 8E4000 

EC66 BEDf 

EC68 f81COO 

EC6B 6B0400 

EC6E ESFFO} 

Ee7l e8264000 

Ee75 8A264100 

EC79 80FCO) 

Ee7t FS 

EC7D SA 

Ee7E 50 

[e7F SF 

EC8Q Sf 

EC8l IF 

Ee62 59 

Ecel 58 

E(84 CA0200 

Ee87 

2290 

2291 

2292 

2293 

2294 

2295 

2296 

2297 

2296 

2299 

2300 

2301 

2302 

2303 PROC FAR 

2304 

2]05 ex 

2306 ex 

2307 os 

2308 51 

Z309 01 

2310 BP 

2311 ox 

2312 BP.SP 

e313 

SI,DATA 

2314 OS,SI 

2315 Jl 

2316 BX,4 

2317 

2318 

2319 

2320 eMP AH,J ; SET THE CARRY fLAG TO INDICATE 

2321 eMe I SUCCESS OR FAILURE 

2322 POP ox i RESTORE ALL REGISTERS 

232:3 POP BP 

2324 POP 01 

2325 POP 51 

2326 POP OS 

2327 POP CX 

2328 POP BX ; RECOVER ADDRESS 

2329 RET ; THROW AWA'( SAVED FLAGS 

2330 DISKETTE_IO E~mp 

2:331 Jl PROC ~lEAR 

A-32


EC87 BA.fO 

EC89 60l63F007F 

EceE 0"E4 

£C90 7427 

£C92 FEte 

EC94 7474 

EC96 C606410000 

~ EC9B eOFA04 

EC9E 7313 

ECAO FEte 

feA,l 746A. 

ECA4 FEte 

ECA6 7503 

2:5'32 HOV OH,Al '; SAVE. SECTot;!S IN DH 

2333 AND ;. INDICATE A READ OPERATION 

2334 OR AH,AH • AH=O 

,335 JZ DISK_RESET 

U16 DEC AH ; AH=l 

2337 JZ DISK_STATUS 

2:336 HOV ; RESET THE STATUS INDICATOR 

2339 CMP Dl.4 I TEST FOR DRIVE IN 0-3 RANGE 

2340 JAE J3 ; ERROR IF ABOVE 

2341 DEC AH i AH=2: 

2342 JZ nISK_READ 

2343 DEC AH ; AH=3 

2344 JHZ 

J' 

; TEST_DISK_VERF 

ECAB £99600 

ECAB 

2:345 JMP 

2346 J2 : 

eCAB FEte 

feAD 7468 

fCAF FEte 

feel 7468 

Eee3 

ECB3 C6064100111 

ECBS C3 

EC59 

ECB9 BAFZ03 

fCBC FA 

EeeD A03FOO 

feeD BI04 

eeel OZEO 

Ece4 A82:0 

£CC6 750C 

fees A,840 

ECCA 7506 

Ecce A860 

ECCE 7406 

EeDO FEtO 

ECD2 FEtD 

ECD4 FE.tD 

fCD6 oe08 

ECOB EE 

ECD9 C6063£0000 

ECDE C606410000 

feEl OC04 

fees EE 

fCEb FB 

ftE7 £8280Z 

EeEA A04200 

fCED 3etO 

EceF 7407 

fCFI 600£410020 

ECF6 EBII 

ECFa 

ECFe 8403 

fCFA £84701 

fCFO 880100 

EDOO E86DOl 

E003 880300 

fD06 £86701 

£009 

£P09 C1 

fDOA 

EDOA A04100 , 

EDOO C3 

2347 DEC 

2348 JZ 

2349 DEC AH ; AH=S 

2350 JZ DISKJORf1AT 

2:351 J3: 

2352 NOV DISKETTE_STATUS.BAD_CND i ERROR CODE. NO SECTORS TRANSFERRED 

2353 RET ; UNDEFINED OPERATION 

2354 Jl ENDP 

2355 

2356 ;------ RESET THE DISKETTE SYSTEM 

2357 

2358 PROC HEAR 

2359 MOV DX.03FZH ; ADAPTER CONTROL PORT 

2360 CLl '; NO INTERRUPTS 

2361 MOV AL,MOTOR_STATUS I WHICH MOTOR IS ON 

236Z HOV CL.4 ; SHIFT CCU~T 

2363 SAL AL.CL ; MOVE MOTOR VALUE TO HIGH HYBBLE 

2364 TEST Al, tOH I SElECT CORRESPOHOIHG DRIVE 

2365 JNZ J5 I JUMP IF MOTOR ONE IS Ot~ 

2366 TEST AL. 40H 

2367 JHZ J4 1 JUMP IF HOTOR TWO IS ON 

2:368 TEST AL. SOH 

2:369 JZ J6 ; JUMP IF MOTOR ZERO IS ON 

2370 IHC Al 

2371 J4: ItIC Al 

2372 J5: IIle Al 

2373 J6: OR AL,S j TURN ON INTERRUPT EHABlE 

2374 OUT OX,AL ; RESET TH~ AnAPTER 

2375 MOV SEEK_STATUS, 0 ; SET RECAl REQUIRED ON ALL DRIVES 

2376 MOV DISKETTE_STATU5.0 j SET OK STATUS FOR DISKETTE 

2.377 OR Al.4 ; TURN OFF RESET 

2378 OUT DX.Al , TURN OFF THE RESET 

2379 STI ; RHNABlE THE INTERRUPTS 

2380 CALL CHK_STAT3 ; DO SENSE INTERRUPT STATUS FOLLOWING RESET 

USI MOV AL.NEC_STATUS IGNORE ERROR RETURN AND 00 OWN TEST 

uat CNP AL,OCOH I TEST FOR DRIVE READY TRANSITION 

U83 JZ J7 ; EVERYTHING OK 

2384 OR OISKETTE_STATUS.BAO_NEC ; SET ERROf;! CODE 

2385 

JMP 

".. 

SHORT J8 ; RESET_RET 

2387 ;------ SEND SPECIFY CotR1ANO TO HEC 

2388 

2389 J7: ; DRIVE_READY 

2390 MOY AH,03H ; SPECIFY COMMAND 

2391 CALL NEC_OUTPUT ; OUTPUT TH E COMMAND 

2:392 MaV ex.l ; FIRST BYTE PARM IN BLOCK 

2393 CALL GET_PARM ; TO THE NEe COtHROLLER 

2394 MOV I SECOND BYTE PARtl IN BLOCK 

2395 CALL ; TO THE NEC COIHROLLER 

2396 1 RESET_RET 

J8: 

2397 RET ; RETURN TO CALLER 

2398 ENDP 

2399 

2400 ;------ DISKETTE STATUS ROUTINE 

2401 

2402 PROC NEAR 

2403 NOV AL. DISKETTE_STATUS 

2404 

2405 ENDP 

2406 

A-33

LOC OS! LINE SOURCE 

2407 ;------ DISKETTE READ 

2408 

EOOE 2409 PROC NEAR 

EDOE 8046 2410 Al,046H ; READ COMNAHO fOR DNA 

E010 2411 J9: t DISK_READ_CONT 

EOIO ESMOl 2412 CALL DHA.SETUP • SET UP THE DNA 

EOll 8466 ~413 HOV AH,066H SET UP READ COMMAND FOR NEe CONTROLLER 

E015 EB16 2414 JMP SHORT RW.OPN ; GO 00 THE OPERATION 

:415 ENDP 

2416 

2411 ; ----- DISKETTE VERIFY 

2418 

E017 2419 DISK_VEPF PROC NEAR 

E017 8042 2420 ~10V Al.0421" ; VER I F Y COMMAND FOR OMA 

E019 ESF5 2421 JMP J9 ; DO AS IF DISK READ 

2422 DISK_VERF EtfDP 

2423 

;------ DISKETTE FORNAT 

2425 

EDIB 2426 DISK]ORHAT PROC NEAR 

EOIB 800E3FOOSO 2421 OR HOTOR_STATUS.80H ; IHDICATE WRITE OPERATION 

EOZD B04A 2428 NOV AL,04AH 1 WILL WRITE TO THE DISKETTE 

£022 £8A701 2429 CALL OHA_SETUP j SET UP THE DNA 

E025 8440 2430 May AH,04DH ; ESTABLISH THE FORMAT COMMAHD 

EDZl EB24 2431 JMP SHORT RW_OPN ; DO THE OPERATION 

E029 2432 JIO: ; CONTINUATION OF RW_OPN FOR FMT 

E029 880700 2433 HOV BX,7 ; GET THE 

Eoze E84101 2434 CALL GET.PARM ; BYTES/SECTOR VALUE TO NEe 

EDlF 680900 2435 MOV BX,9 ; GET HIE 

EDll E83BOI 2436 CALL GET.PARM j SECTORS/TRACK VALUE TO NEC 

E035 BBOFOO 2437 HOV BX,15 ; GET THE 

E038 E83501 2438 CAll GET_PARM j GAP LENGTH VALUE TO NEC 

E03B B81100 2439 MOV BX,17 j GET THE FILLER BYTE 

EDlE E9ABOD 2440 JMP JI6 ; TO THE CONTROLLER 

2441 DISK]ORMAT ENDP 

2442 

2443 ;------ DISKETTE WRITE ROUTINE 

2444 

E041 2445 PROC NEAR 

E041 800E3FOD80 2446 OR MO rOR_STATUS ,80H ; IHDICATE WRITE OPERATION 

E046 8044 2447 MOV AL.04AH j DNA lomITE COMMAND 

f048 E88101 2448 CAL l DHA_SETUP 

E04S 8445 2449 MOV AH ,045H ; NEC COHHAt.lD TO WRITE TO DISKETTE 

2450 ENOP 

2451 ;----- ALLOW WRITE ROUTINE TO FALL INTO RW_OPN 

2452 i ------------------------------------ 

2453 ; RW.OPN 

2454 THIS ROUTINE PERFORMS THE READ/WRITE/VERIFY OPERATION 

2455 ; .-------- ----- - - ------------------- 

E040 2456 

£040 7308 2457 JNe JII TEST FOR DMA ERROR 

E04f C606410009 2458 May DISKETTE_STATUS,DMA_BOUNDARY i SET ERROR 

ED 54 BODO 2459 MOV Al.O ; NO SECTORS TRANSFERRED 

EDS6 C] 2460 RET ; RETURN TO HAIN ROUTINE 

E057 2461 Jll: I DO_RW_OPN 

ED57 50 2462 PUSH AX ; SAVE THE COMMAND 

2463 

2464 ; ----- TURN ON THE MOTOR AND SelECT THE DRIVE 

2465 

EO 58 51 2466 PUSH ex I SAVE THE T/S PARNS 

EDS9 SACA 2467 May Cl.Ol j GET DRIVE NUMBER AS SHIfT COUNT 

ED58 B001 2468 May Al,} I MASK FOR DETERMINING MOTOR BIT 

Ease 02EO 2469 SAL Al.Cl ; SHIFT THE MASK BIT 

EOSF FA 2470 eLI ; NO ItHERRUPTS WHILE DETERMINING MOTOR STATUS 

E060 C6064000FF 2471 May MOTOR_COUNT,OFFH ; SET LARGE COUNT DURUIG OPERATION 

E065 84063FOQ 2472 TEST AL,110TOR_STATUS ; TEST THAT MOTOR FOR OPERATING 

E069 7531 2473 J~IZ J14 ; IF RUNHING, SKIP THE WAIT 

EDbB e0263FOOfO 2474 AND I1OTOR_STATUS.OFOH ; TURN DFF ALL MOTOR BITS 

£070 08063FOO 2475 OR MOTOR_STATUS,AL j TURN ON THE CURRENT MOTOR 

£074 FB 2476 STI ; INTf.RRUPTS BACK ON 

E075 BOlO 2:477 MOV AL,IOH ; ~1ASK BIT 

Eon 02EO 2478 SAL Al,CL ; DEVelOP BIT MASK FOR MOTOR EHABLE 

£079 04C2 2479 OR AL.Ol ; GET (JRIVE SELECT BITS IN 

E078 oeoe 2480 OR AL,OCH ; NO RESET, EIIABLE DNA/INT 

f07D 52 2481 PU5H ox ; SAVE REG 

E07E SAFl03 248~ MOV DX.03F2H ; CO~HROL PORT ADDRESS 

E081 EE 2483 OUT DX,Al 

A-34

LOC OBJ LINE SOU-RCE 

~ 

f082: 5A 2464 

2485 

E08l F60b3F0080 

EO&6 7412 

EDBA B81400 

EDeD E8EOOO 

£090 0.4.£4 

E092 

Eon 7408 

E094 2BC9 

E096 E2FE 

ED98 FEce 

ED9A fBF6 

EDge 

EDge FB 

ED90 59 

ED9E £8EOOO 

EoAl 58 

fOAl 8AFe 

EDA4 6600 

EDAb 7246 

EDA8 BEF1ED90 

EOAe 56 

EDAD E89400 

EDBD 8A6601 

EoB3 DOE4 

EoBS 00E4 

EOB7 80£404 

EDBA OAE2 

EDBC E86500 

EDBF 60FF4D 

£oe.2 7503 

EDC4 E96ZFF 

EOC7 BAES 

Eoe9 £87800 

Eoce 8MbOl 

EOCF f87200 

E002 8AEl 

EDD4 E86000 

E007 B60700 

EDDA E89300 

EOoD B60900 

£OEO £88000 

EDEl 860600 

EDE6 f88700 

EOE9 eeoooo 

fDEC 

EDEC E88100 

EDEF 5f 

fDFO £84001 

EOFl 

EOF3 7245 

EDFS £67301 

fDFS 7.23F 

EOFA Fe 

EDFB 6£4200 

EOFE AC 

EOFF 24eo 

2486 

2487 

2488 

2489 

2490 

2491 

2492 

2493 

2494 

2495 

2496 

2497 

2:498 

2499 

2500 

2501 

2502 

2503 

2504 

2505 

2506 

Z507 

2508 

Z50~ 

Z510 

Z511 

2512 

2513 

2514 

2515 

2516 

2517 

2518 

2519 

2520 

2521 

2522 

2523 

2524 

2525 

2526 

2527 

2528 

2529 

2530 

2531 

2532 

2533 

2534 

2535 

2536 

2537 

2538 

2539 

2540 

2541 

~542 

2543 

2544 

2545 

2546 

2547 

2548 

254';1 

2550 

2551 

2.552 

2553 

2.554 

2555 

2556 

2557 

2558 

2559 

2560 

POP ox ; RECOVER REGISTER'S 

;------ WAIT FOR MOTOR' IF WRITE OPERATION 

J12: 

J13: 

J14: 

TEST 

JZ 

MaV 

CALL 

DR 

JZ 

SUB 

lOOP 

DEC 

JMP 

STI 

POP 

MOTOR.:,.STATUS.80H 

J14 

BX.20 

GET_PARH 

AH.AH 

Jl4 

cx.ex 

J13 

AH 

Jlt 

ex 

~------ 00 THE SEEK OPERATION 

; IS THIS A WRITE 

; NO. CONTINUE WITHOUT WAIT 

; GET THE MOTOR WAIT 

; PARAMETER 

; TEST FOR NO WAIT 

; TEST_WAIT_TIME 

; EXIT WITH TItlE EXPIRED 

; SET UP 1/8 SECOND LOOP TIME 

; WAIT FOR THE REQUIRED TIME 

; DECREMENT TIME YALUE 

; ARE WE DONE YET 

; MOTOR_RUNNING 

INTERRUPTS BACK ON FOR BYPASS WAIT 

CAll SEEK ; MOVE TO CORRECT TRACK 

POP AX ; RECOVER COMMAUO 

NOV BH, Aft l SAVE COH11AND IN BH 

HOV DH.O ; SET NO SECTORS READ IN CASE OF ERROR 

JC J 17 ; IF ERROR. THEt! EXIT AFTER MOTOR Off 

MOV 51 ,OffSET J17 ; DUMMY RETURN ON STACK FOR ~IEC_OUTF'UT 

PUSH 51 ; SO THAT IT WILL RETURN TO MOTOR Off LOCATION 

}------ SEND OUT THE PARAMETERS TO THE CONTROllER 

CALL 

MOY 

SAL 

SAL 

AIm 

OR 

NEC_OUTPUT 

AH,[ BP+ II 

AH,l 

AH.l 

AH.4 

AH.DL 

j------ TEST FOR FORMAT COMMAND 

JlS~ 

J16: 

eMP 

Jt~E 

JMP 

MOV 

CALL 

MOV 

CALL 

MOV 

CALL 

MOV 

CAll 

MOV' 

CALL 

MOY 

CALL 

nov 

6H .04DH 

JIS 

JIO 

AH,CH 

AH, [BPtl J 

NEe_OUTPUT 

AH,CL 

NEC_OUTPUT 

BX.7 

GET _PARM 

BX.9 

GET_PARM 

BX,Il 

GET_PARM 

BX.13 

CALL GET_PARM 

POP 51 

;------ LET THE OPERATION HAPPEN 

J17: 

CALL 

Je 

CALL 

Je 

J21 

RESULTS 

J20 

; OUTPUT THE OPERATION COMMANO 

I GET THE CURRENT HEAD NUMBER 

j MOVE IT TO BIT 2 

; ISOLATE THAT BIT 

; OR IN. THE OP.IVE NUMBER 

I IS THIS A fORMAT OPERATION 

; NO. CONTINUE WITH R/W/V 

; IF SO. HAt.fDlE SPECIAL 

; CYlINDER NUMBER 

HEAD NUt1BER FROM STACK 

SECTOR NUMBER 

; BHES/SECTOR PAPM FROM BLOCK 

TO THE NEe 

i EOT PARM FRaN BLOCK 

I TO THE NEe 

; GAP LEHGTH PARI1 FROM BLOCK 

i TO THE NEe 

j OTl PARM fRCi~ BLOCK 

; Rll_OFt~_FItHSH 

; TO THE NEC 

CAN NOW DISCARD THAT DUHtI'f RETlIRN ADDRESS 

I WAIT FOR THE INTERRUPT 

; MOTOR_OFF 

; LOOK FOR ERROR 

; GET THE NEC STATUS 

; LdaK fOR ERROR 

;------ CHECK THE RESULTS RETURNED BY THE CONTROllER 

; set THE CORRECT DIRECTION 

CLD 

MOV 51 ,OFFSET NEC_STATUS ; porNT TO STATUS FIElD 

LODS NEC_STATUS 

; GET STO 

AND Al.OCOH ; TEST fOR NORMAL TERMINATION 

A-35


(Eol 7438 

fE03 3C40 

EEOS 1529 

EE07 AC 

EE08 ODED 

EEOA 8404 

EEOC 7224 

EEOE OOEO 

EEIO ODED 

Efl2 8410 

EE14 721C 

EE16 DOEO 

EElS 8408 

EEU 7216 

EEle OOEO 

EElf OOEO 

Ef20 8404 

EE22 nOE 

E:E24 ODED 

EE26 6403 

EEM nOB 

EEZA OOEO 

EEzt 8402 

EEZE 72:02: 

EnD 

EE30 8.20 

EE32 

ED2 06264100 

EE36 E67701 

EEl9 

EE39 C3 

EE3A 

EE3A E82E01 

EE3D C3 

EnE 

EDE E86FOl 

EE"1 32E4 

£E43 C3 

EE44 

EE44 52 

EE45 51 

EE46 BAF401 

EE49 33C9 

EE48 

EE48 EC 

EE4C A840 

E£4E 740C 

EESO E2:f9 

fE5, 

2561 JZ 

2562 CtlP Al,040H j TEST FOR ABNORMAL TERMINATION 

2563 JHZ JI8 j NOT ASNORHAl, BAD NEe 

2564 

2565 1------ AE'.NORMAl TERMINATION, FIND OUT WHY 

2566 

2:567 lOoS NEC_STATUS ; GET STl 

2568 SAL AL,I , TEST FOR EaT FOUND 

2569 HOV AH .RECORD_NOT_FND 

2570 JC JI. ; RWJAIL 

2571 SAL AL.I 

ZS7Z SAL AL,l ; TEST FOR CRC ERROR 

2573 HOV AH.BAD_CRC 

2574 JC JI. • RWJAIL 

2575 SAL ALol i TEST FOR DttA OVERRUN 

2576 HOV AH.BAD_DMA 

2.577 JC JI. 

2:578 SAL AL,I 

2579 SAL At,l TEST FOR RECORD HOT FOUND 

2560 MOV AH,RECORD_NOTJHD 

2561 JC JI. ; RWJAIL 

2!i9.2 SAL AL,t 

2583 HOV AH ,WRITE]ROTECT 

2564 JC Jl9 ; RWJAIL 

2585 SAL AL.l ; TEST HISSING ADDRESS HARK 

25&6 HOV AH ,BAD_ADDR_ttA~K 

2587 Je JI' ; RWJAIL 

2568 

2569 j------ NEC MUST HAVE FAILED 

2S'i'D 

2591 JI8: ; RW-NEe-FAIL 

2592 HOV 

ZS93 J19: : RW-FAIL 

2594 OR DISKETTE_STATUS ,AH 

2595 CALL NUM_TRANS I HOW HAtty WERE REALLY TRANSFERRED 

2596 J20: ; FlN_H!R 

2597 RET ; RETURN TO CALLER 

ZS98 

2599 J21: ; RN_ERR_RES 

2&00 CALL RESULTS ; FLUSH THE RESULTS BUFFER 

2601 RET 

2602 

2603 ~------ OPERATION WAS SUCCESSFUL 

260'4 

260'5 J22: ; OPH_OK 

260'6 CALL NUM_TRANS ; HOW HANY GOT HOVED 

2607 XOR AH,AH ; NO ERRORS 

26()8 RET 

260'9 RW_OPN ENDP 

261 () ; ------------------------------------------- 

2611 ; NEC_OUTPUT 

2612 THIS ROUTINE SEttOS A BYTE TO THE HEC CONTROLLER 

2613 AFTER TESTING FOR CORRECT DIRECTION AND COHTROLlER READY 

2:614 THIS ROUTINE WIll TIHE OUT IF THE BYTE IS NOT ACCEPTED 

2:615 WITHIN A REASONABLE AHOUNT OF TIttE. SETTING THE DISKETTE STATUS 

2:616 ON COMPLETION 

2:617 INPUT 

2618 (AH) BYTE TO BE OUTPUT 

2:619 OUTPUT 

2:620 CY = 0 SUCCESS 

2621 CY = 1 FAILURE -- DISKETTE STATUS UPDATED 

262:2 IF A FAILVRE HAS OCCURRED. THE RETURN IS MADE ONE LEVEL 

2623 HIGHER THAN THE CALLER OF NEC_OUTPUT 

2624 THIS REMOVES THE REQUIREMENT OF TESTING AFTER EVERY CALL 

2:62:5 OF NEC_OUTPUT 

2:626 (At) DESTROYED 

262:7 ; ---------------------- - -------------------- 

2:62:8 NEC_OUTPUT !"ROC NEAR 

2:629 PUSH ox ; SAVE REGISTERS 

2630 PUSH ex 

2:631 HOV DX,O'3F4H ; STATUS PORT 

XOR CX,CX ; COUNT FOR TIME OUT 

"'2 

2633 J23: 

2:634 It. Al,ox ; GET STATUS 

2635 TEST AL,040H ; TEST DIRECTION BIT 

2:636 JZ J25 ; DIRECTION OK 

2637 LOOP J2J 

2638 J2:4: TIME_ERROR 

A-36


r""\ 

EE52: 800£410080 2639 OR oISKETTE_STATUS. TIME_OUT 

££57 59 2640 POP CX 

EE58 SA 2641 POP OX ; SET ERROR CODE AND RESTORE REGS 

EES9 56 2.642 POP AX ; DISCARD THE RETUF!N ADDRESS 

EESA F9 2643 STC ; INDICATE ERROR TO CALLER 

EES9 C3 2644 Rn 

2645 

EESC 2646 J25: 

EESC 33C9 2647 XOR cx.cx ; RESET THE COUUT 

EESE 2648 J26: 

EESE EC ~649 IN .u,ox ; GET THE STATUS 

EESF AB80 2650 TEST AL.OBOH J IS IT READY 

fE61 7504 2651 J"" J27 I YES. GO OUTPUT 

fE63 E2F9 2652 LOOP J2. J COUNT omm AHD TRY AGAIN 

fE65 EBEB 2653 J"P J2' J ERROR CONDITION 

fE67 2654 J2:7: ; OUTPUT 

fE67 84C4 2655 t10V AL,AH • GET BYTE TO OUTPUT 

E£69 BAF501 2656 ""V DX,03F5H ; DATA PORT 

Efbe EE 2657 OUT OX.AL ; OUTPUT THE BYTE 

EE60 59 2:658 POP CX ; RECOVER REGISTERS 

fE6E 5A 2659 POP OX 

EE6F C3 2.660 Rn ; CY = 0 FROM TEST INSTRUCTION 

2661 NEt_OUTPUT ENOP 

2662 ; ----------------------------------------- 

2663 ; GET_PARM 

2664 I THIS ROUTINE fETCHES THE IHOEXED POINTER FROM 

2665 I THE DISK_BASE BLOCK POINTED AT BY THE DATA 

2666 I VAF!IABLE DISK_POINTER 

2667 ; A eYTE FROM THAT TABLE IS THEN HOVED INTO AH, 

2668 ; THE INDEX OF THAT BYTE BEING THE PARrt IN ex 

2669 ; ENTRY - 

2670 BX = INDEX OF BYTE TO BE FETCHED * 2 

2671 IF THE lOW BIT OF ex IS ON. THE BYTE IS IMMEDIATELY 

2672 OUTPUT TO THE NEC CONTROLLER 

2673 EXIT - 

2674 AH = THAT BYTE fROM BLOCK 

2675 ; ------------------------------------------- 

r""\ 

EE70 2676 GET_PARl1 PROC t~EAR 

E£70 IE 2677 PUSH as SAVE SEGMENT 

EE71 2BCO 2678 SUB AX.AX J ZERO TO AX 

EE73 8E08 2679 "OV OS,AX 

2680 ASSUME OS:ABSO 

E£75 C5367800 2681 LOS 51 ,DISK_POINTER ; POINT TO BLOCK 

EE79 DIES 2682 SHR ax,l ; DIVIDE BX BY 2. AND SET flAG FOR EXIT 

EE7B 8A20 2683 "OV AH,lSI+BXl ; GET THE WORD 

EE7D IF 2684 POP OS j RESTORE SEGMENT 

r""\ 

268S ASSUME OS:OATA 

EE7E 72C4 2686 JC NEC_OUTPUT ; IF FLAG SET, OUTPUT TO CONTROLLER 

EE80 C3 2687 RET ; RETURN TO CALLER 

2688 GET_PARI1 ENOP 

2689 ;------------------------------------------- 

2690 ; SEEK 

2691 THIS ROUTINE WILL MOVE THE HEAD ON THE NAMED DRIVE 

2692 TO THE NAMED TRACK. IF THE DRIVE HAS NOT BEEN ACCESSED 

2693 SINCE THE DRIVE RESET COMMAND WAS ISSUED, THE DRIVE WILL BE 

2694 RECALIBRATED. 

2695 ; INPUT 

.2:696 (DU = DRrVE TO SEEK ON 

2697 (CH) = TRACK TO SEEK TO 

2698 ; OUTPUT 

2699 CY = 0 SUCCESS 

2700 CY = 1 FAILURE -- DISKETTE_STAn../S SET ACCORDINGLY 

2701 (AX I DESTROYED 

2702 ; ---------------------------------- --------- 

EE81 2703 SEEK PROC HEAR 

EE8l· 8001 2704 MV AL,1 ; ESTABLISH MASK fOR RECAL TEST 

EE63 51 2705 PUSH CX ; SAVE INPUT VALUES 

EE84 8ACA 2706 ""V CL,OL ; GET DRIVE VALUE INTO CL 

EE86 D2CO 2707 ROL AL,CL ; SHIFT IT BY THE DRIVE VALUE 

EE88 59 2708 POP CX ; RECOVER TRACK VALUE 

EE89 84063EOO 2709 TEST AL,SEEK_STATUS ; TEST FOR REeAL REQUIRED 

EE8D 7513 2710 JIlZ J2. -; NO_RECAl 

EE8F 06063EOO 2711 OR SEEK_STATUS,AL ; TURn ON THE HO RECAL BIT IN FLAG 

EE93 6407 2712 "OV AH ,07H i RECALIBRATE COMMAND 

EE95 E6ACFF 2713 CALL NEC_OUTPUT 

EE98 6AE2 2714- "OV AH,DL 

EE9A E6A7FF 2715 CALL tlEC_OUTPUT ; OUTPUT THE DRIVE HUMBER 

A-37


Ef'tD £67200 2716 CAll CHK_STAT_2 ; GET THE INTERUPT AND SENSE INT STATUS 

fEAG 7229 2717 JC J32 ; SEEK_ERROR 

2718 

fEA2 2721 J28: 

2719 ;---- DRIVE IS IN SYHCH WITH CONTROLLER. SEEK TO TRACK 

2nD 

fEAt 840F 2722 HOY AH,OfH ; SEEK COt1t1AND TO NEe 

EEA4 E89DFF 2723 C.6.LL tlfC_OUTPUT 

EfA7 6A£2 2724 HOY AH,Dl ; DR lYE NUMBER 

EfA9 E896FF 2725 CALL NEC_OUTPUT 

£EAC 8AE5 2726 MOV AH,CH ; TRACK tu1BER 

EEAE £893FF 2727 CALL NEC_OUTPUT 

fEB 1 £85£00 2728 CAll CHK_STAT_2 J GET ENDING INTERRUPT AND SENSE STATUS 

2729 

2730 ;----- WAIT FOR HEAD SUTlE 

2731 

EE84 9t 2732 PUSHF ; SAYE STATUS FLAGS 

fEes B81200 2733 HOY BX,l8 ; GET HEAD SETTLE PARAMETER 

fEB8 f8BSFF 2734 CALL GET_PARM 

fEBB 51 2.735 PUSH CX ; SAVE REGISTER 

fE8C 2736 J29: ; HEAD_SETTlE 

EEBC 892602 2737 MOV CX,550 ; 1 HS lOOP 

fEBf OAE4 2736 OR AH,AH ; TEST FOR TIME EXPIRED 

EECI 740b 2739 JZ J31 

EEe] E2FE 2740 J30: LOOP J30 ; DELAY FOR 1 NS 

EEtS FEce 2741 DEC AH ; DECREMENT THE COUNT 

EEe7 ESFl 2742 JMP J'9 ; DO IT SONE NOR E 

EEC9 2743 J31: 

EfC9 59 2744 POP ex ; RECOVER STATE 

EEeA 90 2745 POPF 

fEeB 2746 J32: ; SEEK_ERROR 

EEeB C3 2747 RET ; RETURN TO CALLER 

2748 SEEK ENOP 

2749 ; ------------------------------------------ 

2750 ; DNA_SETUP 

2751 THIS ROUTINE SETS UP THE DNA FOR READ/WRITE/VERIFY 

2752 OPERATIONS. 

2753 I INPUT 

2754 (AL) = NOOE BYTE FOR THE DNA 

2755 (ES:BX) - ADDRESS TO READI'WRlTE THE DATA 

2756 ; OUTPUT 

2757 {AXI DESTROYED 

2756 

eEee 2759 DNA_SETUP PROC NEAR 

EEce 51 2760 PUSH CX ; SAVE THE REGISTER 

EECD Eboe 2761 OUT DMA+12.AL ; SET THE FIRST/LAST F/F 

eEeF E60a 2762 OUT ONA+Il.AL ; OUTPUT THE MOOE BYTE 

fEDl aceD 2763 HOV AX,ES ; GET THE ES VALUE 

fED3 8104 2764 MDV CL,4 ; SHIFT COUNT 

fEOS 03eo 2765 ROL AX.CL ; ROTATE LEFT 

fED7 8A£8 2766 HOV CH .AL ; GET HIGHEST NYBLE OF ES TO CH 

EED9 24FO 2767 AND AL.OFOH ; ZERO THE LOW NYBBLE FROM SEGMENT 

fEoe 03e] 2766 ADD Ax.ex ; TEST FOR CARRY FROM ADDITION 

EEOD 7302 2769 JNC J33 

HOF FEes 2770 INC CH I CARRY MEANS HIGH 4 BITS MUST BE INC 

fEEL 2771 J33: 

fEEl 50 2772 PUSH AX ; SAVE START ADDRESS 

fEEZ £604 2773 OUT DMA+4.AL ; OUTPUT LOW ADDRESS 

EEE4 8AC4 2774 NOV AL,AH 

EEE6 £604 2775 OUT DHA+4,AL I OUTPUT HIGH ADDRESS 

fEES 8ACS 2776 HOV AL.CH ; GET HIGH 4 BITS 

fEEA 240F 2777 MiD AL.OFH 

EEEC E681 2778 OUT oalH,At ; OUTPUT THE HIGH 4 BITS TO PAGE REGISTER 

2779 

2780 ;------ DETERMINE COUNT 

2761 

EEEE 8Af6 2782 MOY AH,DH ; NUNBER OF SECTORS 

EEFO 2ACO 2783 sua AL,Al ; TINES 256 INTO AX 

EEFt 01E8 2784 SHR AX,I • SECTORS * 128 INTO AX 

EEF4 50 2765 PUSH AX 

EEF5 880600 2766 MOV BX,6 ; GET THE BYTES/SECTOR F'ARH 

fEFS Ea7sFF 2787 CALL GET_PARM 

EHB BAce 2788 HOV Cl,AH ; USE AS SHIFT Coutrr {(I=128. 1=256 ETC) 

fEFO 58 2789 POP AX 

fEFE 03EO 2790 SHL AX.CL ; MULTIPLY BY CORRECT AMOUNT 

EFOO 48 2791 DEC AX ; -1 FOR DMA VALUE 

EF01 50 2792 PUSH AX ; SAVE COUNT VALUE 

A-38

LOt OBJ LINE SOURCE 

fFOZ E605 

fF04 8;'C4 

EFOb E60S 

EFDa 59 

EF09 58 

EFOA 03Cl 

fFoe S9 

EFOD B002 

EFOF E60A 

EFll C3 

EFI2 

Eft2: E81EOO 

EFlS 7214 

EFI? 8408 

Ef19 E828FF 

EFtC EMCOD 

EFIF 720A 

EF21 A04200 

EF24 2460 

EF26 3e60 

EF2:6 7


2870 I ~- ----------------------------------------- 

ze71 ; DISK_IHT 

zan 

2873 ;INPUT 

2674 ; NONE 

2875 ; OUTPUT 

THIS ROUTINE HANOlES THE DISKETTE INTERRUPT 

287-6 THE INTERRUPT FUG IS seT IS SEEK...STATUS 

za77 ;------------------------------------------- 

EF57 2878 DISK.INT ""DC FAR 

EFS7 FB 2879 STI ; RE ENABLE INTERRUPTS 

EFsa IE 2:880 PUSH DS 

EF59 50 Z8a1 PUSH AX 

EFSA 884000 Z68

lDC OBJ LINE SOURCE 

EF9E E2FE 2946 )43: lOOP J43 

HAD 4A 2947 DfC OX ; pOlin AT STATUS PORT 

EFAl EC 2948 IN AL.DX ; GET STATUS 

EFA2 A810 2949 TEST AL,OlOH ; TEST FOR NEe STILL BUSY 

EFA4 7406 2950 JZ J44 ; RESULTS omlE 

EFA6 FEes 2951 DEC BL I DECREMENT THE STATUS COUNTER 

EFAS i5CA 2952 JHZ JJ8 ; GO BACK FOR MORE 

~ EFAA fBEJ 2953 JMP J41 ; CHIP HAS FAILED 

2954 

2955 ;------ RESULT OPERATION IS DONE 

2956 

EFAC 2957 J44: 

fFAt 58 2958 POP BX 

fFAD SA 2959 POP OX 

EFAE 59 2960 POP ex ; RECOVER REGISTERS 

EFAF C3 2961 PET ; GOOD RETURN CODE FROM TEST INST 

2962 ; - -- - - --------------------- ---- 

2963 ; HUH_TRANS 

2964 nus ROUTINE CALCULATES THE HUMBER OF SECTORS THAT 

2965 WERE ACTUALLY TRANSFERREO TO/FROM THE DISKETTE 

2966 INPUT 

2967 (CH) = CYLINDER OF OPERArION 

2968 I CLl = START SECTOR OF OPERATION 

2969 ; OUTPUT 

2970 (AU = NUMBER ACTUALLY TRANSFERRED 

2971 HO OTHER REGISTERS MODIFIED 

2972 ; ---- - - ----------------------- 

fFBO 2973 Nut1_TRANS PROC NEAR 

EFBO "04500 2974 MOV A.L,NEC_STATUS+3 ; GET CYlINDER E~mEO UP ON 

EFS3 3AC5 2975 eMP AL.CH ; SANE AS WE STARTED 

EFes A04700 2976 MOV AL ,HEC_STATUS+5 GET ENDING SECTOR 

EFBS 740.6. 2977 Jl J

LOC (lBJ LINE SOURCE 

3007 j --- INT 17 -------------------------------- 

3006 ; PRIfHER_IO 

3009 TliIS ROUTINE PROVIDES COMMUNICATION WITH THE PRINTER 

3010 (AH)=O F'RIHT THE CHARACTER IN (All 

3011 ON RETUIHI, AH=1 IF CHARACTER COULD NOT BE PRINTED (TIME OUT) 

3012 OTHER BITS SET AS ON NORMAL STATUS CALL 

3013 (AH)=1 INITIALIZE THE PRunER PORT 

3014 RETURNS WITH (AH) SET WITH PRINTER STATUS 

3015 (AH)=2 READ THE PRINTER STATUS INTO UH) 

3016 

3017 TIME OUT 

3018 

3019 

51 i 

t1. ,::1 ~~~~:D 

3020 _ 1 ::. SElECTED 

3021 1 '" OUT OF PAPER 

3022 1 = ACKNOWLEDGE 

'3023 1 = BUSY 

3024 

3025 (OX) = PRINTER TO BE USED (0.1.2) CORRESPONDING TO ACTUAL VALUES 

3026 I IN PRINTER_BASE AREA 

3027 ; DATA AREA PRINTER_BASE CONTAItIS THE BASE ADDRESS OF THE PRINTER CAROlS) 

3028 AVAILABLE (LOCATED AT BEGINNWG OF DATA SEGMENT, 408H ABSOLUTE, 3 WORDS) 

3029 ;REGISTER5 AH IS MODIfIED 

3030 • ALL OTHERS UNCHANGED 

3031 ; ---- --------------------------------------- 

3032 ASSUME CS: CODE ,DS:DATA 

EF02 3033 PRINTER _10 PROC fAR 

EFOZ Fe 3034 STI INTERRUPTS BACK ON 

EF03 IE 3035 PUSH os j SAVE SEGMENT 

EFD4 52 3036 PUSH OX 

EFOS 56 3037 PUSH 

5' 

EF06 51 3038 PUSH CX 

HD7 53 3039 PUSH ex 

EFDB 8E4000 3040 NOV 51 ,DATA 

EFDB BEDE 3041 NOV DS,SI ; ESTABLISH PRINTER SEGMENT 

£FDD BaFl 3042- HOV SI,DX ; GET PRINTER PARM 

EFOF 01E6 3043 5HL 51,1 ; WORD OFFSET INTO TABLE 

EFEl 88940800 3044 HOV OX,PRINTER_BASE[SI) ; GET BASE ADDRESS FOR PRINTER CARD 

EFES 0802 3045 OR OX,OX j TEST OX FOR ZERO, INDICATING NO PRINTER 

EFE7 740C 3046 JZ Bl j RETURN 

EFE9 0.6.£4 3047 OR AH,AH TEST FOR {AH )=0 

EFEB 740£ 3048 JZ e. PRINT_AL 

£FED FEee 3049 DEC AH TEST FOR CAH)=1 

EFEF 7442 3050 JZ .B 

INIT_PRT 

EFFl FEee 3051 DEC AH TEST FOR (AH )::.2 

EFF3 742.6. 3052- JZ 6S PR INTER STATUS 

£FFS 3053 Bl : RETURN 

EFF5 58 3054 POP ex 

EFF6 S9 3055 POP ex 

EfF7 5£ 3056 POP 

5' 

j RECOVER REGISTERS 

EFFS 5A 3057 POP ox j RECOVER REGISTERS 

EFF9 IF 3058 POP Os 

EFFA CF 3059 IRET 

3060 

3061 j------ PRINT THE CHARACTER IN (ALI 

3062 

EFF6 3063 82: 

EFFB 50 3064 PUSH AX SAVE VALUe TO PRINT 

EFfC 830A 3065 HOV st.IO TIME OUT VALUE 

EFFE 33C9 3066 XOR ex,Cx ESTABLISH SHIFT COUNT 

FOOD EE 3067 OUT DX,AL ; OUTPUT CHAR TO PORT 

FOOl 42 3068 we ox ; PorNT TO STATUS PORT 

FOOl 3069 83: ; WAIT_BUSY 

FOOZ EC 3070 AL,DX ; GET STATUS 

F003 8AEO 3071 r.OV 

'" 

AH,AL j STATUS TO AH ALSO 

Foes A880 3072 TEST At,SOH ; IS TtfE PRINTER CURRENTLY BUSY 

F007 750E 3073 Jt~Z 6. j OUT_STrlOBE 

F009 EZF] 3074 LOOP 63 ; DECREMENT COUNT ON TIME OUT 

FODe FEee 3075 DEC 6L 

FOOD 75F3 3076 JHZ 63 ; WAIT FOR NOT BUSY 

FOOF BOCCOI 3077 OR AH,l ; SET EPROR FLAG 

FOl2 80E4F9 3078 Arm AH,OF9H ; TURN OFF THE OTHER BITS 

Fots EBI4 3079 JHP 5HORT 87 ; RETUPtl WITli ERROR flAG SET 

FOl7 30BO 84: ; OUT_STReBE 

FOl7 BOOO 3081 HOV AL,OOH j SET THE STROBE HIGH 

F019 42 3082 we DX ; STROBE IS BIT 0 OF PORT C OF 8255 

A-42


~ 

~ 

FOIA EE 

FOIB BoDe 

FOlD EE 

FOIE 58 

FOlf 

FOIF 50 

FOlD 

FOZD 88940800 

f024 42 

fOZ5 EC 

f026 BAED 

fOZ6 BOE4F8 

F02B 

FOZB SA 

F02e BAC2 

FaZE 80F448 

FOll EBC2 

FOll 

FOl3 SO 

F034 83C202 

f037 8008 

F039 EE 

F03A B8E603 

FOlD 

F03D 46 

F03E 75FO 

F040 BOOC 

F042 EE 

F043 EBOB 


3084 MOV Al,OCH SET THE STROBE lOW 

3065 OUT OX.Al 

3066 POP AX RECOVER THE OUTPUT CHAR 

3087 

3068 J------ PRINTER STATUS 

3089 

3090 85: 

3091 PUSH AX ; SAVE AL REG 

3092 86: 

3093 MOV OX, PRINTER_BASE lSI ] 

3094 ItlC OX 

3095 IN AL,OX ; GET PRINTER STATUS 

3096 MOV AH,Al 

3097 AND AH,OF8H I TURN OFF UNUSED BITS 

3098 87: j STATUS_SET 

3099 POP OX j RECOVER AL REG 

3100 NOV AL,UL ; GET CHARACTER INTO AL 

3101 XOR AH ,48H FLIP A COUPLE OF BITS 

3102 JMP .1 ; RETURN FROM ROUTINE 

3103 

3104 ;------ INITIALIZE THE PRINTER PORT 

3105 

3106 B8: 

3107 PUSH AX SAVE At 

3106 AOD OX,2 POINT TO OUTPUT PORT 

3109 MOV AL,8 SET INIT LINE LOW 

3110 OUT OX,Al 

3111 NOV AX,lOOO 

3112 89: INIT_lOOP 

3113 DEC AX lOOP FOR RESET TO TAKE 

3114 J~lZ .9 I !NIT_LOOP 

3115 NOV AL,OCH NO INTERRUPTS, NON AUTO LF, INIT HIGH 

•• 


3117 JNP PIH_STATUS_1 

3116 PRINTER_IO ENOP 

3119 ; --- INT 10 -------------------------------- 

3120 VIDEO_IO 

3121 THESE ROUTINES PROVIDE THE CRT INTERFACE 

3122 THE FOllOWItlG FUNCTIONS ARE PROVIDED: 

3123 (AH)=O SET HaDE (All CONTAINS HODE VALUE 

3124 (AlI=O 40X25 Bioi (POWER ON DEFAULT) 

3125 (AlI=1 40X25 COLOR 

3126 {AlI=2 80X25 Bioi 

3127 ( AL J=3 80X25 COLOR 

3128 GRAPHICS HODES 

3129 (ALI=4 320X200 COLOR 

3130 {All:5 320X200 Bioi 

3131 (All=6 640X200 BW 

3132 CRT HOOE = 7 80X25 B&W CARD (USED INTERNAL TO VIDEO ONLYJ 

3133 *** NOTE BW MODES OPERATE SAME AS COLOR HODES, BUT COLOR 

3134 BURST IS NOT ENABLED 

3135 (AHI=l SET CURSOR TYPE 

313~ (CH) = BITS 4-0 = START LINE FOR CURSOR 

3137 H HARDWARE WILL ALWAYS CAUSE BLINK 

3138 ** SETTING BIT 5 OR 6 WILL CAUSE ERRATIC BLIHKING 

3139 OR NO CURSOR AT All 

3140 (ClI::;- BITS 4-0 = END LINE FOR CURSOR 

3141 (AHJ=2 SET CURSOR POSITION 

3142 (OH,Ol) = ROW,COLUMN (O,O) IS UPPER LEFT 

}14 "' !BH I = PAGE NU;13ER (HUST BE 0 FOR CRAPHICS ~IODES) 

3144 (AHI=3 READ CURSOR POSITION 

3145 (BH) = PAGE NUMBER (MUST BE 0 FOR GRAPHICS MODES) 

3146 ON EXIT (oH,Ul) = ROW,COLUMN OF CURRENT CURSOR 

3147 (CH,Cll = CURSOR MODE CURRENTLY SET 

3148 (AH )=4 READ LIGHT PEN POSITION 

3149 ON EXIT: 

3150 (AH) = 0 -- LIGHT PEN SWITCH NOT DOWN/NOT TRIGGERED 

3151 (AH) = 1 -- VALID LIGHT PEN VALUE IN REGISTERS 

3152 {OH,DU ;: ROW,COLUMN OF CHARACTER LP POSN 

3153 (CHI = RASTER LINE (0-199' 

3154 (BX) = PIXEL COLUMN (0-319,639) 

3155 (AHI=5 SELECT ACTIVE DISPLAY PAGE (VALID ONLY FOR ALPHA MODES) 

3156 (AU=NEW PAGE VALUE (0-7 FOR HODES 0&1, 0-3 FOR MODES 2&3) 

A-43

laC OBJ LINE SOURCE 

3157 (AH}=6 SCROLL ACTIVE PAGE UP 

3158 {AU ;; NUMBER OF LINES. INPUT LINES BLANKED AT BOTTon OF WINDOW 

3159 At :: 0 MEANS BLANK ENTIRE WINlOW 

3160 (CH,ell :; IWW.COLUMN OF UPPER lEFT CORNER OF SCROLL 

3161 IDH.OLl :; ROW,COLUMN OF LOWER RIGHT CORNER Of $CROLl 

3162 f BH) :: ATTRIBUTE TO BE USED ON BLANK LINE 

3163 (AH)=7 SCROLL ACTIVE PAGE DOWN 

3164 (AU:; HUMBER OF LINES. INPUT LINES BLANKED AT TOP OF wINOOW 

3165 AL = 0 HEANS BLANK ENTIRE WINDOW 

3166- (CH.CLI :; ROW,COLUMN OF UPPER LEFT CORNER OF SCROLL 

3167 IDH,DU = ROW,COllJHN OF LOWER RIGHT CORNER OF SCROLL 

3168 (BH) = ATTRIBUTE TO BE USED ON BLANK LINE 

3169 

3170 CHARACTER HANDLING ROUTINES 

3171 

3172 I AH I = 8 READ ATTRIBUTE/CHARACTER AT CURRENT CURSOR POSITION 

3173 ISHI = DISPLAY PAGE IVALID FOR ALPHA NODES ONLYI 

3174 ON EXIT: 

3175 I ALI = CHAR READ 

3176 IAH I ::I ATTRIBUTE Of CHARACTER READ (ALPHA MODES ONLY) 

3177 UH) = 9 WRITE ATTRIBUTE/CHARACTER AT CURRENT CURSOR POSITION 

3178 {BHI = DISPLAY PAGE IVALID FOR ALPHA MODES ONLY) 

3179 I CX I = coutrr OF CHARACTERS TO WRITE 

3180 tAL) = CHAR TO WRITE 

3181 IBU = ATTRIBUTE OF CHARACTER ULPHA)/COLOR OF CHAR (GRAPHICSI 

3182 SEE NOTE ON WRITE DOT FOR BIT 7 OF BL = 1. 

3183 (AH) = 10 WRITE CHARACTER ONLY AT CURRENT CURSOR POSITION 

3184 (BHI = DISPLAY PAGE IVALID FOR ALPHA I10DES ONLY) 

3185 I CX I = COUNT Of CHARACTERS TO WRITE 

3186 I AL) = CHAR TO WRITE 

3187 FOR READ/WRITE CHARACTER INTERfACE WHILE IN GRAPHICS I1DDE, THE 

3188 CHARACTERS ARE FORNED FROM A CHARACTER GEHERATOR IMAGE 

3189 MAINTAINED IN THE SYSTEM RON. ONLY THE 1ST 12:8 CHARS 

3190 ARE CONTAINED THERE. TO READ/WRITE THE SECOND 128 CHARS, 

3191 THE USER MUST INITIALIZE THE POINTER AT ItlTERRUPT IFH 

)192 (LOCATION 0007CH I TO POINT TO THE lK BYTE TABLE CONTAINING 

3193 THE CODE POINTS FOR THE SECOND 128 CHARS (128-2551. 

3194 fOR WRITE CHARACTER INTERFACE IN GRAPI-lICS NODE, THE REPLICATION FACTOR 

3195 CONTAINED IN (CX) ON ENTRY IoIIlL PRODUCE VALID RESULTS ONLY 

3196 FOR CHAP-ACTERS CONTAINED ON THE SANE ROW. COmHlUATION TO 

3197 SUCCEEOHIG LINES WILL NOT PRODUCE CORREtHY. 

3198 

3199 GRAPHICS INTERFACE 

3£:00 (AH I = 11 SET COLOR PALETTE 

3:::01 

3202 

(eH I = PALLETTE COLOR 10 BEING SET (0..1271 

(eu = COLOR VALUE TO BE USEO WIT$i THAT COLOR 10 

3203 NOTE: fOR THE CUPRENT COLO~ CARD. THIS ENTRY POINT ftAS 

320


F04S 

F045 FeFO 

F047 CFFI 

F049 Fon 

F04B JAF2 

F040 A9F7 

F04F 30F, 

FOS1 9CF2 

F05] 41F3 

FOSS 70n 

Fost C3f3 

F059 F6F3 

FOSS 54F2: 

rOSO 38F4 

FOSF 27F4 

F06! 22F7 

F063 7AF2 

0020 

FObS 

FObS FB 

F066 Fe 

F061 06 

F06,8 IE 

F069 52 

FObA 51 

F068 53 

F06C 56 

F060 57 

F06E 50 

F06F 8AC4 

F071 32E4 

F073 DIED 

F075 68FO 

F071 302000 

F07A n04 

F07e 58 

F07D E94701 

f080 884000 

F083 8E08 

F085 B80066 

f088 863ElOOO 

F08e 81E73000 

F090 83FF30 

F093 7503 

F095 880080 

F098 8Eeo 

F09A 58 

F098 8A2:6490D 

F09F 2EfFA445FO 

FOA4 

3232 (AH) 15 CURREI'ff VIDEO STATE 

32:33 RETURNS THE CURRENT VIDEO STATE 

3234 (All ::: HOOE CURRWTLY SET I SEe AH=O FOR EXPLANATION) 

3235 (AH) :: NU11BER Of CHARACTER COLUMNS ON SCREEN 

3236 (BH) :: CURRENT ACTIVE DISPLAY PAGE 

3237 

3238 CS,SS,DS,ES,8X,CX,DX PRESERVED DURING CALL 

3239 ALL OTHERS DESTROYED 

~2:40 ; ------------------------- ---------------- 

32:41 ASSUME CS :CODE IDS:DATA ,ES :VIOEO_RAM 

32:42: 

3243 HI LABEL WORD I TABLE OF ROUTINES WITHIN VIDEO I/O 

32:44 OW OFFSET SET_MOOE 

32:45 ow OFFSET SET_CTYPE 

3246 ow OFf'SET SET_CPOS 

32:47 ow OfFSET READJUPSOR 

32:48 ow OFFSET READ_LPEH 

32:49 ow OffSET ACT_crsp_PAGE 

3250 0" 

OFFSET SCROLL_UP 

3251 ow OFFSET SCROLL_DOWN 

32:52: ow OFFSET READ_AC_CURREtIT 

3253 0" OFFSET WRITCAC_CURRENT 

3254 0" 

OFFSt:T WRlTE_C_CURRENT 

3255 0" OFFSET SET_COLOR 

3256 

0" 

OFFSET I-'RITE_OOT 

3257 

0" OFFSET READ_DOT 

3258 

OFFSET WRITE_TTY 

0" 

3259 0" OFFSET VIDEO_STATE 

3260 HIL EOU $-Ml 

3261 

3262 rROC tl::AR 

3263 STI ; INTERP-UPTS BACK ON 

3264 CLO SET DIRECTION FORWARD 

3265 PUSH ES 

3266 PUSH DS ; SAVE SEGMENT REGISTERS 

3267 PUSH ox 

3268 PUSH CX 

3269 PUSH ex 

3270 PUSH 51 

3271 PUSH 01 

3272 PUSH AX ; SAVE AX VALUE 

3273 MOV AL,AH ; GET INTO LOW BYTE 

3274 XOR AH IAH I ZERO TO HIGH BYTE 

3215 SAL AX,1 *2 FOR TABLE LOOKUP 

3276 MOV SI,AX PUT INTO SI FOR BRANCH 

3277 CMP AX , 111L TEST FOR WITHIN RANGE 

3278 JB 11£ 1 BRANCH AROUND BRANCH 

3279 POP AX THROW AWAY THE PARAMETER 

3280 JMP VIDEO_RETURN ; DO NOTHING IF NOT IN RANGE 

3281 MOV AX,OATA 


3283 MOV AX , OB800H SEGMENT FOR COLOR CARD 

3284 MOV 01 I EqUIP_FLAG GET EQUIPMENT SETTING 

3285 AHD DI , 30H ISOLATE CRT SWITCHES 

3286 CMP OI,30H IS SETTING FOR Bioi CARD? 

3287 JNE M3 

3288 MOV AX,OBOOOH ; SEGMnlT FOR Bioi CARD 

3289 MOV ES,AX I SET UP TO POINT AT VIDEO RAI1 AREAS 

3290 POP AX ) RECOVER VALUE 

3291 MOV AH,CRT_HOOE I GET CURRENt MODE INTO AH 

3292 JMP WORD PTR CS:[SI.. OFFSET MIl 

3293 VIDEO_IO ENDP 

3294 ; --------------------------------------- 

3295 ; SET_MODE 

3296 THIS ROUTINE INITIALIZES THE ATtACHMENT TO 

3297 THE SELECTED MODE. THE SCREEN IS BLANKEO. 

3296 ; INPUT 

3299 {ALI ::: MODE SELECTED (RANGE 0-9) 

3300 i OUTPUT 

3301 NONE 

3302 ; ------- ----- ---------------------------- 

3303 

3304 i------ TABLES FOR USE IN SEn!NG OF MODE 

3305 

3306 LABEL 'BYTE 

3307 1------ !NIT_TABLE 

A-45

lOC OBJ LINE SOURt.:E 

FOA43828ZDOAIF0619 3306 DB 38H. 28H,2DH ,OAH .IFH,6 .19H SET UP FOR 40X25 

FOAB lC02070607 3309 DB 

FOBO 00000000 3310 DB 0,0.0.0 

0010 3311 M4 EoU 

3312 

FOB4 7l505AOAIF0619 3313 DB 7lH,50H .5AH, OAH ,1FH,6 ,19H ; SET UP FOR 80X2S 

FOBe lC02:070607 3314 DB 

FOCO 00000000 3315 DB 0.0.0.0 

3316 

FOC4 38Z82DOA7F0664 3317 08 38H, 28H, 2DH, OAH, 7FH ,6 ,64H J SET UP FOR GRAPHICS 

Foce 7002010607 3318 08 70H,2.1.6,7 

FOO~ 00000000 3319 DB 0,0,0,0 

3320 

FOD4 61S0520F 190619 3321 DB 61H ,SOH .52H, OFH, 19H.6 .19H SET UP FOR 80X25 B&W CARD 

FODe 19020DOBOC 3322 DB 19H. 2, OOH, oaH. OCH 

FOED 00000000 3323 DB 0,0 ,0,0 

3324 

FOE4 3325 M5 LABEl WORD J TABLE OF REGEN LENGTHS 

FOE4 0006 3326 OW 2048 ; 40X25 

FOE6 0010 3327 OW 4096 ; 80X:!5 

FOEB 0040 3328 OW 16384 ; GRAPHICS 

fOEA 0040 3329 OW 16384 

3330 

3331 ; ----- COLUMNS 

FOEe 3332 M6 LABEL BYTE 

FOEC 282850502:8285050 3333 DB 40,40.80.80,40,40.80.80 

3334 

3335 ;------ C_REG_TAB 

FOF4 3336 M7 LABEl BHE ; TABLE OF MODE SETS 

FOF4 2C282D29ZA2E!E29 3337 DB 2CH ,28H, 2DH, 29H, 2AH, 2EH .1EH. 29H ; 

3338 

FOFC 3339 PROC NEAR 

FOFe 8A0403 3340 MOV DX.03D4H ; ADDRESS OF COLOR CARD 

FOFF B300 3341 MOV BL.O ; MODE SET FOR COLOR CARD 

FIOl 83FF10 3342 CMP or, JOH ; IS B~ CARD INSTALLED 

Fl04 7507 3343 JNE M8 ; OK WITH COLOR 

FI06 B007 3344 MOV AL.7 ; INDICATE B~ CARD MODE 

Floe 8A8403 

3345 

MOV Ox , 03B4H 

; ADDRESS OF BW CARD 

FIOB FEel 3". 

INC BL 

; MODE SET FOR Bioi CARD 

FICO 8AEO 3347 Me: MOY AH,AL ; SAVE MODE IN AH 

FIOF A24900 3348 MOV CRT_MODE ,Al ; SAVE IN GLOBAL VARIABLE 

F1l2 89166300 3349 MOV ADDR_6845.0X SAVE ADDRESS OF BASE 

F1l6 IE 3350 PUSH OS SAVE POINTER TO DATA SEGMENT 

Fll750 3351 PUSH AX SAVE MODE 

Fl18 52 3352 PUSH ox SAVE OUTPUT PORT VALUE 

f1l9 63C204 3353 ADD DX,4 POINT TO CONTROL REGISTER 

FIle 6AC3 3354 HOV Al.Bl ; GEl HODE SET FOR CARD 

FilE EE 3355 OUT DX.AL ; RESET VIDEO 

FllF SA 3356 POP OX ; BACK TO BASE REGISTER 

FI2e 28CO 3357 SUB AX,AX I SET UP FOR ABsa SEGMENT 

FIZZ 8E08 3358 MOV DS,AX ESTABLISH YECTOR TABLE ADDRESSING 

3359 ASSUME DS:ABSO 

F124 C51E7400 3360 lOS BX.PARN_PTR GET POINTER TO VIDEO PARMS 

F128 56 3361 POP AX ; RECOVER PARMS 

3362 ASSUME DS:COOE 

FI29 891000 3363 MOV CX.M4 LENGTH Of EACH ROW Of TABLE 

Flle 80FCOZ 3364 CMP AH.2 DETERMWE WHICH DNE TO USE 

Fl2F 7210 3365 JC M9 MODE IS 0 OR 1 

FBI 0309 3366 ADD Bx,ex MOVE TO NEXT ROW OF INIT TABLE 

FI33 BOFC04 3367 CMP AH,4 

Fl36 7209 3368 JC N9 ; MODE IS 2 OR 3 

Fl3S 0309 3369 ADD BX,CX ; NOVE TO GRAPHICS ROW OF INIT_TABLE 

F13A BOFC07 3370 eMP AH,7 

F13D 7202 3371 JC N9 MODE IS 4,5. OR 6 

F13F 0309 3372 ADO BX.CX HOVE TO BW CARD ROW OF INIT_TABLE 

3373 

3374 ;------ BX POINTS TO CORRECT ROW OF INITIALIZATION TABLE 

3375 

F141 3376 M9: 

F141 50 3377 PUSH AX • SAVE I':OOE IN AH 

Fl42 32E4 3378 XOR AH,AH ; AH WILL SERVE AS REGISTER NUMBER DURItlG LOOP 

3379 

3380 ;------ LOOP TllRCUGH TABLE. OUTPUTTTING REG ADDRESS, THEN VALUE FROM TABLE 

3381 

F144 3382 HID: ; nUT LOOP 

Fl44 8AC4 3383 NOV AL,AH ; GET 6845 REGISTER ~ruMBER 

A-46


F146 EE 

F147 42 

Fl48 FEC4 

Fl4A 8A07 

F14C EE 

Fl4D 43 

Fl4E 4A 

~ Fl4F E2F3 

FISl 58 

Fl52 IF 

Fl53 33FF 

Fl55 893E4EOO 

Fl59 C606620000 

FISE B90020 

Fl6l aOFC04 

F164 noc 

Fl66 80FC07 

F169 7404 

Fl6B :33CO 

Fl60 EB06 

Fl6F 

FI6F B90008 

FI72 

F172 B82007 

F175 

F175 F3 

FI76 AS 

FIn C7066000-6700 

Fl7D A04900 

~ Fl8032E4 

F182 8BFO 

F184 8BI66300 

FI88 83C204 

FI8B 2E8A84F4FO 

F 1 90 EE 

Fl n A26500 

FI94 2E8A84ECFO 

FI99 32E4 

F 19B A34AOO 

F19E 81E60EOO 

FlA2 2E6B8CE4FO 

FIA7 890E4COO 

FlAB 890800 

FlAE BF5000 

FIBI IE 

FIB2 07 

FIB3 nco 

FIBS F3 

FIS6 AB 

FIB7 42 

FiB8 B030 

FIBA 803E490006 

FIBF 7502 

FICI B03F 

FIC! EE 

FIC4 A266DO 

3384 OUT OX.Al 

3385 INC ox ; POINT TO DATA PORT 

3366 INC AH ; NEXT REGISTER VALUE 

3367 MOV Al.[BX) ; GET TABLE VAlUE 

3388 OUT OX.Al ; OUT TO CHIP 

3369 INC BX ; UEXT IN TABLE 

3390 OEC OX ; BACK TO POINTER REGISTER 

3391 LOOP MID DO THE WHOLE TABLE 

3392 POP AX GET MODE BACK 

3393 POP OS RECOVER SEGMENT VALUE 

3394 ASSUME OS:OATA 

3395 

3396 ;------ FILL REGEN AREA WITH BLANK 

3397 

3398 XOR 01.01 ; SET UP POINTER FOR REGEN 

3399 MOV CRT_START .01 ; START ADDRESS SAVED IN GLOBAL 

3400 MOV ACTIVE_PAGE ,0 ; SET PAGE VALUE 

3401 MOV CX.8192 ; NUMBER OF WORDS IN COLOR CARD 

3402 CMP AH ,4 TEST FOR GRAPHICS 

3403 JC MI2 NO_GRAPHICS_INIT 

3404 CHP AH , 7 TEST FOR Bioi CARD 

340S JE MIl BW_CARD_INIT 

3406 XOR AX, AX FILL FOR GRAPHICS MODE 

3407 JHP SHORT Ml3 CLEAR_BUFFER 

3408 MIl: 

3409 HOV CX,2048 ; BUFFER SIZE ON BW CARD 

3410 M12; ; NO_GRAPHICS_INIT 

3411 MOV AX,' '+7*256 FIll CHAR FOR ALPHA 

3412 M13: CLEAR_BUFFER 

3413 REP STOSW FILL THE REGEN BUFFER WITH 8UNKS 

3414 

3415 ;------ ENABLE VIDEO AND CORRECT PORT SETTING 

3416 

3417 MOV CURSOR_MOoE.67H ; SET CURRENT CURSOR MODE 

3418 MOV j GET THE MODE 

3419 XOR AH,AH INTO AX REGISTER 

3420 MOV SI,AX TABLE POINTER. WDEXEo BY MODE 

3421 MOV DX.ADDR_6845 PREPARE TO OUTPUT TO .... IOEO ENABLE PORT 

3422 AOO DX,4 

3423 HOV AL.CS: I SI+OFFSET M7] 

34~4 OUT DX.Al ; SET VIDEO ENABLE PORT 

3425 MOV CRT_MOOE_SET,Al ; SAVE THAT VALUE 

3426 

3427 ; ------ DETERMINE NUMBER OF COLUMNS. BOTH FOR ENTIRE DISPLAY 

3428 ;------ AND THE NUMBER TO BE USED FOR TTY INTERFACE 

3429 

3430 MOV AL.CS:IS1 + OFFSET M6J 

3431 XOR AH.AH 

3432 MOV CRT_COlS,AX ; HUMBER OF COLUMNS IN THIS SCREEN 

31133 

3434 ;------ SET CURSOR POSITIONS 

3435 

3436 ANO SI.OEH ; WORD OFFSET INTO CLEAR lENGTH TABLE 

3437 MOV CX.CS:[SI + OFFSET tiS) j lENGTH TO CLEAR 

3438 MOV CRT_lEN.CX • SAVE lENGTH OF CRT -- HOT USED FOR Bioi 

3439 MOV CX,a ; ClEAR ALL CURSOR POSITlmiS 

3440 MOV oI.OFFSET CURSOR_POSr~ 

3441 PUSH OS ESTABLISH SEGMENT 

3442 POP ES ADDRESSINS 

3443 XOR AX,AX 

3444 REP STOSW ; FILL WITH ZEROES 

3445 

3446 ;------ SET UP OVERSCAN REGISTER 

3447 

3448 INC OX SET OVERSCAN PORT TO A DEFAULT 

3449 MOV Al,30H VALUE OF 3'OH FOR ALL MODES EXCEPT 640X200 

3450 CMP CRT.MODE,6 SEE IF THE HaDE IS 640X200 Bioi 

3451 JNZ M14 IF IT IS:n 640X20D. THEN GOTO REGULAR 

3452 MOV Al,3FH IF IT IS 640X200, THEN PUT IN 3FH 

3453 M14: OUT oX.Al OUTPUT THE CORRECT VALUE TO 309 PORT 

3454 MOV CRT.PALLETTE ,Al SAVE THE VALUE FOR FUTURE USE 

3455 

3456 ;------ NORMAL RETU~N FROM ALL VIDEO RETURNS 

3457 

A-47


FtC7 3458 VIDEO_RETURN: 

FIC7 Sf 3459 POP 01 

Flce 5E 346. POP S! 

flC9 58 3461 POP BX 

FICA 3462 MIS: j VlOEO_RETURN_C 

FICA 59 3463 pOP CX 

Fica SA 3464 POP ox 

Flee IF 3465 POP DS 

fleD 07 3466 POP ES I RECOVER SEGMENTS 

Fle( Cf 3467 IRET ; ALL DONE 

3468 SET_MODE ENIlP 

3469 ; .--------------------------..------------- 

3470 1 SET_CTYf'E 

3471 THIS ROUTINE SETS THE CURSOR VALUE 

3472 I INPUT 

3473 I (eXI HAS CURSOR VALUE CH-Sf.ART LINE, CL-STOP LINE 

3474 j OUTPUT 

3475 NONE 

3476 ; ------------------ -- ------- - - - -------- 

FIeF 3477 PROt NEAR 

FIeF 840A 3418 AH,10 J 6845 REGISTER FOR CURSOR SET 

FIOI 890E6000 3479 HOV CURSOR_f1ODE ,CX ; SAVE IN DATA AReA 

FID5 £80200 3480 CALL M16 J OUTPUT ex REG 

FID8 EBED 3481 JHP 

3482 

3483 i ----- THIS ROUTINE OUTPUTS THE ex REGISTER TO THE 6845 REGS HAMED IN AH 

3484 

FIDA 3485 N16: 

FIDA 8B166300 3486 HOV oX,ADDR_6845 , ADDRESS REGISTER 

FIDE 6AC4 3487 HOV AL,AH i GET VALUE 

FlED EE 3488 OUT DX,AL ; REGISTER SET 

FIEI 42 3489 INC OX ; DATA REGISTER 

FJE2 8AC5 3490 11.0V AL,CH i DATA 

F1E4 EE 3491 OUT OX,AL 

FIES 4A 3492 DEC DX 

FIE6 8AC4 3493 HOV AL,AH 

FlEB FEtD 3494 INC AL ; POINT TO OTHER DATA REGISTER 

FlEA EE 3495 OUT OX,AL J SET FOR SECOND REGISTER 

FlEB 42 3496 INC OX 

FlEe 6ACl 3497 MOV AL ,CL ; SECOND DATA VALUE 

FlEE EE 3498 OUT OX.Al 

FIEF C3 3499 RET ; ALL DONE 

3500 SET_CTYPE nmp 

350 I ; -------------------------- ----------- ---- 

3502 J SET_CPOS 

3503 THIS ROUTINE SETS THE CURRENT CURSOR POSITION TO THE 

3504 NEW X-Y VAI.UES PASSED 

3505 INPUT 

3506 ox - ROW.COLUMN OF NEW CURSOR 

3507 BH - DISPLAY PAGE OF CURSOR 

3508 ; OUTPUT 

3509 I CURSOR IS SET AT 6845 IF DISPLAY PAGE IS CURRENT DISPLAY 

3510 i ----..------------- ------ --- - - ---- ---- 

FIFO 3511 SET_CPOS PROC NEAR 

FIFO BACF 3512 HOV CL,BH 

FIF2 3ZED 3513 XO. CH,CH I ESTABLISH LOOP COUHT 

FIF4 DlEl 3514 SAL CX.l I WORO OFFSET 

FIF6 88Fl 3515 HOV SI,CX ; USE INDEX REGISTER 

FIF8 89945000 3516 MOV (SI+OFFSET CURSOR_POSNI,OX ; SAVE THE POINTER 

FIFC 383E6200 3517 CMP 

Floa 7505 3518 JHZ HI7 ; SET_CPOS_RETURN 

F202 88C2 3519 I10V AX,OX ; GET ROW/COLUMN TO AX 

F204 E80200 352. CAl.l HIS ; CURSOR_SET 

F207 3521 M17: I SET_CPOS_RETURN 

F207 'f;BBE 3522 JHP 

3523 ENOP 

3524 

3525 ;------ SET CURSOR POSITION, AX HAS ROW/COLUMN FOR CURSOR 

3526 

F209 3521 MI8 PRoe NEAR 

F209 £87FOO 3528 CALL POSITION ; DETERMINE I.OCATION IN REGEN BUFFER 

FlOC 88C8 3529 MOV eX,AX 

F20E 030[4EOO 3530 ADO CX,CRT_START ; ADD IN THE START ADDRESS FOR THIS PAGE 

F212 01F9 3531 SAR CX,l ; DIVIDE BY 2 FOR CHAR ONLY COUNT 

F214 640E 3532 MOV AH.14 ; REGISTER NUI1BER fOR CURSOR 

A-48


FZ16 E8CIFF 3533 CALL 1116 ; OUTPUT THE VALUE TO THE 6845 

F219 C3 3534 RET 

3535 H18 WOP 

3536 ;---------------------------_ ...-------------- 

3537 ; READ_CURSOR 

3538 THIS ROUTINE READS THE CURRENT CURSOR VALUE FROM THE 

3539 6B45, FORHATS IT, AND SENDS IT BACK TO THE CALLER 

354. i INPUT 

3541 BH - PAGE OF CURSOR 

3542 ; OUTPUT 

3543 OX - ROW, COLUMN OF THE CURRENT CURSOR POSITION 

3544 CX - CURREHT CURSOR MODE 

3545 ;------------------------------------------ 

Fl1A 3546 READ_CURSOR PROC HEAR 

F21A SADF 3547 MOV Bl.BH 

FZIC 3ZFF 3548 XOR SH,BH 

F2IE DIEl 3549 SAL eX,l ; WORD OFFSET 

FZ2:0 88975000 3550 HOV DX,(BX+OFFSET CURSOR_POSH] 

F2:24 880E6000 3551 HOV eX.CURSOR_MODE 

F228 SF 3552 POP 01 

F229 SE 3553 POP SI 

F22'" 58 3554 POP BX 

F22:8 58 3555 POP AX ; DISCARD SAVED CX AND ox 

F2:2:C 58 3556 POP AX 

F22:0 IF 3557 POP OS 

F22:E 07 3558 POP ES 

F22:F Cf 3559 IRET 

3560 READ_CURSOR WOP 

3561 ;------------------- - ----------------------- 

356Z ; ACT_DISF_PAGE 

3563 THIS ROUTINE SETS THE ACTIVE DISPLAY PAGE. ALLOWING 

3564 THE FULL USE Of THE RAM SET ASIDE FOR THE VIDEO ATTACHMENT 

3565 INPUT 

3566 AL HAS THE NEW ACTIVE DISPLAY PAGE 

3567 ; OUTPUT 

3568 J THE 6845 IS RESET TO DISPLAY THAT PAGE 

3569 1------------------------------------------- 

F230 3570 ACT_DISP_PAGE PROC NEAR 

F2;30 A2:6200 3571 MOV ACTlVE_PAGE,AL J SAVE ACTIVE PAGE VALUE 

F233 8BOE4COO 3572 MOV CX.CRT_LEN ; GET SAVED LENGTH OF REGEN BUFFER 

F237 98 3573 CBW I CONVERT AL TO WORD 

F238 SO 3574 PUSH AX ; SAVE PAGE VALUE 

F239 F7Et 3575 NUL ex ; DISPLAY PAGE TII1ES REGEtl LENGTH 

F2:38 A34EOO 3576 HOV CRT_START ,AX ; SAVE START ADDRESS FOR LATER REQUIREMENTS 

F23E 8BC8 3571 HOV eX.AX ; START ADDRESS TO ex 

f240 01F9 3578 SAR ex ,I ; DIVIDE BY Z FOR 6845 HANDLING 

F242 B40C 3579 MOV AH,lZ ~ 6845 REGISTER FOR START ADDRESS 

F244 E893FF 3580 CALL M16 

F2:47 58 3581 POP 8X ; RECOVER PAGE VALUE 

F248 aIE3 358Z SAL BX.l f *2 FOR WORD OFFSET 

F2it" 88875000 3583 MOV AX,lBX + OFFSET CURSOR_paStil ; GET CURSOR FOR THIS PAGE 

F2:4E EBBSFF 3584 CALL NlB f SET THE CURSOR POSITION 

F251 E973FF 3585 JMP VIDEO_RETURN 

3587 ; ------------------------------------------- 

3588 , SET COLOR 

3589 THIS ROUTINE WILL ESTABLISH THE BACKGROUND COLOR, THE OVERSCAN COLOR, 

3590 AND THE FOREGROUND COLOR SET FOR MEOIlIt1 RESOLUTION GRAPHICS 

3591 INPUT 

3592 (BH 1 HAS COLOR ID 

3593 IF BH=O, THE BACKGROUND COLOR VALUE IS SET 

3594 FROl1 THE LOW BITS OF BL (0-31) 

3595 IF BH=l, THE PALLETTE SELECTION IS MADE 

3596 BASED ON THE LOW BIT OF st: 

3597 0 = GREEN. RED, YEllOW FOR COLORS l,Z.:S 

3598 1 = BLUE, CYAN. MAGENTA FOR COLORS 1.2.3 

3599 {Bll HAS THE COLOR VALUE TO BE USED 

3600 ; OUTPUT 

3601 THE COLOR SELECTION IS UPDATED 

3602 ; ------------------------------------------- 

F254 3603 SET_COLOR !',we NEAR 

F254: 88166300 3604 HOV ; 1/0 PORT FOR PALETTE 

F25B 83C205 3605 ADD DX.S ; OVERSCAN PORT 

F2:58 A06600 3606 HOV AL.CRT]ALLETTE ; GET THE CURRENT PAllETTE VALUE 

F2:5E OAFF 3607 OR BH.BH ; IS THIS COLOR O? 

A-49


F260 750E 

f2:62 24Eo 

F264 80EllF 

Fl67 OAe3 

F269 

F269 EE 

Fl6A A26600 

Fl60 E957FF 

F27Q 

FHO 24Df 

F272 DOEB 

F274 73F3 

FZ76 OC20 

F278 EBEF 

F27A 

F27A 8A264AOO 

F27E 1.04900 

F281 8A3E6200 

H8S SF 

F286 Sf 

F287 59 

FleB E93FFF 

F2eB 

F2aB S3 

Flac 8808 

Fl8E 8AC4 

F290 F6264AOO 

F294 32FF 

F296 03e3 

F298 OlEO 

F29A 58 

F29B C3 

F29C 

F29C 8A08 

F29E 80FC04 

3606 JNZ H2O ; OUTPUT COLOR 1 

3609 

3610 j------ HANDLE COLOR 0 BY SETTING THE BACKGROUND COLOR 

3611 

3612 AND Al,DEOH t TURN OFF LOW 5 BITS Of CURRENT 

3613 .ND BL,OlFH ; TURN OFF HIGH 3 BITS OF INPUT VALUE 

3614 OR Al,Bl ; PUT VALUE IHTO REGISTER 

3615 N19: ; OUTPUT THE PALLETTE 

3616 OUT OX,AL ioutput c.olor selection to 3d9 port 

3617 MOV CRT_PAlLETTE,AL ; SAVE THE COLOR VALUE 

3616 JHP VIDEO_RETURN 

3619 

3!J20 ;------ HANDLE COLOR 1 BY SELECTING THE PALLETTE TO BE USED 

3621 

3622 H2O: 

3623 AND AL,OaFH ; TURN OFF PALlETTE SElECT BIT 

3624 SH. BL.l ; TEST THE LOW ORDER BIT Of BL 

3625 JNC MI. i ALREADY DONE 

3626 OR Al,20H TURN au PAllETTE SElECT BIT 

3627 JMP MI. iGODOIT 

3628 SET_COLOR ENDP 

3629 i ------------------------------------------- 

3630 iVIDEO STATE 

3631 RETURNS THE CURRENT VIDEO STATE IN AX 

3632 AH = NUMBER OF COLUMNS ON THE SCREEN 

3633 AL = CURRENT VIDEO MODE 

3634 ; BH = CURRENT ACTIVE PAGE 

3635 i ------------------ - ------------------------ 

3636 VIDEO_STATE PROC NEAR 

3637 "OV AH,BYTE PTR CRT_COLS ; GET NUMBER OF COLUMNS 

3638 "OV AL,eRT_MODE ; CURRENT MODE 

3639 HOV BH.ACTIVE]AGE i GET CURRENT ACTIVE PAGE 

3640 pop 01 f RECOVER REGISTERS 

3641 pop 51 

3642 POP CX DISCARD SAVED ex 

3643 JHP MIS RETURN TO CALLER 

3644 VIDEO_STATE ENDP 

3645 i ---------------------------------- 

3646 POSITION 

3647 THIS SERVICE ROUTINE CALCULATES THE REGEN BUFFER ADDRESS 

3648 OF A CHARACTER IN THE ALPHA MOOE 

3649 ; INPUT 

3650 AX = ROW, COLUMN POSITION 

3651 i OUTPUT 

3652 AX = OFFSET OF CHAR POSITION IN REGEN BUffER 

3653 

3654 POSITION PROC NEAR 

3655 PUSH BX SAVE REGISTER 

3656 HOV eX,AX 

3657 HOV AL,AH , ROJ.IS TO AL 

3658 MUL BYTE PTR CRT_COLS ; DETERMINE BYTES TO ROW 

3659 XOR BH,BH 

3660 AOO AX,BX ADD IN COLUMN VALUE 

3661 SAL AX,1 * 2 FOR ATTRIBUTE BYTES 

3662 POP BX 

3663 RET 

3664 POSITION ENDp 

3665 ; ----------------------------------------- 

3666 ; SCROLL UP 

3667 THIS ROUTINE MOVES A BLOCK OF CHARACTERS UP 

3668 ON THE SCREEN 

3669 ; INPUT 

3670 (AH) = CURRENT CRT MODE 

3671 (Al) '" NUME',ER OF ROWS TO SCROLL 

3672 ICXI :: ROW/COLUMN OF UPPER LEFT CORNER 

3673 (OX) = ROW/COLUMN OF LOWER RIGHT CORNER 

3674 (BH) = ATTRIBUTE TO BE USED ON BLANKED LINE 

3675 (oS) = DATA SEGMENT 

3676 IES) = REGEN BUFrER SEGMENT 

3677 j OUTPUT 

3678 NONE -- THE REGEN BUFFER IS MODIFIED 

3679 ; ------ --------- -- ------------------- ------ 

3680 ASSUME CS:COOE,DS:DATA,ES:DATA 

3681 SCROLL_UP PROC HEAR 

3682 MOV BL.AL f SAVE LINE COUNT IN BL 

3683 CMP AH.4 ; TEST FOR GRAPHICS MODE 

A-50


F2Al n08 

F2A3 80FC07 

f2Ab 7403 

FlAB E9F301 

flAB 

fZAB 53 

f2AC saCl 

FUE E83900 

F2Bl 7433 

F2:83 03FO 

F2:85 8AE6 

F287 2:AE3 

F2.89 

F289 E87500 

FZBC 03F5 

FZBE 03FO 

F2:CO FEee 

F2C2 7SFS 

F2:C4 

F2C4 58 

F2CS· B020 

F2C7 

F2C7 E87000 

F2eA 03FO 

Flee FEC8 

F2CE 75F7 

F200 

F200 884000 

F2:03 8ED8 

F205 803E490007 

F2DA 7407 

F2DC A06500 

FlOf SADeD3 

F2E2 EE 

FtE3 

F2f3 E9EIFE 

F2E6 

F2E6 SADE 

F2:E8 EeDA 

FlEA 

f2EA 803E490002 

FtEF 7219 

FtF 1 803E490003 

F2Fb 7712 

FHS 52 

F2F9 SADAa] 

F2FC 50 

F2FD 

F2FO EC 

FtFE A808 

F30D 74F8 

F302 B025 

F304 BA0803 

F307 EE 

noe 58 

n09 5A 

nOA ES7EFF 

noD 03064EOO 

F311 88f8 

FlU 8BFO 

Fl15 2801 

F3l7 fEe6 

F319 FEe2 

F318 32EO 

F310 882E4AOO 

F321 03EO 

F3Z3 8AC3 

F325 F6264AOO 

F3Z9 03eO 

3684 JC HI ; HANDLE SEPARATELY 

3685 CMP AH.7 ; TEST FOR BW CARD 

~8. JE HI 

3687 JMP 

3688 Nl: ; UP_CotnIHUE 

3689 PUSH ex j SAVE FILL ATTRIBUTE IN 8H 

3690 NOV AX.CX I UPPER lEFT POSITION 

3691 CAll SCROLL_POSITION i DO SETUP FOR SCROLL 

3692 JZ N7 I BLANK_FIELD 

3693 ADD SI,AX ; FROM ADDRESS 

3694 NOV AH,DH ; • ROWS IN BLOCK 

3695 SUB AH,Bl ; # ROWS TO BE MOVED 

3696 

3697 CAll HID ; MOVE ONE ROW 

3698 ADD SI.B? 

3699 ADD DI,B? ; POINT TO NEXT LINE IN BLOCK 

3700 DEC All ; COUNT OF LINES TO HOVE 

3701 JHZ 

H' 

3702 H3: ; CLEAR_ENTRY 

3703 pop AX J RECOVER ATTRIBUTE IN AH 

3704 NOV AL, • I FILL WITH BLANKS 

3705 J CLEAR_lOOP 

3706 CALL Nil ; CLEAR THE ROW 

3707 ADD DI,B? ; POINT TO NEXT LINE 

3708 DEC BL ; COUNTER OF LINES TO SCROLL 

3709 JNZ H4 ; CLEAR_lOOP 

3710 NS: ; SCROLL_END 

3711 MOV AX,OATA ; GET LOCATION 

3712 MOV OS,AX 

3713 CNP CRT_HODE,7 ; IS THIS THE BLACK AND WHITE CARD 

3714 JE ~16 ; IF SO, SKIP THE MODE RESET 

3715 NOV AL.CRT_tfODE_SET ~ GET THE VALUE OF THE MODE SET 

3716 NOV DX,0308H ; ALWAYS SET COLOR CARD PORT 


3718 

3719 JMP 

3720 N7: ; BLANK_FIELD 

3721 NOV BL,OH GET ROW COUNT 

3722 JMP 

H' 

; GO CLEAR THAT AREA 

3723 ENDP 

3724 

3725 ; ----- HANllE COMMON SCROLL SET UP HERE 

3726 

3127 SCROll_POSITION PROC NEAR 

3128 CM? CRT_MOOE,2 I TEST FOR SPECIAL CASE HERE 

3129 J8 N9 ; HAVE TO HANDLE 80X25 SEPARATELY 

3730 CMP CRT_MODE, 3 

3731 JA N9 

3732 

3733 j ----- 80X2S COLOR CARD SCROll 

3734 

3735 PUSH OX 

3736 MOV oX,30AH ; GUARANTEED TO BE COLOR CARD HERE 

3737 PUSH AX 

3738 i WAIT_DISP_ENABLE 

3739 IN AL,oX ; GET PORT 

3740 TEST AL.S ; WAIT FOR VERTICAL RETRACE 

3741 JZ H8 ; WAIT_DISP_ENABLE 

3742 NOV AL,25H 

3743 MOV OX , 030SH 

3744 OUT OX.Al ; TURN OFF VIDEO 

3745 POP AX i DURING VERTICAL RETRACE 

3746 POP OX 

3747 N9: CALL POSITION ; CONVERT TO REGEN POINTER 

3748 ADD AX.CRT_START ; OFFSET OF ACTIVE PAGE 

3749 HOV OI,AX ; TO ADDRESS FOR SCROll 

3750 HOV 5I,AX ; fROM ADDRESS fOR SCROLL 

3751 SUB OX,CX ; OX = #ROWS, WCOLS IN BLOCK 

3752 INC DH 

3753 INC Dl J INCREMENT FOR 0 ORIGIN 

3754 XOR CH,CH J SET HIGH BYTE OF COUNT TO ZERO 

3755 MOV BP,CRT_COLS ; GET NUMBER OF COLUMNS IN DISPLAY 

3756 AOO BP,BP ; TIMES 2 FOP ATTRIBUTE BYTE 

3757 MOV AL,Bl ; GET LINE COUNT 

3758 MUl BYTE PTR CRT_COLS ; DETERMINE OFFSET TO FROM ADDRESS 

3759 ADD AX,AX ; *2 FOR ATTRIBUTE BYTE 

A-51


F32B 06 3760 PUSH ES ESTABLISH ADDRESSING TO REGEN BUFFER 

F3ZC IF 3761 pop OS FOR BOTH POINTERS 

F32:0 SOFBOO 3762 CMP BL.O o SCROll MEANS BLANK FIELD 

F330 C3 3763 RET ; RETURN WITH FUGS SET 

3764 SCROLL_POSITION ENOP 

3765 

3766 j------ MOVE_ROW 

F331 3767 HIO PROC NEAR 

f331 SACA 3768 MOV Cl,Dl • GET • OF eOLS TO MOVE 

F333 56 3769 PUSH 51 

F334 57 3770 PUSH 01 I SAVE START ADDRESS 

F33S F3 3171 REP MOVSW ; MOVE THAT LlUE ON SCREEN 

F336 A5 

F337 SF 3772 POP 01 

F336 Sf 3773 POP 51 I RECOVER ADDRESSES 

F339 C3 3774 RET 

3775 HID ENDP 

3776 

3777 j------ CLEAR_ROW 

F33A 3778 HII PROC NEAR 

F33A SACA 3779 MOV Cl.Dl I GET I CCUJMNS TO CLEAR 

F33C 57 3780 PUSH 01 

F33D F3 3781 REP STQSW I STORE THE fILL CHARACTER 

F33E AS 

F33f SF 3782 pop 01 

F340 C3 3783 RET 

3784 Nil ENDP 

3765 ;-------------------------- --- --- 

3766 ; SCROLL_DOWN 

3787 THIS ROUTINE MOVES THE CHARACTERS WITHIN A DEFINED 

3788 BLOCK DOWN ON THE SCREEN, FILLING THE TOP LINES 

3789 WITH A DEFINED CHARACTER 

3790 ; INPUT 

3791 (AH I = CURRENT CRT MODE 

3792 (All = NUMBER OF LINES TO SCROLL 

3793 (CX I = UPPER LEFT CaRtIER OF REGION 

3794 (OX) = LOWER RIGHT CORNER OF REGION 

3795 (BHJ = FILL CHARACTER 

3796 (OS I = DATA SEGMENT 

3791 'ESJ = REGEN SEGMENT 

3798 ;OUPUT 

3799 NOHE - SCREEN IS SCROllED 

3800 ; -- --- ---- ------------------------ 

F341 3801 SCROLL_DO~N FROC NEAR 

f341 FD 1802 STD ; DIRECTION FOR SCROLL DOWN 

f342 8AD8 3803 NOV BL,AL ; LINE COUtIT TO BL 

F344 80FC04 3804 CMP AH,4 ; TEST FOR GRAPHICS 

F347 7208 3805 JC HI2 

F349 80FC01 3806 CNP AH,7 i TEST FOR BW CARD 

F34C 7403 3S07 JE HI2 

F34E E9A601 3808 JMP GRAPHICS_DOWN 

F351 1809 NI2.: ; CONTINUE_DOWN 

F351 53 3810 FUSH BX ; SAVE ATTRIBUTE IN 8H 

F352 8BCZ 3811 NOV AX,OX ; LOWER RIGHT CORNER 

F354 E893FF 3812. CALL SCROll.POSITION ; GET REGEN LOCATION 

F357 742.0 3811 JZ HI. 

F3S9 2BfD 3814 SUB SI,AX ; SI IS FROM ADDRESS 

f358 8AE6 3815 MOV AH,OH ; GET TOTAL II ROWS 

F35D un 3816 SUB AH,Bl ; COUNT TO MOVE IN SCROLL 

F35F 3817 N13: 

F3SF E8CFFF 3816 CALL NID ; MOVE ONE ROW 

F362 2.BF5 3819 SUB SI,ep 

F364 2BFD 3820 SUB DI,BP 

F366 fEce 3821 DEC AH 

F368 75F5 3622 J~lZ HI3 

F36A 3823 N14: 

F36A 58 3824 POP AX t RECOVER ATTRIBUTE IN AH 

F368 B020 3825 MOV AL, • 

F36D 3826 N15: 

F36D ESCAFF 3827 CAlL HII ; CLEAR ONE ROW 

F370 2BFa 3828 SUB aI,BP ; GO TO NEXT ROW 

F372 FEee 3829 DEC 8L 

F374 75F7 3830 JNZ HIS 

F376 E957FF 3831 JMP HS ; SCROll.END 

F379 3832 N16: 

F379 8ADE 3833 HOY BL,DH 

A-52

lOC 08J LINE SOURCE 

F376 fBED 3834 JMP N14 

3835 SCROL~OO!J:N ENDP 

3836 ; ----------------------- ------------------ 

3837 ; READ_At_CURRENT 

3838 THIS ROUTINE READS THE ATTRIBUTE AND CHARACTER AT THE CURRENT 

3839 CURSOR POSITION AHO RETURNS THEM TO THE CALLER 

3a40 

; INPUT 

3841 (AH) :: CURRENT CRT t10DE 

3842 (8H) :: DISPLAY PAGE ( ALPHA HODES ONLY 1 

3843 (as) = DATA SEGMENT 

3844 (ES) = REGEN SEGMENT 

3845 ;OUTPUT 

3846 (ALI = CHAR READ 

3347 (AH) :: ATTRIBUTE READ 

3848 ; -------------------- - - ------------------- 

3849 ASSUME CS:CQDE.DS:DATA.ES:DATA 

F37D 3850 READ_AC_CURRENT PROt NEAR 

F37C 80FC04 3851 eMP AH,4 ; IS THIS GRAPHICS 

n80 7Z0B 3852 JC PI 

f382 80FC07 3853 CMP AH.7 ; IS THIS ew CARD 

F38S 7403 3854 JE PI 

Fl87 E9A902 3855 JMP GRAPHICS_READ 

FlSA 3856 PI: ; READ_AC_CONTINUE 

F3eA E81,o..OO 3857 CALL FINO_POSITION 

F38D 8BF3 3858 MOV SI,ex j ESTABLISH ADDRESSING IN 51 

3659 

3S60 

3861 

j------ WAIT FOR HORIZONTAL RETRACE 

F3SF 8BI66300 3862 MOV DX.AOOR_6845 ; GET BASE ADDRESS 

F393 83C206 3863 ADD OX.6 i POINT AT STATUS PORT 

F396 06 3864 PUSH ES 

F397 IF 386$ POP OS ; GET SEGMENT FOR QUICK ACcESS 

F398 3866 P2 : ; W.IT FOR RETR.CE LOW 

F398 EC 3867 IN AL,OX ; GET STATUS 

F399 ,0..801 3868 TEST AL,1 ; IS HaRZ RETRACE LOW 

f39B 75FB 3869 JNZ P2 ; WAIT UNTIL IT IS 

F39D FA 3870 CLI j NO MORE INTERRUPTS 

r'\ 

F39E 3871 P3: ; WAIT FOR RETRACE HIGH 

F39E EC 3872 IN AL.OX ; GET STATUS 

f39F ,0..801 3873 TEST AL.! ; IS IT HIGH 

FlAl 74F8 3874 JZ P3 ; WAIT UNTIL IT IS 

FlA.3 AD 3875 lOOSW ; GET THE CHAR/ATTR 

F3A4 E9Z0Ff 3876 JMP VIDEO_RETURN 

3877 RE.O_AC_CURREHT ENDP 

3878 

FlA7 3879 

nA7 8ACF 3880 MQV CL,BH ; DISPLAY PAGE TO CX 

F3A9 3ZED 3881 XOR CH.CH 

FlAB 86Fl 3882 NOV 5I.CX ; MOVE TO SI fOR INDEX 

F3AO DIE6 3883 SAL 51.1 ; • 2: FOR WORD OFFSET 

F3AF 88845000 3884 I10V AX,[SI+ OFFSET CURSOR]OSNJ ; GET ROW/COLUMN OF THAT PAGE 

F3B3 330B 3885 XOR ex.ex SET START ADDRESS TO ZERO 

F3BS n06 3686 JCXZ P5 

nB7 3887 P4: 

F367 031£4COO 3888 ADD BX.CRT_LEN LENGTH Of BUFfeR 

FlBB EZFA 3889 lOOP P4 

FlBD 3890 ps: ; NO_PAGE 

F3BD E8CBFE 3891 CALL POSITlON ; DETERMINE LOCATION IN REGEN 

nco 0308 3892 AOO BX.AX ; ADD TO START OF REGEN 

F3C2 C3 3893 RET 

3694 FINO_POSITION Et.'OP 

3895 ; ----- ~----------- ----------------------- 

3896 ;WRITE_AC_CURRENT 

3897 THIS ROUTINE WRITES THE ATTRIBUTE AND CHARACTER AT 

3696 THE CURRENT CURSOR POSITION 

38'99 ; INPUT 

3'900 ! AH) = CURRENT CRT MODE 

3901 (BH) = DISPLAY PAGE 

3902 (CXl = COUNT OF cHARACTERS TO WRITE 

3903 (AU = CHAR' TO WRITE 

3904 tBLl = ATTRIBUTE Of CHAR TO WRITE 

3905 CDS) .. DATA SEGMENT 

3906 (ES) = REGEN SEGMENT 

3907 ;OUTPUT 

3908 NONE 

3909 ; --------- ------------- --------------------- 

A-53


F3Cl 3910 NEAR 

F3C3 60fC04 3911 CMP AH,4 i IS THIS GRAPHICS 

F3C6 7208 3912 JC P6 

nCB BOFC07 3913 CMP AH,7 I IS THIS BW CARD 

nCB 7403 3914 J' P6 

nco E98101 3915 JMP 

noo 3916 P6: i WRITE_AC_CONTINUE 

Floa 8An 3917 HOV AH,BL ; GET ATTRIBUTE TO AH 

F30Z 50 3918 PUSH AX I SAVE ON STACK 

Fl03 SI 3919 PUSH ex ; SAVE WRITE COUNT 

F3D4 ESC OFF 39Z0 CALL FlNO_POSITlOH 

F30? 8BFB ]92:1 HOY DI.BX • ADDRESS TO 01 REGISTER 

n09 59 3922 POP ex ~ WRITE COUNT 

FlOA 58 3923 pop ex J CHARACTER IN BX REG 

F30B 3924 1'7: ; WRITE_LOOP 

3925 

3926 ; ------ WAlT FOR HORIZONTAL RETRACE 

3927 

F30B 8B166300 3n8 MOY DX.ADDR_6645 ; GET BASE ADDRESS 

nOf 63C206 3929 ADD DX.6 i POINT AT STATUS PORT 

F3El 3930 P6: 

F3E2 EC 3931 IN Al,DX ; GET STATUS 

BE3 A801 3932 TEST Al.t I IS IT LOW 

F3E5 75FB 39~3 JUZ P6 I WAIT UNTIL IT IS 

F3E7 FA 3934 ell ; NO MORE INTERRUPTS 

FlEa 3935 P9: 

FlEe EC 3936 IN .U,DX ; GET STATUS 

F3E9 ASOI 3937 TEST Al,l ; IS IT HIGH 

FlEB 74FB 3936 JZ P9 ; WAIT UNTIL IT IS 

FlED 8BC3 3939 MOV Ax.ex ; RECOVER THE CHAR/ATTR 

F3EF AS 3940 STOSW ; PUT THE CHAR/ATTR 

F3FO Fa 3941 sn ; INTERRUPTS BACK ON 

F3F1 E2E8 3942 j AS MANY TIMES AS REQUESTED 

F3F3 E9DIFD 3943 

3944 

3945 .---------------------------------------- 

394. .WRITE_C_CURRENT 

3947 THIS ROUTINE WRITES THE CHARACTER AT 

3946 THE CURRENT CURSOR POSITION. ATTRIBUTE UNCHANGED 

3949 ;INPUT 

3950 ( AH) : CURRENT CRT MODE 

3951 (BH) = DISPLAY PAGE 

3952 (CX) : COUNT OF CHARACTERS TO WRITE 

3953 tAll = CHAR TO WRITE 

3954 (OS) = DATA SEGMENT 

3955 (ES) = REGEN SEGMEtlT 

3956 .OUTPUT 

3957 NONE 

3956 ; --------------------________________--- 

F3F6 3959 WRITE_C_CURRENT PROC NEAR 

F3F6 BOFC04 396-0 eMP AH.4 IS THIS GRAPHICS 

F3F9 7208 396.1 JC PI0 

F3FB 80FC07 3962 CMP AH.7 IS THIS Bioi CARD 

F3FE 7403 3963 

J' 

Pl. 

F400 E97EOI 3964 JMP GRAPHICS_WRITE 

F403 3965 PIO: 

F403 50 396-6 PUSH AX ; SAVE ON STACK 

F404 51 3967 PUSH CX ; SAVE WRITE COUNT 

F40S E89FFF 3966 CALL FIND_POSITION 

F40e SBFB 3969 HOV DI.BX ; ADDRESS TO 01 

F40A S9 3970 POP CX ; WRITE coutn 

F40B 58 3971 POP ; BL HAS CHAR TO WRITE 

F40C 3912 PH: i WRITE_LOOP 

3973 

3974 j------ WAIT FOR HORIZONTAL RETRACE 

3975 

F40C 8S166300 3976 HOY OX , AODR_6845 ; GET BASE ADDRESS 

F410 83C206 3977 ADD DX.6 I POINT AT STATUS PORT 

f413 3976 pt2: 

F413 EC 3979 IN AL.DX GET STATUS 

F414 A801 3960 TEST AL,I IS IT LOW 

F416 7SfB 3961 JNZ PI2 ; WAIT UNTIL IT IS 

F418 FA 3962 ClI ; NO MORE INTERRUPTS 

F419 3963 PI3: 

F419 EC 3964 IN AL,OX I GET STATUS 

F41A A801 3965 TEST Al.t ;; IS IT HIGH 

A·54


f41C 74F8 3986 JZ P13 ; WAIT UNTIL IT IS 

F41£ BAC3 3987 MDV AL,BL ; RECOVER CHAR 

F420 AA 3968 SlOSS ; PUT THE CHAR/ATTR 

F421 47 3989 INC Dr ; BUNP POINTER PAST ATTRIBUTE 

F422 E2E8 3990 LOOP P11 ; AS MANY TII1ES AS REQUESTED 

F424 E9AOFD 3991 JMP VIDEO_RETURN 

3992 WRITE_C_CURRENT EHOP 

3993 j ------------------------------------------- 

3994 j READ DOT -- WRITE DOT 

3995 ; THESE ROUTINES WIll WRITE A DOT. OR READ THE 

3996 DOT AT THE INDICATED LOCATION 

3997 ENTRY - 

399S OX = ROW (0-199) (THE ACTUAL VALUE DEPENDS ON THE MODE) 

3999 C'I( = COLUMN ( 0-639) ( THE VALUES ARE NOT RANGE CHECKED) 

4000 Al = DOT VALUE TO WRITE (I. 2 OR 4 BITS DEPENDING ON MODE. 

4001 REQ'D FOR WRITE DOT ONLY. RIGHT JUSTIFIED) 

4002 BIT 7 OF AL : 1 INDICATES XOR WE VALUE INTO THE LOCATION 

4003 OS = DATA SEGMENT 

4004 ES = REGEN SEGMENT 

4005 

4000 EXIT 

4007 AL :: DOT VALUE REAO, RIGHT JUSTIFIED, READ ONLY 

4008 J------------------------------------------- 

4009 ASSUME CS :CODE .DS:DATA. ES: DATA 

F427 4010 REAO_oDT PROC NEAR 

F427 E83100 4011 CALL 03 • DETERMINE BYTE POSITION Of DOT 

F42A 268A04 4012 HOV AL,ES:(SIJ ; GET THE BYTE 

F420 22C4 4013 AND AL.AH • MASK OFf THE OTHER BITS IN THE BYTE 

F42F 02EO 4014 SHL AL,CL ; LEFT JUSTIfY THE VALUE 

F431 8ACE 4015 HDV Cl,DH ; GET NUMBER OF BITS IN RESULT 

F433 02CO 4016 OOL AL,CL ; RIGHT JUSTIFY THE RESULT 

F435 E98FFD 4017 JHP VIDEO.RETURN ; RETURN FROM VIDEO 10 

4018 ENOP 

4019 

F436 4020 IomITE.DOT PROC NEAR 

F438 50 4021 PUSH AX SAVE DOT VALUE 

1"""""\ F439 50 4022 PUSH AX TWICE 

F43A E61EOO 4023 CALL R3 DETERMINE BYTE POSITION OF THE ~OT 

F430 02E8 4024 SHR AL.CL SHIFT TO SET UP THE BITS fOR OUTPUT 

F43F 22C4 4025 Mm AL.AH STRIP OfF THE OTHER BITS 

F441 268AOC 4026 MOV CL,ES:[SI1 ; GET THE CURRENT BYTE 

F444 58 4027 POP BX ; RECOVER XOR flAG 

F445 F6C380 4028 TEST BL.80H ; IS IT ON 

F448 750D 4029 JNZ ., 

; YES. XOR THE DOT 

F44A F604 4030 NOT AH ; SET THE MASK TO REMOVE THE INDICATED BITS 

F44C 22CC 4031 AND CL,AH 

F44E QAel 4032 00 AL.CL ; OR IN THE NEW VALUE OF THOSE BITS 

F450 4033 Rl : ; FINISH_DOT 

F450 268804 4034 MOV ES:(SI1.AL ; RESTORE THE BYTE IN MEMORY 

F453 58 4035 rop AX 

F454 E970FO 4036 JMP VIDEO.RETURN ; RETURt~ FROM VIDEO 10 

F457 4037 R2 ; ; XOR_OOT 

F457 32Cl 4038 XOO AL,CL ; EXCLUSIVE OR THE DOTS 

F459 ESFS 4039 JMP ., 

; FINISH UP THE W1HTWG 

4040 WRITE.DOT ENOP 

4041 ; ------------------------------------------- 

4042 ; THIS SUBROUTINE DETERMINES THE REGEN BYTE LOCATION OF THE 

4043 ; IHDICATED ROW COLUMN VALUE IN GRAPHICS MODE. 

4044 ENTRY - 

4045 OX :: ROW VALUE (0-1991 

4046 ex = COLUMN VALUE (0-639) 

4047 EXIT - 

4048 51 ;: OFFSET INTO REGEN BUFFER FOR BYTE OF INTEREST 

4049 AH = MASK TO STRIP OFF THE BITS OF INTEREST 

4050 CL ::; BITS TO SHIFT TO RIGHT JUSTIFY THE MASK IN AH 

4051 CH = # BITS IN RESULT 

4052: j ------------------------------------------- 

F458 4053 03 PROC HEAR 

F4SB 53 4054 PUSH BX ; SAVE ex OURING OPERATION 

F45C 50 4055 PUSH AX ; WILL SAVE AL DURING OPERATION 

4056 

4057 ;------ DETERMINE 1ST BYTE IN IDICATEO ROW BY MULTIPLYING ROW VALUE BY 40 

4058 ;------ ( LOW BIT OF ROW DETERMINES EVEN/ODD. 80 BYTES/ROW 

4059 

F450 B028 4060 MOV AL.40 

F45F 52 4061 PUSH OX ; SAVE ROW VALUE 

A-55

laC OBJ LINE SOURCE 

1'460 80HfE 

F46J F6E2 

F465 SA 

F466 F6t201 

F469 '7403 

F46B 050020 

F46E 

F46E aeFO 

F470 58 

F471 seDl 

F473 B&e002 

F476 B90203 

F479 803£490006 

F47E n06 

1'480 BB8001 

F483 B90307 

F486 

1'486 22EA 

F488 03EA 

F4814. 031'2 

F48C 8AF7 

F48e 2AC9 

1'490 

F490 DOCS 

F492 otco 

F494 FECI' 

1'496 751'8 

F498 8AE3 

1'4914. D2EC 

F49C S8 

F49D Cl 

F49£ 

F49E 8AD8 

F4Ao 8BCl 

F4A2 E86A02 

f4A5 8BF8 

4062 AND Dl.OFfH ; STRIP OFF ODDIEVEN BIT 

4063 MUL DL ; AX HAS ADDRESS OF 1ST BnE OF INDICATED ROW 

4064 PDP OX ; RECOVER IT 

4065 

TEST DL.l 

I TEST FOR EVEN/ODD 

4066 Jl 

J JUMP IF EVEN ROW 

•• 

4067 ADD AX,2000H ; OFFSET TO LOCATION OF 000 ROWS 

4068 R4: J EVEN_ROW 

4069 I10V SI,AX I HOVE POINTER TO SI 

4070 POP AX ; RECOVER AL VALUE 

4071 I10V DX,CX j COLUMN VALUE TO ox 

4072 

4073 j------ DETERMINE GRAA-UCS NOOE CURRENTLY IN EFFECT 

4074 

4075 , SET UP THE REGISTERS ACCORDING TO THE HOOE 

4076 ,CH :: MASK FOR LOW OF COLUt1N ADDRESS ( 7/3 FOR HIGttmf:D RES) 

4077 Cl :: • OF ADORESS BITS IN COlUMH VALUE ( 3/2 FOR HIH) 

4078 BL = MASK TO SELECT BITS FROH POINTED SHE (80H/COH fOR H,"' 

4079 ~ BH:: NUMBER OF VALID BITS IN pOINTED BYTE ( 1/~ fOR H/M) 

4080 

4081 I1DV BX.2COH 

4082 I10V CX.302H J sEl PAR"S FOR MED RES 

4083 CMP CRT_HODE.6 

4084 JC .s J HANDLE IF MED ARES 

4085 MOV BX,180H 

4086 MOV CX,703H ~ SET PARH$ FOR HIGH IlES 

4087 

40ee ;-----~ DETERMINE BIT OFFSET IN BYTE FROM' COllR1N HAst< 

4089 RS: 

4090 AND CH,OL ; ADDRESS OF PEl WItHIN BytE TO CH 

4091 

4092 I--~"-~ DETERI1INE: BytE OFFSET FOR THIS lOCA'rION IN COLUHN 

4093 

4094 SH. DX.CL ; SHIFT BY cORRECT AnoUHT 

4095 ADD SI,DX ; IUCREMENT THE POINTER 

4096 HOV DH,BH i GET THE I OF BITS IN RESULT TO DH 

4097 

4098 J------ MULTIPLY BH (VALID SItS IN BYTE) BY CH (BIT OFFSET) 

4099 

4100 SUB Cl.CL ; ZERO INTO STORAGE LOCATION 

4101 R6: 

4102 .0. AL,1 ; lEFT JUSTIFY THE VALUE IN AL (FOR WRITE) 

4103 ADD CL.CH ; ADO I~ THE BIT OFFSET VALUE 

4104 DEC aH I lOOP CONTROL 

4105 JNl o. ; ON EXIT, Cl HAS SHIFT COUNT TO RESTORE BITS 

4106 MDV AH,SL ; GET MASK TO AH 

4107 SH. AH,CL ; HOVE THE MASK TO CORRECT LOCAtION 

410S PDP BX ; RECOVER REG 

4109 

.ET 

; RETURN WITH EVERYTlUNG SET UP 

., 

4110 EHOP 

4111 j ------------------------------------------- 

4112 ; SCROll UP 

4113 I THIS ROUTINE SCROLLS UP THE INFORMATION ON THE CRT 

4114 ENTRY - 

4115 ; CH.CL --=: UPPER LEFT CORNER OF REGION TO SCROLL 

4116 DH.Dl = LOWER RIGHT CORNER OF REGION TO SCROll 

4117 80TH OF THE ABOVE ARE IN CHARACTER POSITIONS 

4118 BH = FILL VALUE FOR BLANKED LINES 

4119 I AL = • LINES TO SCROLL (AL=O MEANS BLANK THE ENTIRe FIElD) 

412:0 OS = DATA SEGMENT 

412:1 ; ES = REGEN SEGMENT 

4122 EXIT - 

4123 NOTHING. THE SCREEN IS SCROllED 

4124 j ---------------------------_.. _ .. _ ..-------- 

412:5 GRAPHICS_UP PRoe NEAR 

4126 MOV BL.AL ; SAVE LINE COUNT IN BL 

4127 MOV AX.CX ; GET UPPER LEFT POSITION INTO AX REG 

4128 

4129 ;------ USE CHARACTER SUBROUTINE FOr:! POSITIONING 

4130 ,------ ADDRESS RETURNED IS MULTIPLIED BY 2 FROM CORRECT VALUE 

413] 

4132 

4133 MOV OI.AX , SAVE RESULT AS DESTINATION ADDRESS 

4134 

413S j ----- DETERMINE SIZE OF WINDOW 

4136 

A-56

loe OBJ 

LINE 

SOURCE 

F4A7 2BOl 

F4A9 81C20101 

F4AO DOE6 

F4AF DOE6 

r"'\ F481 803£490006 

F486 7304 

F488 00E2 

F4SA DIE7 

FItSe 

F4SC 06 

F480 1f 

F48E 2AED 

F4eo OOEl 

F4e2 001:3 

F4C4 7420 

F4C6 SAC] 

F4CB 8450 

F4CA F6E4 

F4CC BBF7 

F4CE 03FO 

F4DO 8AE6 

F4DZ: ZAf3 

F404 

F404 EaMOD 

F407 8IEEBOlF 

F4DS 81EFBOIF 

F40F FEee 

r"'\ F4El 75Fl 

r"'\ 

F4E3 

F4E3 8AC7 

F4ES 

F4ES E88800 

FitE8 81EFBOIF 

F4EC FECB 

F4EE 75F5 

F4FO E9D4FC 

F4H 

F4F3 8AOE 

F4FS EBEC 

F4H 

F4F7 FD 

F4F8 SADS 

F4FA 8BCl. 

F4FC E81002 

4137 SUB ox.ex 

4138 ADO OX,lOlH I ADJUST VALUES 

4139 SAL DH.l I NULTIPLY a- ROWS BY It SINCE 8 VERT DOTS/CHAR 

414Q SAL OHt! I AND EVEN/ODD ROWS 

4141 

4142 1------ DETERMINE CRT HODE 

4143 

4144 CMP CRT_mlOE.6 J TEST FOR MEDIUM RES 

4145 JNC R7 FIHO_SOURCE 

4146 

4147 1------ MEDIUM RES UP 

4148 SAL OL.! ; I COLUMNS * 2:, SINCE ;2 BYTES/CHAR 

4149 SAL Old ; OFFSET *2 SINCE 2: BYTES/tHAR 

4150 

4151 ;------ DETERttINE THE SOURejE ADDRESS IN THE BUfFER 

4152 R7: ; FIND_SOURCE 

4153 PUSH ES ; GET SEGMENTS BOTH POINTING TO REGEN 

4154 POP OS 

4155 SUB CHtCH I ZERO TO HIGH OF COUNT REG 

4156 SAL Bl.t ; MULTIPLY tU1BER OF LINES BY 4 

4157 SAL Bl.l 

4158 JZ ; IF ZERO. THEN BLANt< ENTIRE FIELD 

4159 NOV "" Al.St ; GET NUMBER OF LItlES IN AL 

4160 MOV AH,80 J 80 SrTES/ROW 

4161 NUL AH t DETERMINE OFfSET TO SOURCE 

4162 NOV SI,D! ; SET UP SOURCE 

4163 ADO 51,AX ; ADD IN OFFSET TO IT 

4164 HOY AH,DH I NUMBER OF ROWS IN FIELD 

4165 SUB AH,Ol ; DETERMINE NUt1BER TO MOVE 

4166 

4167 ,------ LOOP THROUGH. MOVING ONE ROW AT A TIME, BOTH EVEN AND ODD fIELDS 

4168 pa: ; ROW_lOOP 

4169 CALL "17 ; MOVE DUE ROW 

4170 SUB SI.2000H-8.0 ; ttOVE TO NEXT ROW 

4171 SUB DX ,2000H-80 

4172 OEC AH I NUMBER OF ROWS TO tfOVE 

4173 J»Z .s J CONTINUE TILL ALL HOVED 

4174 

4175 ;------ FILL IN THE VACATED LINE(S) 

4176 R9: i CLEAR_ENTRY 

4177 MOV Al,SH ; ATTRIBUTE TO FILL NITH 

4178 RIO: 

4179 CAll Rle I CLEAR THAT ROW 

4180 SUB DI.2:000H-80 POINT TO NEXT LINE 

41S1 DEC BL NUHBER OF LINES TO FIll 

4182 JNZ RIO ; CLEAR_LOOP 

41S3 JMP VIDEO_RETURN j EVERYTHING DONE 

41S4 

41SS Rll: ; BLANKJIElO 

4186- HOV BL,DH ; SET BLANK COUNT TO EVERYTHING IN FIElD 

4187 JNP .9 

f CLEAR THE FIELD 

4188 GRAPHICS_UP ENDP 

4189 ;---------- .....---..--------------------------- 

4190 I SCROll DOWN 

4191 I THIS ROUTINE SCROllS DOriN THE INFORMATION ON THE CRT 

4192 ; ENTRY - 

4193 I CH .CL = UPPER LEFT CORNER OF REGION TO SCROLL 

4194 DH,DL ::; LOWER RIGHT CORNER OF REGION TO SCROLL 

4195 BOTH OF THE ABOVE ARE IN CHARACTER POSITIONS 

4196 BH- = FILL VALUE FOR BLANKED LIHES 

4)97 I AL ::; I LINES TO SCROll fAL=O MEANS BLAHI< THE ENTIRE FIELD) 

4198 OS =DATA SEGMENT 

4199 I ES ::; REGEN SEGMENT 

4200 I EXIT - 

4201 ; NOTHING, THE SCREEN IS SCROLLED 

42:02 1------------------------------------------- 

4203 

4204 GRAPHICS_DOWN PROC NEAR 

4205 5TO ; SET DIRECTION 

4206 NOV BL,AL J SAVE LINE COUNT IN BL 

4207 NOV AX ,ox. ; GET LOWER RIGHT POSITION INTO AX REG 

4208 

4209 ; ------ USE CHARACTER SUBROUTINE FOR POSITIONING 

4210 ; ..----- ADDRESS RETURt~ED IS tlULTIPLIED BY 2 FROt! CORRECT VAWE 

4211 

4212 CALL GRAPH_POSN 

A-57


F4FF BSFB 4213 MOV DI,AX SAVE RESULT AS DESTINATION ADDRESS 

4214 

42:15 ;------ DETERMINE SIZE OF WINDOW 

4216 

F501 2BDI 4217 SUB DX,ex 

F503 81C20101 4218 ADO OX.I01H ; ADJUST VALUES 

F507 OOE6 4219 SAL DH.1 ; NULTIPLY I ROWS BY 4 SINCE 8 VERT DOTS/CHAR 

F509 DOE6 4220 SAL DH .I ; AND EVEN/ODD ROWS 

4221 

4222 ;------ DETERMINE CRT HOOE 

4223 

F508 603E490006 4224 CMP ; TEST FOR MEDIUM RES 

F510 7305 4225 JNC FIND_SOURCE_OOWN 

4226 

4227 ;------ MEDIUM RES DOWN 

F512 00£2 4228 SAL CL.l I .. COLUMNS v 2, SINCE 2 SYTES/CHAR (OFFSET OK J 

F514 DIE7 4229 SAL DI,! ; OFFSET -112 SINCE 2. BYTES/CHAR 

F516 47 4230 INC 01 ; POINT TO LAST BYTE 

4231 

4232 ; ----- DETERMINE THE SOURCE ADDRESS IN THE BUFFER 

F517 4233 R12! ; FIND_SOURCE_DOWN 

F517 06 4234 PUSH ES ; BOTH SEGMENTS TO REGEN 

Fs18 IF 4235 POP OS 

F519 2AEO 4236 SUB CH.CH ; ZERO TO HIGH OF COUNT REG 

F516 81C7FOOO 4237 ADO 01.240 ; POINT TO LAST ROW OF PIXELS 

FSlF Don 4238 SAL BLol ; MULTIPLY NUMBER OF LINES BY 4 

F52.1 Don 4239 SAL BL.I 

F523 742E 4240 JZ RI. ; IF ZERO. THEN BLANK ENTIRE FIELD 

F525 8AC3 4241 MOV AL,BL ; GET NUtlBER OF LINES IN AL 

F527 8450 4242 MOV AH,80 ; 80 BYTES/ROW 

F529 F6E4 4243 MUl AH ; DETERMIHE OFFSET TO SOURCE 

F526 8BF7 4244 MOV 51,01 ; SET UP SOURCE 

F520 2BfO 4245 SUB SI,AX ; SUBTRACT THE OFFSET 

F52:f 8AEo 42460 MOV AH,OH j NUMBER OF RO~S IN FIELD 

F53) ZAn 4247 SUB AH,6L ; DETERMINE NUMBER TO MOVE 

4248 

4249 ;------ LOOP THROUGH, MOVING ONE ROW AT A TIME, BOTH EVEN AND ODD FIelDS 

F533 4250 PH: ; ROW_LOOP_OO\o.'N 

F533 E62100 4251 CALL RI7 ; MOVE OI~E ROW 

F536 SlEE50l0 4252 SUB SI,2000H+80 ; MOVE TO NEXT ROW 

F53A 81EF5020 4253 SUB OI,2000H+80 

F53E FEee 4254 DEC AH ; NUMBER OF ROWS TO MOVE 

F540 75F1 4255 JNZ R13 ; CONTINUE TILL ALL MOVED 

4256 

4257 ;------ FILL IN THE VACATED LINE(S) 

F542 4258 RI4: ; CLEAR_ENTRY_DOWN 

F542 8AC7 4259 MOV AL.BH ; ATTRIBUTE TO FILL WITH 

F544 42600 RIS: ; CLEAR_LOOP_OOWN 

F544 E82900 4261 CALL RIB ; ClEAR A ROW 

F547 81EfSOZO 4262 SUB DI.2000H+BO ; POINT TO NEXT LINE 

F548 FECB 4263 DEC Bl ; NUMBER OF LINES TO FILL 

F54D 75FS 4264 JtlZ RI5 ; CLEAR_ LOOP_DOI.IN 

F54F Fe 4265 CLO ; RESET THE OIREcTION FLAG 

F550 E974FC 4266 JMP VIDEO_RETURN ; EVERYTHING DONE 

4267 

F553 4268 RI6: ; BLA~IKJIELO_OOWN 

F553 SADE 4269 MOV BL,OH ; SET BLANK COUNT TO EVERYTHING IN FIElD 

F555 EBEB 4270 JMP RI4 ; CLEAR THE FIELD 

4271 GRAPHICS_DOWN ENOP 

4272 

427"> ;------ ROUTINE TO MOVE ONE ROW OF INFORMATION 

4274 

F557 4275 RI7 PROC NEAR 

F557 BACA 4276 MOV CL,DL ; NUMBER OF BYTES IN THE ROW 

F559 56 4277 PUSH SI 

F55. 57 4278 FUSH 01 SAVE POIHTERS 

F558 F3 4279 REP MOVSB MOVE THE EVEN FIELD 

F55C A4 

F550 SF 4280 POP 01 

F55E Sf 4281 POP S1 

F55F 81C6002:0 4282 ADO SI,ZOOOH 

F563 81C70020 4283 ADO 01.2000H ; POINT TO THE ODD FIelD 

F567 56 4284 PUSH SI 

FSb8 57 4285 PUSH 01 ; SAVE THE POINTERS 

F569 BACA 4286 MOV CL.Ol I COUNT BA.CK 

A-58


FS6B F3 4287 REP MOVSB ; MOVE THE ODD FIELD 

FS6C A4 

FS6D SF 4288 POP or 

FS6E SE 4289 rop 5r ; POINTERS BACK 

FS6F C3 4290 RET ; RETURN TO CALLER 

4291 R17 ENOP 

4292 

~ 

4293 ;------ CLEAR A SINGLE ROW 

4294 

F570 4295 R18 PROC NEAR 

F570 6ACA 4296 MOV Cl,Dt ; NUMBER OF BYTES IN FIELD 

F572 57 4297 PUSH or SAVE POINTER 

F573 F3 4298 REP STOSB STORE THE ~lEW VALUE 

F574 AA 

FS7S SF 4299 POP or POINTER BACK 

F576 61C70020 4300 ADO OI.2000H i POINT TO 000 FIELD 

F57A 57 4301 PUSH or 

FS7B 6ACA 4302 MOV Cl,DL 

F57D F3 4303 REP STOSB FILL THE ODD FIlElD 

FS7E AA 

F57F SF 4304 POP or 

FS80 C3 4305 RET ; RETURN TO CALLER 

4306 Ria ENOP 

4307 ; --------------------------------------- 

4308 ; GRAPHICS WRITE 

4309 THIS ROUTINE WRITES THE ASCII CHARACTER TO THE CURRENT 

4310 POSITION ON THE SCREEN. 

4311 ENTRY - 

4312 Al = CHARACTER TO WRITE 

4313 Bl = COLOR ATTRIBUTE TO BE USED FOR FOREGROUND COLOR 

4314 IF BIT 7 IS SET I THE CHJ\R IS XOR '0 INTO THE REGEN BUFFER 

4315 (0 IS USED FOR THE BACKGROUND COLOR) 

4316 CX = NUMBER OF CHARS TO WRITE 

4317 OS = DATA SEGMENT 

4318 ES = REGEN SEGMENT 

4319 EXIT - 

4320 NOTHING IS RETURNED 

4321 

4322 GRAPHICS READ 

4323 THIS ROUTINE READS THE ASCII CHARACTER AT TIiE CURRENT ClrnSOR 

4324 POSITION ON THE SCREEN BY MATCHING THE DOTS ON THE SCREEN TO THE 

4325 CHARACTER GENERATOR CODE POINTS 

4326 ENTRY - 

4327 NONE (0 IS ASSUMED AS THE BACKGROUNO COLOR 

4326 ; EXIT - 

4329 Al ; CHARACTER READ AT THAT POSITION (0 RETURNED IF NONE FOUND) 

4330 

4331 I FOR BOTH ROUTINES, THE IMAGES USED TO FORM CHARS ARE CONTAINED IN ROM 

4332 FOR THE 1ST 128 CHARS. TO ACCESS CHARS IN THE SECOND HALF, THE USER 

4333 MUST INITIALIZE THE VECTOR AT INTERRUPT lFH (LOCATION 0007CH) TO 

4334 POItn TO THE USER SUPPLIED HBlE OF GRAPHIC IMAGES (6X6 BOXESL 

4335 FAILURE TO 00 SO WILL CAUSE IN STRANGE RESULTS 

4336 ; ------------------------- - ------------ 

4337 ASSUME CS: CODE ,DS:DATA. ES : DATA 

FS81 4338 GRAPHICS_~?ITE PROC NEAR 

F581 B400 4339 MOV AH,O ; ZERO TO HIGH Of CODE POINT 

F583 50 4340 PUSH AX i SAVE CODE POINT VALUE 

4341 

4342 ;------ DETERMINE POSITION IN REGEN BUFFER TO PUT CODE POINTS 

4343 

FS84 E88501 4344 CALL S26 ; FINO LOCATION IN REGEN BUFFER 

F587 8BF8 4345 MOV DI,AX i REGEN POINTER IN 01 

4346 

4347 ;------ DETERMINE REGION TO GET CODE POINTS FROM 

4348 

~ FS8958 4349 pOP AX RECOVER CODE POINT 

F58A 3C80 4350 eMP AL,80H IS IT IN SECOND HALF 

F58C 7306 4351 JAE 51 YES 

4352 

4353 j------ IMAGE IS IN FIRST HALF, CONTAINED IN ROM 

4354 

F58E BE6EFA 4355 MOV SI,OFA6EH OFFSET CRT_CHAR_GEN-OFFSET OF IMAGES 

F591 OE 4356 PUSH e5 ; SAVE SEGMENT ON STACK 

F592 EBOF 4357 JMP SHORT S2 ; DETERMINE_NODE 

4358 

A-59


4359 j------ IMAGE IS IN SECOND HALF. IN USER RAM 

4360 

F594 4361 51: 

F594 2e60 4362 SUB AL.SOH j ZERO ORIGIN FOR SECOND HALF 

F596 1E 4363 PUSH OS SAVE DATA POINTER 

F597 28F6 4364 SUB SI.SI 

F599 BEDE 4365 tIDV OS.SI ESTABLISH VECTOR ADDRESSING 

4366 ASSUME OS:ABSO 

F598 C5367COO 4367 LOS SI.EXT_PTR GET THE OFFSET OF THE TABLE 

F59F BCDA 4368 MOV OX.OS GET THE SEGMENT OF THE TABLE 

4369 ASSUME OS : DATA 

F5Al IF 4370 POP OS ; RECOVER DATA SEGMENT 

F5AZ S2 4371 PUSH OX l SAVE TABLE SEGMENT ON STACK 

4372 

4373 ; ----- DETERMINE GRAPHICS MODE IN OPERATION 

4374 

F5A3 4375 52 : ; DETERMINE_MODE 

FSA3 OlEO 4376 SAL AX,! I tlULTIPLY CODE POINT 

F5A5 OlEO 43n SAL AX,! ; VALUE BY 8 

F5A7 OlEO 4378 SAL AX.! 

F5A9 03FO 4379 ADD SI.AX ; SI HAS OFFSET OF DESIRED CODES 

F5AB 803£490006 4380 CMP CRT_MOOE.6 

F580 IF 4381 POP DS j RECOVER TABLE POIHTER SEGMEHT 

F581 7:2C 4382 JC 57 ; TEST FOR MEDIUM RESOLUTIOH MODE 

4383 

4384 1------ HIGH RESOLUTION MODE 

F5B3 43~5 S3: j HIGH_CHAR 

F583 57 4381:> PUSH ['II j. SAVE REGEN POINTER 

F584 56 4387 PUSH 51 ; SAVE CODE POINTER 

FSB5 6604 "388 MOV OH,4 ; HUl'18ER OF TIMES THROUGH LOOP 

F587 4389 54: 

F587 At 4390 Loose ; GET eYTE fROM CODE POINTS 

F586 F6C360 4391 TEST eL,S"1-I ; SHOULD WE USE TKE FUNCTION 

F5BB 7516 4392 JNl 56 ; TO PUT CHAR IN 

F580 AA 4393 STOSB STORE IN REGEN BUFFER 

F58E AC 4394 Loose 

F5SF 4395 $5: 

F5BF 266885FFIF 4396 MOV ES: (DI+2000H-l J.AL ; StORE IN SECONO HALF 

F5C4 83C74F 4397 ADD 01.79 j MOVE TO NEXT ROW IN REGEN 

F5C7 FEtE 4398 DEC DH j DONE WITH LOOP 

F5C9 75EC 4399 JNZ 54 

F5CB 5£ 4400 POP 51 

F5CC SF 4401 POP 01 ; RECOVER REGEN POINTER 

FSCD 47 4402 INC 01 ; POINT TO NEXT CHAR POSITION 

FSCE EtEl 4403 LOOP S3 j MORE CHARS TO WRITE 

F500 £9F4F8 4404 JMP 

4405 

F503 4406 56: 

F503 263205 4407 XOR AL.E5:tOIJ i EXCLUSIVE OR WITH CURRENT 

F506 AA 4408 STOSB ; STORE THE CODE POINT 

F507 At 4409 LeDse ; AGAIN FOR ODD FIELD 

F508 263285FFIf 4410 XOR AL.ES:IOl+2000H-ll 

F50D EBED 4411 JMP 55 ; BACK TO MAINSTREAM 

4412 

4413 ; ----- MEDIUM RESOLUTION WRITE 

F50F 4414 S7: 

F5DF 6A03 4415 MOV OL.eL ; SAVE HIGH COLOR BIT 

F5£1 D1E7 4416 SAl 01,1 ; OFFSET*2 SINCE 2 BYTES/CHAR 

F5E3 £80100 4417 CALL 519 ; EXPAND BL TO FULL WORD OF COLOR 

F5£6 4418 S8: ; MEO_CHAR 

F5£6 57 4419 PUSH 01 ; SAVE REGEN POINTER 

FSE7 56 4420 pUSH SI j SAVE THE CODE POINTER 

F5£6 6604 4421 HOV OH.4 ; NUMBER OF LOOPS 

F5EA 4422 59: 

F5EA At 4423 Loose j GET CODE POINT 

F5EB £80EOO 4424 CALL 521 ; DOUBLE UP ALL THE BITS 

F5EE 23C3 4425 AND AX.BX ; CONVERT THEH TO FOREGROUNl) COLOR ( 0 BACK J 

F5FO F6C280 4426 TEST oL,BOH ; IS THIS XOR FUNCTION 

F5F3 7407 4427 JZ 510 ; NO, STORE IT IN AS IT IS 

F5F5 263225 4428 XOR AH,ES:tDIJ ; DO FUNCTION WITH HALF 

F5F8 26324501 4429 

FSFC 4430 S10: 

XOR AL,ES:IDI+ll ; AND WITH OTHER HALF 

, 

F5FC 268825 4431 MOV ES:[OIJ.AH I STORE FIRST BYTE 

F5FF 26884501 4432 MOV ES;[oI+1J,AL ; STORE SECOND BYTE 

F603 AC 4433 LOOSS ; GET CODE POUlT 

F604 E8t500 4434 CALL 521 

A-60


F607 23C3 4435 AND Ax.ex ; CONVERT TO COLOR 

F609 F6C280 4436 TEST DL.80H J AGAIN. IS THIS XOR FlmCTION 

F60e 740A 4437 JZ S11 ; NO I JUST STORE THE VAlUES 

F60E 2632"50020 4438 XOR AH.ES:{Dh2000HJ I FUNCTION WITH fIRST HAlF 

F613 2632850120 4439 XOR AL,ES:[oli-2001HJ i AND WITH SECOND HAlf 

F618 4440 511: 

F616 2688ASOO2:0 4441 MOV ES:(DH2000H),AH 

F610 2688850120 4442 MOV ES: [01+2000H+l "Al ; STORE IN SECOND PORTION OF BUFFER 

F622 83C7$O 4443 ADO 01.60 I POINT TO NEXT LOCATION 

F625 FEtE 4444 DEC OH 

F627 75CL 4445 JNZ S9 ; KEEP GOING 

F629 SE 4446 POP 51 ! RECOVER CODE PONTEA 

F62A SF 4447 POP 01 I RECOVER REGEN POINTER 

F628 83e702 4448 ADO DI.~ ; POINT TO NEXT CHAR POSITION 

F62:E f2B6 4449 LOOP 58 ; NORE TO WRITE 

F630 £994F8 4450 JMP VIDEO_RETURN 

4451 GRAPHICS_WRITE EHOP 

4452 j -----------------"'-... ------------------ 

4453 j GRAPHICS READ 

4454 ; -------------..-- - -------------------- 

F633 4455 GRAPHICS_READ PROC NEAR 

F633 [80600 445. CAll 52& ; CONVERTED TO OFFSET IN REGEN 

F636 BBFO 4451 MOV SI,AX ; SAVE IN 51 

'638 83Ee08 4458 sua SP.8 ; AllOCATE SPACE TO SAVE THE READ CODE POINT 

F61B 88EC ..459 MOV BP.SP POINTER TO SAVE AREA 

4460 

"461 ;------ DETERMINE GRAPHICS MODES 

4462: 

F630 803E490006 4463 

F642 06 4464 

F643 IF 4465 POP OS • POINT TO REGEN SEGMENT 

F644 1ZlA 4466 JC 5.. ; I'IEDIut1 RESOLUTION 

4467 

4468 1------ HIGH RESOLUTION READ 

4469 

4470 ;------ GET VALUES FAoM REGEN BUFFER AI«) CONVERT TO CODE POINT 

F646 8604 4471 MOV ; NUMBER OF PASSES 

F648 4472 512: 

F648 BA04 4473 MOV AL.IsIJ ; GET FIRST BYTE 

F64A 884600 4474 MOV lsPI,Al I SAVE IN STORAGE AREA 

F640 45 4475 INC BP , NEXT LOCATION 

F64E 8A840020 4476 MOV Al.tsi+200OHI I GET LOIolER REGION BYTE 

F652 884600 4477 MOV (SPhAL J ADJUST AND STORE 

F655 45 4478 INC BP 

'6$6 83C650 4479 ADO SI,60 ; POINTER INTO REGEN 

F659 FECE 4480 DEc DH ; LOOP CONTROL 

F6se 75E8 4481 JHZ SIt ; DO IT SOME HORE 

F65D £81790 4462 JtIP SiS I GO MATCH TH-E SAVED CODE POINTS 

4483 

4484 1------ HEDIUH RESOLUTION READ 

F660 448S 513: ; MED_RES_READ 

F660 01E6 4486 SAL SId ; OFFSET*! SINCE Z BYTES/CHAR 

F662 8604 4487 NOV OH,4 ; NUMBER OF PASSES 

F664 4488 S14: 

F664 E88600 4469 CALL 52:3 I GET PAIR BYTES FROM REGEN INTO SINGLE SAVE 

F667 81C60020 4490 ADD 51. 2000H ; GO TO LOWER REGION 

fi6S £68100 4491 CALL sn ; GET THIS PAIR INTO SAVE 

F66E 8lE:EBOIF 4492 sua SI.2:000H-80 ; ADJUST POINTER BACK INTO UPPER 

F672 FEtE 4493 DEC DH 

F674 75EE 4494 JHZ 514 J KEEP GOING UNTl L ALL 8 DONE 

4495 

4496 1--... ---- SAVE AREA HAS CHARACTER IN IT, MATCH IT 

F676 4497 515: I FIND_CHAR 

F676 BF6EF. 4498 MOV Dr ,OFA6EH I OFFSET CRT_CHAR_GEN-ESTABlISH ADDRESSING 

F679 DE 4499 PUSH CS 

F67A 07 4500 POP ES I CODE POINTS IN CS 

F678 83ED08 4501 SUB BP.8 ADJUST POINTER TO BE6IHt-lING OF SAVE AREA 

F67£ 8BFS 4502 Mov SIIBP 

F680 Fe 4503 eLD ; ENSURE DIRECTION 

F681 BODO 4504 MOV Al,O ; CURRENT CODE POINT BEING MATCHED 

F683 450S 516: 

F683 16 4506 PUSH SS ; ESTABLISH ADDRESSING TO STACK 

F684 IF 4507 POP OS ; FOR THE STRING COMPARE 

F685 8"8000 4508 MOV DX,l2& 1 NIJt1BER TO TEST AGAINST 

F688 4509 S17: 

F688 56 4510 PUSH 51 ; SAVE SAVE AREA POINTER 

A-61


F689 57 4511 PUSH 01 i SAVE CODE POINTER 

F68A B90800 4512 MOV (x.a i NUMBER OF BYTES TO MATCH 

F66D F3 4513 REPE CMPSB COMPARE THE 8 BYTES 

f68E A6 

F68F SF 4514 POP 01 RECOVER THE POINTERS 

f690 Sf 4515 POP 51 

F691 741E 4516 JZ 518 J IF ZERO FLAG SET, THEN MATCH OCCURRED 

F693 FEeo 4517 INC AL ; NO MATCH, MOVE ON TO NEXT 

F695 83C708 4518 ADD 01.6 I NEXT COOE POINT 

F698 4A 451'9 DEC OX lOOP CONTROL 

F699 75EO 4520 JHZ 517 j DO ALL OF THEM 

4521 

4522 j--._-- CHAR NOT HATCHED, HIGHT BE IN USER SUPPLIED SECOND HALF 

4523 

F69B 3eoo 4524 CHP Al.O AL 0 IF ONL'( 1ST HALF SCAHHEO 

F690 7412 4525 JE 51. IF = 0, THEN ALL HAS BEEN SCANNED 

F69F 2BCO 4526 SUB AX,AX 

F6A1 8E08 452.7 HOV DS,AX ESTABLISH ADDRESSING TO VECTOR 

4528 ASSUME DS:ABSO 

F6A3 C43E7COO 4529 LE5 OI,EXT_PTR j GET POINTER 

F6,6,7 aceD 4530 MOV AX,ES ; SEE IF THE POINTER REALLY EXISTS 

F6A9 OBC7 4531 OR AX,DI ; IF ALL 0, THEN DOESN'T EXIST 

F6AB 7404 4532 JZ 51. ; NO SENSE LOOKING 

F6AD B080 4533 MOV AL,I,S I ORIGIN FOR SECOND HALF 

F6AF EBD2 4534 JMP 51. ; GO BACK AND TRY FOR IT 

4535 ASSUME Ds:OATA 

4536 

4537 j------ CHARACTER IS FOUND ( AL=O IF NOT FOUND I 

F6Bl 4538 S18: 

F6Bl 83C408 4539 ADO SP,8 ; READJUST THE STACK. THROW AWAY SAVE 

F664 E910FB 4540 JHP VIDEO.RETURN ; ALL DONE 

4541 GRAPHICS.READ ENDP 

4542 ; ------------------------------------------- 

4543 EXPAND.MED.COLOR 

4544 THIS ROUTINE EXPANDS THE LOW 2 BITS IN BL TO 

4545 FILL THE ENTIRE BX REGISTER 

4546 ENTRY -- r"-. 

4547 BL = COLOR TO BE USED ( LOW , BITS ) 

4548 EXIT - 

4549 BX = COLOR TO BE USED ( 8 REPLICATIONS OF THE 2: COLOR BITS I 

4550 ; ------------------------------------------- 

F6B7 4551 51. PROC NEAR 

F6B7 80E303 455, Atm BL,3 ; ISOLATE THE COLOR BITS 

F6BA 8AC3 4553 HOV Al,Bl ; COPY TO AL 

F6BC 51 4554 PUSH CX ; SAVE REGISTER 

F6BD B90300 4555 MOV CX,3 ; NUMBER OF TIMES TO DO THIS 

F6CO 4556 S20: 

f6CO ODED 4557 SAL AL,l 

F6C2 DOEO 4558 SAL AL,I ; lEFT SHIFT BY 2 

F6C4 OAD8 4559 OR Bl.Al ; ANOTHER COLOR VERSION INTO 8L 

F6C6 E,F8 4560 lOOP 52. ; FILL ALL OF BL 

F6C8 8AFB 4561 MOV BH,Bl ; FI LL UPPER PORTION 

F6CA 59 4562 POP CX ; REGISTER BACK 

F6CB C3 4563 RET ; ALL DONE 

4564 51. Etmp 

4565 1------------------------------------------- 

4566 EXPAND.BHE 

4567 THIS ROUTII1E TAKES THE BYTE IN AL AND DOUBLES ALL 

4568 OF THE BITS, TURNING THE 8 BITS INTO 16 BITS. 

4569 THE RESULT IS lEFT IN AX 

4570 ; ------------------------------------------- 

F6CC 4571 521 PRoe NEAR 

F6CC 52 4572 PUSH OX ; SAVE REGISTERS 

F6CD 51 4573 PUSH CX 

F6CE 53 4574 PUSH BX 

F6CF BAOOOO 4575 HOV OX,O J RESULT REGISTER 

F602 B90100 4576 HOV CX,1 ; MASK REGISTER 

F605 4577 S,,: 

F605 8BD8 4578 MOV eX,AX ; BASE INTO TEMP 

F607 ,309 4579 AND BX,ex USE MASK TO EXTRACT A BIT 

F6D9 OB03 4580 OR DX,ex PUT INTO RESULT REGISTER 

F6DS OlEO 4581 5HL AX,l 

F60D D1E1 4582 SHL ex,! SHIFT 6ASE AND MASK BY 1 

F6DF 8608 4583 MOV eX.AX ; BASE TO TEMP 

F6E1 ,309 4584 AND BX,ex EXTRACT THE SAME BIT 

F6El OB03 4585 OR DX,BX ; PUT INTO RESULT 

A-62


F6E5 DIE 1 4586 5Hl eX.l ; SHIFT ONLY MASK NOW. MOVING TO NEXT BASE 

F6E7 73fC 4587 JNe 522 ; USE MASK BIT COMING OUT TO TERMINATE 

F6E9 8BC2 4588 MOV AX.OX ; RESULT TO PARM REGISTER 

F6EB 5B 4589 POP BX 

F6EC 59 4590 POP ex j RECOVER REGISTERS 

F6ED SA 4591 POP ox 

F6EE C3 4592 RET I ALL DONE 

4593 521 ENDP 

4594 l------------ - - - ------- - - ------------------- 

4595 J HED_READ_BYTE 

4596 f THIS ROUTINE WILL TAKE 2 BYTES FROM rtfE REGEN BUFFER. 

4597 I COMPARE AGAINST THE CURRENT fOREGROUND COLOR. AND PLACE 

4598 ; THE CQRRESPQtmING ONIOFF BIT PATTERN INTO THE CURRENT 

4599 POSITION IN THE SAVE AREA 

4600 ENTRY - 

4601 SI,OS :: POINTER TO REGEN AREA OF INTEREST 

4602 ,BX = EXPANDED FOREGROUND COLOR 

4603 BP = POINTER TO SAVE AREA 

4604 , EXIT - 

4605 ; SP IS INCPEMENT AFTER SAVE 

4606 1------------------------------------------- 

F6EF 4607 S23 PRoe NEAR 

F6EF 8A24 4608 HOV AH. [SI 1 ; GET FIRST BYTE 

F6Fl 844401 4609 MOV AL.[SI+l1 ; GET SECOND BYTE 

F6F4 6900CO 461D HOV eX.DCODDH ; 2: BIT MASK TO TEST THE ENTRIES 

F6F7 B200 4611 HOV DL.O ; RESULT REGISTER 

F6F9 4612 S24: 

F6F9 85Cl 4613 TEST AX.CX ; IS THIS SECTION BACKGROUHD? 

F6FB F8 4614 eLe ; CLEAR CARRY IN HOPES THAT IT IS 

F6FC 7401 4615 JZ 525 ; IF ZERO. IT IS BACKGROUND 

F6FE '9 4616 5Te , WASN'T, so SET CARRY 

F6FF 0002 4617 S25: ReL DL,! ; MOVE THAT BIT INTO THE RESULT 

F701 DlE9 4618 SHR CXol 

F703 DJE9 4619 5HR CX,! , MOVE THE MASK TO THE RIGHT BY 2 BITS 

F705 73F2 462. JNe 52. ; DO IT AGAm IF MASK DIDN'T FALL OUT 

F707 885600 4621 MOV [BPl,DL ; STORE RESULT IN SAVE AREA 

nOA 45 4622 It~C BP ; ADJUST POINTER 

F70B C3 4623 RET ; ALL DONE 

4624 S23 ENOP 

4625 ; - - ----- - - ------------------------------ - 

4626 ; V4_POSITION 

4627 ; THIS ROUTINE TAKES THE CURSOR POSITION CONTAINED IN 

4626 THE MEMORY LOCATION. AND COtNERTS IT INTO AN OFFSET 

4629 I INTO THE REGEN BUFFER, ASSUMING ONE BYTE/CHAR. 

4630 FOR MEDIUM RESOLUTION GRAPHICS, THE NUMBER MUST 

4631 BE DOUBLED. 

4632 ENTRY -- NO REGISTERS,MEMORY LOCATION CURSOR_POSH IS USED 

4633 EXIT- 

4634 AX CONTAINS OFFSET INTO REGEN BUFFER 

4635 ; --------------------------------- ------- 

F70C 4636 52. PROC NEAR 

FlOC A15000 4637 HOV AX.CURSOR_POSN ; GET CURRENT CURSOR 

F70F 4638 GRAPH_POSH LABEL NEAR 

F70F 53 4639 PU5H BX I SAVE REGISTER 

F710 8808 4640 HOV BX,AX ; SAVE A COpy OF CURRENT CURSOR 

F712 8AC4 4641 HOV AL.AH I GET ROWS TO AL 

F714 F6264AOO 4642 HUl BYTE PTR CRT_COLS ; NULTIPLY BY BYTES/COLUMN 

F7l8 DIED 4643 5HL AX'! ; MULTIPLY * 4 SINCE 4 ROWS/BYTE 

F7lA DIED 4644 SHl AXd 

F71C 2AFF 4645 SUB BH,BH ; ISOLATE COLUMN VALUE 

F7lE 03C3 4646 ADO AX,BX ; DETERMINE OFFsET 

F720 56 4647 POP BX ; RECOVER POINTER 

F721 C3 464& RET ; ALL DONE 

4649 526 ENDP 

4650 ;------------------------------------------- 

4651 

4652 , THIS INTERFACE PROVIDES A TElETYPE LIKE INTERFACE TO THE 

4653 VIDEO CARD. THE INPUT CHARACTER IS WRITTEN TO THE CURRENT 

4654 ClJ;!SOR POSITION. AND THE CURSOR IS MOVED TO THE NEXT POSITION. 

4655 IF THE CURSOR LEAVES THE LAST COLUMN OF THE FIELD, THE COLUMN 

4656 IS SET TO ZERO. AND THE ROW VALUE IS INCREMENTED. IF THE ROW 

4657 ROW VALUE LEAVES THE FIELD. THE CURSOR IS PLACED ON THE LAST ROW. 

4658 FIRST COLUMN, AND THE ENTIRE SCREEN IS SCROLLED UP ONE LIUE. 

4659 WHEN THE SCREEN IS SCROLLED UP. THE ATTRIBUTE FOR FILLING THE 

4660 NEWLY BLANKED LINE IS READ FROM THE CURSOR POSITION ON THE PREVIOUS 

4661 LINE BEFORE THE SCROLL. lH CHARACTER MODE. IN GRAPHICS MODE, 

A-63

lOC OBJ LINE SOLIRCE 

4662 THE 0 COLOR IS USED. 

4663 ~ ENTRY - 

4664 (AH) = CURRENT CRT MODE 

4665 (AL) = CHARACTER TO BE WRInEN 

4666 NOTE THAT BACK SPACE, CAR RET, BEll AND LINE FEED ARE HANDLED 

4667 AS COI1MANOS RATHER THAN AS DISPUYABLE GRAPHICS 

4668 (BLI = FOReGROUND COLOR FOR CHAR WRITE IF CURRENTLY IN A GRAPHICS f10DE 

4669 EXIT - 

4670 All REGISTERS SAVED 

~671 

F722 

F722 50 

F723 50 

F724 8403 

F726 COlO 

F728 58 

F7Z9 3C08 

f'728 7459 

F72D 3COD 

F72F 745£ 

F731 3eOA 

F733 745E 

F735 lC07 

F737 7461 

F739 6A3E6200 

F73D B40A 

F73F 890100 

F742 COlO 

F7" FEe2 

F746 3Al64AOO 

F74A 753(, 

F74C B200 

F74E 80F£18 

F751 7520 

F753 

F753 B402 

F755 8700 

F757 COlO 

F759 A04900 

F75C 3C04 

F75E 12.06 

F760 3e07 

F762 B700 

F764 7506 

F766 

F766 6408 

F768 COlO 

f76A SAFe 

F76C 

F76C 880106 

F76F 690000 

F772 B618 

F774 8A164ADO 

F778 FECA 

F77A 

F77A COlO 

F77C 

F77C 58 

46n: ASSUME CS:CQDE.DS:DATA 

4673 WRITE_TTY PROC NEAR 

4674 PUSH AX • SAVE REGISTERS 

4675 PUSH Ax ; SAVE CHAR TO WRITE 

4676 MOV AH.3 

4677 INT 10H ; READ THE CURRENT CURSOR POSITION 

4678 POP AX ; RECOVER CHAR 

4679 

4680 ;------ DX NOW HAS THE CURRENT CURSOR pOSITION 

4681 

4682 CM' AL,e ; IS IT A BACKSPACE 

4683 JE U8 j BACK_SPACE 

4684 CM" Al.ODH j IS IT CARRIAGE RE11.mN 

4685 JE U9 ; CAR_RET 

4686 CMP ALtOAH ; IS IT A LINE FEED 

4687 JE UIO ; LINEJEED 

468a Ct1P AL,07H ; IS IT A BELL 

4689 JE Ull ; BELL 

4690 

4691 ;------ WRITE THE CHAR TO THE SCREEN 

4692 

4693 MOV BH.ACTIVE_PAGE; GH THE CURRENT ACTIVE PAGE 

4694 MOV AH.I0 ; I..'RIT£ CHAR ONLY 

4695 t1Qy CX.l ; ONLY ONE CHAR 

4696 tNT 10H i WR ITE THE CHAR 

4697 

4698 ;------ POSITION THE CURSOR FOR NEXT CHAR 

4699 

4700 IHC OL 

4701 eMP OL,BYTE PTR CRT_COLS ; TEST FOR COLUMN OVERflOW 

4702 JNl U7 ; SET_CURSOR 

4703 MOV DL,D ; COLUMN FOR CURSOR 

4704 CM' DH,24 

4705 JHZ U6 

4706 

4707 ; ------ SCROLL REQUIRED 

4708 VI: 

4709 

4710 HOV AH.2 

4711 MOV BH,O 

4712 INT 10" ; SET TH E CURSOR 

4713 

4714 1------ DfTERMINE VALUE TO FILL WITH DURING S'ROLL 

4715 

4716 l10V Al.eRT_MOOE GET THE CURRENT HOOE 

4717 CM' Al.4 

4718 JC ua READ-CURSOR 

4719 CM" Al.7 

4720 MOV 8H,0 ; FILL a.llTH BACKGROUND 

4721 JNE U3 ; SCROLL-UP 

4722 

4723 U2: ; READ-CURSOR 

4724 HOV AH,e 

4725 INT IOH ; READ CHAR/AHR AT CURRENT CURSOR 

4726 MOV BH.AH STORE IN BH 

472.7 

4128 U3: I SCROLL-UP 

4729 I10V AX.601H SCROLL ONE LINE 

4730 HOV CX,O ; UPPER LEFT CORNER 

4731 MOV OH,24 ; LOWER RIGHT ROW 

4732 MOV OL,BYTE PTR CRT_COLS ; LOlolfR RIGHT COLutIN 

4733 DEC OL 

4734 lJ4, , VIDEO-CALL-RETURN 

4735 INT 10H ; SCROLL UP THE SCREEN 

4736 us: ; TTY-R!;TURN 

4737 POP AX ; JilESTORE THE CHARACTER 

A-64


F77D E947FA 4738 JHP VIDEO_RETURN RETURN TO CAllER 

4719 

nea 4740 U6: l SET-CURSOR-INC 

F7BD FEC6 4741 INC DH ; NEXT ROW 

F782 4742 U7: SET-CURSOR 

F762 B40Z 4743 HOV AH .2 

F784 EBF4 4744 JHP U4 J ESTABLISH THE NEW CURSOR 

~ 4745 

4746 ;------ BACK SPACE FOUND 

4747 

F786 4748 US: 

F786 eOFAao 4749 CHP OL.O ; ALREADY AT END OF LINE 

F789 74F7 4750 JE U7 SET_CURSOR 

F7BB FECA 4751 DEC Dl NO - JUST MOVE IT BACK 

F7BD f6F! 4752 JMP U7 SET_CURSOR 

4753 

475'1 j-----~ CARRIAGE RETURN FOUND 

4755 

F78F 4756 U9: 

F7Sf 82:00 4757 HDV CL,O ; HOVE TO FIRST COlUtfN 

f7'91 EBEF 4758 J"P U7 ; SET_CURSOR 

4759 

4760 ;------ LINE FEED FOUND 

4761 

F793 4762 UlO: 

F793 BOFEle 4763 CMP OH.24 ; BOTTOM OF SCREEN 

F796 75E8 4764 JNE U. ; YES, SCROLL THE SCREEN 

F798 ESB9 4765 JHP Ul ; NO. JUST SET THE CURSOR 

4766 

4767 j~----- BElL FOUND 

4768 

F79A 4769 Ull: 

F79A 8302 4770 HOV BL,Z ; SET UP COUNT FOR BEEP 

F79C ESC7EE 4771 CALL BEEP ; SOUND THE POD BElL 

F79f fBDB 477Z jMP U5 ; TTY_RETURN 

4773 ENDP 

~ 4774 j ~------------------------------------------ 

4775 LIGHT PEN 

4776 THIS ROUTINE TESTS THE LI~HT PEN SWITCH AND THE LIGHT 

4777 PEN TRIGGER. IF BOTH ARE SET, THE LOCATION OF THE LIGHT 

4778 PEN IS DETERMINED. OTHERWISE, A RETURN WITH NO INFORMATION 

4779 IS MADE. 

4780 ON EXIT: 

4781 IAH) :: 0 IF NO LIGHT PEN INFORMATION IS AVAILABLE 

4782: Bx.ex,Ox ARE DESTROYED 

4783 'AH) :: 1 IF LIGHT PEN IS AVAILABLE 

4784 {OH,OU :: ROW,COLUMN OF CURREtrr LIGHT PEN POSITION 

4785 (CHI = RASTER POSITIml 

4786 (BX) = BEST GUESS AT PIXEL HORIZONTAL POSITION 

4787 ; ------------------------------------------- 

4788 ASSUME CS:COOE.DS:OATA 

4789 j------ SUBTRACT_TABLE 

F7U 4790 Vl LABEL BYTE 

F7Al 0]03050503030304 4791 3.3,5.5.3.3.3.4 ; 

F7A9 4792 PRoe NEAR 

4793 

4794 ;------ WAIT FOR LIGHT PEN TO BE DEPRESSED 

4795 

F7A9 6400 4796 HDV AH,O SET NO LIGHT PEN RETURN CODE 

F7AB 88166300 4797 MDV DX,ADDR_6845 ; GET BASE ADDRESS OF 6845 

F7AF 83C206 4798 ADD OX.6 ; POINT TO STATUS REGISTER 

F7BZ EC 4799 Hi AL.OX ; GET STATUS REGISTER 

FiB3 A804 4800 TEST AL,4 ; TEST LIGHT PEN SWITCH 

F7B5 7578 4801 JNZ V. i NOT SET. RETt.mN 

4802 

4803 j ----- NOW TEST FOR LIGHT PEN TRIGGER 

4804 

F7S? A802: 4805 TEST AL.2 ; TEST LIGHT PEN TRIGGER 

F7B9 747E 4806 JZ V7 j RETURN WITHOUT RESETTING TRIGGER 

4807 

4808 j------ TRIGGER HAS BEEN SET. READ THE VALUE IN 

4809 

FlBB 8410 4810 MDV AH.l6 ; LIGHT PEN REGISTERS ON 6845 

4811 

4812 ;----- WPUT REGS POINTED TO BY AH, AND COHVERT TO ~OW COLUMN IH OX 

4813 

F7BO 88166300 4814 HOV j JlODRESS REGISTER FOR 6845 

A-65


F7Cl 8AC4 

F7e] EE 

F7C4 42 

F7C5 EC 

F7C6 SAEe 

F7e8 4.1. 

F7C9 FEC4 

F7CB 8AC4 

F7CD EE 

F7eE 42 

F7CF EC 

F700 8AE5 

F102 8A1E4QOO 

F706 ZAFF 

F70B ZE8A9FAIF7 

FlOD 2BC3 

nOF 26064EOO 

F7E3 790] 

PES B80000 

F7E8 

F7E8 8103 

F7EA 803E490004 

F7EF 722A 

F7F 1 803E490007 

F7F6 7423 

F7F8 62:28 

F7FA F6FZ 

F7FC 8AE8 

F7FE 02EO 

F800 BADe 

F802 ZAFF 

F804 803E490006 

F809 7504 

F808 6104 

F90D DOE4 

F80F 

F80F D3E3 

F811 8.1.04 

F813 8AFO 

F815 DOEE 

F817 DOEE 

F619 EB12 

F818 

F81B F6364AOO 

F81F 8AFO 

F821 8.1.04 

F823 02EO 

F625 8AE8 

F827 BADe 

F829 32F'F 

F828 D3E3 

F820 

F820 8401 

F8ZF 

FeZF 52 

F630 68166300 

F634 83C207 

F837 EE 

4615 MOV Al.AH ; REGISTER TO READ 

4816 OUT DX,AL I SET IT UP 

4817 INC ox ; DATA REGISTER 

4818 IN AL,OX ; GET THE VALUE 

4819 MOV CH,AL ; SAVE IN CX 

4820 DEC OX ; ADDRESS REGISTER 

4821 INC AH 

4822 MOV AL.AH SECDND DATA REGISTER 


4824 INC OX POINT TO DATA REGISTER 

4925 IN Al,DX GET SECOND DATA VALUE 

4626 MOV AH,CH ; AX HAS INPUT VALUE 

4827 

4826 ;------ AX HAS THE VALUE READ IN FROM THE 6845 

4629 

4630 MOV BL,CRT_MODE 

4831 SUB BH,BH ; MODE VALUE TO ax 

4832 HOV 8l,CS:vUBXl ; DETERMINE AMOUNT TO SUBTRACT 

4633 SUB AX.BX ; TAKE IT AWAY 

463,+ SUB AX,CRT_START ; CONVERT TO CORRECT PAGE OOIGIN 

4635 JNS V2 IF POSITIVE. DETERMINE HaDE 

4636 HOV AX,Q ;


F636 5.60 4891 POP OX ; RECOVER VALUE 

F839 4892 V7: RETURN_NO_RESET 

F839 SF 4893 POP Dr 

F83A 5f 4894 POP sr 

F83B IF 4895 POP os ; DISCARD SAVED BX,CX,DX 

Fe3C IF 4896 POP os 

F83D IF 4897 POP OS 

F83E IF 4698 PDP os 

r"\ 

F83F 07 4899 POP ES 

F840 CF 4900 IRET 

4901 READ LPEN EHDP 

4902 ;--- INT 12 -------------------------------- 

4903 ; HENORY_SIZE_DETERMINE 

4904 THIS ROUTINE DETERMINES THE AHOUNT OF MEMORY IN THE SYSTEM 

4905 AS REPRESENTED BY THE SWITCHES ON THE PLANAR. NOTE THAT 

4906 THE SYSTEM HAY NOT BE ABLE TO L;SE I/O MEMORY UNLESS THERE 

4907 IS A FULL COMPLEMENT OF 64K BYTES ON THE PLANAR. 

4908 INPUT 

4909 NO REGISTERS 

4910 THE MEMORY SIZE VARIABLE IS SET DURING POWER ON DIAGNOSTICS 

4911 ACCORDING TO THE FOLLOWING HARDWARE ASSUMPTIONS: 

4912 PORT 60 BITS 3.2 =- 00 - 16K BASE RAM 

4913 01 - 32K BASE RAM 

4914 10 - 46K BASE RAM 

4915 11 - 64K BASE RAM 

4916 PORT 62 BITS 3-0 INDICATE AMOUNT Of I/O RAM IN 32K INCREMENTS 

4917 E. G•• 0000 - NO RAM IN 1/0 CHANNEl 

4918 0010 - 64K RAM IN I/O CHANNEl, ETC. 

4919 ; OUTPUT 

4920 (AX I = NUMBER OF CONTIGUOUS lK BLOCKS Of MEMORY 

4921 ; ------------------------------------------- 

4922 ASSUME CS:CODE,DS:DATA 

f841 4923 MEMORY_SIZE_DETERMINE PROC FAR 

F841 FB 4924 STI j INTERRUPTS BACK ON 

FS42 IE 4925 PUSH OS ; SAVE SEGMENT 

F843 684000 4926 HOV AX. DATA ; ESTABLISH ADDRESSING 

r"\ F846 BED8 4927 HOV DS.AX 

F848 A11300 4928 HOV AX. MEMORY_SIZE ; GET VALUE 

F848 IF 4929 POP OS ; RECOVER SEGMENT 

F84C CF 4930 IRET ; RETURN TO CALLER 

4931 MEMORY_SIZE_DETERMINE. ENDP 

4932 ;--- INT 11 -------------------------------- 

4933 EQUIPMENT DETERMINATION 

4934 THIS ROUTINE ATTEMPTS TO DETERMINE WHAT OPTIONAL 

4935 DEVICES ARE ATTACHED TO THE SYSTEM. 

4936 j INPUT 

4937 NO REGISTERS 

4936 THE EqUIP_FLAG VARIABLE IS SET DURING THE POWER ON DIAGNOSTICS 

4939 USING THE fOLLOWING HARDWARE ASSUMPTIONS: 

4940 PORT 60 = LOW ORDER BYTE Of EQUPMENT 

4941 PORT 3FA = INTERRUPT 10 REGISTER OF 8250 

4942 BITS 7-3 ARE ALWAYS 0 

4943 PORT 376 = OUTPUT PORT Of PRINTER -- 6255 PORT THAT 

4944 CAN BE READ AS WELL AS WRITTEN 

4945 ; OUTPUT 

4946 (AX) IS SET. BIT SIGNIfICANT, TO INDICATE ATTACHED I/O 

49'47 BIT 15,14 = NUMBER OF PRINTERS ATTACHED 

4948 BIT 13 NOT USED 

4949 BIT 12 = GAME I/O ATTACHED 

4950 BIT 11.10.9 = NUMBER Of RS232 CARDS ATTACHED 

4951 BIT 8 UNUSED 

4952 BIT 7.6 :: NUMBER OF DISKETTE DRIVES 

4953 00=1. 01=2. 10=3. 11=4 ONLY IF BIT 0 :: 1 

4954 BIT 5.4 :: INITIAL VIDEO MODE 

4955 00 - UNUSED 

4956 01 - 40X25 Bioi USING COLOR CARD 

4957 10 - aOX25 Bioi USING COLOR CARD 

4958 11 - aOX25 BW USING BW CARD 

4959 BIT 3.2 = PLANAR RAM SIZE (OO=16K,Ol=32K.IO=48Koll=64KI 

4960 BIT 1 NOT USED 

4961 BIT 0 = IPl FRaN DISKETTE -- THIS BIT INDICATES THAT THERE ARE DISKETTE 

4962 DRIVES ON THE SYSTEM 

4963 

4964 NO OTHER REGISTE~S AFfECTED 

4965 ; ------------------------------ ------------- 

4966 ASSUMf CS:CQOE.DS:DATA 

A-67


F840 4967 EQUIPMENT PROC FA. 

F840 F8 4968 ST! • INTERRUPTS BACK ON 

F84E IE 4969 PUSH DS j SAVE SEGMENT REGISTER 

F84F 884000 4970 MOV AX. DATA ; ESTABLISH ADDRESSING 

F852 SEDS 4971 MOV OS,AX 

F654 A11000 4972 NOV AX. EQUIP_FLAG i GET THE CURRENT SETTINGS 

F857 IF 4973 pop OS ; RECOVER SEGMENT 

f8S8 CF 4974 IRET I RETURN TO CALLER 

4975 EQUIPMENT ENDP 

4976 ;--- INT 15 -------------------------------- 

4977 ; CAssenE 1/0 

4976 (AH) = 0 TURN CASSETTE HOTOR ON 

4979 (AH) :; 1 TURN CASSETTE HOTOR OFf 

4980 [AH) = 2 READ 1 OR MORE 256 BYTE BLOCKS FROM CASSETTE 

4981 (ES,BX) :;: POINTER TO DATA BUFFER 

4982 {ex) = COUNT OF BYTES TO READ 

4983 ON EXIT: 

4984 f!S.BX) = POINTER TO LAST BYTE READ + 1 

4985 (OX) = COUHT OF BYTES ACTUALLY READ 

4986 (Cv) = a IF NO ERROR OCCURRED 

4987 = 1 IF ER~OR OCCURRED 

4988 (AH J :;; ERROR RETURN IF (eYJ: 1 

4989 ;: 01 IF CRC ERROR WAS DETECTED 

4990 = 02 IF DATA ~ANSITIONS ARE LOST 

4991 = 04 IF tlO DATA WAS FOUt~D 

49n 

{AH 1 = 3 WRITE 1 OR MORE 256 BYTE BLOCKS TO CASSETTE 

4993 (ES.BX) .:: POINTE~ TO DATA BUFfn 

4994 (ex) = COUNT OF BYTES TO WRITE 

4995 ON EXIT: 

4996 (EX,8Xl = POINTER TO LAST BYTE WRITTEN + 1 

4997 (CXI = 0 

4996 (AM) = ANY OTHER THAN ABOVE VALUES CAUSES (CYJ= 1 

4999 AND (AH)= 60 TO BE RETURNED UtNALID COHMAND). 

5000 ;------------------------------------------- 

5001 ASSUME DS:DATA, ES:NOTHING.SS:NOTHING.C5:CODE 

F859 5002 CASSETTE_IO PRoe FAR 

F859 F8 5003 STI INTERRUPTS BACK ON 

F85.&. 1E 5004 PUSH as I ESTABLISH ,.,DDRESSIHG TO DATA 

Fase 50 5005 PUSH AX 

Fast 884000 5006 MOV AX. DATA 

F85F 8£08 5007 NOV os. AX 

F861 802671007F 5006 AND BIOS_BR EAK. 7FH i HAKE SURE BREAK flAG IS OFF 

F866 56 5009 POP AX 

F867 E80400 5010 CALL WI J CASSETTE_IO_CONT 

F86.&. 1F 5011 POP os 

F868 CA02:00 5012 RET INTERRUPT RETVRN 

5013 CASSETTE_IO ENDP 

F86E 5014 NI PROC NEAR 

5015 1------------------------------------------ 

5016 ; PURPOSE: 

5017 I TO CALL APPROPRIATE ROUTINE DEPENDING ON REG AH 

5018 

5019 AH ROUTINE 

5020 

5021 MOTOR ON 

502:2 I I MOTOR OFF 

5023 ; 2 READ CASSETTE BLOCK 

5024 WRITE CASSETTE BLOCK 

5025 

5026 

F86£ OA£4 5027 OR AH,AH f TURN ON MOTOR? 

F870 7413 502:8 JZ MOTOR_ON iYES. 00 IT 

F872: FEte 502:9 DEC AH ;TURN OFF MOTOR? 

F874 7418 5030 JZ MOTOR_OFF IYES, DO IT 

F876 FEee 5031 DEC AH ,READ CASSETTE BLOCK? 

F678 741A 5032 JZ READ_BLOCK ,YES, DO IT 

F67A FEte 5033 DEC AH ;WRITE CASSETTE BLOCK? 

Fe7t 7503 5034 JNZ W2 ; NOT_DEFINED 

F87E E92101 5035 J"P WRITE_BLOCK ;YES, DO IT 

5036 

F881 5037 W2: jCOMHAND NOT DEFINED 

F881 8480 5038 MOV AH,080H ;ERROR. UNDEFINED OPERATION 

FSS3 F9 5039 STC ;ERROR FLAG 

f884 C3 5040 RET 

5041 WI 'NOP 

5042 

A-68


~ 

F8es 5043 tIDTOR_ON PROC NEAR 

5044 j----------------.. --------------- 

5045 j PURPOSE: 

5046 , TO TURN ON CASSETTE MOTOR 

5047 1--------------------_... 

Fee5 [461 5048 IH AL,PORT_B jREAD CASSETTE OUTPUT 

F887 t4F7 5049 AHIJ AL.NOl OSH ; ClEAR BIT TO TURN ON MOTOR 

F889 £661 5050 W3: OUT PORT.B.AL ;WRITE IT OUT 

FeSB 2AE4 5051 SUB AH,AH ;ClEAR AH 

F88D C3 S05Z RET 

5053 HOTDR.ON ENOP 

5054 

F... 5055 MOTOR.OfF PROC HEAR 

5056 i ............... -----------.----------- 


5058 

• 

5059 

TO TURN CASSETTE MOTOR OFF 

1------------------------..----------- ... 

'88£ E461 5060 IH At.PORT_B ;READ CASSETTE OUTPUT 

f890 oeoe 5061 OR At,.oeH ; SET BIT TO TURN OF f 

F892 ESF5 5062 JHP WJ ;WRITE IT, CLEAR ERROR, RETURN 

5063 tIOTOR_OFF ENDP 

Fa.. 5064 READ.BLOCK PROe: NEAR 

5065 ; ---------------------.-------------------- 


5067 I TO READ 1 OR MORE 256 BYTE BLOCKS FROI1 CAsSEnE 

5068 

5069 I ON ENTRY: 

5070 ES IS SEGMENT FOR MEMORY BUFFER (FOR COMPACT CODE) 

5071 i ex POINTS TO START OF MEMORY BUFFER 

5012 I CX COt~TAINS NUMBER OF BYTES TO READ 

5073 f ON EXIT: 

5074 ex POINTS 1 BYTE PAST LAST BYTE PUT IN MEM 

5075 CX CONTAINS DECREMENTED BYTE COUNT 

5076 ox CONTAINS NUMBER OF BYTES ACTUALLY READ 

5077 

5078 CAR~Y flAG IS CLEAR IF NO ERROR DETECTED 

• 

~ 5079 CARRY flAG IS SET IF CRC ERROR DETECTED 

5080 j -----------------------------_.._----------- 

~ 

F894 53 5081 PUSH BX ;SAVE BX 

F895 51 5082 PUSH CX ;SAVE CX 

F896 56 5083 PUSH 51 ; SAVE 51 

F897 BE0700 5084 HOV 51. 7 ; SET UP RETRY COUNT FOR LEADER 

F89A Eet201 5085 CALl. BEGItCOP ; BEGIN By STARTING MOTOR 

F89D 5086 W4: ; SEARCH FOR LEADER 

F89D E462 50S7 IN Al,PORT.C ;GET INTIAL VALUE 

F89F 2410 50S8 ANO AL.OIOH ;MASK OFF EXTRANEOUS BITS 

F8Al A26BOO 50S9 HOV LAST.VAL,AL ;SAVE IN Lot lAST.VAL 

F8A4 BA7A3F 5090 MOV DX,16250 ; I OF TRANSITIONS TO LOOK FOR 

5091 

F8A7 5092 W5: j WAIT.FOR.EDGE 

F8A7 F606710080 5093 TEST BIOS.BREAK. 80H ; CHECK FOR BREAK KEY 

FSAt 7403 SO" JZ W. I JUMP IF NO BREAK KEY 

F8AE E98AOO 5095 JHP W17 ~ JUMP IF BREAK KEY HIT 

SO" 

FS81 4A 

5097 .., DEC ox 

F882 7503 5098 JHZ W7 I JUMP IF BEGINNING OF LEADER 

F8B4 E98400 5099 JHP W17 ; JUMP IF NO LHDER FOUND 

5100 

F887 E8C600 5101 1017: CALL READ.HAlF.BIT ;IGNORE FIRST EDGE 

FSBA BEB 5102 JCXZ WS ; JUMP IF NO EDGE DETECTED 

F8BC BA7803 5103 I10V OX.0378H ; CHECK FOR HALF BITS 

F8BF B90002 5104 MOV CX.ZOOH .MUST HAVE AT LEAST THIS MANY ONE SIZE 

5105 • PULSES BEFORE CHECKNG FOR SYNC BIT (0) 

F8C! E421 5106 IH AL. 021H • INTERRUPT MASK REGISTER 

Fac4 OC01 5107 OR AL.I ; DISABLE TIMER INTERRUPTS 

f8C6 E621 5108 OUT 021H. AL 

Feea 5109 1.18: ; SEARCH-LOR 

F8C8 F6Q6710080 5110 TEST BIOS_BREAK, 80H ; CHECK FOR BREAK KEY 

F8CD 756C 5111 JNZ W17 ; JlJ:1P IF BREAK KEY HIT 

FeCF 51 5112 PUSH CX ,SAVE REG CX 

F800 ESAOOO 5113 CALL PEAD.HALF_BIT ;GET PULSE WIDTH 

F6D3 OBC9 5114 OR CX. cx ; CHECK FOR TRANSITION 

F8D5 59 5115 POP CX ,RESTORE ONE BIT COUNTER 

F806 74CS 5116 JZ "4 1 JUMP IF NO TRANSITION 

F8D8 3B03 5117 CHP OX,BX ;CHECK PULSE WIDTH 

A-69


F8DA E304 5116 JCXZ W9 ;IF ex::o THEN WE CAN LOOK 

5119 iFQR SYNC BIT (0) 

FeDe 73BF 5120 JHC W4 i JUMP IF ZERO BIT (NOT GOOD LEADER) 

FaDE flEe 5121 lOOP we iDEe ex AND READ ANOTHER HALF ONE BIT 

FeEO 5H2 W9: fIND-SYNC 

FeED 72Eb 5123 JC W8 ; JUMP IF ONE BIT (STILL LEADER J 

5124 

5125 I A SYNCH BIT HAS BEEN FOUND. READ SYN CHARACTER: 

~ 

512.6 

FaE2 E89600 5127 CALL READ_HALF_BIT .SKIP OTHER HALF Of SYNC BIT (0) 

FBES E86AOO 5128 CAll READ_BYTE ; READ 5YN BYTE 

FBE8 3C16 5129 CMP AL, 16H SYNCHRotUZATION CHARACTER 

faEA 7549 5130 JHE W16 ; JUHP IF BAD LEADER FOUND. 

$131 

5132 ;------ GOOD CRe so READ DATA BLOCKIS) 

FeEC Sf 5133 POP 51 ; RESTORE REGS 

faED S9 5134 pop CX 

FeEf 58 5135 POP BX 

5136 ; ------------------------------------------- 

5137 ; READ 1 OR MORE 256 BYTE BLOCKS FRON CASSETTE 

5138 

5139 j ON ENTRY: 

5140 ES IS SEGMENT FO~ HEMORY BUFFER I FOR COMPACT CODE) 

5142 CX COtHAINS NUMBER OF BYTES TO READ 

5141 ; BX POItHS TO START OF MEMORY BUFFER 

, 

5~43 ; ON EXIT: 

5144 BX POINTS 1 BYTE PAST LAST BYTE PUT IN HEM 

5145 ; CX CONTAINS DECREHEHTEO BYTE COllNT 

5146 ; ox CONTAINS NUMBER OF BYTES ACTUALLY READ 

5147 ; ------------------------------------------- 

F8EF 51 5148 PUSH CX ;SAVE BYTE COUNT 

F8FO 5149 JCOME HERE BEFORE 10110: EACH 

5150 1256 BYTE BLOCK IS READ 

F8FO 5151 ;INIT CRC REG 

C7066900FFFF "OV CRC_REG,OFFFFH 

F8F6 BAOOOI 5152 MOV DX,256 ;SET OX TO DATA BLOCK SIZE 

F8F9 5153 10111: RO_BlK 

FSF9 5154 CHECK FOR F606710080 TEST BIDS_BREAK, 80H , BREAK KEY 

,""-"'" 

F8FE 7523 5155 JHZ WI3 ; JUMP IF BREAK KEY HIT 

F900 E64FOO 5156 CALL READ_BYTE JREAD BYTE FROM CASSETTE 

F903 72IE 5157 JC W13 ,CY SET INDICATES NO DATA TRANSITIONS 

F905 n05 5156 JCXl W12 ;IF WE'VE ALREADY REACHED 

5159 ;END OF MEMORY BUFFER 

5160 ;SKIP REST OF BLOCK 

F907 268807 5161 MOV ES:tBXJ,Al ;STORE DATA BYTE AT BYTE PTR 

F90A 43 5162 INC BX ;INC BUFFER PTR 

F90B 49 5163 DEC CX ;OEC BYTE COUNTER 

F90C 5164 ; LOOP DATA BLOCK HAS BEEN REAO FROM CASSETTE. 

10112: UNTIL 

F90C 5165 ,DEC BLOCK CtH 

4A OEC OX 

F90D 7FEA 5166 JG W11 , RD_BlK 

F90F E84000 5167 CALL READ_BYTE ,NOW READ HID CRC BYTES 

F912 E83DOO 5168 CALL READ_BYTE 

F915 2AE4 5169 SUB AH,AH ,CLEAR AH 

F917 813E6900oFlD 5170 CMP CRC_REG,IDOFH i IS THE CRC CORRECT 

F910 7506 5171 JNE W14 i IF NOT EQUAL CRC IS BAD 

F91F n06 5172 JCXZ W15 ;IF BYTE COUNT IS ZERO 

517:3 I THEH WE HA.VE READ ENOUGH 

5174 ISO WE WILL EXIT 

Fnl EeCD 5175 JMP WID ,STILL MORE, SO READ ANOTHER BLOCK 

F923 5176 ;MISSING-DATA 

10113: 

5177 ,NO DATA TRANSITIONS SO 

F923 5176 ;SET AH:02 TO INDICATE 

8401 MOV AH,OIH 

5179 ;DATA TUlEOUT 

F925 5180 ; BAD-CRe 

10114: 

F925 5181 ,EXIT EAR LYON FEC4 IHC AH ERROR 

5182 ;SET AH=OI TO INDICATE CRC ERROR 

F927 5183 ; RD-BLK-EX 

10115: 

F927 SA 5184 POP ox ICALCULATE COUNT OF 

F928 2801 S185 SUB DX,CX IDATA BYTES ACTUALLY READ 

SI66 IRETURt~ COUNT IN REG OX 

F92A 50 SI87 

PUSH AX 

iSAVE AX (RET CODE) 

F92B F6C403 5188 TEST AH, 03H 

; CHECK FOR ERRORS 

F92E 7513 5189 JtiZ W18 ; JUHP IF ERROR DETECTED 

F930 E81FOO 5190 CALL READ_BYTE ;READ TRAILER 

F933 EBOE 5191 JHP SHORT 10118 ,SKIP TO TURN OFF MOTOR 

F935 5192 ; BAD-LEADER 

10116: 

F935 SIn, " ~~F.':I' ~FTI?IES 4E C[(. SI 

A-70


~ 

F936 7403 5194 JZ W17 JUtlP IF TOO MANY RETRIES 

F938 E962FF 5195 JMP W4 JUMP IF NOT TOO MANY RETRIES 

F938 5196 10117: NO VALID DATA FOUND 

5197 j------ NO DATA FROM CASSETTE ERROR, I.E. TIMEOUT 

5198 

F938 5E 5199 POP 51 RESTORE REGS 

F93C 59 5200 POP CX lRESTORE REGS 

F93D 58 5201 POP BX 

F93E 2B02 5202 SUB OX,OX ,ZERO NUMBER OF BYTES READ 

F940 8404 5203 HOV AH,04H ; TIME OUT ERROR I NO LEADER) 

F942 50 5O 1 

F950 F5 5212 CHC 

F951 C3 5213 RET iFItUSHED 

5214 READ_BLOCK ENOP 

5215 ; ---------------------------------------- 

F952 5216 PROC NEAR 

5217 PURPOSE: 

5218 TO READ A BYTE FROM CASSETTE 

5219 

5220 ON EXIT REG AL CONTAINS READ DATA BYTE 

5221 

F952 53 5222 PUSH BX ,SAVE REGS BX,CX 

F953 51 5223 PUSH CX 

F954 BI08 52


F97E EBF9 5268 "20 

5269 ENDP 

5270 ; ------------------------------------------ 

f9BO 5271 NEAR 

5272 PURPOSE: 

5273 TO COMPUTE TIME TIll ~EXT DATA 

5274 TRANSITION (EDGE) 

5275 

5276 ; ON ENTRY: 

5Z77 ; EDGE_CNT CONTAINS LAST EDGE COUNT 

5278 

5279 ; ON EXIT: 

52&0 ; AX CONTAINS OLD LAST EDGE COUNT 

5281 I BX CONTAlNS PULSE WIDTH {HALF Bn I 

5282 ; ------------- ---------.--------------. 

F'eo 696400 5283 MOV ex. 100 j SET TIME TO WAn FOR BIT 

F983 BA266BOO 5284 MOV AH.LAST_VAl JGET PRESENT INPUT VALUE 

F987 5285 Nee: ~ Fm-H-BIT 

F987 E462 5286 IN AL.POIH_C ; INPUT DATA BIT 

f989 2410 5237 AND AL,OlOH ;MASK OFF EXTRANEOUS BITS 

F988 3AC4 5288 CMP AL,AH ;SAME AS BEFORE? 

FgeD ElFS 5269 LOOPE 

"22 

; LOOP TILL IT CHANGES 

F9SF A26BOO 5290 MOV LAST_VAL,AL JUPDATE LAST_VAL WITH NEW VALUE 

F992 BOOD 5291 MOV Al;O jREAD TIMER'S COUNTER eONHA.ND 

F9'94 E643 5292 OUT TIM_CTL,AL ; LATCH COUNTER 

F996 E440 5293 HI AL, TIMERO ;GET LS eYTe 

F998 8AEO 52'4 I10Y AH,Al ,SAVE IN Aft 

fY.,,,, 1:'"0 SUS IN Al,TIMERO ,GET HS BYTE 

F99C 8bC" 5296 XCHG Al,AH ,XCHG Al,AH 

F99E 8Bl£6700 5n7 MOV BX,EDGE_CNT ; BX GETS LAST EDGE COUNT 

F942 2B08 5298 SUB BX,AX ; SET BX EQUAL TO HALF BIT PERIOD 

F9"4 1\36700 5299 MOV EDGE_CNT ,AX ; UPDATE EDGE CO""'T; 

F9A7 Cl 5300 RET 

5301 !fEAD_HALF_BIT ENDP 

5302 ;--------------------_ ..._--_.._------------ 

F9A8 5303 PROC NEAR 

5304 

5305 ; WRITE 1 OR MORE 256 BYTE BLOCKS TO CASSETTE. 

5306 THE OATA IS PADDED TO FILL OUT THE LAST 256 BYTE BLOCK. 

5307 

530S ; ON ENTRY: 

5309 BX POINTS TO MEMORY BUFFER ADDRESS 

5310 ex CONTAINS HUMBER OF BYTES TO WRITE 

5311 

;:512 ; ott EXIT: 

5313 BX POINTS 1 BYTE PAST LAST BYTE WRITT-EN TO CASSETTE 

5314 ex IS ZERO 

5315 ;------------------------------------------- 

F9AS 53 5316 PUSH ax 

F9.9 51 5317 PUSIt cx 

F9,u, E461 5318 IN AL,PORT_B ;DISABLE SPEAKER 

f9AC 24FO 53n AND AL,NOT 02H 

F9AE DeOI 5320 OR AL. 01H ENABLE TInER 

F980 E661 5321 OUT PORT_B.AL 

F962 BOB6 5322 MOV AL,OB6H SET UP TIMER .. - MODE 3 SQUARE WAVE 

F964 E643 $3,3 OUT TIM_CTLtAl 

F9B6 E8A600 5324 CALL BEGIN.OP ; START MOTOR AND DELAY 

F9B9 BeA004 5325 NOV AX,llS4 ; SET NORMAL BIT SIZE 

F98C E88500 5326 CALL 

"" 

J SET_TIMER 

F9BF MOOOS 5327 MOV CX.0800H ;SH CX FOR lEADER BYTE COUNT 

F9C2 5328 W23: ; WRITE LEADER 

F9C2 F9 53,9 STC ; WR ITE ONE BITS 

F9Cl E86800 5330 CALL Wl?ITE_BIT 

F9C6 EZFA 5331 LOOP "e> ; LOOP • TIL LEADER IS WRITTEN 

F9C8 F8 5332 CLC ;tRITE SYNC BIT to J 

F9C9 £86200 5333 CALL WRITE...8IT 

F9CC S9 5334 pop ex ;RESTORE REGS CX,BX 

FqCD 58 5335 POP BX 

F9CE B016 5336 MoV AL. 16M I WRITE SYH CHARACTER 

F900 E84400 5337 CALL WRITE_BYTE 

A-72


~ 

5338 ;------------------------------------------- 

5339 I WRITE 1 OR HORE 256 BYTE BLOCKS TO CASSETTE 

5340 

5341 I ON. ENTRY: 

5342 ax POINTS TO MEMORY BUFFER ADDRESS 

5343 ex CONTAINS NUMBER OF BYTES TO WRITE 

5344 

5345 ON EXIT: 

5346 BX POUITS 1 BYTE PAST LAST BYTE WRITTEN TO CASSETTE 

5347 

5348 

ex IS ZERO 

; ......------------------- ..-------------- --- 

FOO3 5349 WR_BLOCK: 

F9D3 C7066900fFFF 5350 HOV CRC_REG,OFFFfH IINIT CRe 

F909 BAgDOl 5351 MOV DX,256 ;FOR 2:56 BYTES 

F90C 5352 W24: ; W~-BlK 

~ 

~ 

F9DC 268A07 5353 HOV AL,Es:[ex] ; READ BYTE FROM MEM 

F90F E83500 5354 CALL WRITE_BYTE jWRITE IT TO CASSETTE 

F9EZ £302 5355 JCXZ "25 jUNLESS CX=O, ADVANCE PTRS & DEC COUNT 

F9£4 43 5356 INC OX j INC BUF f ER POINTER 

F9E5 49 5357 DEC CX 50EC BYTE COUNTER 

F9E6 5358 WZ5: f SKIP-ADV 

F9E6 4A 535' DEC ox ,DEC BLOCK CNT 

F9E7 7FFl 5360 JG H2. ; LOOP TILL 256 BYTE BLOCK 

5361 ; IS WRITTEN TO TAPE 

5362 ;------------------- WRITE eRe ------------- 

5363 I WRITE l'S COHPLEMENT OF eRe REG TO CA~SETTE 

536. ; WHICH IS CHECKED FOR CORRECTNESS WHEN THE BLOCK IS READ 

5365 

5360 ; REG AX IS MODIFIED 

5367 ,... ---------------------------------------- 

F9E9 A16900 5365 HOV AX,CRC_REG ;WRITE THE ONE'S CQtlPLEMENT OF THE: 

5369 ; TWO BYTE CRC TO TAPE 

F9EC F7DO 5370 NOT AX ; FOR l'S COMPLEMENT 

F9EE SO 5371 PUSH AX ;SAVE IT 

F9EF UEO 5372: XCH. AH,Al ;WRITE t15 BYTE FIRST 

F9Fl 182300 5373 CALL WRITE_BYTE ;WRITE IT 

F9F4 58 5374 POP AX ,GET IT BACK 

F9F5 E81FOO 5375 CALL WRlTE_BYTE ,NOlo! WRITE LS BYTE 

F9F6 OBe9 5376 OR CX,CX ;IS BYTE COUNT EXHAUSTED? 

F9FA 7507 5377 JHZ WR_BLOCK ;JUHP IF NOT DONE YET 

F9FC 51 5378 PUSH CX iSAVE REG ex 

F9FD 892000 5379 MOV ex, 32 ;WRITE OUT TRAILER BITS 

FAOO 5380 WZ6: j TRAIL-LOOP 

FAOO F9 5381 STC 

FA01 E82AOO 5382 CALL WRITE_BIT 

FA04 E2FA 5383 LOOP HZO I WRITE UNTIL TRAILER WlunEN 

FA06 59 5384 POP CX ,RESTORE REG CX 

FA07 B080 5385 MOV AL. OBOH ; TURN TIttER2 Off 

FA09 £643 5386 OUT TIt-ccn, AL 

FAOB B80100 5387 HOV AX. 1 

FADE E83300 5388 CALL W31 ; SET_TIMER 

FAll E87AFE 5389 CALL MOTOR_OFF I TURN HOTOR OFF 

FA14 2BCO 5390 SUB AXJAX ;NO ERRORS REPORTED ON WRITE OP 

FAll. C3 5391 RET ;FINlsHEO 

5392 WRITE_BLOCK EHOP 

5393 1----------------------------------------- 

FA17 53" WRITE_BYTE PRoe NEAR 

5395 ; WRITE A BYTE TO CASSETTE. 

5396 ; BYTE TO WRITE IS IN REG At. 

5397 ; ---- ...---------------_ ... _------------------- 

FA17 51 5398 PUSH CX ;SAVE REGS CX,AX 

FA18 50 5399 PUSH AX 

FA19 8Af8 5400 MDV CHJAL ;AL=BYTE TO WRITE. 

5401 f NS BIT WRIITEN FIRST} 

FA1S BI08 5402 NOV CL.8 ;FOR e DATA BITS IN BYT!. 

5403 NOTE: TWO EDGES PER BIT 

'AID 5404 W27: I DISASSEMBLE THE DATA BIT 

FA1D 0005 5405 RCL eH,1 IROTATE MS BIT lNTO CARRY 

FAIF 9C 5406 PUSHF ;SAVE FLAGS. 

5407 NOTE: DATA 81T IS IN CARRY 

FA20 E80BOO 5408 CALL WRITE_BIT ;WRITE DATA BIT 

FA2:3 90 54•• POPF ,RESTORE CARRY FOR CRC CALC 

FA24 E82400 541. CALL CRC_GEN ,CQt1PUTE CRC ON DATA BIT 

FA27 FEC9 5411 DEC CL flOOP TILL All 8 BITS DONE 

FA29 75F2 5412 JHZ "27 ; JUMP IF NOT DONE YET 

FA2B 58 5413 POP AX ;RESTORE REGS AX.CX 

FA2C 59 5414 POP CX 

A-73


H20 C3 5415 RET ;WE ARE FINISHED 

5416 WRITE_BYTE ENDP 

5417 1--------- ------------------------------ 

FAZE 5418 WRITE_BIT PROC NEAR 

5419 ; PURPOSE: 

5420 

5421 TO WRITE A oAT A BI T TO CASSETTE 

5422 CARRY FLAG CONTAINS DATA BIT 

5423 I. E. IF SET DATA BIT IS A ONE 

5424 IF ClEAR DATA BIT IS A ZERO 

5425 

5426 NOTE: TWO EDGES ARE WRITTEN PER BIT 

5427 ONE BIT HAS 500 USEe BETWEEN EDGES 

5428 FOR A 1000 USEC PERIOD (1 MllLISEC) 

5429 

5430 ZERO BIT HAS 250 USEC BETWEEN EDGES 

5431 fOR A. SOD USEC PERIOD (.5 MIlLISEC) 

5432 ; CARRY FLAG IS DATA BIT 

5433 1------------------------------------------ 

5434 ;ASSUME IT'S A 

',' 

w,. 

FAZE 88,6.004 5435 MOY AX.1l84 ; SET AX TO NOMINAL ONE SIZE 

FA31 7203 5436 JC ; JUMP IF ONE BIT 

FA33 885002 5437 MOY AX,59Z ; NO, SET TO NOMINAL ZERO SIZE 

FA36 5438 10126: ; WRITE-BIT-AX 

FA36 50 5439 PUSH AX iWRITE BIT WITH PERIOD EQ TO VALUE AX 

FA37 5440 10129: 

FA37 E462 5441 IN AL,PORT_C ; INPUT TIMER_O OUTPUT 

FH9 2420 5442 AND AL,020H 

FA38 74F,6. 5443 Jl WZ9 ,lOOP TIll HIGH 

FA30 5444 10130: 

FA30 E462 5445 IN Al.PORT_C ;NOW WAIT TILL TIMER'S OUTPUT IS LOW 

F,6.3F 2420 5446 AND AL,020H 

FA41 75FA 5447 JHZ W3. 

5448 jRElOAD TIMER WITH PERIOD 

5449 iFOR NEXT DATA BIT 

FA43 58 5450 POP ;RESTQRE PERIOD COUNT 

FA44 5451 10131: SET TIMER 

FA44 E642 5452 , OUT "042H, AL ; SET LOW BYTE OF TIMER 2: 

FA46 BAC4 5453 MOV AL, AH 

FA48 E642 5454 OUT 042H. AL ; SET HIGH BHE OF TIME~ 2 

FA4A C3 5455 RET 

545~ WRITE_BIT ENDP 

,""Ii' " ~;~=~;~---------;;~~----~;~;------------- 

FA48 

5458 

.. 5459 UPDATE CRC REGISTER WITH NEXT DATA BIT 

5460 

.. 5461 CRe IS USED TO DETECT READ ERRORS 

:\ 

5462 

, 

REG AX IS MODIFIED 

FLAGS ARE MODIFIED 

• ." , 5463 ASSUMES DATA BIT IS IN CARRY 

5467 

F,6.48 ,6.16900 5468 MOY 

5469 j THE FOLLOWING INSTUCTIONS 

.. 

5470 JWILL SET THE OVERFLOW FLAG 

5471 j IF ~ARRY AND MS BIT OF CRe 

5472 JARE UNEQUAL 

FA4E 0108 5473 RCR AX.1 

FA50 0100 5474 RCL AX,I 

1A52 F8 5475 eLe ;CLEAR CARRY 

FA53 7104 5476 JNO 

W" 

,SKIP IF NO OVERflOW 

5477 ;IF DATA BIT XORED WITH 

5478 ; CRe REG BIT 15 IS ONE 

FA55 351008 5479 xtJR AX.D810H ; THEN XOR CRC REG WITH 

5480 ; oa10H 

FA58 F9 5461 STC ;SET CARRY 

F,6.59 5482 10132: 

FA59 0100 5483 RCL AX., 

iROTATE CARRY (DATA BIT) 

5484 jlNTO CRe REG 

FA5B ,6.36900 5485 Mev CRC_REG.AX ;UPDATE CRC_REG 

FASE C3 5486 RET ; FINISHED 

5487 CRe_GEN ENDP 

5488 ;------------------------------------------- 

F,6.5F 5469 PROC NEAR ; START TAPE AtJO DELAY 

A-74 

5490 

5491 ; -------------------------------------------


FASF EeZ3FE 5492: CAll HOTOR_ON ; TURN ON MOTOR 

FA62 8342 5493 MOV BL,42H ;OELAY FOR TAPE DRIVE 

FA64 5495 W33: 

5494 ;TO GET UP TO SPEED (112: SEC) 

FA64 890007 5496 ttOV eX,700H ;INNER LOOP; APPROX. 10 MILlISEC 

FA67 ElFE 5497 1


fC46 0030300000303060 5568 DB 000H.030H.030H,OOOH,OOOH.030H,030H.060H ; ; 0_3B 

FC4E 183060C060301800 55b9 DB 018H.030H,060H,OCOH,060H,030H.018H,000H ; < 0_3C 

FC56 OOOOF(OOOOFCOOOO 5570 DB OOOH.OOOH.OFCH,OOOH,OOOH,OFCH,OOOH,OOOH ~ = o_30 

reSE 6030180C18306000 5571 DB 060H,030H,018H.00CH.018H,030H,060H,OOOH ; > 0_3E 

FC66 78CCOCI830003000 5572 DB 078H.OCCH,OOCH.018H,030H,OOOH,030H,OOOH ; "? 0_3F 

5573 

FCbE 7CC6DEDEDEC0780D 5574 DB 07CH.OC6H,ODEH,OOEH.ODEH.OCOH.078H.OOOH i a 0_40 

FC76 3078CCCCFCCCCCOO 5575 DB 030H,076H.OCCH t OCCH,OFCH,OCCH,OCCH,OOOH ; A o_41 

Fe?f FC66667C6666FCOO 5576 DB OFCH.066H.066H.07CH.066H.066H.OFCH.OOOH ; B o_42 

FC86 3C66COCOC0663COO 5577 DB 03CH.06bH,OCOH.OCOH.OCOH,066H.03CH.OOOH ; C 0_43 

FCBE F86C6666666CF80D 5576 DB OF8H,06CH.066H,066H.066H,06CH,OF8H,OOOH ; 00_44 

FC96 FE6268786862FEOQ E.579 DB OFEH,Ob2H,068H,078H,066H,062H,OFEH,OOOH ; E 0_45 

FC9E fE6268786860FOOO 5580 DB OFEH,062H,066H.078H.068H,060H,OFOH,000H ; F -0_46 

FCAb lC6E>COCOCEb63EOO 5581 DB 03CH.066H,OCOH.OCOH.OCEH,066H,03EH,OOOH I G 0_47 

FCAE CCCCCCFCCCCCCCOO 5582 DB OCCH,OCCH,OCCH.OFCH,OCCH,OCCH,OCCH.OOOH H 0_46 

FCBb 7830303030307800 5583 DB 078H.030H.030H.030H.030H.030H,078H,OOOH ; 10_49 

FcaE lEOCOCOCCCCC7800 5584 DB OlEH,OOCH.00CH.00CH.OCCH,OCCH,078H,OOOH ; J 0_4A 

FCC6 Eb666C786CUE600 5585 DB OE6H.066H.06CH,078H.06CH.066H.OE6H.OOOH ; K 0_48 

FeCE F06060606266F£00 5586 DB OFOH.060H,060H.060H.062H,066H.OFEH,OOOH j L 0_4C 

FC06 C6EEF£FED6C6C600 5587 DB OC6H.OEEH,OfEH,OfEH.006H.OC6H.OC6H.OQOH ; M 0_40 

FCDE C6E6F6DECEC6C600 5588 DB OC6H.OE6H,OF6H.ODEH.OCEH.OC6H,OC6H,000H ; H D_4E 

FCEb 366CC6C6C66C3600 558~ DB 038H,06CH,OC6H,OC6H.OC6H,06CH,03SH.OOOH ; a 0_4F 

5590 

FeEl FC66&67C6060FOOO 5591 DB OFCH.066H,066H.07CH.060H,060H,OFOH,OOOH ; PO_50 

FCF. 78CCCCCCDC781COO 5592 DB 078H,OCCH.OCCH,OCCH,OJCH,078H,01CH,OOOH ; Q 0_51 

FeFE FC66667C6C66£600 5593 DB OFCH.066H.06MI,07CH.OfCH,066H,OE6H,OOOH i R 0_52 

FD06 78CC£0701CCC7800 5594 DB 078H.OCCH,OEOH.070H.OICH,OCCH,078H,000H ; SO_53 

FDOE FCB4303030307800 5595 DB OFCH.084H.030H,030H.030H,030H,078H,OOOH ITO_54 

F016 CCCCCCCCCCCCFCOO 5596 DB OCCH.OCCH,OCCH,OCCH,OCCH,OCCH,OFCH,OOOH ; U 0_55 

fOlE CCCCCCCCCC78300G 5597 DB OCCH,OCCH.OCCH.OCCH.OCCH,078H,030H.OOOH ; II 0_56 

FD26 C6C6C6D6fEEEC60D 5598 DB OC6H,OC6H,OC6H.006H.OFEH.OEEH.OC6H.000H ; W 0_57 

FOlE C6C66C36366CC600 5599 DB OC6H,OC6H.06CH'(138H.038H,06Ctt,OC6H.OOOH ; X o_58 

F036 CCCCCC7830307800 5600 DB OCCH,OCCH.OCCH.078H,030H.030H.078H.000H ; YO_59 

F03E FEC68C183Z66FEOO 5601 DB OFEH.OC6H,08CH.OI8H,032H.066H.OFEH,OOOH ; Z 0_5A 

F046 7860606060607800 5602 DB 078H.060H.060H,060H,060H,060H.078H,OOOH i [ 0_5B 

F04E C06030180C060200 5603 DB OCOH.060H.030H.018H,OOCH,006H.002H,000H ; BACKSLASH D_5C 

F056 7818181818167800 5604 DB 078H.018H.018H.018H.016H,018H.078H,OOOH i J 0_50 

F05E 10366CC600000000 5605 DB 010H.038H,06CH.OC6H.OOOH,OOOH,000H,OOOH ; CIRCUMFLEX 0_5E 

F066 OOOOOOOOOOOOOOFF 5606 DB oOOH.OOOH,OOOH,OOOH,OaOH,oooH,OOOH.OFFH ; _ 0_5F 

5b07 

F06E 3030180000000000 5608 DB 030H. 030H ,OISH. OOOH. OOOH, OOOH. OOOH, OOOH o_60 

F076 0000780C7CCC7600 5609 DB 000H,000H.078H,OOCH,07CH.DCCH.076H,OOOH LOWER CA~E A 0_61 

F07E E060607C6666oCOO 5bl0 DB OEQH,060H.060H,07CH,066H.066H,OOCH,OOOH L.C. B 0_62 

FD86 000078CCCOCC7800 5611 DB 000H.OOOH,078H,OCCH,OCOH.OCCH,078H,OOOH L.C. C o_63 

F08E lCOCOC7C[CCC7600 5612 DB 0ICH.00CH,OOCH.07CH.OCCH.OCCH.076H.O(JOH L.C. 0 o_64 

Fo~6 000078C[FCC07800 5613 DB 000H.OOOH.078H.OCCH,OFCH,OCOH,078H,OOOH L.C. E 0_65 

F09E 366[60F06060FOOO 5614 DB 038H.06CH.060H.OFOH,060H.060H,OFOH,OOOH L.C. F 0_66 

FOA6 000076CC[C7COCF6 5b15 DB 000H,OOOH.076H.OCCH.OCCH,07CH.00CH,OF8H L.C. G 0_67 

FOAE E0606C766666E600 5blb DB OEOH.060H.06CH,076H,066H,066H,OE6H,OOOH ; L.C. H 0_66 

FOB6 3000703030307800 Sb17 DB 030H,OOOH.070H.030H,030H,030H,078H.000H L.C. 10_69 

FDBE OCOOOCOCOCCCCC76 5618 DB 00CH.OOOH.OOCH.OOCH,OOCH.OCCH,OCCH,078H L.C. J D_6A 

FOC6 E060666C766CE600 5619 DB OEOH,060H,066H,06CH.078H,06CH,OE6H,OOOH L.C. K 0_68 

FoeE 7030303030307800 5620 DB 070H,030H,030H,030H.030H.030H,07BH.OOOH l.C. L D_6e 

F006 0000CCFEfE06C600 5621 DB 00OH.000H,OCCH,OFEH,OFEtI.006H.OC6H.OOOH L.C. M o_60 

FODE 0000F8CCCCCCCCOO 5622 DB OOOH,OOOH,OFBH,OCCH,OCCH.OCCH.OCCH.OOOH l.C. N 0_6E 

FOE6 000078CCCCC[7800 Sbn DB 000H,OOOH,078H.OCCH.OCCH.OCCH.078H.OOOH L.C. OO_6F 

5b24 

FDEE 00000[66667C60FO 5625 DB OOOH.OOOH.ODCH,066H.066H.07CH.060H.OFOH l.C. P 0_70 

FoF6 000076CCCC7cac I E 5626 DB OOOH.OOOH.076H.OCCH,OCCH,07tH,OOCH,OIEH ; Le. Q D_71 

FOFE 0000DC766b60FOOO 5627 DB 000H.OOOH.COCH.076H.Cl66H,060H,OFOH,000H L.C. R 0_12 

FE06 00007CC0780CF800 5628 DB OOOH,OOOH.07CH,OCOH,078H,OOCH,OF8H.OOOH L.C. 5 o_73 

FEOE 10307C3030341800 5629 DB 010H.030H,07CH.030H.030H,034H,018H.OOOH L.C. T o_74 

F£l6 0000CCCCCCCC7600 5630 DB 000H.OOOH,OCCH.OCCH.OCCH,OCCH,076H,OOOH i L.C. U o_75 

FElE 0000CCCCCC783000 5631 DB OOOH,OOOH.OCCH,OCCH.OCCH,078H.030H,OOOH ; L.C. Y 0_76 

FE26 0000[606FEFE6COO 5b32 DB 000H,OOOH,OC6H,006H.OFEH.OfEH.06CH,OOOH ; L.C. W 0_77 

FE2E 0000(66C386CC600 5633 DB 000H,OOOH,OC6H,06CH,038H,06tH.OC6H.OOOH L.C. X 0_78 

fE36 OOOOCCCCCC7COCF8 5634 DB OOOH.OOOH.OCCH,OCCH.OCCH.07CH.OOCH.OFSH L.C. Y 0_79 

FE3E 0000fC983064FCOO 5635 DB 000H.000H,OFCH,096H.030H.OMH.OFCH.000H l.C. Z D_7A 

F£46 lC3030£030301COO 5b3b DB OlCH. 030H. 030H. OEOH, 030H.030H. 01CH. OOOH 0_76 

FE4E 1618180018181800 5637 DB 018H. 018H. 0 18H, OOOH, 018H,018H. 018H ,OOOH D_7C 

FE56 E030301C3030EOOO 5638 DB OEOH.030H.030H.OICH,030H,030H,OEOH.OOOH; 0_70 

FE5E 760COOOOOOOOOOOO 5639 DB 076H.OOCH.000H,OOOH.000H.OOOH,OOOH.000H i 0_7E 

FE66 0010386CC6C6FEOO 5640 DB 000H.OIOH.038H.o6CH,OC6H,OC6H,OfEH,OOOH , DELTA 0_7F 

A-76


5641 ;--- INT lA ------------------------------ 

5642 TIME_OF _DAY 

5643 THIS ROUTINE ALLOWS THE CLOCK TO BE SET/READ 

5644 

5645 INPUT 

5646 IAH) = 0 READ THE CURRENT CLOCK SETTING 

5647 RETURNS ex = HIGH PORTION Of COUNT 

5648 OX = lOW PORTIOt~ Of COUNT 

5649 AL = 0 IF TIHER HAS NOT PASSED 24 HOURS SINCE LAST READ 

5650 0 IF ON ANOTHER DAY 

5651 IAH) = 1 SET THE CURRENT ClOCK 

5652 CX = HIGH PORTION OF COUUT 

5653 OX = LOW PORTION OF COUNT 

5654 NOTE: COut-ITS OCCUR AT THE RATE OF 1193180/65536 COUIITS/SEC 

5655 lOR ABOUT 18.2 PER SECOND - SEE EQUATES BELOW) 

5656 ; ---------------------------------------- 

5657 ASSUME CS:CODE.DS:DATA 

FE6E 5658 TIME_OF_DAY PROC FAR 

FE6E Fe 5659 STI INTERRUPTS BACK ON 

FE6f IE 5660 PUSH DS SAVE SEGMENT 

FE70 50 5661 PUSH AX SAVE PARN 

FE7l 884000 5662 MOV AX.DATA 

FE74 8E08 5663 MOV DS.AX I ESTABLISH ADDRESSING TO VALUES 

FE76 56 5664 POP AX i GET BACK INPUT PARM 

FEn OAE4 5665 OR AH.AH ; AH=O 

FE79 7407 5666 JZ T2 ; READ_TIME 

FE7B FEee 5667 DEC AH I AH=1 

FE7D 7416 5668 JZ n ; SET_TINE 

FE7F 5669 Tl: ; TOO_RETURN 

FE7F FB 5670 STI ; INTERRUPTS BACK ON 

FEeD IF 5671 POP os ; RECOVER SEGMENT 

FEel CF 567Z IRET ; RETURN TO CAllER 

5673 

FEel 5674 12: I READ_TIME 

FEez FA 5675 CLI ; NO TIMER INTERRUPTS WHILE READING 

FEB3 A07000 5676 MOV AL.TINER_OFl 

~ FE86 C606700000 5677 MOV TIMER_OFL.O ; GET OVERFLOW. AND RESET THE FLAG 

FEes 860E6EOO 5678 MDV CX. TIMER_HIGH 

FE8F 88166COO 5679 MOV OX. TIMER_LOW 

FE93 EBEA 5680 JMP Tl 

5681 

FE 95 5682 T3: SET_TIME 

FE95 FA 5683 CLI NO INTERRUPTS WHILE WRITING 

FE96 69166COO 5684 MOV TINER_LOW. OX 

FE9A 890E6EOO 5685 MOV TIMER_HIGH .CX SET THE TIME 

FE9E C606700000 5686 MOV TIMER_OFl.O RESET OVERflOW 

FEU EBDA 5667 JMP Tl TOO_RETURN 

TIME_OF _DAY 

568~ ; ---------------------------------------- 

5690 ; THIS ROUTINE HANDLES THE TINER INTERRUPT fROM 

56~1 ; CHANNEL 0 OF THE 8253 TIMER. INPUT FREQUENCY IS 1.19318 HHZ 

5692 ; AHD THE DIVISOR IS 65536 , RESULTING IN APPROX. 18. Z INTERRUPTS 

5693 ; EVERY SECOND. 

5694 

5695 THE INTERRUPT HANDLER MAINTAINS A COUNT OF INTERRUPTS SINCE POWER 

5696 ON TIME. WHICH MAY BE USED TO ESTABLISH TINE OF DAY. 

5697 THE INTERRUPT HANDLER ALSO DECREMENTS THE MOTOR COtHROl COUNT 

5698 OF THE DISKETTE, AND WHEU IT EXPIRES, WILL TURN OFF THE DISKETTE 

5699 NOTOR. AND RESET THE MOTOR RU~INING FLAGS 

5700 THE INTERRUPT HAf'..'OLER WILL ALSO INVOKE A USER ROUTINE THROUGH INTERRUPT 

5701 lCH AT EVERY' TIME TICK. THE USER MUST CODE A ROUTINE AND PLACE THE 

5702 CORRECT ADDRESS IN THE VECTOR TABLE. 

5703 

HAS 5704 TIMER_INT PROC FAR 

FEAS Fe 5705 STI ; INTERRUPTS BACK ON 

~FEA61E 5706 PUSH DS 

FEA7 50 5707 PUSH AX 

FEAB 52 5708 PUSH DX ; SAVE MACHINE STATE 

FEA9 884000 5709 MDV AX.DATA 

FEAC BED8 5710 MOV DS,AX ESTABLISH ADDRESSABIlITY 

FEAE FF066COO 5711 INC TIMER_lOW INCREMENT TIt1E 

FEBZ 7504 5712 JIIZ T4 TEST_DAY 

FEB4 FF066EOD 5713 INC TIMER_HIGH UICREMENT HIGH WORD OF TIME 

FEBS 5714 T4: TE!"T_DAY 

A-77


FEBS 833E6E0018 5715 CMP TIMER_HIGH.DISH ~ TEST FOR COUNT EQUALLING 24 HOURS 

FEBD 7519 5716 JHZ T5 

FEBF 813E6C008000 5717 CMP TIMER_LOW,oaOH 

FEes 7511 5718 JHZ T5 

5719 

5720 1------ TINER HAS GONE 24 HOURS 

5721 

FEe7 C7066EOOOOOO 5722 MOV TIMER_HIGH J 0 

FEeD C7066COOOOOO 5123 MOV TIMER_LOW. 0 

FED3 C606700001 572:4 MOV TIMER_OFl.l 

5725 

5726 ;------ TEST FOR DISKETTE TIME OlIT 

5727 

FEDS 5728 TS: ; DISKETTE_CTL 

FEDe FEOE4000 5729 DEC MOTOR_COUNT 

FEOC 7508 5730 JHZ T. ; RETURN IF COUNT NOT OUT 

FEDE 80263FOOFO 5731 AND HOTOR_STATUS,OFOH TURN OFF MOTOR RUNNING 8ITS 

FEEl BoDe 5732 MOV AL.OCH 

FEES SAFlO] 5733 MOV DX.03F2H FOC en PORT 

FEEB EE 5734 0I1T DX,AL I TURN OFF THE MOTOR 

5735 

FEE9 5736 16: TIMER_RET: 

FEE9 COle 5737 INT IC" TRANSFER CONTROL TO ... USER ROUTINE 

FEEB B020 5738 MOV Al,EOI 

FEED E620 5739 OUT 020H,Al END OF INTERRUPT TO 8259 

HEr SA 5740 POP OX 

FEFO 58 5741 POP AX 

fEFl IF 5742 POP OS RESET MACHINE STATE 

FEF2 CF 5743 IRET RETURN FROM INTERRUPT 

5744 TIMER_INT ENDP 

5745 • ------------------------------------------ 

5746 ; THESE ARE THE VECTORS WHICH ARE MOVED INTO 

5747 ; THE 6086 1HTEP.RUPT AREA DURING POWER ON 

5748 ,-------------- --------------------------- 

FEF3 5749 VECTOR_TABLE LABEL WORD ; VECTOR TABLE FOR MOVE TO INTERRUPTS 

5750 

FEF3 ASH 5751 ow OFFSET TIMER_INT ; INTERRUPT 8 

FEFS DOFD 5752 OW CODE 

5753 

FEF? 87E9 5754 OW OFFSET KB_IHT INTERRUPT 9' 

FEF9 OOFO 5755 OW CODE 

5756 

FEFS 00000000 5757 00 i INTERRUPT A 

FEFf 00000000 5756 00 INTERRUPT B 

FF03 00000000 5759 00 INTERRUPT C 

fF07 00000000 5760 00 INTERRUPT 0 

5761 

HOB 57EF 5762 ow OFFSET DISK_ItiT INTERRUPT E 

FFOO OOFO 5763 OW COOE 

5764 

FFOF 00000000 5765 00 INTERRUPT F 

5766 

FF13 65fO 5767 ow OFFSET VIDEO_IO I INTERRUPT 10H 

FF15 OOFO 5768 OW CODE 

5769 

FF1740F8 5770 ow OFFSET EQUIPMENT ; INTERRUPT llH 

FF19 DOFa 5711 ow CODE 

5772 

FFIB 41F8 5713 ow OFFSET HEMORY_SIZE_DETERMINE INT l2H 

FFlO OOFO 5774 ow CODE 

5775 

FFIF 59EC 5776 ow OFFSET DISKETTE_IO I INTERRUPT 13H 

FF21 OOFO 5777 ow CODE 

5778 

FF23 39E7 5779 ow OFFSET RS232_IO ; INTERRUPT l4H 

FFZS OOFO 5780 ow CODE 

5781 

FF27 59F8 5782 ow OFFSET CASSETTE_IO HITERRUPT ISH 

FF2:9 OOFO 5783 ow CODE 

5784 

FFZB ZEES 5785 ow OFFSET KEYBOARD_IO INTERRUPT 16H 

FF20 DOFO 5786 ow CODE 

5787 

FF2F 02EF 5788 ow OFFSET PRINTER_IO INTERRUPT 17H 

FFll OOFO 5789 ow CODE 

5790 

A-78


r"\ 

,,-...., 

5856 

FF33 0000 57'H ow ooaOOH INTERRUPT ISH 

Ff35 OOf6 5792 ow OF600H ROM BASIC ENTRY POINT 

S7'B 

FF37 F2E6 5794 ow OFFSET BOOT_STRAP ; INTERRUPT 19H 

FF39 COFO 5795 ow CODE 

5796 

FFlB 6EFE 5797 0" TIME_OF_DAY j INTERRUPT lAH -- TIME OF DAY 

FF3D OOFe 5798 0" CODE 

5799 

FFlF 53FF 5800 0" DUMMY_RETURN INTERRUPT IBH .- KEYBOARD BREAK ADDR 

FF41 OOFO 5601 0" CODE 

5802 

FF4l 53FF 5803 0" DUMMY.RETURN INTERRUPT 1 C -- TIMER BREAK ADDR 

FF45 oaf 0 5604 OW CODE 

5805 

FF47 A4FO 5806 0" VIOEO_PARMS INTERRUPT 10 -- VIDEO PARAMETERS 

FF49 OaFQ 5807 0" COOE 

5608 

FF48 C7EF 5809 0" OFFSET DISK.BASE I INTERRUPT IE -- DISK PARMS 

FF4D OOFO 5810 OW CDDE 

5811 

FF4F 00000000 5812 DO INTERRUPT IF -- POINTER TO VIDEO EXT 

5813 

FFS3 5614 DUMNY.RETImN: 

FFSl CF 5815 IRET ; DUMHY RETIJRN FOR BREAK FROM KEYBOARD 

5816 J-- INT 5 ----------------------.----------- 

5817 THIS LOGIC WILL BE INVOKED BY INTERRUPT 05H TO PRINT 

5818 THE SCREEN. THE CURSOR POSITION AT THE TIME THIS ROUTINE 

5819 IS INVOKED WIll BE SAVED AND RESTORED UPON COMPLETION. THE 

5820 ROUTINE IS INTENDED TO RUN WITH INTERRUPTS ENABLED. 

5821 IF A SUBSEQUENT • PRINT SCREEN KEY IS DEPRESSED DURING THE 

5822 UME THIS ROUTINE IS PRINTING IT WIll BE IGNORED. 

5823 ADDRESS 50:0 CONTAINS THE STATUS OF THE PRINT SCREEN: 

5824 

5825 50:0 '0 EITHER PRINT SCREEN HAS NOT BEEN CALLED 

5826 OR UPON RETURN FROM A CAll THIS INDICATES 

5827 A SUCCESSFUL OPERATION. 

5828 

5829 0) PRINT SCREEN IS IN PROGRESS 

5830 

5831 =377 ERROR ENCOUNTERED DURING PRINTING 

5832 ;------------------------------------------- 

5833 ASSUME CS: CODE ,DS:XXDATA 

5834 

fFS4 5835 PRINT_SCREEN PROC FAR 

FFS4 F8 5836 5TI ;I1UST R\..R'>I WITH INTERRUPTS ENABLED 

FFS5 IE 5837 PUSH 05 jMUST USE 50:0 FOR DATA AREA STORAGE 

FF56 50 5838 PUSH AX 

FF57 53 5839 pUSH ex 

FF56 51 5840 PUSH ex iWIlL USE THIS LATER FOR CURSOR LIMITS 

FF59 52 5841 PUSH ox iWIlL HOLD CURRENT CURSOR POSITION 

FF5A 885000 5842 MOV AX,XXOATA jHEX 50 

FF5D 8E08 5843 MOV OS.AX 

FF5F 803£000001 5844 eMP STATUS.BYTE,l ,SEE IF PRINT ALREADY IN PROGRESS 

FF64 745F 5845 JZ EXIT ; Jt.n1P IF PRINT ALREADY IN PROGRESS 

FF66 C606000001 5846 MDV STATUS_BYTEd ; INDICATE PRINT NOW IN PROGRESS 

Ff6B 84OF 5847 MDV AH,15 iWIlL REQUEST THE CURRENT SCREEN MODE 

FF60 COlO 5848 INT )OH [All=1'10DE 

5849 [AH ]=NUMBER COLUMNS/LINE 

5850 t BH J::VISUAl pAGE 

5851 

J**********************lflf************ 

5852 AT THIS POINT WE KNOW THE COLUMNS/LINE ARE IN 

5853 [AX] AND THE PAGE IF APPLICABLE IS IN tBHJ. THE STACK 

5854 HAS OS,AX.BX,CX,DX PUSHED. [ALI HAS VIDEO MODE 

5855 

j ******* ************************* **** 

FF6F BACC 5857 MDV CL.AH iWILL MAKE USE OF [CXI REGISTER TO 

FF71 B519 5858 MOV CH.25 ;CONTROL ROW & COLUHNS 

FF73 £85500 5859 CALL CRLF ;CARRIAGE RETURN LINE FEED ROUTINE 

FF76 51 5860 PUSH CX ; SAVE SCREEN BOUNDS 

FF77 8403 5861 MOV AH,3 jWILl NOW READ THE CURSOR. 

FF79 COlO 586Z INT )OH iAHD PRESERVE THE POSITION 

FF7B 59 5863 POP ex jRECALL SCREEN BOUNDS 

FF7C 52 5864 PUSH OX .RECALl [BH};;;VISUAL PAGE 

FF7D 3302 5865 XOR OX.OX jWIll SET CURSOR POSITION TO (0,0) 

A-79


5866 ;.*.-••••._•••*.******.*************.**•••if•• 

5867 THE LOOP FROM PRIlO TO THE INSTRUCTION PRIOR TO PA120 

5868 IS THE LOOP TO READ EACH CURSOR POSITION FROl1 THE SCREEN 

5869 AND PR INT • 

5870 ,•••**.*••**_.*************.*.*************** 

'='F7F 8402 5871 PRIlO: MOV AH,2 iTO INDICATE CURSOR SET REQUEST 

=F81 COlO 5872 INT 10H iHEW CURSOR POSITION ESTABLISHED 

:F83 8408 5873 MaY AH.8 ;TO INDICATE READ CHARACTER 

=F85 COlO 5874 INT 10H ,CtiARACTER NOW IN (All 

FF87 OACO 5875 OR AL .... L iSEE IF VALID CHAR 

FF89 7502 5876 Jt~Z PRIIS jJUMP IF VALID CHAR 

FFSB BOZO 5877 MOV IMAKE A BLANK 

ffan 5878 PRIIS: 

FfSO 52 5879 PUSH OX iSAVE CURSOR POSITION 

fFSE 3302 5880 XOR DX,DX jINDICATE PRINTER 1 

FF90 32E"t 5881 XOR AH,AH ;TO INDICATE PRINT CHAR IN [All 

FF92 C017 5M2 INT 17H j PRINT THE CHARACTER 

FF94 SA 5883 POP OX JRECALL CURSOR POSITION 

FF95 F6C425 5884 TEST AH. 25H ; TEST FOR PRINTER ERROR 

FF98 7521 5885 JNZ ERRtO ; JUMP IF ERROR DETECTED 

FF9A fEtz 5886 INC OL ; ADVANCE TO NEXT COLUNN 

FF9C lACA 5887 CMP CL,DL ;SEE IF AT END OF LINE 

FF9E 750F 5888 JNZ PRIIO ; IF NOT PROCEED 

HAD 3202 58139 XOR DL,Dl ;BACK TO COLlR1N 0 

FFAe 84£2 5890 MOV AH,DL j[AHJ=O 

FFA4 52 5891 PUSH OX ; SAVE NEW CURSOR POSITION 

FFAS E82300 5892 CALL tRLF ; LINE FEED CARRIAGE RETURN 

FFAS SA 5893 POP OX jRECALL CUI?SOR POSITION 

FFA9 FECb 5894 WC OH jAOVAHCE TO NEXT LINE 

FFA8 3AEE 5895 eMP CH.DH ;FINISHED? 

HAD 7500 5896 JNZ PRIIO ; IF NOT COHTlNUE 

FFAF SA 5897 PR120: POP OX jRECALl CURSOR POSITION 

FFBD 8402 5898 MaY AH,Z ;TO INDICATE CURSOR SET REQUEST 

FFB2 COlO 5899 INT lOH ,CURSOR POSITION RESTORED 

FFB4 C606000000 5900 tlOV STATUS_BYTE, a jINDICATE FINISHED 

Ff59 EBOA 5901 JMP SHORT EXIT ; EXIT THE ROUTIt~E 

FFBB SA 5902 ERRIO: POP ox ;GET CURSOR POSITION 

FFec 8402 5903 MOV AH.2 ;TO REQUEST CURSOR SET 

FFBE COlO 5904 INT 10H ;CURSOR POSITIOtl RESTORED 

FFCO C6060000FF 5905 ERR20: MOV STATUS_BYTE,OfFH IINDICATE ERROR 

5906 

fFes SA 5907 EXIT: pop ox jRESTORE ALL THE REGISTERS USED 

FFCb 59 5908 POP ex 

FFC7 sa 5909 POP ex 

Ffce 58 5910 pop AX 

FFC9 IF 5911 POP as 

FFCA CF 5912 IRET 

5913 

5914 

5915 1------ C...RRI... GE RETURN. LINE FEED SUBROUTINE 

5916 

FFCB 5917 C~lF PRot NEAR 

FFCB 3302 5918 XOR OX,OX ;PRINTER a 

FFCD 32E4 5919 XOR AH.AH iioULL NOW SEND INITIAL IF,CR TO PRINTER 

FFCF BOOA 5920 MOY AL.12Q ; IF 

FFOI C017 5921 INT 17H ; SEND THE LINE FEED 

H03 32E4 sn2 XOR AH,AH ;NOW FOR THE CR 

FFOS BODO 5923 MOV Al.t5Q iCR 

FF07 CD17 5924 INT 17H jSENO THE CARRIAGE RETURN 

fF09 C3 5925 RET 

5926 CRLF ENOP 

5927 CODE ENDS 

5928 

5929 ; -------------------------------- 

5930 i POIolER ON RESET VECTOR 

5931 1--------------------------------- 

FFH 5932 VECTOR SEGMWT AT OFFf"FH 

5933 

5934 ; ----- POWER Ot-l RESET 

5935 

0000 EA580000FO 5936 JMP RESET 

5937 

0005 30342F32342F38 5938 DB • 04/24/81' RELEASE MARKER 

31 

A-80 • 

5939 VECTOR ENOS 

5940 END

Notes For The BIOS Listing 

1. The wait loop for the printer times out on form 

feed of >51 lines. - line ref (3069) 

2. Mode controls for the 320 x 200 video have 

Color/BW reversed. - line ref (3338) 

3. The RS232 Timeout is 80 decimal, not SO 

hexadecimal. - line ref (1566) 

4. The Base Pointer register is destroyed by some 

video calls. 

5. D_04 0 character in the character generator has 

OS as it's last value, S/SO. -line ref (5511) 

6. If you hit print screen in the Color/Graphics 

80x25 Character Mode, the screen may not 

display during the print cycle. 

A-Sl

A-82 

NOTES

Appendix B. Assembly Instruction Set 

Reference 

B-1

8088 

REGISTER MODEL 

AX: AH Al ACCUMULATOR 

BX: BH Bl BASE 

CX: CH CL COUNT 

u.. 

OX: DH DL DATA ..Ja: 

I 

«W 

SP STACK POINTER 

a: I- 

W~ 

BP BASE POINTER 

ZC!l 

ww 

C!la: 

SI 

~====================~ SOU RCE IN DEX 

01 DESTINATION INDEX 

~============~ 

I-------.----------lilNSTRU IP CTI ON POI NTE R 

I FLAGSH I FLAGSL . STATUS FLAGS 

t 

~===============~====: 

CS CODE SEGMENT } ~ 

OS DATA SEGMENT I-- ~ 

SS 

:==========~==========: STAC K SE G M ENT 

L-________ ~ ~ 

ES EXTRA SEGMENT ~~ Cl)a: 

I 

W 

..J 

Instructions which reference the flag register file as a 16-bit object 

use the symbol FLAGS to represent the file: 

15 7 0 

'X , X IX I X , OF , OF 'IF ITF I SF I ZF t X IAF IX I PF IX ICF , 

X = Don't Care 

AF: AUXILIARY CARRY - BCD } 

CF: CARRY FLAG 

PF: PARITY FLAG 8080 FLAGS 

SF: SIGN FLAG 

ZF: ZERO FLAG 

OF: DIRECTION FLAG (STRINGS)} 

IF: INTERRUPT ENABLE FLAG 8088 FLAGS 

OF: OVERFLOW FLAG (CF E8 SF) 

TF: TRAP - SINGLE STEP FLAG 

B-2

OPERAND SUMMARY 

"reg" field Bit Assignments: 

16-Bit (w=l) a-Bit (w=O) Segment 

000 AX 000 AL 00 ES 

001 CX 001 CL 01 CS 

010 OX 010 OL 10 SS 

011 BX 011 BL 11 OS 

100 SP 100 AH 

101 BP 101 CH 

110 SI 110 OH 

111 01 111 BH 

SECOND INSTRUCTION BYTE SUMMARY 

Imod Ixxx Irim I 

mod 

Displacement 

00 OISP = 0*, disp-Iow and disp-high are absent 

01 OISP = disp-Iow sign-extended to 16-bits, disp-high is absent 

10 OISP = disp-high: disp-Iow 

11 rim is treated as a "reg" field 

rIm 

Operand Address 

000 (BX) + (SI) + DISP 

001 (BX) + (01) + DISP 

010 (BP) + (SI) + OISP 

011 (BP) + (01) + OISP 

100 (SI) + DISP 

101 (01) + OISP 

110 (BP)+OISP* 

111 (BX) + OISP 

OISP follows 2nd byte of instruction (before data if required). 

*except if mod = 00 and rim = 110 then EA = disp-high: disp-Iow. 

B-3

MEMORY SEGMENTATION MODEL 

LOGICAL 

MEMO RY SPACE 

t~ 

o 

..[ ot FFFFFH 

P 

64KB CODE SEGMENT r"'\ 

} 

~ XXXXOH 

i=: 

OFFSET 

ADORESS 

15 0 

I DISPLACEMENT 

I- 

----! I 

01 SP LAII'M ,NT 

:~ 

} STACK SEGMENT 

I 

I 

I 

I 

MSB 

I 

15 0 

I I WORD { 

SELECTED 

LSB } DATA SEGMENT 

CS 0000 r- 

SEGMENT 

BYTE 

REGISTER SS 0000 ~ 

OS 0000 

CS,SS, OS, ES 

ES 0000 

OR NONE 

:: 

~ 

FOR I/O, INT ~, 

.-- 

I 

~ 7 :; 

V 

I 

I 

I 

EXTRA DATA 

I } SEGMENT 

I 

I ADDER 

I 

I 

I 

I 

L T OOOOOH 

19 > 0 

PHYSICAL 

ADDRESS 

LATCH 

SEGMENT OVERRIDE PREFIX 

IOOlregl101 

USE OF SEGMENT OVERRIDE 

OPERAND REGISTER DEFAULT WITH OVERRIDE PREFIX 

IP (code address) CS Never 

SP (stack address) SS Never 

BP (stack address or stack marker) SS BP + DS or ES, or CS 

SI or D 1 (not incl. strings) OS ES, SS, or CS 

SI (implicit source addr for strings) OS ES, SS, or CS 

01 (implicit dest addr for strings) ES Never 

B-4

MOV = Move 

Register/memory to/ from register 

DATA TRANSFER 

11 0 0 0 1 0 d w I mod reg rIm 

Immediate to register/memory 

1 1 0 0 0 1 1 w mod 0 0 0 rIm data data if w=l 

Immediate to register 

1 0 1 1 w reg data data if w=l 

Memory to accumulator 

101 0 0 0 0 w addr-Iow addr-high 

Accumulator to memory 

1010001w addr-Iow 

addr-high 

Register/memory to segment register 

11 0 0 0 1 1 1 0 I mod 0 reg rim 

Segment register to register/memory 

11 0 0 0 1 1 0 0 mod 0 reg rIm 

PUSH = Push 

Register/memory 

11 1 1 1 1 1 1 1 mod 1 1 0 rim 

Register 

0 1 0 1 0 reg 

Segment register 

I0 0 0 reg 1 0 

r---... 

POP =Pop 


1 0 0 0 1 1 1 

Register 

1 0 1 0 1 1 reg 

1 mod 0 0 0 rim 

Segment register 

10 0 0 reg 1 1 

B-S

XCHG =Exchange 

RegisterImemory with register 

11 0 0 0 0 1 1 w 1 mod reg rIm 

Register with accumulator 

110010regl 

IN = Input to AL/AX from 

Fixed port 

11 1 1 0 0 1 0 w port 

Variable port (OX) 

11110110W 

OUT =Output from ALIAX to 

Fixed port 

11 1 1 0 0 1 1 w port 

Variable port (OX) 

11 1 10111w 

XLAT =Translate byte to AL 

1110101111 

LEA =Load EA to register 

I 1 0 0 0 1 1 0 1 I mod reg rIm 

LDS =Load pointer to OS 

11 1 0 0 0 1 0 1 mod reg rIm 

LES =Load pointer to ES 

11 1 0 0 0 1 0 0 mod reg rIm 

LAHF =Load AH with flags 

1100111111 

SAHF =Store AH into flags 

1100111101 

PUSHF = Push flags 

110011100 

POPF = Pop flags 

110011101 

B-6

ARITHMETIC 

ADD =Add 

Reg./memory with register to either 

1 0 0 0 0 0 0 d w I mod reg rIm I 


~ 

11 0 0 0 0 0 s w 

I 

mod o 0 0 rim data data if s:w=01 I 

~ 

Immediate to accumulator 

1 0 0 0 0 0 1 0 w data data if w=l 

I 

ADC = Add with carry 

Reg./memory with register to either 

1 0 0 0 1 0 0 d w mod 

I 

reg rim 


0 0 0 0 0 s w mod 0 1 0 rim data data if s:w=Ol I 

11 

1 

Immediate to accumulator 

0 0 0 1 0 1 0 w data data if w=l I 

INC = Increment 

Register/memory 

1 1 1 1 1 1 1 w mod 0 o 0 rim 

Register 

I0 1 0 0 0 reg I 

AAA = ASCII adjust for add 

I 0 0 1 1 0 1 1 

1 I 

DAA = Decimal adjust for add 

0 0 1 0 0 1 1 1 I 

~ 

su B = Subtract 

Reg./memory and register to either 

I0 0 1 0 1 0 d w mod reg rim 

I 

Immediate from register/memory 

11 0 0 0 0 0 s w mod 1 0 1 rim data data if s:w=Ol 

I I 

Immediate from accumulator 

0 0 1 0 1 1 0 w data data if w=l 

B-7

SBB = Subtract with borrow 

Reg./memory and register to either 

1 0 0 0 1 1 0 d w 1 mod reg rIm 

Immediate from register/memory 

11 0 0 0 0 0 s w 1 mod 0 1 1 rIm data data if s:w=Ol 

Immediate from accumulator 

10001110w data 

data if w=l 

DEC = Decrement 


11111111w mod 

0 0 1 rIm 

Registe,· 

1 0 1 0 0 1 reg 1 

NEG = Change sign 

11111011w mod 

0 1 1 rIm 

CMP = Compare 

Register/memory and register 

1 0 0 1 1 1 0 d w 1 mod reg rIm 

Immediate with register/memory 

11 0 0 0 0 0 s w 1 mod 1 1 1 rim data data if s:w=Ol 

Immediate with accumulator 

1 0 0 1 1 1 lOw 1 data data if w=l 

AAS = ASC" adjust for subtract 

1001111111 

DAS = Decimal adjust for subtract 

1001011111 

MU L = Multiply (unsigned) 

11 1 1 1 0 1 1 w 1 mod 1 0 0 rim 

IMU L = Integer multiply (signed) 

11 1 1 1 0 1 1 w 1 mod 1 0 1 rim 1 

B-8

AAM =ASC II adjust for mUltiply 

\1 1 01 01 00 \ 0 0001 0 1 0 

DlV = Divide (unsigned) 

\1 1 1 1 0 1 1 w mod o rim 

,,-....,.., IOIV = Integer divide (signed) 

11 1 1 1 0 1 1 w 1 mod rim 

AAO = ASCII adjust for divide 

111010101 100001010 

CBW =Convert byte to word 

1100110001 

CWO = Convert word to double word 

11 00 1 1 001 

lOGIC 

NOT =Invert 

!1111011W mod 0 1 0 rim 

SH l/SAl =Shift logical/arithmetic left 

11 1 0 1 0 0 v w I mod 1 0 0 rim 

SHR =Shift logical right 

1110100vW mod 

1 0 1 rim 

SAR = Shift arithmetic right 

11 1 0 1 0 0 v w I mod 1 1 1 rim 

ROl = Rotate left 

11 1 0 1 0 0 v w I mod 0 0 0 rim 

ROR = Rotate right 

1110100vw mod 

0 0 1 rim 

RCl = Rotate through carry left 

~\ 11 1 0 1 0 0 v w 1 mod 0 1 0 rim 

RC R= Rotate through carry right 

11 1 0 1 0 0 v w mod 0 1 1 rim 

B-9

AND = And 


1 0 0 1 0 0 0 d w mod 

I 

reg rim 


11 0 0 0 0 0 0 w I mod 1 0 0 rim data data if w=1 I 

Immediate to accumulator 

10 0 1 0 0 1 0 w I data data if w=1 I 

TEST = And function to flags, no result 

RegisterImemory and register 

11 0 0 0 0 1 0 w I 

mod reg rim 

Immediate data and register/memory 

11 1 1 1 0 1 1 w I mod 0 0 0 rim data data if w=1 

Immediate data and accumulator 

11 0 1 0 1 0 0 w data data if w=1 

OR = Or 


10 0 0 0 1 0 d w I mod reg rim 


11 0 0 0 0 0 0 w I 

mod o 0 1 rim data data if w=1 


10 0 0 0 1 1 0 w data data if w=1 

XOR = Exclusive or 


10 0 1 1 0 0 d w I 

mod reg rim 


11 0 0 0 0 0 0 w mod 1 1 0 rim data data if w=1 

I 


0 1 1 0 1 0 w data data if w=1 

10 

,~ 

B-10

STRING MANIPULATION 

REP = Repeat 

11111001z1 

,...-., MOVS = Move String 

11 010010w 

CMPS = Compare String 

1101 0011W 

SCAS =Scan String 

/1010111W 

LODS = Load String 

11010110w 

STOS =Store String 

11010101W 

CONTROL TRANSFER 

CALL = Call 

Direct within segment 

/11101000 

disp-Iow 

disp-high 

Indirect within segment 

11111111 

mod 

0 1 0 rIm I 

Direct intersegment 

/10011010 

offset-low 

seg-Iow 

offset-high 

seg-high 

Indirect intersegment 

11 1 1 1 1 1 1 

mod 

0 1 1 rIm 

JMP =Unconditional Jump 

~ Direct within segment 

11 1 1 0 1 0 0 1 

Direct within segment-short 

11 1 1 0 1 0 1 1 

1 disp-Iow disp-high 

I disp I 

B-ll

Indirect within segment 

11111111 mod 1 0 0 rIm 

Direct intersegment 

111101010 offset-low 

seg-Iow 

offset-high 

seg-high 

Indirect intersegment 

11111111 mod 1 0 1 rIm 

RET =Return from CALL 

Within segment 

1110000111 

Within seg. adding immed to SP 

11 1 0 0 0 0 1 0 I data-low data-high 

Intersegment 

11 1 001 01 1 

Intersegment, adding immediate to SP 

11 1 0 0 1 0 1 0 I data-low 

JE/JZ = Jump on equallzero 

I0 1 1 1 0 1 0 0 I disp I 

data-high 

JL/JNGE =Jump on less/not greater or equal 

I 0 1 1 1 1 1 0 0 I disp I 

JLE/JNG =Jump on less or equal/not greater 

I 0 1 1 1 1 1 1 0 I disp I 

JB/JNAE =Jump on below/not above or equal 

I0 1 1 1 0 0 1 0 I disp I 

JBE/JNA =Jump on below or equal/not above 

I0 1 1 1 0 1 1 0 I disp I 

JP/JPE =Jump on parity/parity even 

I0 1 1 1 1 0 1 0 I disp I 

JO =Jump on overflow 

I0 1 1 1 0 0 0 /0 

disp I 

B-12

JS =Jump on sign 

10 1 1 1 1 0 0 0 disp 

JNE/JNZ =Jump on not equal/not zero 

10 1 1 1 0 1 0 1 I disp 1 

IN L/JG E =Jump on not less/greater or equal 

I0 1 1 1 1 1 0 1 I disp 1 

IN LE/JG =Jump on not less or equal/greater 

I0 1 1 1 1 1 1 1 I disp 1 

IN B/JAE =Jump on not below/above or equal 

1 0 1 1 1 0 0 1 1 1 disp 1 

JNBE/JA =Jump on not below or equal/above 

I0 1 1 1 0 1 1 1 1 disp 1 

JNP/JPO =Jump on not parity/parity odd 

10 1 1 1 1 0 1 1 1 disp 1 

~ JNO =Jump on not overflow 

I0 1 1 1 0 0 0 1 

disp I 

JNS =Jump on not sign 

10 1 1 1 1 0 0 1 disp 1 

LOOP = Loop ex times 

11 1 1 0 0 0 1 0 disp 1 

LOOPZ/LOOPE = Loop while zero/equal 

11 1 1 0 0 0 0 1 1 disp 1 

LOOPNZ/LOOPNE = Loop while not zero/not equal 

11 1 1 0 0 0 0 0 disp 

JCXZ =Jump on ex zero 

r", 11 1 1 0 0 0 1 1 disp 

B-13

8088 CONDITIONAL TRANSFER OPERATIONS 

Instruction Condition Interpretation 

JE or JZ ZF = 1 "equal" or "zero" 

JL or JNGE (SF xor OF) = 1 "less" or "not greater or equal" 

JLEorJNG ((SP xor OF) or "less or equal" or "not greater" 

ZF) = 1 

JB or JNAE CF =1 "below" or "not above or equal" 

JBE or JNA (CForZF)=l "below or equal" or "not above" 

JP or JPE PF = 1 "parity" or "parity even" 

JO OF = 1 "overflow" 

JS SF =1 "sign" 

JNE or JNZ ZF = 0 "not equal" or "not zero" 

JNLorJGE (SF xor OF) = 0 "not less" or "greater or equal" 

JNLE or JG ((SF xor OF) or "not less or equal" or "greater" 

ZF) = 0 

JNB or JAE CF =0 "not below" or "above or equal" 

JNBE or JA (CF or ZF) = 0 "not below or equal" or "above" 

JNP or JPO PF =0 "not parity" or "parity odd" 

JNO OF = 0 "not overflow" 

JNS Sf = 0 "not sign" 

*"Above" and "below" refer to the relation between two unsigned 

values, while "greater" and "less" refer to the relation between 

two signed values. 

INT = Interrupt 

Type specified 

11 1 0 0 1 1 0 1 type 1 

Type 3 

111001101 

INTO = Interrupt on overflow 

1110011101 

IRET =Interrupt return 

11 1 001 1 1 1 

CLC =Clear carry 

PROCESSOR CONTROL 

STC = Set carry 

1 1 1 1 1 1 0 0 oI 1 1 1 1 0 0 

11 

CMC =Complement carry NOP = No operation 

11 1 1 1 0 1 0 1 I 11 0 0 1 0 0 0 oI 

B-14

CLD = Clear direction 

S1D = Set direction 

1111111001 111 111 1 0 

C II = Clear interrupt 

S11 = Set interrupt 

1111110101 111111011 

HL1= Halt 

WAI1 = Wait 

111101001 10011011 

LOCK = Bus lock prefix 

ESC =Escape (to external device) 

11110000\ 1 1 0 1 1 x x x I mod x x x rIm 

Footnotes: 

if d = 1 then "to"; if d = 0 then "from" 

if w = 1 then word instruction; if w = 0 then byte instruction 

if s:w = 01 then 16 bits of immediate data from the operand 

if s:w = 11 then an immediate data byte is sign extended to form the 

16·bit operand 

ifv =0 then "count" = 1; if v =1 then "count" in (C Ll 

x =don't care 

~ z is used for some string primitives to compare with ZF FLAG 

AL = 8·bit accumulator 

AX = 16-bit accumulator 

CX = Count register 

DS = Data segment 

DX = Variable port register 

ES = Extra segment 

Above/below refers to unsigned value 

Greater = more positive; 

Less = less positive (more negative) signed values 

B-lS

BOBBINSTRUCTION SET MATRIX 

LO 

HI 0 1 2 3 4 5 6 7 

0 ADD ADD ADD ADD ADD Add PUSH PDP 

b.f.r/m w.f.r/m b,t,r/m w,t,r/m b.ia w.ia ES ES 

1 AoC ADC AoC AoC AoC AoC PUSH PDP 

b.l.r/m w.f.r/m b,t.r/m w,t,r/m b.i w.i SS SS 

2 AND AND AND AND AND AND SEG oAA 

b.f.r/m w.l.r/m b,t,r/m w,t.r/m b.i w.i =ES 

3 XoR XoR XoR XDR XOR XDR SEG AAA 

b.t.r/m w,t,r/m b,t,r/m w,t,r/m b.i w.i =SS 

4 INC INC INC INC INC INC II~C INC 

AX CX OX BX SP BP SI 01 

5 PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH 


6 

7 JD JND JBI JNBI JEI JNEI JBEI JNBEI 

JNAE JAE JZ JNZ JNA JA 

8 Immed Immed Immed Immed TEST TEST XCHG XCHG 

b.r/m w.r/m b.r/m is.rim b.r/m w.r/m b.r/m w.r/m 

9 NOP XCHG XCHG XCHG XCHG XCHG XCHG XCHG 

CX OX BX SP BP SI 01 

A MoV MOV MOV MOV MOVS MOVS CMPS CMPS 

m~AL m~AX AL .. m AX~m b w b w 

B MOV MOV MOV MOV MOV MOV MOV MOV 

i-'>AL i+CL i.. oL i-'>BL i..AH i..CH i.. oH i .. BH 

C RET. RET LES LOS MOV MDV 

(j+SP) b.i.r/m w.i.r/m 

0 Shift Shift Shift Shift AAM AAD XLAT 

b w b.v w.v 

E LOOPNZI LOOPZI LOOP JCXZ IN IN OUT OUT 

LOOPNE LOOPE b w b w 

F LOCK REP REP HLT CMC Grp 1 Grp 1 

Z b.r/m w.r/m 

b = byte operation 

d = direct 

f = from CPU reg 

i = immediate 

ia = immed. to accum. 

id = indirect 

is = immed. byte, sign ext. 

I = long ie. intersegment 

m = memory 

rim = EA is second byte 

si = short intrasegment 

sr = segment register 

t = to CPU reg 

v = variable 

w = word operation 

z = zero 

B-16

HI 

LO 

8088 INSTRUCTION SET MATRIX 

8 9 A B C 0 E F 

0 OR OR OR OR OR OR PUSH 

b.f.r/m w.t.r/m b,t,r/m w,t,r/m b.i w.i CS 

1 SBB SBB SBB SBB SBB SBB PUSH POP 

b.f.r/m w.f.r/m b,t,r/m w,t,r/m b.i w.i OS OS 

2 SUB SUB SUB SUB SUB SUB SEG OAS 

b.f.r/m w.l.r/m b,t,r/m w,t,r/m b.i W.I CS 

3 CMP CMP CMP CMP CMP CMP SEG AAS 

b.f.r/m w.l.r/m b,t,r/m w,t,r/m bj w.i OS 

4 DEC DEC DEC DEC DEC DEC DEC DEC 


5 POP POP POP POP POP POP POP POP 


6 

7 JS JNS JPI JNPI JL/ JNl/ JLEI IN LEI 

JPE .IPO JNGE JGE JNG JG 

8 MOV MOV MOV MDV MDV LEA MOV POP 

b.t.r/m w.f.r/m b,t,r/m w,t,r/m sr.t.r/m sr.f.r/m rim 

9 CBW CWO CALL WAIT PUSHF POPF SAHF LAHF 

I.d 

A TEST TEST STOS STOS LOOS LODS SCAS SCAS 

b.i w.i b w b W b W 

B MOV MOV MOV MOV MOV MOV MDV MDV 

i...AX i~CX i~OX i.... BX i+SP i... BP i-+SI i...OI 

C RET RET INT INT INTO IRET 

1,(i+SP) I Type 3 (Any) 

0 ESC ESC ESC ESC ESC ESC ESC ESC 

0 1 2 3 4 5 6 7 

E CAll JMP JMP JMP IN IN OUT OUT 

d d I.d si.d v.b v.W v.b v.W 

F CLC STC Cli STI CLD STO Grp 2 Grp 2 

b.r/m w.r/m 

where 

modO rim 000 001 010 011 100 101 100 111 

Immed ADD OR AOC SBB AND SUB XOR CMP 

Shift ROL ROR RCL RCR SH L/SAL SHR SAR 

Grp 1 TEST NOT NEG MUl IMUL OIV 10lV 

Grp 2 INC DEC CALL CALL JMP JMP PUSH 

id I,id id 1,;0 

B-17

INSTRUCTION SET INDEX 

Mnemonic Page Mnemonic Page Mnemonic Page 

AAA 6 JG 12 MOV 4 

AAD 8 JGE 12 MOVS 10 

AAM 8 JL 11 MUL 1 

AAS 1 JLE 11 NEG 1 ~ 

ADC 6 JMP 10 NOP 13 

ADD 6 JNA 11 NOT 8 

AND 9 JNAE 11 OR 9 

CALL 10 JNB 12 OUT 5 

CBW 8 JNBE 12 POP 4 

CLC 13 JNE 12 POPF 5 

CLD 14 JNG 11 PUSH 4 

Cli 14 JNGE 11 PUSHF 5 

CMC 13 JNL 12 RCL 8 

CMP 1 JNLE 12 RCR 8 

CMPS 10 JNO 12 REP 10 

CWD 8 JNP 12 RET 11 

DAA 6 JNS 12 ROL 8 

DAS 1 JNZ 12 ROR 8 

DEC 1 JO 11 SAHF 5 

DIV 8 JP 11 SAL 8 

ESC 14 JPE 11 SAR 8 

HLT 14 JPO 12 SBB 7 r-... 

IDIV 8 JS 12 SCAS 10 

IMUL 7 JZ 11 SHL 8 

IN 5 LAHF 5 SHR 8 

INC 6 LDS 5 STC 13 

INT 13 LEA 5 STD 14 

INTO 13 LES 5 STI 14 

IRET 13 LOCK 14 STOS 10 

JA 12 LODS 10 SUB 6 

JAE 12 LOOP 12 TEST 9 

JB 11 LOOPE 12 WAIT 14 

JBE 11 LOOPNE 12 XCHG 5 

JCXZ 12 LOOPNZ 12 XLAT 5 

JE 11 LOOPZ 12 XOR 9 

B-18

Appendix C. Of Characters Keystrokes 

and Color 

08 8 BLACK DARK NO N-D ISPLAY 

GREY 

09 9 BLACK LIGHT HIGH INTENSITY 

/'""""""\ BLUE UNDERLINE 

c5 

BLACK LIGHT HIGH INTENSITY 

GREEN 

OB 11 CTRL K BLACK LIGHT HIGH INTENSITY 

GREEN 

OC 12 CTRLL, BLACK LIGHT HIGH INTENSITY 

VALUE AS CHARACTERS 

AS TEXT ATTRIBUTES 



MONOCHROME 

MONITOR AOAPTER 

OISPLAY 

HEX OEC SYMBOL KEYSTROKES MODES BACKGROUND FOREGROUND ADAPTER 

18 24 

19 25 

t 

GTRL X BLUE DARK 

GREY 

I 

GTRL Y BLUE LIGHT 

BLUE 

HIGH INTENSITY 


UNDERLINE 

lA 26 

- 

CTRL Z BLUE LIGHT HIGH INTENSITY 

GREEN 

lB 27 GTRL [. BLUE LIGHT HIGH INTENSITY 

ESC, SHIFT CYAN 

- 

ESC, CTRL 

ESC 

lC 28 

L 

CTRL " BLUE LIGHT 

RED 


10 29 

- 

CTRL I BLUE LIGHT HIGH INTENSITY 

MAGENTA 

IE 30 ... GTRL 6 BLUE YELLOW HIGH INTENSITY 

IF 31 .... CTRL - BLUE WHITE HIGH INTENSITY 

20 32 BLANK SPACE BAR, GREEN BLACK NORMAL 

(SPACE SHIFT SPACE, 

GTRL SPACE, 

ALT SPACE 

21 33 ! ! SHIFT GREEN BLUE UNDERLINE 

22 34 

.. .. 

SHIFT GREEN GREEN NORMAL 

23 35 -# -# SHIFT GREEN CYAN NORMAL 

24 36 $ $ SHIFT GREEN RED NORMAL 

25 37 % % SHIFT GREEN MAGENTA NORMAL 

26 38 & & SHIFT GREEN BROWN NORMAL 

27 39 

, 

GREEN LIGHT NORMAL 

GREY 

28 40 ( ( SHIFT GREEN DARK HIGH INTENSITY 

GREY 

29 41 ) ) SHIFT GREEN LIGHT HIGH INTENSITY 

BLUE UNDERLINE 

2A 42 * * NOTE 1 GREEN LIGHT HIGH INTENSITY 

GREEN 

2B 43 + + SHIFT GREEN LIGHT CYAN HIGH INTENSITY 

2C 44 GREEN LIGHT HIGH INTENSITY 

RED 

20 45 - - GREEN LIGHT HIGH INTENSITY 

MAGENTA 

2E 46 NOTE 2 GREEN YELLOW HIGH INTENSITY 

C-2


VALUE 

AS CHARACTERS 



MONOCHROME 

MONITOR ADAPTER 

DISPLAY 

HEX DEC SYMBDL [KEYSTROKES MODES BACKGROUND FOREGROUND ADAPTER 

2F 47 / / GREEN WHITE HIGH INTtN!iIIY 

30 48 0 0 INOTE 3 CY, K 

49 1 1 INOTI 3 CYAN BLUE 

32 50 2 2 NOTE 3 CYAN GREEN NORMAL 

33 3 INOTE 3 

34 INOTE 3 REO NOIIMAL 

35 53 5 5 NOTE 3 CYAN MAGENTA NO 

36 54 6 6 NOTE 3 CYJ BR 

37 55 7 7 NOTE 3 CYAN LIGHT NORMAL 

GREY 

38 56 8 8 NOTE 3 CYAN DARK HIGH INTENSITY 

GREY 

39 57 9 9 NOTE 3 CYAN LIGHT HIGH INTENSITY 

~ 


~ 

3A 

3B 

58 

59 

: 

; 

: 

; 

SHIFT 

CYAN 

CYAN 

LIGHT 

GREEN 

LIGHT 

CYAN 

3C 60 

< < 

SHIFT CYAN LIGHT 

RED 



I 


3D 61 = = CYAN LIGHT HIGH INTENSITY 

MAGENTA 

3E 62 

> > 

SHIFT CYAN YELLOW HIGH ,NSITY 

3F 63 ? ? 11FT CYAN WHITE IGI INTENSITY 

40 64 @ @ SHIFT RED BLACK NORMAL 

41 65 A A NOTE 41 BLUE IERLINE 

B NOTE 4 RED GREEN NOR 

67 C NOTE 4 RED CYAN NORMAL 

44 68 0 0 4 IRI 

45 69 E E NI 4 RED MAGENTA NOR 

46 70 F F NOTE 4 RED BROWN NORMAL 

47 71 G G NOTE 4 RED LIGHT NORMAL 

GREY 

48 72 H H NOTE 4 RED DARK HIGH INTENSITY 

GREY 

49 73 I I NOTE 4 RED LIGHT HIGH INTENSITY 


4A 74 J J NOTE 4 RED LIGHT HIGH INTENSITY 

GREEN 

C-3 

~ 

;: 

~





MONOCHROME 


DISPLAY 

HEX DEC SYMBOL KEYSTROKES MODES BACKGROUND FOREGROUND ADAPTER 

4B 75 K K NOTE 4 RED LIGHT HIGH INTENSITY 

CYAN 

4C 76 l L NOTE 4 RED LIGHT HIGH INTENSITY 

RED 

40 77 M M NOTE 4 RED LIGHT HIGH INTENSITY 

MAGENTA 

4E 78 N N NOTE 4 RED YEllOW HIGH INTENSITY 

4F 79 0 0 NOTE 4 RED WHITE HIGH INTENSITY 

50 80 P P NOTE 4 MAGENTA BLACK NORMAL 

51 81 Q Q NOTE 4 MAGENTA BLUE UNDERLINE 

52 82 R R NOTE 4 MAGENTA GREEN NORMAL 

53 83 S S NOTE 4 MAGENTA CYAN NORMAL 

54 84 T T NOTE 4 MAGENTA RED NORMAL 

55 85 U U NOTE 4 MAGENTA MAGENTA NORMAL 

56 86 V V NOTE 4 MAGENTA BROWN NORMAL 

57 87 W W NOTE 4 MAGENTA LIGHT NORMAL 

GREY 

58 88 X X NOTE 4 MAGENTA DARK HIGH INTENSITY 

GREY 

59 89 Y Y NOTE 4 MAGENTA LIGHT HIGH INTENSITY 


5A 90 Z Z NOTE 4 MAGENTA LIGHT HIGH INTENSITY 

GREEN 

5B 91 [ [ MAGENTA LIGHT HIGH INTENSITY 

CYAN 

5C 92 

\ \ 

MAGENTA 

LIGHT 

RED 


50 93 I I MAGENTA LIGHT HIGH INTENSITY 

MAGENTA 

5E 94 1\ 1\ SHIFT MAGENTA YEllOW HIGH INTENSITY 

5F 95 

- 

~ 

SHIFT MAGENTA WHITE HIGH INTENSITY 

60 96 

. . 

YELLOW BLACK NORMAL 

61 97 a a NOTE 5 YELLOW BLUE UNDERLINE 

62 98 b b NOTE 5 YELLOW GREEN NORMAL 

63 99 c c NOTE 5 YelLOW CYAN NORMAL 

64 100 d d NOTE 5 YELLOW RED NORMAL 

65 101 e e NOTE 5 YELLOW MAGENTA NORMAL 

66 102 f f NOTE 5 YELLOW BROWN NORMAL 

C-4





MONOCHROME 

MONITOR AO~PTER 

DISPLAY 


67 103 g g NOTE 5 YELLOW LIGHT NORMAL 

GREY 

68 104 h h NOTE 5 YEllOW DARK HIGH INTENSITY 

GREY 

69 105 i i NOTE 5 YELLOW LIGHT HIGH INTENSITY 


6A 106 i i NOTE 5 YEllOW LIGHT HIGH INTENSITY 

GREEN 

6B 107 k k NOTE 5 YEllOW LIGHT HIGH INTENSITY 

CYAN 

6C 108 I I NOTE 5 YEllOW LIGHT HIGH INTENSITY 

REO 

SO 109 m m NOTE 5 YEllOW LIGHT HIGH INTENSITY 

MAGENTA 

6E 110 n n NOTE 5 YEllOW YEllOW HIGH INTENSITY 

6F 

70 

111 

112 

0 

p 

0 

p 

NOTE 5 

NOTE 5 

YEllOW 

WHITE 

WHITE 

BLACK 


REVERSE VIDEO 

71 113 q q NOTE 5 WHITE BLUE UNDERLINE 

72 114 r r NOTE 5 WHITE GREEN NORMAL 

73 115 s s NOTE 5 WHITE CYAN NORMAL 

74 116 t t NOTE 5 WHITE REO NORMAL 

75 117 u u NOTE 5 WHITE MAGENTA NORMAL 

76 118 v v NOTE 5 WHITE BROWN NORMAL 

77 119 w w NOTE 5 WHITE LIGHT NORMAL 

GREY 

~ 

~ 

::; 

.. 

78 120 x x NOTE 5 WHITE DARK REVERSE VIDEO 

GREY 

79 121 Y Y NOTE 5 WHITE LIGHT HIGH INTENSITY 


7A 122 z z NOTE 5 WHITE LIGHT HIGH INTENSITY 

GREEN 

7B 123 I 

I 

I 

SHIFT WHITE LIGHT 

CYAN 


7C 124 I I SHIFT WHITE LIGHT HIGH INTENSITY 

I I REO 

70 125 I 

I 

I 

I 

SHIFT WHITE LIGHT 

MAGENTA 


7E 126 "-' "-' SHIFT WHITE YelLOW HIGH INTENSITY 

7F 127 

6. 

CTRl- WHITE WHITE HIGH INTENSITY 

c-s





MONOCHROME 


DISPLAY 

HEX DEC SYMBOL KEYSTROKES MODES BACKGROUND FOREGROUND ADAPTER 

* * * 80 HEX - FF HEX ARE FLASHING IN BOTH COLOR & IBM MONOCHROME * * * * 

80 128 ALT 128 NOTE 6 BLACK BLACK NON-DISPLAY 

ct 

81 129 'u ALT 129 NOTE 6 BLACK BLUE UNDERLINE 

82 130 --e ALT 130 NOTE 6 BLACK GREEN NORMAL 

83 131 ~ ALT 131 NOTE 6 BLACK CYAN NORMAL 

84 132 u" ALT 132 NOTE 6 BLACK REO NORMAL 

85 133 it- ALT 133 NOTE 6 BLACK MAGENTA NORMAL 

86 134 a ALT 134 NOTE 6 BLACK BROWN NORMAL 

87 135 ALT 135 NOTE 6 BLACK LIGHT NORMAL 

~ GREY 

88 136 re- ALT 136 NOTE 6 BLACK DARK NON-DISPLAY 

GREY 

89 137 e ALT 137 NOTE 6 BLACK LIGHT HIGH INTENSITY 

BLUE UNOERLINED 

8A 138 iI- ALT 138 NOTE 6 BLACK LIGHT HIGH INTENSITY 

GREEN 

8B 139 i ALT 139 NOTE 6 BLACK LIGHT HIGH INTENSITY 

CYAN 

8C 140 1- ALT 140 NOTE 6 BLACK LIGHT HIGH INTENSITY 

RED 

8D 141 i' ALT 141 NOTE 6 BLACK LIGHT HIGH INTENSITY 

MAGENTA 

8E 142 A ALT 142 NOTE 6 BLACK YELLOW HIGH INTENSITY 

8F 143 P- ALT 143 NOTE 6 BLACK WHITE HIGH INTENSITY 

90 144 E ALT 144 NOTE 6 BLUE BLACK NORMAL 

91 145 re ALT 145 NOTE 6 BLUE BLUE UNDERLINE 

92 146 FE ALT 146 NOTE 6 BLUE GREEN NORMAL 

93 147 -& ALT 147 NOTE 6 BLUE CYAN NORMAL 

94 148 0 ALT 148 NOTE 6 BLUE RED NORMAL 

95 149 d' ALT 149 NOTE 6 BLUE MAGENTA NORMAL 

96 150 it ALT 150 NOTE 6 BLUE BROWN NORMAL 

97 151 li' ALT 151 NOTE 6 BLUE LIGHT NORMAL 

GREY 

98 152 Y ALT 152 NOTE 6 BLUE DARK HIGH INTENSITY 

GREY 

99 153 ii ALT 153 NOTE 6 BLUE LIGHT HIGH INTENSITY 


9A 154 U ALT 154 NOTE 6 BLUE LIGHT HIGH INTENSITY 

GREEN 

C-6


VALUE 

AS CHARACTERS 



MONOCHROME 


DISPLAY 


9B 155 ¢ ALT 155 NOTE 6 BLUE LIGHT HIGH INTENSITY 

CYAN 

9C 156 

£ 

ALT 156 NOTE 6 BLUE LIGHT 

RED 


90 157 ~ ALT 157 NOTE 6 BLUE LIGHT HIGH INTENSITY 

T 

MAGENTA 

9E 158 Pts ALT 158 NOTE 6 BLUE YELLOW HIGH INTENSITY 

9F 159 f ALT 159 NOTE 6 BLUE WHITE HIGH INTENSITY 

AO 160 -11 ALT 160 NOTE 6 GREEN BLACK NORMAL 

Al 161 

/ 

İ ALT 161 NOTE 6 GREEN BLUE UNDERLINE 

A2 162 /0 ALT 162 NOTE 6 GREEN GREEN NORMAL 

A3 

A4 

A5 

A6 

163 

164 

165 

166 

--li 

'"n 

'" N 

~ 

ALT 163 

AU 164 

ALT 165 

ALT 166 

NOTE 6 

NOTE 6 

NOTE 6 

NOTE 6 

GREEN 

GREEN 

GREEN 

GREEN 

CYAN 

RED 

MAGENTA 

BROWN 

NORMAL 

NORMAL 

NORMAL 

NORMAL 

A7 167 .!!. ALT 167 NOTE 6 GREEN LIGHT NORMAL 

GREY 

A8 168 

A9 169 

AA 170 

I 

I 

6 

ALT 168 NOTE 6 GREEN DARK 

GREY 

ALT 169 NOTE 6 GREEN LIGHT 

BLUE 

ALT 170 NOTE 6 GREEN LIGHT 

GREEN 



UNDERLINE 


::;: 

~ 

~ 

:: ;: 

~ 

AB 171 Y, ALT 171 NOTE 6 GREEN LIGHT HIGH INTENSITY 

CYAN 

AC 172 % ALT 172 NOTE 6 GREEN LIGHT HIGH INTENSITY 

RED 

AD 173 . ALT 173 NOTE 6 GREEN LIGHT HIGH INTENSITY 

I 

MAGENTA 

AE 174 

« 

ALT 174 NOTE 6 GREEN YELLOW HIGH INTENSITY 

AF 175 » ALT 175 NOTE 6 GREEN WHITE HIGH INTENSITY 

BO 176 ALT 176 

~b 

NOTE 6 CYAN BLACK NORMAL 

Bl 177 ALT 177 

~~ 

NOTE 6 CYAN BLUE UNDERLINE 

B2 178 ALT 178 

/y~ 

NOTE 6 CYAN GREEN NORMAL 

B3 179 ALT 179 NOTE 6 CYAN CYAN NORMAL 

B4 180 ALT 180 NOTE 6 CYAN RED NORMAL 

B5 181 

== 

ALT 181 NOTE 6 CYAN MAGENTA NORMAL 

B6 182 f----il 

ALT 182 NOTE 6 CYAN BROWN NORMAL 

C-7





MONOCHROME 

MONITOR AOAPTER 

OISPLAY 

HEX DEC SYMBOL KEYSTROKES MODES BACKGROUND FOREGROUND ADAPTER 

B7 183 ALT 183 NOTE 6 CYAN LIGHT NORMAL 

GREY 

11 

B8 184 ALT 184 NOTE 6 CYAN DARK HIGH INTENSITY 

==J 

GREY 

B9 185 ALT 185 NOTE 6 CYAN LIGHT HIGH INTENSITY 

==' BLUE UNDERLINE 

BA 186 ALT 186 NOTE 6 CYAN LIGHT HIGH INTENSITY 

GREEN 

BB 187 AlT 187 NOTE 6 CYAN LIGHT HIGH INTENSITY 

==jl 

CYAN 

BC 188 

d 

AlT 188 NOTE 6 CYAN LIGHT HIGH INTEI~SITY 

RED 

BO 189 --.JJ ALT 189 NOTE 6 CYAN UGHT HIGH INTENSITY 

MAGENTA 

BE 190 ==:d ALT 190 NOTE 6 CYAN YelLOW HIGH INTENSITY 

BF 191 ---, AL T 191 NOTE 6 CYAN WHITE HIGH INTENSITY 

CO 192 L- ALT 192 NOTE 6 RED BLACK NORMAL 

Cl 193 AlT 193 NOTE 6 RED BLUE UNDERLINE 

C2 194 AlT 194 NOTE 6 RED GREEN NORMAL 

I 

C3 195 

f- 

ALT 195 NOTE 6 RED CYAN NORMAL 

C4 196 ALT 196 NOTE 6 RED RED NORMAL 

C5 197 ALT 197 NOTE 6 RED MAGENTA NORMAL 

I 

C6 198 AlT 198 NOTE 6 RED BROWN NORMAL 

- 

....::::: 

GREY 

C7 199 ALT 199 NOTE 6 RED LIGHT NORMAL 

GREY 

C8 200 ALT 200 NOTE 6 RED DARK HIGH INTENSITY 

C9 201 ALT 201 NOTE 6 RED LIGHT HIGH INTENSITY 

BLUE UNOERLINE 

II 

CA 202 

WL 

AlT 202 NOTE 6 REO LIGHT HIGH INTENSITY 

GREEN 

f--r 

CB 203 ALT 203 NOTE 6 RED LIGHT HIGH INTENSITY 

CYAN 

~ 

CC 204 AlT 204 NOTE 6 RED LIGHT HIGH INTENSITY 

RED 

CD 205 ALT 205 NOTE 6 RED LIGHT HIGH INTENSITY 

MAGENTA 

CE 206 ALT 206 NOTE 6 RED YELLOW HIGH INTENSITY 

~~ 

CF 207 ALT 207 NOTE 6 RED WHITE HIGH INTENSITY 

DO 208 II ALT 208 NOTE 6 MAGENTA BLACK NORMAL 

e-8

06 214 ALT 214 NOTE 6 MAGENTA BROWN NORMAL 

07 215 ALT 215 NOTE 6 MAGENTA LIGHT NORMAL 

GREY 

08 216 ALT 216 NOTE 6 MAGENTA DARK HIGH INTENSITY 

GREY 

09 217 ALT 217 NOTE 6 MAGENTA LIGHT HIGH INTENSITY 


DA 218 NOTE 6 MAGENTA LIGHT 

GREEN 

DB NOTE 6 MAGENTA LIGHT 

CYAN 

r""\ 

DC NOTE 6 MAGENTA LIGHT 

RED 

DO NOTE 6 MAGENTA LIGHT HIGH INTENSITY 

MAGENTA 

NOTE 6 

NOTE 6 

NOTE 6 

MAGENTA 

MAGENTA 

r""\ 

E7 231 

E8 232 

'T 

 

ALT 231 NOTE 6 YELLOW LIGHT 

GREY 

ALT 232 NOTE 6 YELLOW DARK 

GREY 

E9 233 

-e- 


BLUE 

EA 234 

n 


GREEN 

NORMAL 



UNDERLINE 


EB 235 ALT 235 NOTE 6 YELLOW LIGHT IGH INTENSITY 

~ CYAN 

C-9





MONOCHROME 


DISPLAY 


EC 236 00 ALT 236 NOTE 6 YELLOW LIGHT HIGH INTENSITY 

RED 

ED 237 

ifJ 

ALT 237 NOTE 6 YEllOW LIGHT 

MAGENTA 


EE 238 E ALT 238 NOTE 6 YELLOW Y~LLOW HIGH INTENSITY 

EF 239 II ALT 239 NOTE 6 YELLOW WHITE HIGH INTENSITY 

FO 240 - ALT 240 NOTE 6 WHITE BLACK REVERSE VIDEO 

Fl 241 ± ALT 241 NOTE 6 WHITE BLUE UNDERLINE 

F2 242 ~ ALT 242 NOTE 6 WHITE GREEN NORMAL 

F3 243 ~ ALT 243 NOTE 6 WHITE CYAN NORMAL 

F4 244 

C 

ALT 244 NOTE 6 WHITE RED NORMAL 

F5 245 0 ALT 245 NOTE 6 WHITE MAGENTA NORMAL 

F6 246 ALT 246 NOTE 6 WHITE BROWN NORMAL 

F7 247 ALT 247 NOTE 6 WHITE LIGHT NORMAL 

~ 

GREY 

F8 248 

F9 249 

FA 250 

FB 251 

0 

• 

• 

"" 

ALT 248 NOTE 6 WHITE DARK 

GREY 

ALT 249 NOTE 6 WHITE LIGHT 

BLUE 


GREEN 


CYAN 

FC 252 Y\ ALT 252 NOTE 6 WHITE LIGHT 

RED 

REVERSE VIDEO 


UNDERLINE 




FD 253 2 ALT 253 NOTE 6 WHITE LIGHT HIGH INTENSITY 

MAGENTA 

FE 254 

I 

ALT 254 NOTE 6 WHITE YELLOW HIGH INTENSITY 

FF 255 BLANK ALT 255 NOTE 6 WHITE WHITE HIGH INTENSITY 

ColO

NOTE 1 Asterisk (*) can easily be keyed using two methods: 

1) hit the IPRTSC Ikey or 2) in shift mode hit the 

[iJ key. * 

NOTE 2 Period (.) can easily be keyed using two methods: 

1) hit thelJ key or 2) in shift or NUM LOCK 

mode hit the [!!;il key. 

NOTE 3 Numeric characters (0-9) can easily be keyed 

using two methods: 1) hit the numeric keys on the 

top row of the typewriter portion of the keyboard 

or 2) in shift or NUM LOCK mode hit the numeric 

keys in the lO-key pad portion of the keyboard. 

NOTE 4 Upper case alphabetic characters (A-Z) can easily 

be keyed in two modes: 1) in shift mode hit the 

appropriate alphabetic key or 2) in CAPS LOCK 

mode hit the appropriate alphabetic key. 

NOTE 5 Lower case alphabetic characters (a-z) can easily 

be keyed in two modes: 1) in "normal" mode hit 

the appropriate alphabetic key or 2) in CAPS LOCK 

combined with shift mode hit the appropriate alphabetic 

key. 

NOTE 6 The 3 digits after the ALT key must be typed from 

the numeric key pad (keys 71-73. 75-77. 79-82). 

Character codes 000 through 255 can be entered in 

this fashion. 

C-ll

Character Set (OO-7F) Quick Reference 

• 

DECIMAL 

VALUE 0 16 32 48 64 80 96 112 

• 

IHEXA. 

le!~I~AL 0 1 2 3 4 5 6 7 

BLANK 

, 

BLANK 

0 0 (NULL) ~ (SPACE) 

0 @ p P 

1 1 ~ ...... I 1 A Q a q 

• 

2 2 @) t I I 2 B R b r 

3 3 

• 

" 

.. =IF 3 C S c s 

4 4 

+ err $ 4 D T d t 

5 5 4t § 0/0 5 E U e u 

•- & , 

6 6 6 F V f v 

7 7 • ~ 7 G W g W 

8 8 i ( 8 H X h x 

Y 

• 

9 9 0 1 ) 9 I Y 1 

. 

10 A --+ • J Z J x 

* • 

• 

11 B d +- 

+ , K [ k 

I 

12 C 9 L , < L I 

13 0 ~~ 

~ - - M ] rn } 

1 

" 1 

14 E ... rv 

.. • > N n 

~~ /\ 

15 F -¢- T 

/ ? 0 - 0 ~ 

• 

C-12

Character Set (80-FF) Quick Reference 

DECIMAL 

VALUE .. 

• 

HEXA· 

DECIMAL 

128 144 160 176 192 208 224 240 

8 9 A B D C E F 

VALUE 

0 0 ct E a ~ 

.. ~ 

/' 

()C 

1 1 U iE 1 ~ fJ + 

,/ 

FE 0 ~ 

y > 

1\ 1\ /' 

3 3 I- 

a 

lL 

0 u 

1T - < 

4 4 a 

·. ·. '" ~ 

0 n b L ( 

"- " 

5 5 a 0 N= F u J 

,/ 

2 2 e 

6 6 

0 1\ 

r- 

a u a ~ 

-H 

f.l • 

"- -..." 

7 7 C; 0 r -..." 

u 

--n 

1\ ·. • 0 

8 8 e y ~ ===I 

·. 

e 0 e 

9 9 ·. I :J • 

. . 

" U ---, ..JL 

n • 

·•. 

1 ~ --- 8 -.r 

10 A e 

11 B ¢ ~ 

~ 

12 c 00 

1 £ 14 d 11 

13 

D "• Y.. 

.. 

,• 

J 2 

1 T 0 

14 E A Pts « bd ~ E I 

A f » n 

n 

15 F 

'FF' 

BLANK 

C-13

C-14 

NOTES

APPENDIX D LOGIC DIAGRAMS 

~ Contents: 

System Board................................... D-2 

Keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-12 

IBM Monochrome Display And Parallel Printer 

Adapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-14 

IBM Monochrome Display. . . . . . . . . . . . . . . . . . . . . . . D-24 

Color/Graphics Monitor Adapter. . . . . . . . . . . . . . . . . D-25 

IBM 80 CPS Matrix Printer. . . . . . . . . . . . . . . . . . . . . . D-31 

Parallel Printer Adapter. . . . . . . . . . . . . . . . . . . . . . . . . . D-34 

5 1/4" Diskette Drive Adapter. . . . .. ... .. ... .. .. .. D-35 

5 1/4" Diskette Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . D-39 

32 KB Memory Expansion. . . . . . . . . . . . . . . . . . . . . . . D-42 

64 KB Memory Expansion . . . . . . . . . . . . . . . . . . . . . . . D-45 

~ Asynchronous Communications Adapter .. . . . . . . . . D-48 

Game Control Adapter. . . . . . . . . . . . . . . . . . . . . . . . . . . D-49 

D-l

SYSTEM BOARD (PROCESSOR AND SUPPORT) 

~;;i,'\j", 

~~ ~~~~: 

I 

N 

- 

Note: Logics one and two of twelve are not applicable 

D-2

~ 

SYSTEM BOARD (WAIT STATE GENERATOR) 

, 

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(SHT 4,6) 

(SHT 4,6) 

(5HT 4,6) 

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(SHT "I) 

(5HT 6) 

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Appendix E 

Unit Specifications 

System Unit 

~ Size: 

Length--19.6" (500 mm) 

Depth--16.1" (410 mm) 

Height--5.5" (142 mm) 

Weight: 

Without Diskette Drive Unit-20.9 Ibs (9.5 kg) 

With Diskette Drive Unit-25 lbs (11.4 kg) 

Power Cable: 

Length--6'O" (1.83 mm) 

Size--18 AWG 

Environment: 

Air Temperature 

System ON, 60° to 90° - F (15.6° to 32.2° C) 

System OFF, 50° to 110° - F (10° to 43° C) 

Humidity 

System ON, 8% to 80% 

System OFF, 20% to 80% 

Heat Output, 1083 BTU/HR (Maximum) 

Noise Levels: 

Without Printer, 59 DBS 

With Printer, 66 DBS 

Electrical: 

Nominal-120 VAC 

Minimum-l04 VAC 

Maximum-127 VAC 

KVA-.3175 maximum 

Keyboard 

Size: 

Length--19.6" (500 mm) 

Depth--7.87" (200 mm) 

Height-2.2" (57 mm) 

Weight: 

6.5 lbs (14.3 kg) 

E-!

IBM Monochrome Display 

Size: 

Length--14.9" (380 mm) 

Depth-13.7" (350 mm) 

Height--ll" (280 mm) 

Weight: 

17.3 lbs (7.9 kg) 

Heat Output: 

325 BTU/HR 

Power Cable: 

Length--3.0" (914 mm) 

Size--18 AWG 

Signal Cable: 

Length--4'0" (1.22 mm) 

Size--22 A WG 

IBM 80 CPS Matrix Printer 

Size: 

Length--15.7" (400 mm) 

Depth--14.5" (370 mm) 

Height-4.3" (110 mm) 

Weight: 

12.9 lbs (5.9 kg) 

Power Cable: 

Length--6.0" (1.83 mm) 

Size--18 AWG 

Signal Cable: 

Length--6'0" (1.83 mm) 

Size-22 AWG 

Heat Output: 

341 BTU/HR (Max.) 

Electrical: 

Nominal-120 VAC 

Minimum-104 V AC 

Maximum-127 VAC 

E-2

GLOSSARY 

1. Address Buss: A set of wires or signals carrying the binarycoded 

address from the Intel-8088 microprocessor throughout 

the rest of the IBM Personal Computer System Unit. 

2. AEN: Address Enable. (Refer to System Board I/O Channel 

Descriptions). 

3. ALE: Address Latch Enable. (Refer to System Board I/O 

Channel Descriptions). 

4. Analog: (1) Pertaining to representation by means of continuously 

variable physical quantities. (2) Contrast with digital. 

5. A!N: Alphanumeric: Pertaining to a character set that contains 

letters, digits, and usually other characters, such as punctuation 

marks. Syonymous with alphameric. 

6. AO-AI9: Address bits 0-19. (Refer to System Board I/O 


7. APA: All points addressable graphics. 

8. ASCII: American Standard Code of Information Interchange. 

The standard code, using a coded character set consisting of7 

bit coded characters (8 bits including parity check), used for 

information interchange among data processing systems, data 

communication systems and associated equipment. The 

ASCII set consists of control characters and graphic 

characters. 

9. Assembler: A computer program used to assemble. Synonymous 

with assembly program. 

10. BASIC: (Beginner's all-purpose symbolic instruction code). A 

programming language with a small repetoire ofcommands and 

a simple syntax, primarily designed for numerical application. 

11. BAUD: (1) A unit of signaling speed equal to the number of 

discrete conditions or signal events per second in Morse code, 

one bit per second in a train of binary signals, and one 3-bit 

value per second in a train of signals each ofwhich can assume 

one of eight different states. (2) In asynchronous transmission, 

the unit ofmodulation rate corresponding to one unit ofinterval 

per second, i.e. if the duration of the unit interval is 20 

milliseconds, the modulation rate is 50 baud. 

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12. Binary: (1) Pertaining to a selection, choice, or condition that 

that has two possible values or states. (2) Pertaining to a fixed 

radix numeration system having a radix of two. 

13. BIOS: Basic Input/Output System. 

14. Bootstrap: A technique or device designed to bring itself into a 

desired state by means ofit's own action, e.g. a machine routine 

whose first few instructions are sufficient to bring the rest of 

itself into the computer from an input device. 

15. Buffer: An area of storage that is temporarily reserved for use in 

performing an input/output operation, into which data is read or 

from which data is written. Synonymous with I/O area. A 

portion of storage for temporarily holding input or output data. 

16. Bus: One or more conductors used for transmitting signals or 

power. 

17. Byte: (1) A binary character operated upon as a unit and 

usually shorter than a computer word. (2) The representation of 

a character. 

18. CLK: Clock. (Refer to System Board I/O Channel 


19. Code: (1) A set ofunambiguous rules specifying the manner in 

which data may be represented in a discrete form. Synonymous 

with coding scheme. (2) A set of items such as abbreviations 

representing the members of another set. (3) Loosely, one 

or more computer programs, or part of a computer program. 

(4) To represent data or a computer program in a symbolic form 

that can be accepted by a data processor. 

20. Computer: A data processor that can perform substantial 

computation, including numerous arithmetic operations, or 

logic operations, without intervention by a human operator 

during the run. 

21. CPS: Characters per second. 

22. CRC: The cyclic redundancy check character. 

23. CRT: (1) A Cathode ray tube display. (2) A display device, 

such as the IBM Monochrome Display, that uses a cathode ray 

tube. 

24. CTS: Conversational Terminal System. (2) Clear to Send. 

Associated with modem control. 

25. DACKO-DACK3: DMA Acknowledge 0 to 3. (Refer to 

System Board I/O Channel Description). 

G-2

26. Data: (1) A representation offacts, concepts or instructions in a 

formalized manner suitable for communication, interpretation, 

or processing by humans or automatic means. (2) Any representations 

such as characters or analog quantities to which 

meaning is, or might be assigned. 

27. Din Connectors: One of the connectors specified by the Din 

standardization committee. 

28. DIP: "Dual In-Line Package." A widely used container for an 

integrated circuit. DIP's are pins usually in two parallel rows. 

These pins are spaced on 1/10" inters and come in different 

configurations ranging from a 14-pin assembly to a 40-pin 

configuration. 

29. Display: A visual presentation of data. 

30. DMA: Direct Memory Access. 

31. DO-D7: Data Bits 0 to 7. (Refer to System Board I/O Channel 


32. DRQI-DRQ3: DMA Request 1 to 3. (Refer to System Board 

I/O Channel Descriptions). 

33. DSR: Data Set Ready, associated with modem control. 

34. DTR: Distribution Tape Reel. 

35. Edge Connector: An opening which joins with the end of a 

circuit board. The purpose ofthis interface is to send electrical 

signals back and forth. 

36. EIA/CCITT Drives: Electronic Industries Association/ 

Consultative Committee on International Telegraphy and 

Telephony Drives. 

EPROM or 'PROM': Tern1 for "Programmable Read-Only 

Memory." An EPROM or 'PROM' is actually Read-Only 

Memory (ROM) but the contents may be changed by electrical 

means. EPROM or 'PROM' information is not destroyed when 

the power is cut off. 

37. Firmware: Memory chips with the software programs already 

built in. 

38. Graphics: Symbols Produced by a process such as handwriting, 

drawing or printing. Synonymous with graphic symbol. 

39. Hexadecimal: Pertaining to a selection, choice, or condition 

that has sixteen possible values or states. These values or states 

usually contain 10 digits and six letters A through F. Hexadecimal 

digits are equivalent to a power of 16. 

G-3

40. Hertz (Hz.): A unit offrequency equal to one cycle per second. 

41. High order position: The leftmost position in a string of 

characters. 

42. Input/Output (I/O): Pertaining to a device or to a channel that 

may be involved in an input process, and, at a different time, in 

an output process. (2) Pertaining to a device whose parts can be 

performing an input process and an output process at the same 

time. 

43. Integrated Circuit: A combination of interconnected circuit 

elements inseperably associated on or within a continuous 

substrate. 

44. Interpreter: A computer program used to interpret. Synonymous 

with interpretive program. 

45. Interrupt: (1) A suspension of a process, such as the execution 

of a computer program, in such a way that the process can be 

resumed. (2) To stop a process in such a way that it can be 

resumed. (3) In data transrnission, to take an action at a 

receiving station that causes the transmitting station to terminate 

a transmission. 

46. I/O Channel: Input/Output Channel. In a data processing 

system, a functional unit, controlled by the processing unit, that 

handles the transfer of data between main storage and peripheral 

equipment. 

47. I/OCH CK: I/O Channel Check. (Refer to System Board I/O 


48. I/O CH ROY: I/O Channel Ready. (Refer to System Board 


49. IMR: Interruption Mask Register. 

50. lOR: I/O Read Command. (Refer to System Board I/O 


51. lOW: I/O Write Command: (Refer to System Board I/O 


52. IRQ2-IRQ7: Interrupt Request 2 to 7. (Refer to System Board 


53. K: An abbreviation for the prefix kilo, i.e. 1000 in decimal 

notation. To the tenth power, 1024 in decimal notation. 

54. KB: Kilobyte. 

55. Khz: Kilohertz. A unit of frequency equal to 1,000 hertz. 

G-4

--..., 

56. Low order position: The rightmost position in a string of 

characters. 

57. Machine Language: (1) A language that is used directly by a 

machine. (2) Another term for computer instruction code. 

58. Memory Address: A two-byte value selecting one specific 

memory location on a memory map. 

59. Memory Location: The most specific part of a memory map 

that the computer can refer to. 

60. Memory Map: The list ofmemory locations addressed directly 

by the microprocessor. 

61. MEMR: Memory Read Command. (Refer to System Board 


62. MEMW: Memory Write Command. (Refer to System Board 


63. MFM Coded: Modified Frequency Modulation. It is double 

density encoding of information on a diskette. 

64. Mhz: Megahertz. A unit of frequency equal to one million 

Hertz. 

,~ 65. Microprocessor: A processing unit, or part ofa processing unit, 

that consists ofmicrocode. In the IBM Personal Computer, the 

microprocessor is the Intel-8088. 

66. Mnemonic: Symbol or symbols used instead of terminology 

more difficult to remember. Usually a mnemonic has two or 

three letters. 

67. Mode: (1) A method of operation; for example, the binary 

mode, the interpretive mode, the alphanumeric mode. (2) The 

most frequent value in the statistical sense. 

68. Monitor: (1) A device that observes and verifies the operation 

of a data processing system and indicates any specific departure 

from the norm. (2) A television type display such as the 

IBM Monochrome Display. (3) Software or hardware that 

observes, supervises, controls, or verifies the operations of a 

system. 

69. Multiplexer: A device capable ofinterleaving the events oftwo 

or more activities or capable of distributing the events of an 

interleaved sequence to their respective activities. 

G-5

70. OR: A logic operator having the property that if P is a 

statement, Q is a statement, R is a statement. .., then the OR of 

P,Q,R, is true if at least one statement is true, false if all 

statements are false. P OR Q is often represented by P+Q, 

PVQ. The term is synonymous with boolean add; logic add. 

71. "ORed": Past tense of OR. 

72. OSC: Oscillator. (Refer to System Board I/O Channel 


73. Output: Pertaininng to a device, process, or channel involved in 

an output process, or to the data or states involved in an output 

process. 

74. Personal Computer: A small home or business computer 

complete with a System Unit, keyboard, and available with a 

variety ofoptions such as monochrome display and a dot matrix 

printer. 

75. Pinout: A diagram of functioning pins on a pinboard. 

76. Printed Circuit Board: A piece of material, usually fiberglass, 

which contains a layer of conductive material, usually metal. 

The metallic layer is then etched and electronic equipment is 

then attached to the fiberglass. The electronic equipment then 

has the capacity to transmit electronic signals through the board 

by way of the etched metal tracks. 

77. Program: (1) A series of actions designed to achieve a certain 

result. (2) To design, write and test computer programs. 

78. Read/Write Memory: Random access storage. 

79. Reset Drv: Reset Driver. (Refer to System Board I/O Channel 


80. RF Modulator: The device used to convert the composite video 

signal to the antenna level input of a home TV. 

81. ROM: Read-only Memory. 

82. ROM BIOS: Read-only Memory/Basic Input Output System. 

83. RS 232 Port: Asynchronous Type Communications. 

84. RTS: Ready to Send. Associated with modem control. 

G-6

85. Scan Line: The use of a cathode beam to test the cathode ray 

tube of a display used with a personal computer. 

86. Schematic: The description, usually in diagram form, of the 

logical structure and physical structure of an entire data base 

according to a conceptual model. 

~ 87. Software: (1) Computer programs, procedures, rules, and 

possibly associated documentation concerned with the operation 

of a data processing system. (2) Contrast with hardware. 

88. Strobe: (1) An instrument used to determine the exact speed of 

circular or cyclic movement. (2) A flashing signal displaying an 

exact event. 

89. Text: In ASCII and data communication, a sequence of 

characters treated as an entity if preceded and terminated by 

one STX and one ETX transmission control respectively. 

90. TX Data: Transmit Data. External connections ofthe RS 232 

Asynchronous Communications Adapter interface. 

91. Video: Computer data shown or displayed on a cathode ray 

tube monitor or display. 

G-7

G-8 

NOTES

BIBLIOGRAPHY 

IBM Publications 

1. IBM Personal Computer Guide to Operations 

1"""""'\ PN 6025000 

General information on using the IBM Personal 

Computer. 

2. IBM Personal Computer Hardware and Service 

PN 6025072 

Information on hardware and steps necessary when 

servicing this IBM Personal Computer. 

3. IBM Personal Computer BASIC-PN 6025010 

Information for programmers who are using BASIC. 

4. IBM Personal Computer Disk Operating System (DOS) 

PN 6024001 

Information for programmers who are using DOS. 

5. IBM Personal Computer MACRO Assembler 

PN 6024002 

Infomlation for experienced assembly language 

programmers using the Macro Assembler. 

6. IBM Personal Computer Pascal Compiler-PN 6024010 

Information for programmers who are familiar with the 

Pascal language. 

Bib-l

Other Related Publications 

7. NATIONAL SEMICONDUCTOR 

INS 8250 Asynchronous Communications Element 

This book documents physical and operating characteristics 

of the INS 8250. ~ 

8. INTEL 

The 8086 Family Users Manual 

This manual introduces the 8086 family of microcomputing 

components and serves as a reference in system design 

and implementation. 

9. INTEL 

8086/8087/8088 Macro 

ASSEMBLY Language 

Reference Manual for 8088/8085 Based Development 

System 

The manual describes the 8086/8087/8088 Macro Assembly 

Language, and is intended for use by persons who are familiar 

with assembly language. 

10. MOTOROLA 

The complete Microcomputer Data Library ~ 

This book can provide additional information on the Motorola 

6845 CRT Controller used in the IBM Monochrome Display 

and Parallel Printer Adapter, and the Color/Graphics 

Monitor Adapter. 

Bib-2

INDEX 

A 

AO-AI9 (Address Bits 0-19) 2-10 

A.C. Output 2-34 

Adapters 

Asynchronous Communications (RS232) 2-123 

Color/Graphics 2-45 

5 1/4" Diskette Drive 2-89 

Game Control 2-117 

IBM Monochrome Display and Parallel Printer 2-37 

Parallel Printer 2-65 

Adapter Attribute Relationship 2-51 

Adapter Inputs 2-107 

Adapter Outputs 2-106 

Address Bits (AO-AI9) 2-10 

Address Decode 2-118 

Address Enable (AEN) 2-12 

Address Latch Enable (ALE) 2-10 

Address Strobe (ADS) 2-129 

ADS (Address Strobe) 2-129 

AEN (Address Enable 2-12 

ALE (Address Latch Enable) 2-10 

Algorithms 3-8 

All Points Addressable (APA) 2-45 

Alphanumeric Mode 2-49 

American Standard Code for Information Interchange (ASCII) 1-2 

Analog Input 2-122 

A/N (Alphanumeric) 2-49 

Appendices A-O 

A - ROM BIOS Listing A-I 

B - Assembly Instruction Set Reference B-1 

C - Of Characters, Keystrokes and Color C-l 

D - Logic Diagrams D-l 

E - Unit Specifications E-l 

APA (All Points Addressable) 2-45 

ASCII - (See American Standard Code for Information 

Interchange) 1-2 

ASCII Coding Table 2-78 

ASCII Control Codes 2-79 

ASCII (Extended) 3-11 

Assembly Instruction Set Reference Appendix B 

Assembly Language Reference Guide (See Bibliography) 

Assessable Registers 2-154 

1-1


Block Diagram 2-124 

Current Loop Interface 2-127 

Input/Output Decode 2-125 

Input/Output Signals 2-133 

Input Signals 2-129 

Interface Description 2-126 

Interface Specifications 2-147 

Interrupt 2-126 

Interrupt Enable Register 2-141 

Interrupt Identification Register 2-139 

INS 8250 Accessible Registers 2-134 

INS 8250 Functional Pin Description 2-129 

INS 8250 Line Control Register 2-134 

INS 8250 Programmable Baud Rate Generator 2-135 

Line Status Register 2-137 

Logic Diagram D-48 

Modem Control Register 2-142 

Modem Status Register 2-143 

Modes of Operation 2-125 

Output Signals 2-132 

Programming Considerations 2-133 

Receiver Buffer Register 2-144 

Reset Functions 2-133 

Selecting the Interface Format 2-146 

Transmitter Holding Register 2-145 

B 

BASIC (Beginner's all-purpose symbolic instruction code) 

80 Interpreter 1-1 

Reserved Interrupts 3-23 

Screen Editor Special Functions 3-19 

Workspace Variables 3-23 

Baud (See ,INS 8250 Programmable Baud Rate Generator) 2-132 

Baud Out (BAUDOUT) 2-132 

BEL (Bell) 2-82 

Bell (BEL) 2-82 

Berg Pin Connectors 2-63 

BIOS 

(Basic Input Output System) 3-2 

Cassette Logic 3-8 

Memory Map 3-7 

Interrupt Vector Listing 3-3 

Parameter Passing 3-2 

1-2

BIOS (continued) 

Programming Tip 3-2 

ROM (Read Only Memory) 3-2 

Use of 3-2 

Vectors With Special Meaning 3-5 

BIT 

I/O Address 2-42 

I/O Bit Map 2-24 

Output Port Cassette 2-19 

Output Port Speaker 2-22 

Status Register 2-59 

Block Diagrams 

Asynchronous Communications Adapter 2-124 

Cassette Motor Control 2-20 

Cassette Interface Read 2-19 

Cassette Interface Write 2-20 

Color/Graphics Monitor Adapter 2-47 

5 1/4" Diskette Drive Adapter 2-90 

Game Control Adapter 2-117 

Keyboard Interface 2-15 

IBM Monochrome Display Adapter 2-38 

Parallel Printer Adapter 2-66 

System 1-4 

Bootstrap 3-3 

Byte: 

Attribute Definition 2-49 

Display Buffer 2-61 

c 

CAN (Cancel) 2-81 

Cancel (CAN) 2-81 

Carriage Retum(CR) 2-79 

Cassette 

Circuit Block Diagrams 2-19 

Data Record Architecture 3-10 

Error Recovery 3-10 

Interface Connector Specifications 2-21 

~ Interrupt 15 3-8 

Jumpers 2-19 

Logic (BIOS) 3-8 

Read 3-9 

Write 3-8 

1-3

Character 

Codes 3-11 

Generator 2-48 

"Of Characters, Keystrokes and Color Appendix C 

Set (00-7F) Quick Reference C-12 

Set (80-FF) C-13 

Chip Select Out (CSOUT) 2-132 

Clear To Send (CTS) 2-130 

Clock (4.77 mhz) 2-10 

CLK (Clock) 2-10 

CNTRL (Control) 3-14 

Coding Table (ASCII) 2-78 

Color/Graphics Monitor Adapter 

Block Diagram 2-47 

Character Generator 2-48 

Color/Graphics Mode 2-51 

Color Select Register 2-57 

Composite Color Generator 2-48 

Description of Basic Operations 2-54 

Display Buffer 2-48 

Graphics Storage Map 2-52 

I/O Address and Bit Map 2-61 

Interrupt Level 2-60 

Logic Diagrams D-25 

Major Component Definitions 2-48 

Memory Requirements 2-60 

Mode Register Summary 2-58 

Mode Select Register 2-58 

Mode Set and Status Registers 2-48 

Modes of Operation 2-49 

Monitor Adapter Auxiliary Connectors 2-63 

Monitor Adapter Direct Drive and Composite Interface 

Pin Assignment 2-62 

Monochrome Display Adapter Vs. Color/Graphics Adapter 

Attribute Relationship 2-51 

Motorola 6845 CRT Controller 2-48 

Programming the 6845 Controller 2-48 

Programming the Mode Control and Status Registers 2-57 

6845 Register Description 2-56 

Sequence of Events 2-59 

Timing Generator 2-48 

Composite Phone Jack 2-62 

Computer (IBM Personal) 1-1 

Command Phase 2-93 

1-4

Command Status Registers 

Register 0 2-100 




Control Codes 

CPS (Characters Per Second) 2-70 

CPU (Central Processing Unit) see System Board, 

Microprocessor 2-3 

CR (Carriage Return) 2-79 

CRT: 

(Cathode Ray Tube) 2-37 

Output Port 1 (I/O Address '3B8') 2-42 

Status Port (I/O Address '3BA') 2-43 

CTS (Clear To Send) 2-130 

CSOUT (Chip Select Out) 2-132 

Current 2-34 

Cursor 2-14 

D 

DO-D7 JData Bits 0-7) 2-10 

DACK - DAcK3 (DMA Acknowledge 0 to 3) 

DATA 

Bit (DO-D7) 2-10 

Bus Buffer/Driver 2-118 

Input Strobe (DISTR, DISTR) 2-129 

Output Strobe (DOSTR, DOSTR) 2-129 

Rates 2-39 

Record Architecture 3-10 

Set Ready (DSR) 2-131 

Data Flow (System) 2-6 

Data Flow (System) 2-6 

DC 1 (Device Control 1) 2-81 




DC Output 2-34 

DEL (Delete) 2-81 

Delete (DEL) 2-81 

Device Control 1 (DC 1) 2-81 




Digital Output Register (DOR) 2-91 

2-12 

1-5

DIN (Connectors) 2-5 

DIP (Dual In-Line Package) 2-28 

Diskettes 2-111 

Diskette Drive (5 1/4") 2-110 

Diskette Drive (5 1/4") Adapter 

Adapter Inputs 2-106 

Adapter Outputs 2-107 


Command Status Registers 2-100 

Command Summary 2-96 

Comments (Programming) 2-104 

Digital Output Register 2-91 

Drive A and B Interface 2-106 

Drive Constants 2-104 

DPC Registers 2-103 

External Interface Specifications 2-109 

Floppy Disk Controller 2-91 

Functional Description 2-91 

Internal Interface Specifications 2-108 

Logic Diagrams D-35 

Programming Considerations 2-94 

Programming Summary 2-103 

System I/O Channel Interface 2-104 

Display (See IBM Monochrome Display) 2-43 

Display Buffer 2-48 

DISTR, DISTR (Data Input Strobe) 2-129 

Divisor Latch 2-136 

DMA (Direct Memory Access) 2-4 

Dos Special Functions 3-19 

DOSTR, DOSTR (Data Output Strobe) 2-129 


Drive Disable 2-132 

DRQ1 - DRQ3 (DMA Request 1 to 3) 2-12 

DSR (Data Set Ready) 2-131 

DTR (Data Terminal Ready) 2-132 

Dual In-Line Package Switches (DIP) 2-28 

E 

Edge Connector 2-108 

Encoding 3-11 

Error Recovery 3-10 

ESC (Escape) 2-82 

ESC A (Escape A) 2-83 

ESC B (Escape B) 2-84 

1-6

ESC C (Escape C) 2-85 

ESC D (Escape D) 2-85 

ESC E (Escape E) 2-86 

ESC F (Escape F) 2-86 

ESC G (Escape G) 2-86 

ESC H (Escape H) 2-87 

ESC 0 (Escape 0) 2-82 





Escape (ESC) 2-82 

Escape A (ESC A) 2-83 

Escape B (ESC B) 2-84 

Escape C (ESC C) 2-85 

Escape D (ESC D) 2-85 

Escape E (ESC E) 2-86 

Escape F (ESC F) 2-86 

Escape G (ESC G) 2-86 

Escape H (ESC H) 2-87 

Escape 0 (ESC 0) 2-82 



Escape 8 (ESC 8) 283 


Execution Phase 2-93 

Extended Codes 3-13 

F 

FDC (Floppy Disk Controller) 2-91 

Floppy Disk Controller (FDC) 2-91 

Fonts 2-48 

Functions and Conditions of DIP Switch 1 2-72 

Functions and Conditions of DIP Switch 2 2-73 



Game Control Adapter 2-118 

INS 8250 2-129 

G 

Game Control Adapter 

Address Decode 2-118 


1-7

Game Control Adapter (continued) 

Connector Specifications 2-122 

Data Bus Buffer/Driver 2-118 

Functional Description 2-118 

Interface Description 2-119 

Joystick Positions 2-118 

Joystick Schematic 2-121 

Trigger Buttons 2-118 

Glossary G-l 

GND (Ground) 2-12 

Graphics Character Extensions (Interrupt 1 FH) 

Graphics Mode (Color) 2-51 


H 

3-6 

Hardware 

Asynchronous Communications Adapter 2-123 

Color/Graphics Monitor Adapter 2-45 

5 1/4" Diskette Drive 2-110 

5 1/4" Diskette Drive Adapter 2-89 

Game Control Adapter 2-117 

IBM Monochrome Display 2-43 

IBM Monochrome Display and Parallel Printer Adapter 2-37 

Memory Expansion Options 32KB and 64KB 2-113 

Printer 2-70 

Parallel Printer Adapter 2-65 

Power Supply 2-33 

System Board 2-3 

Hardware 

Overview 1-1 

Data Flow 2-6 

Hertz (Hz) 1-2 

Horizontal Drive 2-43 

Horizontal Tab (HT) 2-81 

HT (Horizontal Tab) 2-81 

I 

IBM 80 CPS Matrix Printer 2-70 


IBM Monochrome Display and Parallel Printer Adapter 


Data Rates 2-39 

Direct Drive Interface and Pin Assignment 2-44 

1-8

IBM Monochrome Display and Parallel Printer Adapter (continued) 

DMA Channel 2-42 

Interrupt and DMA Response Requirements 2-39 

Interrupt Levels 2-42 


Lines Used 2-39 

Loads 2-39 

Memory Requirements 2-41 


Programming the 6845 CRT Controller 2-41 


Important Operating Characteristics 2-36 

IER (Interrupt Enable Register) 2-141 

IIR (Interrupt Identification Register) 2-139 

Input/Output Signals: 

Data (DO, D7) 2-133 

External Clock Input/Output (XTALl, XTAL2) 2-133 

Input Requirements (Power Supply) 2-34 

Input Signals 

Address Strobe (ADS) 2-129 

Chip Select (SCO, CSl, CS2) 2-129 

Clear to Send (CTS) 2-130 

Data Input Strobe (DISTR, DISTR) 2-129 

Data Output Strobe (DOSTR, DOSTR) 2-129 

Data Set Ready (DSR) 2-131 

Master Reset (MR) 2-130 

Received Line Signal (RCLK) 2-130 

Receiver Clock (RCLK) 2-130 

Register Select (AO, AI, A2) 2-130 

Ring Indicator (RI) 2-131 

Serial Input (SIN) 2~130 

Interface Diagram 


Cassette Connector Specifications 2-21 


5 1/4" Diskette Drive Adapter External 2-109 

5 1/4" Diskette Drive Adapter Internal 2-108 

Game Control 2-122 

IBM Monochrome Display Direct Drive 2-44 

Keyboard Connector Specifications 2-18 

Parallel Printer 2-69 

INTRPT (Interrupt) 2-132 

Interrupt Control Functions 2-140 

Intel 8048 (Keyboard Microcomputer) 2-14 

Intel 8088 (System Unit Microprocessor) 2-3 

1-9

I/O (Input/Output) 

Address Map 2-33 

Channel 2-8 

Channel Description (System Board) 2-10 

Diagram 2-9 

I/O CH CK (I/O Channel Check) 2-10 

I/O CH RDY (I/O Channel Ready) 2-11 

lOR (I/O Read Command) 2-11 

lOW (I/O Write Command) 2-11 

Interrupts 

And DMA Response Requirements 2-39 

Enable Register 2-141 

Identification Register 2-139 

Levels (O-XX) 2-42 

Vector Listing 3-3 

Vectors (O-7F) 3-21 

1 CH - Timer Tick 3-5 

1 DH - Video Parameters 3-5 

1 EH - Diskette Parameters 3-5 

1 FH - Graphics Character Extensions 3-6 

15 3-8 

K 

KB - Kilobyte (See Memory Expansion Options) 

Keyboard 

Break 3-16 

Character Codes 3-11 

Diagram 2-16 

Encoding 3-11 

Extended Codes 3-13 

Extended Functions 3-13 

Interface Block Diagram 2-15 

Interface Connector Specifications 2-18 

Pause 3-16 

Print Screen 3-16 

Scan Codes 2-17 

Shift States 3-14 

Shift Key Priorities 3-15 

Special Handling 3-15 

System Reset 3-15 

Usage 3-17 

Kilobyte (KB) (See Memory Expansion Options) 

1-10

L 

LF (Line Feed) 2-79 

Light Pen 

Interface 2-63 

Mode Control and Status Register 2-57 

Register Description 2-56 

Line Control Register (LCR) 2-134 

Line Feed 2-79 

Line Status Register (LSR) 2-137 

Lines Used 2-39 

Loads 2-39 

Logic Diagrams Appendix D 

Low Memory Maps 

BASIC and DOS Reserved Interrupts (80-3FF) 3-22 

BASIC Workspace Variables 3-23 

Interrupt Vectors (0-7F) 3-21 

Reserved Memory Locations (400-5FF) 3-22 

M 

Major Component Definitions 2-48 

Matrix Printer (IBM 80 CPS) 2-70 

Megabyte 2-3 

Memory 

BIOS Map 3-7 

Map (System) 2-25 

Module Description 2-114 

Module Pin Configuration 2-114 

Other Read/Write Usage 3-6 

Requirements (Color/Graphics) 2-60 

Requirements (IBM Monochrome) 2-41 

System Board Switch Settings 2-30 

32/64 KB Expansion Option Switch settings 2-31 

Memory Expansion Options 

Memory Module Description 2-14 

Memory Module Pin Configuration 2-114 

Operating Characteristics 2-113 

Switch Configurable Starting Address 2-115 

MEMR (Memory Read Command) 2-11 

MEMW (Memory Write Command) 2-11 

MFM (Modified Frequency Modulation) 2-110 

Mhz (Megahertz) 2-43 

Microprocessor 2-3 

1-11

Microsecond 2-3 

Mnemonic B-18 

Mode Set and Status Register 2-48 

Modem Control Register 2-142 

Modem Status Register 2-143 

Modes of Operation 



IBM Monochrome Display Adapter 2-40 

Mode Register Summary 2-58 

Mode Select Register 2-58 

Monitor Type Switch Settings 2-29 

Monochrome Display (IBM) 2-43 

Monochrome Display and Parallel Printer Adapter (See IBM) 

Motorola 6845 CRT Controller 2-48 

MR (Master Reset) 2-130 

N 

NMI (Non-Maskable Interrupt) 

of the 8088 2-4 

to the 8088 2-8 

NMI Mask. Reg. - (I/O Address Map) 2-23 

Nominal Power Requirements 2-24 

NUL (Null) 2-82 

Null (NUL) 2-82 

NUM LOCK 3-14 

o 

Of Characters, Keystrokes and Color C-l 

OHM Resistors 2-67 

Operating Characteristics 

Memory Expansion Options 2-113 

Monochrome Display 2-43 


Options 



5 1/4" Diskette Drive 2-110 

5 1/4" Diskette Drive Adapter 2-89 

Game Control Adapter 2-117 



32/64 KB Memory Expansion Options 2-113 

1-12

Options (continued) 

Parallel Printer Adapter 2-65 

"ORed" 2-65 

OSC (Oscillator) 2-10 

Other Read/Write Memory Usage 3-6 

OUT PORT 2-39 

Output 

AC 2-34 

Address 2-67 

DC 2-34 

Port 2-65 

OUT 1 2-132 

OUT 2 2-132 

Output Signals 

Baud Out (BAUD OUT) 2-132 

Chip Select Out (CSOUT) 2-132 

Data Terminal Ready (DTR) 2-132 

Driver Disable (DDIS) 2-132 

Interrupt (INTRPT) 2-132 

Output 1 (OUTl) 2-132 

Output 2 (OUT2) 2-132 

Request to Send (RTS) 2-132 

Serial Output (SOUT) 2-132 

Overview (Hardware) 1-1 

Over Voltage/Current Protection 2-36 

p 

Parallel Printer Adapter 

ASCII Coding Table 2-78 

ASCII Control Codes 2-79 


Description 2-37 

DMA Channel 2-42 



Interrupt Levels 2-42 

Logic Diagram D-31 

Parallel Interface Description 2-73 

Printer Specifications 2-71 

Programming Considerations 2-67 

Programming the 6845 CRT Controller 2-41 


Setting the DIP Switches 2-72 

Timing 2-77 

1-13

Parameters, 6845 Initialization 2-41 

Parameter Passing, ROM BIOS 3-2 

Parity Flag, 8080 Flags B-1 

Pause, BIOS Cassette Logic Special Handling 3-16 

Pin Connectors 

P2-6 Pin Berg Strip for Light Pen Connector 2-63 

Pl-4 Pin Berg Strip for RF Modulator 2-63 

9 Pin Connector, Color Direct Drive 2-61 

9 Pin Connector, IBM Monochrome Display 2-44 

25 Pin Connector, Parallel Printer Adapter Block Diagram 2-66 

25 Pin'D' Shell Connector, Asynchronous Adapter Block 

Diagram 2-124 

15 Pin'D' Shell Connector, Game Controller Adapter (Analog 

Input Connector Specifications) 2-122 

25 Pin'D' Shell Connector, Parallel Printer Adapter 2-69 

5 Pin Din Connector, Keyboard Interface Connector 

Specifications 2-18 

15 Pin Male 'D' Shell Connector, Joystick Schematic 2-121 

Planar (See System Board 2-3; Intel 8088 2-3) 

Power-on Self-Test 

System Board 2-4 

Keyboard 2-14 

Power Supply 2-33 

AC Output 2-34 

DC Output 2-34 

Important Operating Characteristics 2-36 

Over Voltage/Current Protection 2-36 

Signal Requirements 2-36 

Input Requirements 2-34 

Power Supply Connectors and Pin Assignments 2-35 

Power Supply Location 2-34 

Preface i 

Print Screen, Special Handling 3-16 

Printer, IBM 80 CPS Matrix 2-70 

Printer Specifications 2-71 

Programmable Peripheral Interface (PPI) 8255A-5 2-19 



Asynchronous Communications Reset Functions 2-133 

INS 8250 Accessable Registers 2-134 

INS 8250 Line Control Register 2-134 

INS 8250 Programmable Baud Rate Generator 2-135 

Interrupt Identification Register 2-139 

Interrupt Enable Register 2-141 

Line Status Register 2-137 

Modem Control Register 2-142 

1-14


Asynchronous Communications Adapter (continued) 

Modem Status Register 2-143 

Receiver Buffer Register 2-144 

Transmitter Holding Register 2-145 


Color Select Register 2-57 

Control and Status Register 2-57 

I/O Address and Bit Map 2-61 

Interrupt Level 2-60 

Mode Register Summary 2-58 

Mode Select Register 2-58 

Programming the 6845 Controller 2-55 

Programming the Modem Control and Status Register 2-57 

6845 Register Descriptions 2-56 

Status Register 2-59 

Sequence of Events 2-59 

5 1/4" Diskette Drive Adapter 

Command Status Registers 2-100 

Command Summary 2-96 

Symbol Descriptions 2-94 

IBM Monochrome Display and Parallel Printer Adapter 

DMA Channel 2-42 

I/O Address and Bit Map 2-42 

Interrupt Levels 2-42 

Memory Requirements 2-41 


Programming the CRT Controller 2-41 

Programming the 6845 CRT Controller 2-41 

Comments 2-104 

DPC Registers 2-103 


R 

RAS 2-114 

Rating Amps, Over Voltage/Current Protection 2-36 

Ready Line 2-8 

Read Block 3-9 

Read Data 2-107,2-108 (5 1/4" Diskette Drives, External) 2-109 

Read Status (Parallel Printer Adapter Block Diagram) 2-66 

Read/Write Memory 

Color Monitor 2-50 

Color TV 2-49 

Future Expansion in I/O Channel, 384 KB 2-26 

1-15

Read/Write Memory (continued) 


Hardware Overview 1-1 

I/O Address Map 2-24 

Memory Address Space 2-61 


User 3-7 

Receive Circuit 2-127 

Receiver Clock, (RCLK) 2-128 

Recording Medium 2-111 

Refresh Cycles 2-8 

Registers, Address 

Command Status 2-100 

Data 2-9 

Initialization 

Parameters 2-41 

INS 8250 Accessible 2-134 

INS 8250 Line Control 2-134 

Interrupt Enable 2-141 

Line Control 2-134 

Line Status 2-137 

Main Status 2-9 

Modem Control 2-142 

Modem Status 2-143 

Receiver Buffer 2-144 

Transmitter Holding 2-145 

6845 2-55 

Register File 

Color Select 2-57 

6845 Data 2-41 


6845 Index 2-42 

6845 Initialization Parameters 2-41 

Mode Select 2-58 

Status 2-57, 2-59 

Requirements 

Input (Power Supply) 2-34 

Memory 2-60 

Signal (Power Supply) 2-36 

RESET DRV (Reset Drive) 2-10 

I/O Channel Description 2-119 

ROM Address Space, 256 KB 2-25 

=RESET 2-105 

Reserved Memory Locations (400-5FF) 3-22" 

Result Phase 2-93 

1-16

Response Requirements, Interrupt and DMA 2-39 

Reverse Video 


Color Graphics Monitor Adapter 2-45 

RF Modulator 

Auxiliary Video Connector PI-4 Pin Berg Strip 2-63 


Interface 2-63 

Ring Indicator 2-127 

ROM 

Character Generator 2-48 

Color Graphics Mode 2-52 


Diagram 2-13 

Hardware Overview 1-1 

Keyboard 2-14 


System Board 2-3, 2-4 

System Board Component Diagram 2-13 

System Memory Map 2-27 

ROM and System Usage 3-1 

ROM BIOS 

BIOS Cassette Logic 3-8 

BIOS Memory Map 3-8 

Cassette Read 3-9 

Cassette Write 3-9 

Data Record Architecture 3-10 


Error Recovery 3-10 

Interrupt 15 3-8 

Interrupt ICH Timer Tick 3-5 

Interrupt IDH Video Parameters 3-5 

Interrupt IEH Diskette Parameters 3-5 

Interrupt IFH Graphics Character Extensions 3-6 

Interrupt Vector Listing 3-3 


ROM BIOS Listing Appendix A 

ROS (Read Only Storage) (See ROM) 

ROM, Request for Master 2-92 

RS232-C (See Asynchronous Communications Adapter) 

RTS (Ready to Send) 2-123 

R/W (Read/Write) 

Symbol Description 2-95 

2-123 

1-17

s 

Scan Codes 2-17 

Screen 2-43 

Schematic (See Logic Diagrams) 

SCROLL LOCK 3-15 

Selecting the Interface Format 2-146 


Serial Input (SIN) 2-130 

Serial Output (SOUT) 2-132 

Setting the DIP Switches 2-72 

Shift In 2-80 

Shift Out 2-80 

Shift States 3-14 

SI (Shift In) 2-80 

Signal Requirements 2-36 

SIN ( Serial Input) 2-130 

SO 2-80 

Software Algorithms 3-8 

SOUT (Serial Output) 3-132 

Speaker 

Drive System Block Diagram 2-22 

Interface 2-22 

Special Handling 3-15 

Special Timing 2-39 

Specifications 


Printer 2-71 

System Appendix E 

Status Registers 

Color/Graphics 2-59 

o (5 1/4" Diskette Drive Adapter) 2-100 

1 (5 1/4" Diskette Drive Adapter) 2-101 



Storage (See Memory) 

Strobe 

Address 2-129 

Data Output 2-129 

Summary of Available Colors 2-55 

Switch Settings 

Configurable Start Address 2-115 

5 1/4" Diskette Drives 2-29 

32/64 KB Memory Expansion Option 2-31 

Monitor Type 2-29 

System Board Memory 2-30 

1-18

System Board 

Cassette Interface Connector Specifications 2-21 

Cassette Jumpers 2-19 

Cassette User Interface 2-19 

Circuit Block Diagrams ( Cassette) 2-19 

Component Diagram 2-13 

Data Flow 2-6 

5 1/4" Diskette Drive Switch Settings 2-29 

I/O Address Map 2-23 

I/O Channel 2-8 

I/O Channel Description 2-10 

I/O Channel Diagram 2-9 

Keyboard 2-14 

Keyboard Diagram 2-16 

Keyboard Interface Block Diagram 2-15 

Keyboard Interface Connector Specifications 2-18 

Keyboard Scan Codes 2-17 

32/64 KB Memory Expansion Option Switch Settings 2-31 

Memory Switch Settings 2-30 

Monitor Type Switch Settings 2-29 

Speaker Drive System Block Diagram 2-22 

Speaker Interface 2-22 


System Expansion Slots (See I/O Slots) 2-3 


System Memory Map (16 KB Increments) 2-26 

System Unit 1-1 

System Unit Power Connector 2-35 

System Usage (ROM and) 3-1 

T 

Tab (Vertical) 2-79 

T/C (Terminal Count) 2-12 

Terminal Count (T/C) 2-12 

THR (Transmitter Holding Register) 2-145 

Timing Generator 2-48 

Transmit Circuit 2-127 

Transmit Data (TX) 2-127 

Transmitter Holding Register (THR) 2-145 

Transmitter Output and Receiver Input 2-126 

Trigger Buttons 2-118 

TX Data (Transmit Data) 2-127 

1-19

u 

Unit Specifications Appendix E 

Usage (Keyboard) 3-17 

Use of BIOS 3-2 

User Interface (Cassette) 2-19 

v 

Vectors 

(O-7F Interrupt) 3-21 

(Interrupt Listing) 3-3 

Vectors With Special Meaning 

Interrupt 1 CH Timer Tick 3-5 

Interrupt IDH Video Parameters 3-5 

Interrupt lEH Diskette Parameters 3-5 

Interrupt 1 FH Graphics Character Extensions 3-6 


Vertical Drive 2-43 

Video 

Monitor 2-62 

(Reverse) 2-45 ~ 

Signal 2-43 

Voltage Interchange Information 2-128 

Voltage 


I/O Channel 2-8 

System Board I/O Channel Description 2-10 

Keyboard Interface Connector Specifications 2-18 

Cassette Interface Connector Specifications 2-21 

Speaker Interface 2-22 


Power Supply Location 2-34 

Important Operating Characteristics 2-36 

Color Graphics Monitor Adapter Direct Drive and 

Composite Interface Pin Assignment 2-62 

Color/Graphics Monitor Adapter Auxiliary Video 

Connectors 2-62 

Printer Specifications 2-71 ~ 

Game Controller Adapter (Analog Input) Connector 

Specifications 2-122 

Voltage Interchange Information, Asynchronous Communications 

Adapter 2-128 

Selecting the Interface Format, Asynchronous Communications 

Adapter 2-146 

1-20

w 

Workspace (BASIC Variables) 3-23 

Write (Cassette) 3-8 

Write (Cassette Interface Hardware) 2-20 

r'""\ Write Data 2-106 

Write Enable 2-106 

Write Protect 2-107 

Numerics 



32/64 KB Memory Expansion Options 1-3 

80 CPS Matrix Printer, IBM 2-70 

80 Interpreter, BASIC 1-1 

6845 CRT Controller 2-48 

8080 Parity Flags B-1 

8088, Intel 2-3 

8250 INS Accessible Registers 2-134 

RS232C-A Asynchronous Communications Adapter 2-123 

1-21

1-22 

NOTES

The Personal Computer 

Hardware Library 

Product Comment Form 

TECHNICAL REFERENCE 6025008 

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IBM 5150 PC Technical Reference (6025005, August, 1981) (PDF)

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