IBM 5170 Use and care manual

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Personal Computer
----- Hardware Reference
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library
Technical
Reference

First Edition (March 1984)
The
foDowing 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 manual
"as is," without warranty of any kind, either expressed or implied,
including,
but not limited to, the particular purpose. IBM may make improvements and/or
changes in the product(s) and/or the program(s) described in this manual at any time.
This product 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.
It is possible that this material 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 product and for
technical information about the system should be made
to your authorized IBM Personal
Computer dealer.
The
foDowing 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 Corp., Personal Computer, P.O. Box 1328-C, 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.
All specifications subject to change without notice.
© Copyright International Business Machines Corporation 1984

FEDERAL COMMUNICATIONS
COMMISSION RADIO FREQUENCY
INTERFERENCE STATEMENT
Warning: The equipment described herein 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 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 ifnecessary.
CAUTION
The product described herein is equipped with a
grounded plug for the user's safety.
It is to be used
in conjunction with a properly grounded receptacle
to avoid electrical shock.
/
iii

Notes:
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iv

Preface
This manual describes the various units of the IBM Personal
Computer
AT and how they interact. It also has information
about the basic
input/output system (BIOS) and about
programming support.
The information in this publication
is for reference, and is
intended for hardware and program designers, programmers,
engineers, and anyone else who needs to understand the design
and operation
of the IBM Personal Computer AT.
This manual consists
of nine sections, four of which describe the
hardware aspects
of the IBM Personal Computer AT including
signal charts and register information. Section 5 contains
information about the usage
of BIOS and a system BIOS listing.
Section 6 contains instruction sets for the 80286 microprocessor
and the 80287 math coprocessor. Section 7 provides information
~ about characters, keystrokes, and colors. Section 8 has general
communications information. Section 9 contains information
about the compatibility
of the IBM Personal Computer AT and
the rest
of the IBM Personal Computer family.
A glossary of terms and a bibliography
of related publications are
included.
v

Prerequisite Publications
Guide to Operations for the IBM Personal Computer AT
Suggested Reading
• BASIC for the IBM Personal Computer
• Disk Operating System (DOS)
• Hardware Maintenance and Service for the IBM Personal
Computer
AT
• MACRO Assembler for the IBM Personal Computer
vi

Contents
~
SECTION 1. SYSTEM BOARD ..................... 1-1
Description
.................................. 1-3
Memory
................................ 1-4
Microprocessor
............................... 1-4
System Performance
........................... 1-7
System Timers
............................... 1-8
System Interrupts
............................ 1-10
ROM Subsystem ............................. 1-11
RAM Subsystem ............................. 1-12
Direct Memory Access (DMA)
................. 1-12
I/O Channel ................................ 1-15
Other Circuits
............................... 1-30
Speaker
................................ 1-30
Jumper
................................ 1-30
Type of Display Adapter Switch
............. 1-31
Variable Capacitor
....................... 1-31
Keyboard Controller
...................... 1-31
Real-time Clock/Complementary Metal Oxide
Semiconductor
(RT/CMOS) RAM Information 1-45
Specifications
............................... 1-55
System Unit
............................ 1-55
Connectors
............................. 1-57
Logic Diagrams
.......................... 1-61
SECTION 2.
COPROCESSOR ......••••..•......... 2-1
Description .................................. 2-3
Programming Interface
......................... 2-3
Hardware Interface
............................ 2-4
SECTION 3. POWER SUPPLY
....•................. 3-1
Inputs ...................................... 3-3
Outputs
..................................... 3-3
Output Protection
............................. 3-4
Dummy Load
................................ 3-4
Output Voltage Sequencing
..................... 3-4
No-Load Operation
........................... 3-5
Power-Good Signal
............................ 3-5
vii

Fan-Out ................................ 3-6
Connectors
.................................. 3-6
SECTION
4. KEYBOARD .......................... 4-1
Description
.................................. 4-3
Interface
................................ 4-3
Sequencing Key Code Scanning
.............. 4-3 ~
Keyboard Buffer .......................... 4-3
Keys
................................... 4-3
Functions Performed at Power-On Time
........... 4-4
Power-On Reset
.......................... 4-4
Basic Assurance Test
...................... 4-4
Commands from the System
..................... 4-5
Keyboard Outputs
........................... 4-10
Key Scan Codes
......................... 4-10
Command Codes to the System
................. 4-12
Clock and Data Signals
........................ 4-14
Keyboard Data Output
.................... 4-15
Keyboard Data Input
..................... 4-15
Keyboard Layout
............................ 4-16
Specifications
............................... 4-23
Keyboard Connector
..................... 4-23
SECTION 5. SYSTEM BIOS
........................ 5-1
System BIOS
................................. 5-3
System BIOS Usage
....................... 5-3
Keyboard Encoding and Usage
.............. 5-12
Extended Codes
......................... 5-17
SECTION 6. INSTRUCTION
SET ...........•....... 6-1
Instruction Sets
............................... 6-3
80286 Microprocessor Instruction Set
............ ; 6-3
Data Transfer
............................ 6-3
Arithmetic
............................... 6-6
Logic
.................................. 6-10
String Manipulation
...................... 6-12
Control Transfer
......................... 6-13
Processor Control
........................ 6-19
Protection Control
....................... 6-21
80287 Coprocessor Instruction Set
............... 6-24
Data Transfer
........................... 6-24
Comparison
............................ 6-25
Constants
.............................. 6-26
viii