NCR PC4I Use and care manual

Personal
Computer
PC4i
Technical Reference
Manual

GW-BASIC is a trademark of Microsoft Corporation
January 1986
Copyright '~ ' 1985, 1986 by NCR Corporation
Dayton, Ohio
All Rights Reserved
Printed in
the Federal Republic of Germany
(
It is the policy of NCR Corporation to improve
products as new technology, components, software, and
firmware become available. NCR Corporation,
therefore, reserves the right to change
specifications without prior notice.
All features, functions, and operations described
herein may not be marketed by NCR in all parts of the
world.In some instances, photographs are of equipment
prototypes. Therefore, before using this document
consult your dealer of NCR office for information
that is applicable and current.

(_
INTRODUCTIOR
YOUR RCR PEBSORAL COMPUTER HODEL 41 AND fflIS HARUAL
Your NCR PERSONAL COMPUTER MODEL 4i is a powerful
business/professional personal computer. It is
designed to act not only as an independent, self-
sufficient system, but also as a control center for
systems fulfilling a wide range of business,
scientific and technological requirements.
Essential electronics are contained on the controller
board. Where possible, LSI components have been used,
providing compactness and a high degree of
reliability. The microprocessor is the 8088, which
can be supplemented by the 8087 co-processor, if
required. With the additional support of Direct
Memory Access, high processing speeds can be
achieved. 256 Kilobyte of random access memory are
included in the standard version, over and above
video RAM.
The NCR PERSONAL COMPUTER MODEL 4i is equipped with
Centronics and RS-232-C interfaces as standard. These
are accessed at the rear of the computer without any
dismantling. Full access to the system bus is
available at the internal expansion card assembly.
This assembly can accomodate up to seven cards to
expand the features of your system. One additional
monitor can be connected via an expansion card, so
that the computer can drive a monochrome and a color
display simultaneously.
The NCR PERSONAL COMPUTER MODEL 4i is operationally
compatible with a number of other widely used
personal computers. This provides for portability of
a large number of software applications and hardware
extensions between your NCR PERSONAL COMPUTER 4i and
other personal computers you may have occasion to
use. In addition, your NCR PERSONAL COMPUTER 41
offers the advantages of single cabinet design, an
extended keyboard, and an excellent high-resolution
display in conjunction with a color CRT,

This Manual, consisting of two volumes, is intended
for designers, system integrators, and programmers
who require detailed information about the
construction and operation of the NCR PERSONAL (
COMPUTER MODEL 4i. Volume 1 includes information
about the I/0 bus, signal levels and timing, power
requirements, and pin assignments, not only of the
NCR PERSONAL COMPUTER MODEL 4i itself, but also of
the kits available from NCR. In addition, details are
given about low-level software control of hardware
functions. Volume 2 provides full schematics.
Assembly language listings of the NCR ROM BIOS are
also available as a separate document.
The
NCR PERSONAL COMPUTER MODEL 4i is optionally
available in a version for use with the Videotex
information and communication system. Videotex is
administered under the auspices of the post and
telecommunications authorities of a number of
countries. The Videotex version of the NCR PERSONAL
COMPUTER MODEL 4i is described in a Chapter of its
own in this Manual.
With the help of the information contained in this
Manual, you may be intending to make hardware or
software changes to the NCR PERSONAL COMPUTER 4i for
specialized use. Because of the complex nature of
computer technology, we must stress that NCR cannot
accept responsibility for problems arising from such
changes. At the same time, we are constantly
endeavoring to maintain the quality of information
provided in this Technical Reference Manual.
Therefore, if you find that there is a particular
aspect of information not already provided in this
Manual, or if you want to let us know how useful you
find it, please ask your supplier to forward your
comments to us.

C
NCR PERSONAL COMPUTER MODEL 4i
TECHNICAL REFERENCE
MANUAL
CONTERTS
CHAPTER 1: System Overview
Models and Options ••.••••••••••.•••••••••••••• 1-1
Model
Identification •••••••..••••••••••••••••• 1-4
System Components . . . • • • . • . . . . . . . • . . • . • . . . • • • . . 1-5
System Connection •••••••••••••••••••••••••••• 1-12
I/0 Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
Rack Assembly • . . . . . • • . . . • • . . . • . . . • . • . . . . . . • 1-15
Configuration Switches ••••••••••••••••••.••.• 1-16
Memory Expansion • . . • • • • • • • • • . . . • . • • . • • . . . • . . . 1-18
Memory Map • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • 1-1 9
I/0 Map ••••••••••••••.••••••••••.••.••••••••• 1-21
Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22
Monochrome Systems •••••••••••••••.••••••••• 1-22
Color Systems .............................. 1-23
Specifications •.........•.•.................. 1-25
Alternate Main Processor Board ••••.•••••••••• 1-26
CHAPTER 2: Programmable Intelligence
8088/8087 Co-ordination ••••••••••••••••••••••• 2-3
Programmable Interval Timer •••••••••.•••.••..• 2-4
Hardware Configuration •••••••••••••••••••••• 2-4
Timer Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Output on Terminal Count (Mode 0) ••••••••• 2-6
Programmable One-Shot (Mode 1) •••••••.•••• 2-7
Rate Generator (Mode 2) ••••••••••••••••••• 2-7
Square Wave Generator (Mode 3) •..........• 2-7
Software Triggered Strobe (Mode 4) •••••••• 2-7
Hardware Triggered Strobe (Mode 5) •••••••• 2-8
Timer Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Reading the Counters •••••••••••••••••••••• 2-9
i

Programmable Interrupt Controller (PIC)
Introduction .............................. .
Why use Interrupts? •••••••••••••••••••.••
Interrupts and the 8088 Microprocessor ••.
Interrupt Controller Hardware and Logic
Programming
the PIC ••.•.••••••••••••.••
Initializing the PIC .••.•••••••••••••.•.•
Operation Command Words ••.•••..•.•••.....
Signal Integrity
System Interrupts ......................... .
Interrupt Handling: Examples •••...•••...•••
Parallel Input/Output Interface •••••••.•••..•
Programming the 82 55A .•••.••••••••••••..•.
Mode 1
Mode 2
Mode 3
8255A: System
Use
Direct Memory Access
System Integration ........................ .
8237 Registers
Command Register
Mode Register ........................... .
Request Register ........................ .
Mask Register ......................... .
Status Register ......................... .
Temporary Register ••••••.••.•••.•..•.•...
Current Address Register ...••..•.•.•.•...
Current Count Register .•••.••••.•••.••..•
Base Address and Base Count Registers
DMA Timing ..••.••......•....•..............
8237: System Use
RAM Refresh •••••••.•.•.••.•••.•.•••••••..
Flexible Disk DMA Service
DMA Page Selection •.•••..••.•••.•••••••••
CHAPTER 3: The Operating System
ii
Introduction .......................... .
ROM BIOS
BIOS Data Areas
System
Initialization
2-10
2-10
2-10
2-11
2-12
2-13
2-16
2-19
2-26
2-26
2-28
2-42
2-42
2-43
2-44
2-46
2-48
2-50
2-50
2-54
2-56
2-57
2-58
2-59
2-59
2-60
2-60
2-60
2-61
2-61
2-64
2-64
2-66
2-68
3-1
3-3
3-18
3-24

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0
(,
CHAPTER 4: Printers and Communications
Introduction ••..••••••••..•••••.•••••••••••••• 4-1
RS-232-C
Input/Output •••.••.•••.••.•••.••••••• 4-1
Programming
the Serial Receiver/Transmitter. 4-6
Interrupt Enable Register ••.••.••••••••••• 4-9
Interrupt ID Register •••••••••.•••.•••••• 4-10
Line Control Register •••••..•.•..•.••••.. 4-10
Modem Control Register ••••••••••••••••••• 4-11
Line Status Register ••••••••••••••••••••• 4-11
Modem Status Register ••••••••••••••.••••• 4-12
Internal Diagnostics .•.••••.••••••••.•••••• 4-12
Data Integrity .••••••••.•••.••••••••••.•• 4-13
The Interrupt System • . . • • •• . . • • •. • . • ••. • • 4-1 3
Receiver/Transmitter Timing •••••••.•.•••••. 4-14
Baud
Rate Selection ••••..•••••.•.•••••••••• 4-17
Programming
Hints .••••••••••••••••••••••••• 4-18
Interface Availability ••••••.•.•••••••••• 4-18
Initialization ................•.......... 4-18
Transmit ting Data • . . •. •. •• • • •• •• •• • • •••. . 4-20
Receiving Data ........................... 4-21
Centronics Interface •••••••.••...•••••••.•••• 4-24
Software Control ••••.•••••.•••••••••.•••••• 4-27
Status And Control Registers .••••••••••.• 4-27
Centronics Printer Control ••••••••••••••• 4-28
Printer Status Analysis ••••...•.••••••.•. 4-29
CHAPTER 5: Inhouse DLC Inter~ace
Interface Connections •••.••.•••.••••••••.••••••• 5-1
DLC Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Controller Pin Configuration •••••••••••.•••••• 5-2
Software Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Command Register ••••.••.•••.••••••••.••..••• 5-7
Status Register ••••••••••••••••••..••••••••• 5-8
Interrupt Status Register ••••••..•••••••••• 5-10
Unique Address
Register ••••••.••••.•••••••• 5-10
Programming Considerations ••••••••••••••••.•• 5-11
Transmitting via CPU ••••••••••••••.••••.•.• 5-11
Receiving via CPU •••.•••••••••••••••••••.•. 5-13
Transmitting via DMA .••••••••.•••••••••.•.. 5-15
Receiving via DMA ••••••••••••.••••.•.•••••• 5-17
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CHAPTER 6: Disk Storage
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
48TPI Flexible Disk Drive ••.••.•••••••••••••.• 6-1
Control and Data Signals •••••••••••••••••••• 6-4
Minimum Format Requirements .••••.••••.•••.• 6-13
Flexible Disk Controller ••••.••••••.•.••••• 6-15
Main Status Register •••..•.•••.•••••.•••• 6-16
Disk
Select Register •••••••••.•••.••••••• 6-18
FDC Commands and their Parameters .••.•••. 6-18
Motor On/Off ......................•...•.. 6-39
FDC Status •••••••••••••.••••••••••••.•••• 6-39
Fixed (Winchester) Disk Drive ••••.••••••.•••. 6-46
Control and Data Signals •.••••••••••••••••• 6-48
Fixed Disk Controller ••••.••••••••••••••••• 6-56
Programming
the Fixed Disk Controller •••• 6-58
Fixed Disk Controller Status ••••••••••..• 6-64
Fixed Disk Controller Diagnostics •••.••.• 6-66
Fixed Disk Format •••••••••••••••••••••••• 6-67
External Fixed Disk Connection ..••••.•••••• 6-68
1.2 MB Flexible Disk Drive •.••••••••••••.•••• 6-69
CHAPTER 7: The Screen Display
Available Adapters •. • • •. • •• . • ••• • . . • • . • . •. • • •. 7-1
Connection and Configuration .•.•..••••••.••••• 7-2
Character Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Monochrome Character Display •••.•.••••..•.••• 7-23
Character Display Memory ••..••••••••••.•••• 7-27
Character Display Controller ••..•••••••.•.. 7-28
Character Cursor •••••••••.•.••.••.•.••••••. 7-31
Color Graphics Display .•••••..••••••••...•••. 7-32
Graphics Display Memory .••.••.•...••••.••.. 7-36
Graphics Display Controller •••••••.•••••••• 7-36
Character Mode ..•.......................... 7-38
Graphics Modes ............................. 7-40
Low Resolution ........................... 7-40
Medium Resolution ........................ 7-44
High Resolution •••..•••..••••..•••••.•••• 7-45
Graphics Cursor ............................ 7-63
Controller Data Conversion ••••••.••.•..•••• 7-63
iv

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CHAPTER 8: The Keyboard
Keyboard Performance
Code Generation •••••
Diagnostics
CHAPTER 9: The Loudspeaker
8-10
8-10
8-12
Hardware Characteristics •••••••••••••••••••.•• 9-1
Programming Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
CHAPTER 10: Videotex
Introduction ••••••••
10-1
Switches and Connections • . . . . . . . . . . . . . . . . . . . . 1 0- 3
Monitor Connection
Modem and VLP Connection •••••••••••••••••••
Switches
10-4
10-4
10-7
Videotex Memory Organization ••••••••.•••••.•• 10-9
Display Generation •••••••.••••••••••••••••.•
Videotex Controller •••••••••••••••.•••••••
Character Sets
10-11
10-11
10-12
Standard Characters ••••••••••••••••••••. 10-12
Definable Characters •••••.•••••••••••••• 10-17
Character Attributes
.................... 10-28
Color Selection .......................... .
Color Layers
Color Coding
Color Look-up Table •••••.•••••••••••••••
DRCS Attributes
Transparency ........................... .
Videotex Controller Registers •••••••.•••••••
Scroll Map Registers ••••••••••••••••••••••••
Scrolling ................................ .
10-31
10-31
10-32
10-33
10-33
10-34
10-35
10-40
10-40
Text Display and RAM Access
NCR Software
. . . . . . . . . . . . . . . 10-41
Printing Videotex RAM •••••••••••••••••••••••
.........................
10-42
10-49
10-50
RS-232-C
Interfaces
RS-232-C Software Control
. . . . . . . . . . . . . . . . . 10-5 1
PCI Receiver
............................
PCI Transmitter ........................ . 10-51
10-52
V

Modem Interrupts • . •• • • • •. • •• • •• • •• •• •• . • 10-53
Programming
the PCI • . . • . . • • . •. . . •• . • • • • • 10-53
Programming Asynchronous
Communications. 10-56
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-57
Status Register •••.•••••..•••..•••••..•. 10-58
Adapter Initialization •• . . • ••••. . •• . • . • • •. . • 10-59
Modem Interface •.•••••••••••••••••.••••..• 10-59
Video
Interface ...•.•••••..••.•..•.•.•...• 10-61
Switches and Registers ••••••••••••.•..•••• 10-62
CHAPTER 11: Index
APPENDIX
A Hardware Rererence
(Includes own table of contents)
B The ROM BIOS
(Available as separate document)
vi