IBM XT 5160 Use and care manual

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Technical
Reference
Personal Computer
Hardware Reference
Library

Revised Edition (March 1986)
The following paragraph does not apply to the United Kingdom or any country
where such provisions are inconsistent with local
law: INTERNATIONAL
BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION
"AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANT ABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. Some states do not allow disclaimer of express or
implied warranties in certain transactions, therefore, this statement may not
apply to you.
This publication could include technical inaccuracies
or typographical errors.
Changes are periodically made to the information herein; these changes will be
incorporated in new editions
of the publication. IBM may make improvements
and/ or changes in the product(s) and/or the program(s) described in this
publication at any time.
It is possible that this publication may contain reference to, or information
about, IBM products (machines and programs), programming,
or services that
are not announced in your country. Such references or information must not be
construed to mean
that IBM intends to announce such IBM products,
programming,
or services in your country.
Products are not stocked at the address below. Requests for copies of this
publication and for technical information about IBM Personal Computer
products should
be made to your authorized IBM Personal Computer dealer,
IBM Product Center, or your IBM Marketing Representative.
The following paragraph applies only to the United States and Puerto Rico: A
Reader's Comment
Form is provided at the back of this publication. If the form
has
been removed, address comments to: IBM Corporation, Personal
Computer, P.O. Box 1328-C, Boca Raton, Florida 33429-1328. IBM may use
or distribute any of the information you supply in any way it believes
appropriate without incurring any obligations whatever.
C£? Copyright International Business Machines Corporation 1981, 1986

Federal Communications Commission
Radio FrequencyInterference
Statement
Warning: The equipment described herein has been certified to
comply with the limits for aClass Bcomputing device, pursuant
to Subpart J
of Part 15 of the FCC rules. Only peripherals
(computer
input/output devices, terminals, printers, etc.) certified
to comply with the Class Blimits may be attached to the
computer. Operation with non-certified peripherals
is likely to
result in interference to radio and TV reception. If peripherals
not offered by IBM are used with the equipment, it is suggested to
use shielded grounded cables with in-line filters if necessary.
CAUTION
This product described herein
is equipped with agrounded plug for
the user's safety.
It is to be used in conjunction with aproperly
grounded receptacle to avoid electrical shock.
iii

Notes:
iv

Preface
This publication describes the various components of the IBM
Personal Computer XT and IBM Portable Personal Computer;
and the interaction of each.
The information in this publication is for reference, and is
intended for hardware and program designers, programmers,
engineers, and anyone else with aknowledge of electronics
and/ or programming who needs to understand the design and
operation of the IBM Personal Computer XT or IBM Portable
Personal Computer.
This publication consists of two parts: asystem manual and an
options and adapters manual.
.The system manual
is divided into the following sections:
Section 1, "System Board", discusses the component layout,
circuitry, and function of the system board.
Section 2, "Coprocessor", describes the Intel 8087
coprocessor and provides programming and hardware
interface information.
Section 3,
"Power Supply", provides electrical input/output
specifications as well as theory of operation for both the IBM
Personal Computer
XT power supply and the IBM Portable
Personal Computer power supply.
Section 4, "Keyboard", discusses the hardware makeup,
function, and layouts
of the IBM Personal Computer XT
83-keyand lOl/102-key keyboards and the IBM Portable
Personal Computer keyboard.
In addition, keyboardencod-
ing and usage
is discussed.
Section 5, "System Bios", describes the basic
input/output
system and its use. This section also contains the software
v

interrupt listing, aBIOS memory map, descriptions of vec-
tors with special meanings,
and aset of low memory maps.
Section 6, "Instruction Set", provides aquick reference for
the 8088 and 8087 assembly instruction set.
Section 7, "Characters, Keystrokes, and Colors", supplies the
decimal
and hexadecimal values for characters and text
attributes.
Aglossary, bibliography,
and index are also provided.
The Technical Reference Options and Adapters manual provides
information, logic diagrams, and specifications pertaining to the
options
and adapters available for the IBM Personal Computer
family
of products. The manual is modular in format, with each
module providing information about aspecific option
or adapter.
Modules having alarge amount of text contain individual indexes.
The modules are grouped by type
of device into the following
categories:
•Expansion Unit
•Displays
•Printers
•Storage Devices
•Memory Expansion
•Adapters
•Miscellaneous
•Cables
and Connectors.
Full-length
hard-tab pages with the above category descriptions,
separate the groups of modules;
The term "Technical Reference manual" in the Options and
Adapters manual, refers to the:
•IBM Personal Computer
XT /IBM Portable Personal
Computer Technical Reference manual
•IBM Personal Computer Technical Reference manual
•IBM Personal Computer
AT Technical Reference manual.
The term "Guide to Operations manual" in the Options and
Adapters manual, refers to the:
vi

•IBM Personal Computer Guide to Operations manual
•IBM Personal Computer
XT Guide to Operations manual
•IBM Portable Personal Computer Guide to Operations manual
•IBM Personal Computer
AT Guide to Operations manual.
Prerequisite Publications
•IBM Personal Computer
XT Guide to Operations
•IBM Portable Personal Computer Guide to Operations.
Suggested Reading
• BASIC for the IBM Personal Computer
•Disk Operating System (DOS)
•Hardware Maintenance Service manual
•Hardware Maintenance Reference manual
•Macro Assembler for the IBM Personal Computer.
vii

Notes:
viii

Contents
SECTION 1. SYSTEM BOARD 1-1
Description 1-3
Microprocessor
1-4
Data Flow Diagrams 1-5
System Memory
Map 1-8
System Timers
1-10
System Interrupts 1-11
System Boards
1-12
RAM 1-12
ROM 1-13
DMA 1-14
I/O Channel 1-15
System
Board Diagram 1-19
I/O Channel Description 1-20
I/O Address Map 1-24
Other Circuits 1-26
Speaker Circuit 1-26
8255A I/O Bit Map 1-27
Specifications 1-29
System Unit 1-29
Card Specifications 1-31
Connectors 1-32
Logic Diagrams - 64/256K 1-34
Logic Diagrams - 256/640K 1-46
SECTION 2. COPROCESSOR 2-1
Description 2-3
Programming Interface
2-4
Hardware Interface 2-4
SECTION 3. POWER SUPPLIES 3-1
IBM Personal Computer XT Power Supply 3-3
Description 3-3
Input Requirements 3-4
Outputs 3-4
Overvoltage/Overcurrent Protection 3-5
Power Good Signal 3-5
ix

Connector Specifications and Pin Assignments 3-6
IBM Portable Personal Computer Power Supply 3-7
Description 3-7
Voltage and Current Requirements 3-7·
Power Good Signal 3-8
Connector Specifications and Pin Assignments 3-9
SECTION 4. KEYBOARDS 4-1
Introduction 4-3
83-Key Keyboard Description 4-3
Block Diagram 4-5
Keyboard Encoding and Usage 4-6
Extended Codes 4-9
Keyboard Layouts 4-12
Connector Specifications 4-19
Keyboard Logic Diagram 4-21
101/102-Key Keyboard 4-22
Description 4-22
Power-On Routine 4-25
Commands from the System 4-26
Commands to the System 4-26
Keyboard Scan Codes 4-28
Clock and Data Signals 4-32
Keyboard Encoding and Usage 4-33
Keyboard Layouts 4-44
Specifications 4-51
Logic Diagram 4-52
SECTION 5. SYSTEM BIOS
5-1
System BIOS Usage 5-3
System BIOS Listing -
11/22/85 5-11
Quick Reference -
256/640K Board 5-11
System BIOS Listing -
11/8/82 5-111
Quick Reference -
64/256K Board 5-111
SECTION 6. INSTRUCTION SET 6-1
8088 Register Model 6-3
Operand Summary 6-4
Second Instruction Byte Summary 6-4
Memory Segmentation Model 6-5
Segment Override Prefix 6-6
Use of Segment Override 6-6
8088 Instruction Set 6-7
x

Data Transfer 6- 7
Arithmetic
6-10
Logic 6-13
String Manipulation 6-15
Control Transfer 6-16
8088 Instruction Set Matrix 6-20
8088 Conditional Transfer Operations 6-22
Processor Control 6-23
8087 Coprocessor Instruction Set 6-24
Data Transfer 6-24
Comparison 6-25
Arithmetic 6-26
Transcendental 6-28
Constants 6-28
Processor Control 6-29
SECTION 7. CHARACTERS, KEYSTROKES, AND
COLORS 7-1
Character Codes 7-3
Quick Reference 7 -14
Glossary Glossary-I
Bibliography Bibliography-I
Index Index-I
xi

Notes:
xii

INDEX TAB LISTING
Section 1. System Board .
Section 2. Coprocessor -
Section 3. Power Supplies _
Section
4. Keyboards .
Section 5. System BIOS .
Section 6. Instruction Set .

Notes:
xiv

Section 7. Characters, Keystrokes, and Colors .
Glossary .
Bibliography .
Index .
xv

Notes:
xvi

SystemBlockDiagram (XT)
The following is asystem block diagram of the IBM Personal
Computer XT.
SYSTEM UNIT
System Board Power Supply
130 Watt
4Level
8088
Oscillator
8 Interrupt Speaker
Levels Adapter
Speaker
Keyboard
Read-Only
Memory
Memory
4 Channels Keyboard
Direct Memory Adapter
Access
Math
Coprocessor
(Optional)
678
Extender Card
to
Receiver Card
(See Expansion
Unit Block
Diagram)
345
2 8-Slot
I/O Channel
Note: A"System to Adapter Compatibility Chart," to identify
the adapters supported by each system, and
an "Option to .
Adapter Compatibility Chart," to identify the optio'ns supported
by each adapter, can be found in the front matter of the Technical
Reference Options and Adapters manual, Volume
1.
xvii

System BlockDiagram (Portable)
The following is asystem block diagram of the IBM Portable
Personal Computer.
SYSTEM UNIT
Composite CRT
8 Interrupt Speaker
Levels Adapter
4 Channels Keyboard
Direct Memory Adapter
Access Keyboard
Speaker
Power Supply
114 Watt
4Level
Read-Only
Memory
Oscillator
System Board
8088
Memory
Math
Coprocessor
(Optional)
678
345
2 ~Diskette Adapter
4 Extender Card to Receiver Card*
~ ~Color/Graphics Adapter
See the Expansion Unit Block Diagram
Note: A"System to Adapter Compatibility Chart," to identify
the adapters supported by each system, and an
"Option to
Adapter Compatibility Chart," to identify the options supported
by each adapter, can be found in the front matter of the Technical
Reference Options and Adapters manual, Volume
1.
xviii

ExpansionUnit BlockDiagram
The following is an expansion unit block diagram for the IBM
Portable Personal Computer and IBM Personal Computer
XT
with the 64/256K system board.
EXPANSION UNIT
Power Supply
130 Watt
4Level
Receiver Card
from
Extender Card
a
Expansion Board
Osc i
11 ator
a-Slot
Expanded
I/O Channel
7
6
5
4
3
2
Note: A"System to Adapter Compatibility Chart," to identify
the adapters supported by each system, and an
"Option to
Adapter Compatibility Chart," to identify the options supported
by each adapter, can be found in the front matter of the Technical
Reference Options and Adapters manual, Volume
1.
xix