IBM PC 730 (Type 6877) Technical Information Manual

Technical Information Manual
PC 730 (Type 6877) and PC 750 (Type 6887)

IBM

Technical Information Manual
PC 730 (Type 6877) and PC 750 (Type 6887)

Note

Before using this information and the product it supports, be sure to read the general
information under Appendix B, “Notices and Trademarks” on page 65.

First Edition (June 1996)
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,
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Copyright International Business Machines Corporation June 1996. All rights reserved.

Note to U.S. Government Users — Documentation related to restricted rights — Use, duplication or
disclosure is subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp.

Contents

Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

Manual Style . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Numerics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Chapter 1. System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Personal Computer Description .................................. 2

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

System Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

System Address Maps ....................................... 8

Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Input/Output Address Map ................................... 9

DMA I/O Address Map ..................................... 12

IRQ and DMA Channel Assignments .............................. 13

Interrupt Request Assignments (IRQ) ............................ 13

DMA Channel Assignments .................................. 14

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Power Output Parameters ..................................... 15

PC 730 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

PC 750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Component Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Output Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Connector Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PC 730 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PC 750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Advanced Power Management (APM) .............................. 21

Chapter 2. Optional System Features ............................ 23

Audio Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

DCC Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Audio System Resources ................................... 24

Matrox Millennium Adapter .................................... 24

LAN Wake-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Wake Up On Ring ......................................... 25

Wake Up on Alarm ......................................... 25

PCMCIA and SCSI Devices .................................... 25

Chapter 3. Connectors and Jumpers ............................. 27

Copyright IBM Corp. June 1996 iii

System Board Connectors .................................... 28

Diskette Drive Connector .................................... 28

Hard Disk Drive Connectors (Primary/Secondary) ..................... 29

ISA Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

PCI Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Power Supply Connectors ................................... 33

System Board Memory Connectors .............................. 34

Video Feature Connector .................................... 35

I/O Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Infrared Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Keyboard and Auxiliary-Device Connectors ......................... 38

Serial Port Connectors ..................................... 39

Parallel Port Connector ..................................... 41

Display Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Chapter 4. Memory Subsystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Memory-Module Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Memory-Module Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Cache Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Chapter 5. System Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Hardware Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Diskette Drives and Controller ................................. 52

Hard Disk Drives and Controller ................................ 53

Software Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Software Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Machine-Sensitive Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

BIOS Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

iv

Chapter 6. Bus Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Bus Architecture Descriptions ................................... 56

ISA Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

PCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Expansion-Bus Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Bus Voltage Levels ....................................... 59

Appendix A. Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

POST Error Codes ......................................... 61

Beep Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Appendix B. Notices and Trademarks ............................ 65

Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figures

10. DC Output Parameters (200 Watt) ............................ 16

11. Component Maximum Current ............................... 17

12. Physical Specifications (PC 730) ............................. 19

13. Physical Specifications (PC 750) ............................. 20

14. Advanced Power Management Modes .......................... 21

15. Audio System Resources .................................. 24

16. Diskette Drive Connector Signal and Pin Assignments ................. 28

17. Hard Disk Drive Connector Signal and Pin Assignments ................ 29

18. I/O Channel (ISA bus) Connector ............................. 30

19. PCI Connector Signal and Pin Assignments ....................... 31

20. Power Supply Connector (Internal Devices) Signal and Pin Assignments ...... 33

21. Power Supply Connector (System Board) Signal and Pin Assignments ....... 33

22. Power Supply Connector (3.52 V dc) Signal and Pin Assignments .......... 33

23. System Board Memory Connector Signal and Pin Assignments ........... 34

24. VESA Feature Connector .................................. 35

25. IR Connector Pin Assignments ............................... 37

26. Auxiliary-Device Signal and Pin Assignments ...................... 38

27. Keyboard Signal and Pin Assignments .......................... 38

28. Serial Port Connector Signal and Pin Assignments ................... 39

29. Parallel Port Connector Signal and Pin Assignments .................. 41

30. Display Connector Signal and Pin Assignments ..................... 43

31. Memory-Module Type, Speed, and Size ......................... 46

32. System Memory Table ................................... 46

33. L1 and L2 Cache ...................................... 47

34. 5.25-Inch Diskette Drive Reading, Writing, and Formatting Capabilities ....... 52

35. 3.5-Inch Diskette Drive Reading, Writing, and Formatting Capabilities ........ 52

36. POST Error Messages ................................... 61

37. Beep Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

1. PC System Board Devices, Features, and Options ................... 4

2. System Board Diagram ................................... 7

3. System Memory Map .................................... 8

4. I/O Address Map ....................................... 9

5. DMA I/O Addresses for Memory Addresses, Word Counts, and Command/Status

Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6. Interrupt Request Assignments .............................. 13

7. DMA Channel Assignments ................................ 14

8. AC Input Power Requirements ............................... 15

9. Power Output Parameters (145 Watt) ........................... 15

Copyright IBM Corp. June 1996 v

vi

Preface

This
the IBM PC 750 (Type 6887). It is intended for developers who want to provide hardware
and software products to operate with these IBM computers and provides a more in-depth
view of how these IBM computers work. Users of this publication should have an
understanding of computer architecture and programming concepts.

Technical Information Manual

provides information for the IBM PC 730 (Type 6877) and

Copyright IBM Corp. June 1996 vii

Related Publications

The

Technical Information Manual

publications contain additional information about many of the subjects that are discussed in
this manual and also provide additional information.

IBM publications:

Understanding Your Personal Computer PC 730 (Type 6877) and PC 750 (Type 6887)
Using Your Personal Computer PC 730 (Type 6877) and PC 750 (Type 6887)
Installing Options in Your Personal Computer PC 730 (Type 6877) and PC 750 (Type

6887)
IBM Personal System/2 and Personal Computer BIOS Interface Technical Reference
IBM Personal System/2 Hardware Interface Technical Reference–Common Interfaces
IBM Personal System/2 ATA/IDE Fixed Disk Drives Technical Reference
IBM Personal System/2 Hardware Interface Technical Reference–Architectures

Other publications:

can be used with the following publications. These

S3 Trio64V+
Intel Microprocessor and Peripheral Component Literature

Corporation, Santa Clara, CA

82420/82430 PCISet ISA and EISA Bridges

CA

82430 PCISet Cache/Memory Subsystem

CA

PCI Local Bus Specification
Extended Capabilities Port: Specification Kit,

Redmond, WA

ANSI ATA-2 (AT Attachment)

, published by S3 Incorporated, Santa Clara, CA

, published by Intel Corporation, Santa Clara,

, published by Intel Corporation, Santa Clara,

, published by the PCI Special Interest Group, Hillsboro, OR

published by Microsoft Corporation,

, published by Intel

viii

Manual Style

Warning: The term

changed. Use of reserved areas can cause compatibility problems, loss of data, or
permanent damage to the hardware. When the contents of a register are changed, the state
of the reserved bits must be preserved. When possible, read the register first and change
only the bits that must be changed.

Signals

In this manual, signals are represented in a small, all-capital-letter format (-ACK). A minus
sign in front of the signal indicates that the signal is active low. No sign in front of the signal
indicates that the signal is active high.

Numerics

In this manual, use of the letter “h” indicates a hexadecimal number. Also, when numerical
modifiers such as “K”, “M” and “G“ are used, they typically indicate powers of 2, not powers
of 10 (unless expressing hard disk storage capacity). For example, 1 KB equals 1024 bytes
(210), 1 MB equals 1 048576 bytes (220), and 1 GB equals 1073741824 bytes (230).

When expressing storage capacity, MB equals 1000 KB (1024000). The value is
determined by counting the number of sectors and assuming that every two sectors equals 1
KB.

reserved

describes certain signals, bits, and registers that should not be

Note: The actual storage capacity available to the user can vary, depending on the

operating system and other system requirements.

ix

x

Chapter 1. System Description

Personal Computer Description .................................. 2

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

System Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

System Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

System Address Maps ....................................... 8

Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Input/Output Address Map ................................... 9

DMA I/O Address Map ..................................... 12

IRQ and DMA Channel Assignments .............................. 13

Interrupt Request Assignments (IRQ) ............................ 13

DMA Channel Assignments .................................. 14

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Power Output Parameters ..................................... 15

PC 730 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

PC 750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Component Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Output Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Connector Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PC 730 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

PC 750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Advanced Power Management (APM) .............................. 21

Copyright IBM Corp. June 1996 1

Personal Computer Description

The IBM PC 730 (Type 6877) and PC 750 (Type 6887) is a versatile product designed to
provide state-of-the-art computing power with room for growth in the future. Several model
variations are available. The key features are:

Intel Pentium microprocessor
Up to 128 MB of system memory
S3 Trio64V+ video subsystem
2 MB of video memory

Industry-standard compatibility

ISA/PCI I/O-bus compatibility
ISA/PCI expansion slots
Enhanced EIDE drives
Bus-master EIDE controller
Two 16550-UART serial ports (serial A and serial B)
One infrared I/O port
256 KB of external L2 cache (expandable to 512 KB)
Support for advanced power management

EnergyStar compliant

Support for Plug and Play adapters and monitors

Security features

Ready-to-configure (RTC) CD-ROM containing device drivers for all supported operating

systems

System unit packaging

– The PC 730 has three expansion slots and three drive bays
– The PC 750 has five expansion slots and five drive bays

2 Chapter 1. System Description

System Overview

Microprocessor

- Coprocessor

- L1 Cache

Processor (Local) Bus - 64-Bit

Data Buffers

Control

(ISA, DMA,

IRQ)

CMOS, Flash

Keyboard,

Mouse Ports

I/O Control

. .

Memory
(DRAM)

PCI I/O Bus - 32-Bit

IDE Control

Hard

Disk Drive,

CD-ROM

ISA I/O Bus - 16-Bit

Serial Ports

Controls

(Memory,

L2 Cache,

PCI)

Video Control,

DRAM

Video

Port

Infrared Port

Parallel Port

L2 Cache

(SRAM)

Riser Card

(ISA/PCI Slots)

Diskette Drive

Chapter 1. System Description 3

System Features

The following figure lists the devices and features for the PC 730 and PC 750 system board
in the IBM 700 series personal computer family.

Figure 1 (Page 1 of 3). PC System Board Devices, Features, and Options

Device Features
Microprocessor Intel Pentium (100/133/166 MHz)

External Cache (L2) 256 KB synchronous write-back unified (code and data)

Video Subsystem S3 Trio64V+ SVGA video controller

Bus Architecture ISA/PCI-bus-compatible I/O expansion slots

Flash ROM Subsystem 256 KB flash ROM for POST/BIOS
RAM Subsystem 16 MB standard DRAM, upgradable to 128 MB

CMOS RAM Subsystem 128-byte CMOS RAM with real-time clock, calendar, and battery
ISA/PCI Bridge ISA/PCI interface

DMA Controller Seven AT-compatible DMA channels

32-bit address bus, 64-bit data bus
8 KB internal (L1) write-through code cache
8 KB internal (L1) write-back data cache
Superscalar architecture (two execution units)

Math coprocessor function included in the Pentium
Microprocessor is upgradable for future Intel microprocessor
technology

L2 cache is upgradable to 512 KB (pipeline burst)

Plug and Play monitor support (DDC2B)

Advanced Power Management

Local peripheral bus (LPB) interface

64-bit data path width on PCI-bus

Video streams processor
Integrated DAC

64-bit graphics accelerator
2 MB of 60-ns EDO DRAM

Single-cycle EDO DRAM (deeper colors)

Synchronous 25/30/33 MHz PCI bus
50/60/66 MHz processor bus
Integrated L2 cache controller

60-ns fast page (FP) or extended data output (EDO); parity or
non-parity, dynamic random access memory (DRAM)
Four 72-pin SIMM sockets in two banks

SIMMs (4 MB, 8 MB, 16 MB, or 32 MB)

Matched pairs required in each bank
One 168-pin DIMM socket in one bank

DIMMs (16 MB, 32 MB)

PCI bus-master EIDE interface
ISA-compatible interrupt controller
ISA-compatible DMA controller

Four 8-bit channels

Three 16-bit channels

4 Chapter 1. System Description

Figure 1 (Page 2 of 3). PC System Board Devices, Features, and Options

Device Features

Interrupt Controller 15 levels of system interrupts

System Timers Channel 0–System timer

Audio Subsystem Mwave DSP data collaboration ISA adapter (optional)

Diskette Drive Controller Controller supports two internal diskette drives

Keyboard/Auxiliary-Device
Controller

Parallel Port Controller One ECP parallel port

Serial Port Controller Two 16550-UART serial ports (Serial A and B)

High Speed Infrared (HSIR)
Controller

Hard Disk Drive Controller Controller supports four EIDE devices

Power 145/200 watt power supplies

AT-bus interrupts are edge triggered
PCI bus interrupts are level sensitive

Channel 1–Refresh generation
Channel 2–Tone generation for speaker

Programmable DSP

28.8 Kbps data/fax modem
Sound Blaster Pro compatibility
Front panel audio control

A 3.5-in. diskette drive (1.44 MB and 2.88 MB) is standard
A 5.25-in. diskette drive (360 KB and 1.2 MB) is optional

A second 3.25-in. diskette drive (1.44 MB and 2.88 MB) is
optional and requires a 3.5-in. conversion kit for a 5.25-in.
bay

FIFO operations

101-key or 102-key keyboard
Keyboard connector
Auxiliary-device connector
Password security

Supports standard I/O mode, extended capabilities port (ECP)

mode, and enhanced parallel port (EPP) mode

Note: Serial B is disabled if infrared port is used

One HSIR port

Infrared Data Association (IrDa) interface

Infrared transceiver (optional)

PCI bus-master EIDE interface

Two PCI bus-master channels
One channel for each EIDE connector (primary and

secondary)

SCSI hard disk drives require a PCI SCSI adapter

PC 730: 145 W, 115/230 V ac, 50/60 Hz

PC 750: 200 W, 115/230 V ac, 50/60 Hz
Built-in overload and surge protection
Advanced Power Management

Chapter 1. System Description 5

Figure 1 (Page 3 of 3). PC System Board Devices, Features, and Options

Device Features
Security Power-on password

Administrator password

Startup sequence control
Unattended Start mode
Diskette I/O control
Hard disk I/O control

Lockable cover

Software-readable hardware IDs

Tamper switch

6 Chapter 1. System Description

System Board

The system board might look slightly different from the one shown.
Note: A diagram of the system board, including switch and jumper settings, is attached to

the underside of the computer top cover.

1 Power connector (5 V)
2 J9 modem ring
3 J14 LAN Wake-Up
4 J13 modem ring
5 J15 password jumper (CMOS clear)
6 J16 auxiliary power
7 J18 on/off switch
8 J19 tamper connector
9 Secondary IDE connector
1 Primary IDE connector
11 Diskette connector
12 Tamper (reserved)
13 Battery
14 Voltage regulator connector
15 Power connector (3.3 V)
16 Switch set (SW1)
17 Processor upgrade socket
18 Cache memory module connector
19 Power LED connector
2 Hard disk access LED connector
21 Speaker connector
22 DSP audio connector
23 DIMM/SIMM connectors
24 VESA passthrough connector
25 Riser connector
26 Video port
27 ECP/EPP port
28 Serial (B) port
29 Serial (A) port
3 Mouse port
31 Keyboard port
32 Infrared port

1

20 1

32

31

Figure 2. System Board Diagram

1

Extended capabilities port (ECP) and enhanced parallel port (EPP)

Chapter 1. System Description 7

System Address Maps

Memory Map

The first 640 KB of system board RAM is mapped starting at address 0000000h. A 256-byte
area and a 1 KB area of this RAM are reserved for BIOS data areas. Memory can be
mapped differently if POST detects an error. See the section about BIOS data areas in the

IBM Personal System/2 and Personal Computer BIOS Interface Technical Reference

details.
Note: After POST is completed, portions of the 64 KB segment starting at memory address

E0000h, are available for upper memory blocks and adapters.

Figure 3. System Memory Map

Address Range (hex) Size Description

00000000–0007FFFF 512 KB Conventional
00080000–0009FBFF 127 KB Extended conventional
0009FC00–0009FFFF 1 KB Extended BIOS data
000A0000–000BFFFF 128 KB S3 Trio64V+
000C0000–000C7FFF 32 KB S3 Trio64V+ ROM BIOS (shadowed)
000D8000–000DFFFF 96 KB ISA/PCI space; available to ISA adapter ROMs
000E0000–000FFFFF 128 KB System ROM BIOS (ISA bus, shadowed)

00100000–00FFFFFF 15 MB ISA/PCI space
01000000–07FFFFFF 111 MB PCI space
08000000–72FFFFFF 1712 MB PCI space
07300000–737FFFFF 8 MB S3 Trio64V+ linear frame buffer
73800000–FFFDFFFF 2247.9 MB PCI space
FFFE0000–FFFFFFFF 128 KB System ROM BIOS (ISA bus)

for

E000:0-E800:0 used for Advanced Power Management
(APM)

8 Chapter 1. System Description

Input/Output Address Map

The following figures list the system board I/O address maps. Any addresses that are not
shown are reserved.

Figure 4 (Page 1 of 3). I/O Address Map

Address (Hex) Device

0000–000F DMA 1
0020–003F Interrupt controller 1
0040–0043 Timer 1
0044–0047 Available I/O for ISA/PCI bus
0048–0049 Rapid Resume Advanced Power Management registers
004A–004B, bits 7,6 CPU speed registers
004C–005F Available I/O for ISA/PCI bus
0060 Keyboard controller data byte
0061 System Port B
0062–0063 Available I/O for ISA/PCI bus
0064 Keyboard controller, command and status byte
0065–006F Available I/O for ISA/PCI bus
0070, bit 7 Enable/disable NMI
0070, bits 6:0 Real time clock address
0071 Real time clock data
0072–007F Available I/O for ISA/PCI bus
0077 DCC setup/presence detect
0078 GPIO CPU speed detect
0079 National 87306 GPIO, A17 for flash
007A National 87306 GPIO
007C–007F L2 Cache ID, tamper EEPROM, SMI/PCI IRQ enable
0080 POST Checkpoint register
0080-008F DMA page register
0090–0091 Available I/O for ISA/PCI bus
0092 System Port A (not supported)
0093 Available I/O for ISA/PCI bus
0094 Reserved
0095–009F Available I/O for ISA/PCI bus
00A0–00BF Interrupt controller 2
00C0–00DE DMA 2
00DF–00ED Available I/O for ISA/PCI bus
00EE Reserved
00EF Reserved
00F0 Coprocessor busy–Clear
00F1 Coprocessor reset
00F2–00F3 Available I/O for ISA/PCI bus
00F4 Slow CPU
00F5 Fast CPU
00F6–00FF Available I/O for ISA/PCI bus
0100–0105 Reserved riser
0106–016F Available I/O for ISA/PCI bus
0130–013F Default for data collaboration card (DCC)
0170–0177 IDE channel 1
01B0–01BF Alternate for data collaboration card (DCC)
01F0–01F7 IDE channel 0
01F8–021F Available I/O for ISA/PCI bus
0220–0227 National 87306, serial port 3 or 4
0228–0277 Available I/O for ISA/PCI bus
0230–023F Alternate for data collaboration card (DCC)
0278–027F National 87306, parallel port 3

Chapter 1. System Description 9

Figure 4 (Page 2 of 3). I/O Address Map

Address (Hex) Device

0280–02E7 Available I/O for ISA/PCI bus
02B0–02BF Alternate for data collaboration card (DCC)
02E8–02EF National 87306, serial port 3 or 4
02F0–02F7 Available I/O for ISA/PCI bus
02F8–02FF National 87306, serial port 2 (system board)
0300–0337 Available I/O for ISA/PCI bus
0338–033F National 87306, serial port 3 or 4
0340–0375 Available I/O for ISA/PCI bus
0376–0377 IDE channel 1
0377, bit 7 IDE, diskette change
0378–037F National 87306, parallel port 2
0380–0387 Available I/O for ISA/PCI bus
0388 Available I/O for ISA/PCI bus
0389 Available I/O for ISA/PCI bus
038A Available I/O for ISA/PCI bus
038B Available I/O for ISA/PCI bus
038C–03BB Available I/O for ISA/PCI bus
03B4–03BB S3 Trio64V+
03BC–03BE National 87306, parallel port 1 (system board)
03BF–03DF S3 Trio64V+
03E0–03E7 Available I/O for ISA/PCI bus
03E8–03EF National 87306, serial port 3 or 4
03F0–03F5 National 87306, diskette channel 0
03F6 IDE channel 0
03F7, bit 7 IDE, diskette change
03F7, bits 6:0 IDE channel 0
03F8–03FF National 87306, serial port 1 (system board)
0400–052F Available I/O for ISA/PCI bus
0530–0537 Available I/O for ISA/PCI bus
0530–0537 Available I/O for ISA/PCI bus
0CF8–0CFB PCI configuration address register
0CFC–0CFF PCI configuration data registers
0D00–0E7F Available I/O for ISA/PCI bus
0E80–0E87 Available I/O for ISA/PCI bus
0E88–0F3F Available I/O for ISA/PCI bus
0F40–0F47 Available I/O for ISA/PCI bus
0F47–042E7 Available I/O for ISA/PCI bus
42E8 S3 Trio64V+
42E9–4AE7 Available I/O for ISA/PCI bus
4AE8 S3 Trio64V+
4AE9–82E7 Available I/O for ISA/PCI bus
82E8 S3 Trio64V+
82E9–86E7 Available I/O for ISA/PCI bus
86E8 S3 Trio64V+
86E9–8AE7 Available I/O for ISA/PCI bus
8AE8 S3 Trio64V+
8AE9–8EE7 Available I/O for ISA/PCI bus
8EE8 S3 Trio64V+
8EE9–92E7 Available I/O for ISA/PCI bus
92E8 S3 Trio64V+
92E9–96E7 Available I/O for ISA/PCI bus
96E8 S3 Trio64V+
96E9–9AE7 Available I/O for ISA/PCI bus
9AE8 S3 Trio64V+
9AE9–9EE7 Available I/O for ISA/PCI bus

10 Chapter 1. System Description

Figure 4 (Page 3 of 3). I/O Address Map

Address (Hex) Device

9EE8 S3 Trio64V+
9EE9–A2E7 Available I/O for ISA/PCI bus
A2E8 S3 Trio64V+
A2E9–A6E7 Available I/O for ISA/PCI bus
A6E8 S3 Trio64V+
A6E9–AAE7 Available I/O for ISA/PCI bus
AAE8 S3 Trio64V+
AAE9–B2E7 Available I/O for ISA/PCI bus
B2E8 S3 Trio64V+
B2E9–B6E7 Available I/O for ISA/PCI bus
B6E8 S3 Trio64V+
B6E9–BAE7 Available I/O for ISA/PCI bus
BAE8 S3 Trio64V+
BAE9–BEE7 Available I/O for ISA/PCI bus
BEE8 S3 Trio64V+
BEE9–E2E7 Available I/O for ISA/PCI bus
E2E8 S3 Trio64V+
E2E9 Available I/O for ISA/PCI bus
E2EA S3 Trio64V+
E2EB–FFFF Available I/O for ISA/PCI bus

Chapter 1. System Description 11

DMA I/O Address Map

Figure 5. DMA I/O Addresses for Memory Addresses, Word Counts, and Command/Status

Registers

Address
(Hex)

0000 Channel 0, Memory Address register 00–15 Yes
0001 Channel 0, Transfer Count register 00–15 Yes
0002 Channel 1, Memory Address register 00–15 Yes
0003 Channel 1, Transfer Count register 00–15 Yes
0004 Channel 2, Memory Address register 00–15 Yes
0005 Channel 2, Transfer Count register 00–15 Yes
0006 Channel 3, Memory Address register 00–15 Yes
0007 Channel 3, Transfer Count register 00–15 Yes
0008 Channels 0–3, Read Status/Write Command register 00–07
0009 Channels 0–3, Write Request register 00–02
000A Channels 0–3, Write Single Mask register bits 00–02
000B Channels 0–3, Mode register (write) 00–07
000C Channels 0–3, Clear byte pointer (write) N/A
000D Channels 0–3, Master clear (write)/temp (read) 00–07
000E Channels 0–3, Clear Mask register (write) 00–03
000F Channels 0–3, Write All Mask register bits 00–03
0081 Channel 2, Page Table Address register† 00–07
0082 Channel 3, Page Table Address register† 00–07
0083 Channel 1, Page Table Address register† 00–07
0087 Channel 0, Page Table Address register† 00–07
0089 Channel 6, Page Table Address register† 00–07
008A Channel 7, Page Table Address register† 00–07
008B Channel 5, Page Table Address register† 00–07
008F Channel 4, Page Table Address/Refresh register 00–07
00C0 Channel 4, Memory Address register 00–15 Yes
00C2 Channel 4, Transfer Count register 00–15 Yes
00C4 Channel 5, Memory Address register 00–15 Yes
00C6 Channel 5, Transfer Count register 00–15 Yes
00C8 Channel 6, Memory Address register 00–15 Yes
00CA Channel 6, Transfer Count register 00–15 Yes
00CC Channel 7, Memory Address register 00–15 Yes
00CE Channel 7, Transfer Count register 00–15 Yes
00D0 Channels 4–7, Read Status/Write Command register 00–07
00D2 Channels 4–7, Write Request register 00–02
00D4 Channels 4–7, Write Single Mask register bit 00–02
00D6 Channels 4–7, Mode register (write) 00–07
00D8 Channels 4–7, Clear byte pointer (write) N/A
00DA Channels 4–7, Master clear (write)/temp (read) 00–07
00DC Channels 4–7, Clear Mask register (write) 00–03
00DE Channels 4–7, Write All Mask register bits 00–03
00DF Channels 5–7, 8- or 16-bit mode select 00–07

† Upper byte of Memory Address register

Description

Bits

Byte
Pointer

12 Chapter 1. System Description

IRQ and DMA Channel Assignments

The following figures list the interrupt request (IRQ) and direct memory access (DMA)
channel assignments.

Interrupt Request Assignments (IRQ)

Figure 6. Interrupt Request Assignments

Interrupt
Request

(IRQ)

NMI Critical system error
SMI System/power management interrupt

0 Reserved (internal timer)
1 Reserved (keyboard buffer full)
2 Reserved (cascade interrupt from slave)
3 Serial port 2†
4 Serial port 1‡
5 Parallel port 2†
6 Diskette controller‡
7 Parallel port 1 or business audio if installed‡
8 Reserved (real-time clock)

9 Video adapter (if installed) or business audio†
10 ISA/PCI bus or business audio.
11 ISA/PCI bus or business audio.
12 Mouse port†
13 Reserved (math coprocessor)
14 IDE Channel 1†
15 IDE Channel 2‡

† If not assigned, this resource is available for ISA/PCI bus.
‡ If not assigned, this resource is available for ISA bus.

System Resource

Chapter 1. System Description 13

DMA Channel Assignments

Figure 7. DMA Channel Assignments

DMA

Channel Data Width System Resource

0 8 bits Business audio†
1 8 bits Business audio or LAN†
2 8 bits Reserved (diskette drive)
3 8 bits Business audio or ECP parallel port†
4 Reserved (cascade channel)
5 16 bits ISA bus
6 16 bits ISA bus
7 16 bits ISA bus

† If not assigned, this resource is available for ISA bus.

14 Chapter 1. System Description

Power Supply

The power supply converts the ac input voltage into four dc output voltages and provides
power for the following:

System board
Adapters

Internal DASD drives
Keyboard and auxiliary devices

The power supply requirements are supplied by a 145-watt (PC 730) or 200-watt (PC 750)
power supply. The following figure shows the input power specifications. The power
available for each component with the system is shown in Figure 11 on page 17.

Figure 8. AC Input Power Requirements

Specification Measurements
Input voltage (range is switch selected; sine wave input is required)

Low range 110 (min)–127 (max) V ac
High range 200 (min)–240 (max) V ac

Input frequency 50 Hz ± 3 Hz or 60 Hz ± 3 Hz

Power Output Parameters

The power supply dc outputs shown in the following figures include the current supply
capability of all the connectors including system board, DASD, PCI, and auxiliary outputs.

PC 730

Figure 9. Power Output Parameters (145 Watt)

Output Voltage Regulation Minimum Current

+5 volts +5% to -4% 1.5 A 18.0 A
+12 volts +5% to -4% 0.2 A 4.2 A

-12 volts +10% to -9% 0.0 A 0.4 A

-5 volts +5% to -4% 0.0 A 0.3 A
+3.52 volts +2.5% to -2.5% 0.0 A 10.0 A
+5 volt (auxiliary) +5% to -10% 0.0 A .02 A

Note: Simultaneous loading of +5 V and +3.52 V must not exceed 90 watts.

(amps)

Maximum Current
(amps)

Chapter 1. System Description 15

PC 750

Figure 10. DC Output Parameters (200 Watt)

Output Voltage Regulation Minimum Current

(amps)

+5 volts +5% to -4% 1.5 A 20.0 A
+12 volts +5% to -4% 0.2 A 8.0 A

-12 volts +10% to -9% 0.0 A 0.5 A

-5 volts +5% to -4% 0.0 A 0.5 A
+3.52 volts +2.5% to -2.5% 0.0 A 20.0 A
+5 volt (auxiliary) +5% to -10% 0.0 A .02 A

Maximum Current
(amps)

Note: Simultaneous loading of +5 V and +3.52 V must not exceed 90 watts maximum.

The power supply provides 180 watts of continuous power and 200 watts at peak power to
the system board and peripheral devices. It provides a fan that cools both the power supply
and the microprocessor by drawing external air through the power supply and blowing it onto
the microprocessor. A single connector provides the voltages required by the system board,
including +3.52 V dc. Five connectors are provided for attachment of peripheral devices.

16 Chapter 1. System Description

Component Outputs

The power supply provides separate voltage sources for the system board and internal
storage devices. The following figure shows the approximate power that is provided for
system components. Many components draw less current than the maximum shown.

Figure 11. Component Maximum Current

Supply Voltage (V dc) Maximum Current (mA) Regulation Limits

System Board:

Keyboard Port:

Auxiliary Device Port:

AT-Bus Adapters (Per Slot):

PCI-bus Adapters (Per Slot)†:

Internal DASD:

† For each PCI connector, the maximum power consumption is rated at 25 watts for +5 V and +3.52 V
combined.

+3.52 V dc 3000 mA +2.5% to −2.5%

+5.0 V dc 4000 mA +5.0% to −5.0%

+12.0 V dc 25.0 mA +5.0% to −5.0%

−12.0 V dc 25.0 mA +10.0% to −9.0%

+5.0 V dc 275 mA +5.0% to −5.0%

+5.0 V dc 300 mA +5.0% to −5.0%

+5.0 V dc 4500 mA +5.0% to −5.0%

−5.0 V dc 200 mA +5.0% to −5.0%

+12.0 V dc 1500 mA +5.0% to −5.0%

−12.0 V dc 300 mA +5.0% to −5.0%

+5.0 V dc 5000 mA +5.0% to −4.0%

+3.52 V dc 5000 mA ±300 mV

+5.0 V dc 1400 mA +5.0% to −5.0%

+12.0 V dc 1500 mA +5.0% to −5.0%

Note: Some adapters and hard disk drives draw more current than the recommended limits.

These adapters and drives can be installed in the system; however, the power supply
will shut down if the total power used exceeds the maximum power that is available.

Chapter 1. System Description 17

Output Protection

The power supply protects against output overcurrent, overvoltage, and short circuits.
Please see the power supply specifications for details.

A short circuit that is placed on any dc output (between outputs or between an output and dc
return) latches all dc outputs into a shutdown state, with no damage to the power supply.

If this shutdown state occurs, the power supply returns to normal operation only after the
fault has been removed and the power switch has been turned off for at least one second.

If an overvoltage fault occurs (in the power supply), the power supply latches all dc outputs
into a shutdown state before any output exceeds 130% of the nominal value of the power
supply.

Connector Description

The power supply has up to five 4-pin connectors for internal devices. The total power used
by the connectors must not exceed the amount shown in Figure 11 on page 17. Signal and
pin assignments are shown on page 33.

18 Chapter 1. System Description

Physical Specifications

The following figure describe the physical specifications. Each mechanical package is
described separately.

PC 730

Figure 12. Physical Specifications (PC 730)

Size

Width 360 mm (14.2 in.)
Depth 450 mm (17.7 in.)
Height 130 mm (5.1 in.)

Weight
Minimum configuration 8.6 kg (19.0 lb)

Maximum configuration (fully populated with typical options) 10.4 kg (23.0 lb)

Cables

Power cable 1.8 m (6 ft)
Keyboard cable 3.05 m (10 ft)

Air Temperature

System on 10.0 to 32.0°C (50 to 90°F)
System off 10.0 to 43.0°C (50 to 110°F)

Humidity

System on 8% to 80%
System off 8% to 80%

Maximum Altitude† 2133.6 m (7000 ft)
Heat Output

Minimum configuration 35 W (120 Btu per hour)
Maximum configuration‡ 200 W (685 Btu per hour)

Electrical

Input voltage (range is switch selected; sine wave input is required)
Low range 110 (min) to 127 (max) V ac
High range 200 (min) to 240 (max) V ac

Frequency 50 ± 3 Hz or 60 ± 3 Hz

Input, in kilovolt-ampere (kVA)
Minimum configuration 0.08 kVA
Maximum configuration 0.30 kVA

Electromagnetic Compatibility FCC Class B
† This is the maximum altitude at which the specified air temperatures apply. At higher altitudes,

the maximum air temperatures are lower than those specified.

‡ Based on the 145-watt maximum capacity of the system power supply.

Chapter 1. System Description 19

PC 750

Figure 13. Physical Specifications (PC 750)

Size

Width 420 mm (16.5 in.)
Depth 448 mm (17.6 in.)
Height 160 mm (6.3 in.)

Weight
Minimum configuration 12.7 Kg (28.0 lb)

Maximum configuration (fully populated with typical options) 14.1 Kg (31.1 lb)

Cables

Power cable 1.8 m (6 ft)
Keyboard cable 3.05 m (10 ft)

Air Temperature

System on 10.0 to 32.0°C (50 to 90°F)
System off 10.0 to 43.0°C (50 to 110°F)

Humidity

System on 8% to 80%
System off 8% to 80%

Maximum Altitude† 2133.6 m (7000 ft)
Heat Output

Minimum configuration 35 W (120 Btu per hour)
Maximum configuration‡ 310 W (1060 Btu per hour)

Electrical

Input voltage (range is switch selected; sine wave input is required)
Low range 110 (min) to 127 (max) V ac
High range 200 (min) to 240 (max) V ac

Frequency 50 ± 3 Hz or 60 ± 3 Hz

Input, in kilovolt-ampere (kVA)
Minimum configuration 0.08 kVA
Maximum configuration 0.52 kVA

Electromagnetic Compatibility FCC Class B
† This is the maximum altitude at which the specified air temperatures apply. At higher altitudes,

the maximum air temperatures are lower than those specified.

‡ Based on the 200-watt maximum capacity of the system power supply.

20 Chapter 1. System Description

Advanced Power Management (APM)

The computers come with built-in energy-saving capabilities. Advanced Power Management
(APM) is a feature that reduces the power consumption of systems when they are not being
used. APM, when enabled, initiates reduced-power modes for the monitor, microprocessor,
and hard disk drive after a specified period of inactivity.

The following figure summarizes APM modes.

Figure 14. Advanced Power Management Modes

Mode Power Response

On (Ready) System is at full power Standard operation
On (Standby) System is at reduced power Any use of keyboard, mouse, or

Off System is powered off Power switch restores full power

The BIOS supports APM V1.O AND V1.1. This enables the system to enter a power
managed state, which reduces the power drawn from the ac wall outlet. Advanced Power
Management is enabled through the Configuration/Setup Utility program and is controlled by
the individual operating system.

hard disk drive restores full power

Chapter 1. System Description 21

22 Chapter 1. System Description

Chapter 2. Optional System Features

Audio Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

DCC Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Audio System Resources ................................... 24

Matrox Millennium Adapter .................................... 24

LAN Wake-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Wake Up On Ring ......................................... 25

Wake Up on Alarm ......................................... 25

PCMCIA and SCSI Devices .................................... 25

Copyright IBM Corp. June 1996 23

Audio Subsystem

Some models have a front audio interface panel and an ISA data collaboration card (DCC)
featuring an Mwave digital-signal processor (DSP) subsystem.

The DCC provides the following support:
Programmable DSP

28.8 Kbps data/fax modem
Simultaneous record and playback of CD quality audio
Compatible with Sound Blaster Pro
Front panel headphone and microphone jacks with volume control

DCC Connectors

The DCC consists of a base card and a daughter card attached to the base card. The base
card contains the DSP and audio circuits. The daughter card contains the communication
interface required to access the telephone network. Four cables connect the DCC to the
system board.

Audio System Resources

Figure 15. Audio System Resources

Resource Resource Assignment

ROM none
RAM none
I/O (hex) 77, 130-13F, 1B0-1BF, 230-23F, 2B0-2BF, 300, 330
IRQ 3, 4, 5, 7, 9, 10, 11
DMA 0, 1, 3, 5

Matrox Millennium Adapter

The optional
technology, which provides very fast graphics and video acceleration. It is VGA- and
VESA-compatible (SVGA, DPMS, DDC).

LAN Wake-Up

Some models are configured for LAN connection with an Ethernet adapter or a token ring
adapter. These models are enabled for LAN Wake-Up using LAN adapters that support the
LAN Wake-Up feature.

The LAN Wake-Up feature allows the personal computer to be powered up in an unattended
mode, with keyboard and mouse input locked, when a specific LAN frame is passed to the
PC through the LAN. This feature works in coordination with Advanced Power Management
(APM).

24 Chapter 2. Optional System Features

Matrox Millennium Graphics Adapter

takes advantage of 64-bit graphics engine

Wake Up On Ring

When this option is enabled, the computer is turned on automatically when a ring is detected
on a modem. Two options control this feature:

Serial Ring Detect: Set this option to Enabled if the computer has an external modem

connected to the serial port.

Modem Ring Detect: Set this option to Enabled if the computer has an internal

modem.

Wake Up on Alarm

With this option, you can specify a date and time at which the computer will be turned on
automatically. This can be either a single event or a daily event.

PCMCIA and SCSI Devices

Personal Computer Memory Card International Association (PCMCIA)

System Interface (SCSI) devices support can be added with optional adapters.

and Small Computer

Chapter 2. Optional System Features 25

26 Chapter 2. Optional System Features

Chapter 3. Connectors and Jumpers

System Board Connectors .................................... 28

Diskette Drive Connector .................................... 28

Hard Disk Drive Connectors (Primary/Secondary) ..................... 29

ISA Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

PCI Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Power Supply Connectors ................................... 33

System Board Memory Connectors .............................. 34

Video Feature Connector .................................... 35

I/O Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Infrared Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Keyboard and Auxiliary-Device Connectors ......................... 38

Serial Port Connectors ..................................... 39

Serial-Port Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Data Collaboration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Parallel Port Connector ..................................... 41

Parallel-Port Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Parallel-Port Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Display Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Copyright IBM Corp. June 1996 27

System Board Connectors

The following figures show the connectors that are available on the system board and riser
card.

Diskette Drive Connector

The computer has a 34-pin connector that supports the attachment of up to two diskette
drives. The following figure shows the signal and pin assignments for the system board
diskette drive connector.

Figure 16. Diskette Drive Connector Signal and Pin Assignments

Pin Signal Pin Signal

1 Ground 2 High density select
3 Ground 4 Not connected
5 Ground or key 6 -Data rate select 0
7 Ground 8 -Index
9 Ground 10 -Motor enable 0
11 Ground 12 -Drive select 1
13 Ground 14 -Drive select 0
15 Ground 16 -Motor enable 1
17 Ground or MSEN1 18 -Direction in
19 Ground 20 -Step
21 Ground 22 -Write data
23 Ground 24 -Write enable
25 Ground 26 -Track 0
27 Ground or MSEN0 28 -Write protect
29 Ground 30 -Read data
31 Ground 32 -Head 1 select
33 Ground 34 -Diskette change

28 Chapter 3. Connectors and Jumpers

Hard Disk Drive Connectors (Primary/Secondary)

The computer has a dedicated I/O channel for connecting a hard disk drive. The signals that
are provided by this connector include the 16-bit data bus, address lines A0 to A2, IRQ, and

-IO CS16. These signals operate in the same way as the normal I/O-channel signals. The

interface to the hard disk drive complies with
The address decode logic for the hard disk drive is on the system board. On a valid decode

of A0 through A15 equal to 01F0h through 01F7h, -HFCS0 (0170h through 0177h, -HFCS2 for a
secondary hard disk drive) goes active. On a valid decode of A0 through A15 equal to 03F6h
through 03F7h, -HFCS1 (0376h through 0377h, -HFCS3 for a secondary hard disk drive) goes
active.

The following figure shows the signal and pin assignments for the hard disk drive connector.

Figure 17. Hard Disk Drive Connector Signal and Pin Assignments

Pin Signal Pin Signal

1 -RESET 2 Ground
3 Data bus bit 7 4 Data bus bit 8
5 Data bus bit 6 6 Data bus bit 9
7 Data bus bit 5 8 Data bus bit 10
9 Data bus bit 4 10 Data bus bit 11
11 Data bus bit 3 12 Data bus bit 12
13 Data bus bit 2 14 Data bus bit 13
15 Data bus bit 1 16 Data bus bit 14
17 Data bus bit 0 18 Data bus bit 15
19 Ground 20 Key (Reserved)
21 DRQ0/DRQ1 22 Ground
23 -IO Write 24 Ground
25 -IO Read 26 Ground
27 IO Channel Ready 28 VCC pullup
29 DACK0/DACK1 30 Ground
31 IRQ14/IRQ15 32 VCC pullup
33 Device address A1 34 Ground
35 Device address A0 36 Device address A2
37 -HFCS0 38 -HFCS1
39 Activity # 40 Ground

ANSI ATA-2 (AT Attachment)

.

Chapter 3. Connectors and Jumpers 29

ISA Connector

The I/O channel (ISA bus) is buffered to provide sufficient drive for the 98-pin connectors,
assuming two low-power Schottky (LS) loads per slot.

The following figure shows the signal and pin assignments for the I/O channel connectors.

Rear Panel

Ground
RESET DRV
+5 V dc
IRQ 2

-5 V dc
DRQ2

-12 V dc

-0WS
+12 V dc
Ground

-SMEMW

-SMEMR

-IOW

-IOR

-DACK3
DRQ3

-DACK1
DRQ1

-REFRESH
CLK
IRQ7
IRQ6
IRQ5
IRQ4
IRQ3

-DACK2
TC
BALE
+5 V dc
OSC
Groun

-MEM CS16

-I/O CS16
IRQ10
IRQ11
IRQ12
IRQ15
IRQ14

-DACK0
DRQ0

-DACK5
DRQ5

-DACK6
DRQ6

-DACK7
DRQ7

+5V dc

-MASTER
Ground

B1

B10

B20 A20

B31

D1

D10

A1

A10

A31

C1

C10

C18D18

-I/O CH CK
SD7
SD6
SD5
SD4
SD3
SD2
SD1
SD0
I/O CH RDY
AEN
SA19
SA18
SA17
SA16
SA15
SA14
SA13
SA12
SA11
SA10
SA9
SA8
SA7
SA6
SA5
SA4
SA3
SA2
SA1
SA0

-SBHE
LA23
LA22
LA21
LA20
LA19
LA18
LA17

-MEMR

-MEMW
SD08
SD09
SD10
SD11
SD12
SD13
SD14
SD15

Figure 18. I/O Channel (ISA bus) Connector

30 Chapter 3. Connectors and Jumpers

PCI Connectors

The peripheral component interconnect (PCI) connector is a 124-pin connector. Personal
computers with PCI riser cards support the 32-bit 5-V dc local-bus signalling environment
that is defined in the
pin assignments for the PCI connector.

Note: 3.52 V dc is supplied through an optional 5 V dc to 3.52 V dc regulator.

Figure 19 (Page 1 of 2). PCI Connector Signal and Pin Assignments

Pin Signal Pin Signal

1 A TRST# 32 A Address 16
2A +12 V dc 33 A +3.52 V dc
3 A TMS 34 A FRAME#
4 A TDI 35 A Ground
5A +5 V dc 36 A TRDY#
6 A INTA# 37 A Ground
7 A INTC# 38 A STOP#
8A +5 V dc 39 A +3.52 V dc
9 A Reserved 40 A SDONE

10 A +5 V dc (I/O) 41 A SBO#
11 A Reserved 42 A Ground
12 A Ground 43 A PAR
13 A Ground 44 A Address/Data 15
14 A Reserved 45 A +3.52 V dc
15 A RST# 46 A Address/Data 13
16 A +5 V dc (I/O) 47 A Address/Data 11
17 A GNT# 48 A Ground
18 A Ground 49 A Address/Data 9
19 A Reserved 50 A Connector key
20 A Address/Data 30 51 A Connector key
21 A +3.52 V dc 52 A C/BE0“#
22 A Address/Data 28 53 A +3.52 V dc
23 A Address/Data 26 54 A Address/Data 6
24 A Ground 55 A Address/Data 4
25 A Address/Data 24 56 A Ground
26 A IDSEL 57 A Address/Data 2
27 A +3.52 V dc 58 A Address/Data 0
28 A Address/Data 22 59 A +5 V dc (I/O)
29 A Address/Data 20 60 A REQ64#
30 A Ground 61 A +5 V dc

31 A Address/Data 18 62 A +5 V dc
1B −12 V dc 32 B Address/Data 17
2 B TCK 33 B C/BE2“#
3 B Ground 34 B Ground
4 B TDO 35 B IRDY#
5B +5 V dc 36 B +3.52 V dc
6B +5 V dc 37 B DEVSEL#
7 B INTB# 38 B Ground
8 B INTD# 39 B LOCK#
9 B PRSNT1# 40 B PERR#

10 B Reserved 41 B +3.52 V dc

11 B PRSNT2 42 B SERR#

12 B Ground 43 B +3.52 V dc

13 B Ground 44 B C/BE1“#

PCI Local Bus Specification

. The following figure shows the signal and

Chapter 3. Connectors and Jumpers 31

Figure 19 (Page 2 of 2). PCI Connector Signal and Pin Assignments

Pin Signal Pin Signal

14 B Reserved 45 B Address/Data 14
15 B Ground 46 B Ground
16 B CLK 47 B Address/Data 12
17 B Ground 48 B Address/Data 10
18 B REQ# 49 B Ground
19 B +5 V dc (I/O) 50 B Connector key
20 B Address/Data 31 51 B Connector key
21 B Address/Data 29 52 B Address/Data 8
22 B Ground 53 B Address/Data 7
23 B Address/Data 27 54 B +3.52 V dc
24 B Address/Data 25 55 B Address/Data 5
25 B +3.52 V dc 56 B Address/Data 3
26 B C/BE3“# 57 B Ground
27 B Address/Data 23 58 B Address/Data 1
28 B Ground 59 B +5 V dc (I/O)
29 B Address/Data 21 60 B ACK64#
30 B Address/Data 19 61 B +5 V dc
31 B +3.52 V dc 62 B +5 V dc

32 Chapter 3. Connectors and Jumpers

Power Supply Connectors

The power supply utilizes 4-pin connectors for internal devices. The total power used by the
connectors must not exceed the amount shown in Figure 11 on page 17.

Figure 20. Power Supply Connector (Internal Devices) Signal and Pin Assignments

Pin Signal Pin Signal

1 +12 V dc 3 Ground
2 Ground 4 +5 V dc

The computer has a 12-pin power supply connector. The following figure shows the signal
and pin assignments for the system board power supply connector.

Figure 21. Power Supply Connector (System Board) Signal and Pin Assignments

Pin Signal Pin Signal

1 Power good (+5 V dc) 2 +5 V dc
3 +12 V dc 4 −12 V dc
5 Ground 6 Ground
7 Ground 8 Ground
9 −5 V dc 10 +5 V dc
11 +5 V dc 12 +5 V dc

4321

The computer has an additional 6-pin power supply connector that plugs into the riser card.
The following figure shows the signal and pin assignments for the system board power
supply connector.

Figure 22. Power Supply Connector (3.52 V dc) Signal and Pin Assignments

Pin Signal Pin Signal

1 Ground 2 Ground
3 Ground 4 +3.52 V dc
5 +3.52 V dc 6 +3.52 V dc

Chapter 3. Connectors and Jumpers 33

System Board Memory Connectors

The following figure shows the signal and pin assignments for the 72-pin system board
memory connectors. Data bits 0 through 15 are the low word, and data bits 16 through 31
are the high word.

Figure 23. System Board Memory Connector Signal and Pin Assignments

Pin Signal Pin Signal

1 Ground 37 Parity 1
2 Data 0 38 Parity 3
3 Data 16 39 Ground
4 Data 1 40 Column address strobe 0
5 Data 17 41 Column address strobe 2
6 Data 2 42 Column address strobe 3
7 Data 18 43 Column address strobe 1
8 Data 3 44 Row address strobe 0
9 Data 19 45 Row address strobe 1
10 +5 V dc 46 Reserved
11 Reserved 47 Write enable
12 Address 0 48 Reserved
13 Address 1 49 Data 8
14 Address 2 50 Data 24
15 Address 3 51 Data 9
16 Address 4 52 Data 25
17 Address 5 53 Data 10
18 Address 6 54 Data 26
19 Address 10 55 Data 11
20 Data 4 56 Data 27
21 Data 20 57 Data 12
22 Data 5 58 Data 28
23 Data 21 59 +5 V dc
24 Data 6 60 Data 29
25 Data 22 61 Data 13
26 Data 7 62 Data 30
27 Data 23 63 Data 14
28 Address 7 64 Data 31
29 Reserved 65 Data 15
30 +5 V dc 66 Reserved
31 Address 8 67 Reserved
32 Address 9 68 Reserved
33 Row address strobe 3 69 Reserved
34 Row address strobe 2 70 Reserved
35 Parity 2 71 Reserved
36 Parity 0 72 Ground

34 Chapter 3. Connectors and Jumpers

Video Feature Connector

The computer has a 26-pin connector that supports the attachment of additional video
features. The following figure shows the signal and pin assignments for the video feature
connector.

Figure 24. VESA Feature Connector

Pin Signal Pin Signal

1 Ground 2 Data 0
3 Ground 4 Data 1
5 Ground 6 Data 2
7 Data enable 8 Data 3
9 Sync enable 10 Data 4
11 PCLK enable 12 Data 5
13 Not used 14 Data 6
15 Ground 16 Data 7
17 Ground 18 PCLK
19 Ground 20 BLANK
21 Ground 22 HSYNC
23 Not used 24 VSYNC
25 Ground 26 Ground

Chapter 3. Connectors and Jumpers 35

I/O Connectors

The standard I/O device connectors include:

A keyboard connector
A mouse connector
Two serial connectors (one port is disabled if infrared is used)
An infrared (IR) transceiver module connector
A parallel connector
A monitor connector

The computer might also include:

An internal modem
A data collaboration adapter (modem, fax, voice mail, and audio)
A LAN adapter
A Matrox Millennium graphics adapter

Each I/O connector on the back panel of the computer is identified by a symbol.

Infrared

Keyboard

Serial A

Mouse

I/O Device Connectors

Serial B

Parallel

Display

36 Chapter 3. Connectors and Jumpers

Infrared Connector

The computer comes with an infrared (IR) port for connecting an optional infrared transceiver
module. The infrared transceiver allows wireless communication between the personal
computer and other infrared-capable computers and printers.

The IR connector on the back of the computer is a 9-pin, female, D-shell connector. The
transceiver plugs into this connector and provides a link of up to one meter at a rate of 115
kilobits-per-second (Kbps). The IR connector uses any of the same four port assignments as
the serial port.

The following list shows the pin numbers and signal names assigned to this connector.

Figure 25. IR Connector Pin Assignments

Pin Signal

1 IR transmitted data (output)
2 Signal ground
3 Reserved
4 IR module select 0
5 IR module select 1
6 IR received data (input)
7 Voltage (5 V)
8 IR module select 2
9 Reserved

1

69

5

Note: When the IR port is used, Serial B is disabled.

Chapter 3. Connectors and Jumpers 37

Keyboard and Auxiliary-Device Connectors

The keyboard and auxiliary-device connectors use 6-pin miniature DIN connectors.

4

Figure 26. Auxiliary-Device Signal and Pin Assignments

Pin I/O Signal Name

1 I/O Data
2 NA Reserved
3 NA Ground
4 NA +5 V dc
5 I/O Clock
6 NA Reserved

Figure 27. Keyboard Signal and Pin Assignments

Pin I/O Signal Name

1 I/O Data
2 NA Aux data on keyboard connector
3 NA Ground
4 NA +5 V dc
5 I/O Clock
6 NA Aux clock on keyboard connector

6

5

3

1

2

38 Chapter 3. Connectors and Jumpers

Serial Port Connectors

The two serial connectors on the back of the computer use a 9-pin, male D-shell connector
and pin assignments defined for RS-232D. The voltage levels are EIA only. Current loop
interface is not supported.

The following figure shows the signal and pin assignments for the serial port connector in a
communication environment.

Figure 28. Serial Port Connector Signal and Pin Assignments

Pin I/O Signal Name Pin I/O Signal Name

1 I Data carrier detect 6 I Data set ready
2 I Receive data 7 O Request to send
3 O Transmit data 8 I Clear to send
4 O Data terminal read 9 I Ring indicator
7 NA Signal ground

Use Serial A or Serial B for high-speed modem and printer connections, or for devices such
as a mouse or other pointing device.

1

69

5

Note: When the IR port is used, Serial B is disabled.
The serial ports transfer data one bit at a time (serially), at speeds ranging from 300 to

345600 bits per second (bps). The transfer rate is also referred to as
ports on the computer are 16550-UART (universal asynchronous receiver/transmitter)
compatible so they can support high-speed modems.

Serial-Port Setup

Each serial connector or adapter in the computer can use any of four available port settings,
provided that a different setting is used for each. The settings include the port address (in
hexadecimal) and the IRQ (interrupt request line), which determines how the microprocessor
responds to an interrupt from the serial port. The four available port settings, in sequential
order, are:

3F8h-IRQ 3 or 4
2F8h-IRQ 3 or 4
3E8h-IRQ 3 or 4
2E8h-IRQ 3 or 4

There is no direct relationship among the port connectors, the four available port settings,
and the four COM numbers. When the computer is started, the power-on self-test (POST)
assigns COM numbers to the port addresses that are actually in use at the time. POST
goes down the list of addresses sequentially to assign COM numbers to each address in use

baud rate

. The serial

Chapter 3. Connectors and Jumpers 39

by a serial device. If an address is not in use, a COM number is not assigned. POST
assigns the next available COM number to the next address in use.

The port addresses and IRQ for Serial A and Serial B are preset at the factory to:

Serial A: 3F8h-IRQ 4
Serial B: 2F8h-IRQ 3

POST assigns COM numbers to Serial A and Serial B during startup:

Serial A: 3F8h-IRQ 4 (COM1)
Serial B: 2F8h-IRQ 3 (COM2)

However, if the computer comes with an internal modem, the factory settings and COM
assignments are:

Serial A: 3F8h-IRQ 4 (COM1)
Serial B: 2F8h-IRQ 3 (COM2)
Modem: 3E8h-IRQ 5 (COM3)

The port address and IRQ settings for Serial A and Serial B can be viewed using the
Configuration/Setup Utility program. The COM numbers are not shown on the setup
screens; however, one of the diagnostic programs available with your computer can be used
to view them.

Data Collaboration

Some models include a data collaboration card (DCC), which combines an internal modem
and audio adapter. The modem is a 28800-bps data modem with 14400-bps
send-and-receive fax capabilities.

The modem adapter has two telephone jacks on the back of the adapter.
The modem is set at the factory to communicate with the computer through the COM3 port

using the standard address and IRQ 5. If necessary, the serial-port setting can be changed
using the Configuration/Setup Utility program.

The audio functions provided by the DCC include the ability to record and play back standard
wave (.WAV) files. The adapter also can be set up to emulate a Sound Blaster adapter.
This feature is set at the factory at address 220h, IRQ 9, and DMA 0. These can be
changed using the Configuration/Setup Utility program.

The adapter also combines audio features with the modem functions to provide a speaker
phone and telephone answering machine. these features.)

40 Chapter 3. Connectors and Jumpers

Parallel Port Connector

The parallel port connector is a standard 25-pin D-shell connector. The following figure
shows the signal and pin assignments for the parallel port connector.

Figure 29. Parallel Port Connector Signal and Pin Assignments

Pin I/O Signal Name Pin I/O Signal Name

1 O -STROBE 14 O -AUTO FD XT
2 I/O Data bit 0 15 I -ERROR
3 I/O Data bit 1 16 O -INIT
4 I/O Data bit 2 17 O -SLCT IN
5 I/O Data bit 3 18 NA Ground
6 I/O Data bit 4 19 NA Ground
7 I/O Data bit 5 20 NA Ground
8 I/O Data bit 6 21 NA Ground
9 I/O Data bit 7 22 NA Ground
10 I -ACK 23 NA Ground
11 I BUSY 24 NA Ground
12 I PE 25 NA Ground
13 I SLCT

13

25 14

1

The parallel port supports extended, high-speed modes, which means that it can transfer
data up to 10 times as fast as a standard parallel port.

Parallel-Port Setup

Each parallel connector or adapter on your computer can use any of three available port
settings, provided that a different setting is used for each. The settings include the port
address (in hexadecimal) and the interrupt request line (IRQ), which determines how the
microprocessor responds to an interrupt from the parallel port. The three available port
settings, in sequential order, are the following:

3BCh-IRQ 5 or 7
378h-IRQ 5 or 7
278h-IRQ 5 or 7

There is no direct relationship among the three available port settings and the three LPT
numbers. When you start the computer, the POST program assigns LPT numbers to the
port addresses that are actually in use at the time. POST goes down the list of addresses
sequentially to assign LPT numbers to each address in use by a parallel device. If an
address is not in use, an LPT number is not assigned to it. POST assigns the next available
LPT number to the next address in use.

The port address and IRQ setting for the built-in parallel port is preset at the factory to:
Built-in port: 3BCh-IRQ 7

Chapter 3. Connectors and Jumpers 41

POST assigns an LPT number to the built-in parallel port during startup:
Built-in port: 3BCh-IRQ 7 (LPT1)

If you add another parallel adapter that uses the next sequential address, POST assigns LPT
numbers as follows:

Built-in port: 3BCh-IRQ 7 (LPT1)
Adapter port: 378h-IRQ 5 (LPT2)

The port address and IRQ setting for the built-in parallel port can be viewed using the
Configuration/Setup Utility program. The LPT number are not shown on the configuration
screen; however, one of the diagnostic programs available with your computer can be used
to view them.

The parallel-port setting must be changed if you use ECP, EPP, or ECP/EPP modes
because 3BCh-IRQ 7 cannot be used for these modes. The setting can be changed using
the Configuration Setup Utility program.

Parallel-Port Modes

The parallel port can operate in five different modes. One is a
the other four are

extended,

bidirectional modes that provide additional function and higher

standard,

unidirectional mode;

performance. Refer to the documentation that comes with printers and other parallel devices
to determine the appropriate parallel mode to use and required device drivers.

Standard This

AT-compatible mode

is the default mode. In this mode, the
parallel port is limited to writing information to the device attached to it.
This mode can be used with most IBM-compatible parallel printers.

Bidirectional This

PS/2-compatible mode

is a bidirectional mode used for data

transfer to other PC systems and supported devices.

ECP The

extended capabilities port (ECP)

mode is a high-performance,
bidirectional mode that uses direct memory access (DMA) for data
transfer to a high-speed printer or other devices.

EPP The

enhanced parallel port (EPP)

mode is a high-performance,
bidirectional mode that has capabilities similar to ECP mode; the main
difference is that EPP data transfers are processor-initiated instead of
DMA. EPP supports the connection of up to eight external devices
such as hard disk drives, CD-ROM drives, tape drives, diskette drives,
and a printer to the parallel port. These devices can be connected to
each other in a

daisy-chain

arrangement, or they can be connected
through an external multiplexor. The attachment of multiple devices
requires device drivers supplied by the device manufacturers.

ECP/EPP This mode combines the capabilities of the ECP and EPP modes.

Select this mode to connect both ECP and EPP devices to the parallel
port.

42 Chapter 3. Connectors and Jumpers

Select the mode of operation for the parallel port using the Configuration Setup Utility
program.

Display Connector

The computer has a 15-pin display connector. The following figure shows the signal and pin
assignments for the system board display connector.

Figure 30. Display Connector Signal and Pin Assignments

Pin Signal Pin Signal

1 Red (out) 2 Green (out)
3 Blue (out) 4 Not used
5 Ground 6 Red ground
7 Green ground 8 Blue ground
9 +5 V (DDC2B) 10 Ground
11 Not used 12 DDC2B serial data (I/O)
13 Horizontal sync (out) 14 Vertical sync (out)
15 DDC2B clock (I/O)

Chapter 3. Connectors and Jumpers 43

44 Chapter 3. Connectors and Jumpers

Chapter 4. Memory Subsystems

Memory-Module Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Memory-Module Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Cache Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Copyright IBM Corp. June 1996 45

Memory-Module Description

The computer has four SIMM connectors and one DIMM connector. After memory modules
are installed, the Plug and Play feature of the Configuration/Setup Utility program
automatically detects the additional memory modules.

Notes:

1. Memory modules can have a maximum height of 1.2 inches.

2. Install only parity SIMMs and DIMMs to enable parity.

3. A mix of parity and non-parity SIMMs and DIMMs will be configured as non-parity.

4. A mix of extended-data output (EDO) and fast page (FP) SIMMs and DIMMs can be
installed if matched pairs are installed in each bank.

5. The computer uses industry-standard 60-ns 72-pin tin-lead SIMMs and 168-pin gold-lead
DIMMs.

Memory-Module Configurations

The following shows the typical memory-module configurations.

Figure 31. Memory-Module Type, Speed, and Size

Type Speed Memory-Module Size

SIMM 60 ns 4 MB, 8 MB, 16 MB, 32 MB
DIMM 60 ns 8 MB, 16 MB, 32 MB

Figure 32. System Memory Table

Total

Memory

16 MB 0,0 0,0 16
16 MB 4,4 4,4 0
24 MB 0,0 4,4 16
24 MB 4,4 0,0 16
32 MB 0,0 0,0 32
32 MB 8,8 8,8 0
40 MB 4,4 8,8 16
40 MB 0,0 4,4 32
48 MB 4,4 4,4 32
64 MB 8,8 8,8 32
72 MB 4,4 16,16 32
80 MB 8,8 16,16 32
96 MB 16,16 16,16 32

128 MB 16,16 32,32 32

46 Chapter 4. Memory Subsystems

Bank 0

SIMM 3,4

Bank 1

SIMM 1,2

Bank 2

DIMM

Cache Memory

Cache memory is a RAM storage location between the microprocessor and system memory.
The microprocessor has a 16 KB L1 (internal) cache. The computer also supports up to 512
KB of L2 (external) cache. The following shows the cache supported.

Figure 33. L1 and L2 Cache

L1 Cache Standard L2 Cache Standard L2 Cache Maximum

16 KB 256 KB 512 KB

Chapter 4. Memory Subsystems 47

48 Chapter 4. Memory Subsystems

Chapter 5. System Compatibility

Hardware Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Hardware Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Diskette Drives and Controller ................................. 52

Hard Disk Drives and Controller ................................ 53

Software Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Software Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Machine-Sensitive Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

BIOS Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Copyright IBM Corp. June 1996 49

Hardware Compatibility

This section briefly discusses hardware, software, and BIOS compatibility issues that must be
considered when designing application programs.

Many of the interfaces are the same as those used by the IBM Personal Computer AT. In
most cases, the command and status organization of these interfaces is maintained.

The functional interfaces are compatible with the following interfaces:

The Intel 8259 interrupt controllers (edge-triggered mode).
The National Semiconductor NS16450 and NS16550A serial communication controllers.
The Motorola MC146818 Time of Day Clock command and status (CMOS reorganized).
The Intel 8254 timer, driven from a 1.193 MHz clock (channels 0, 1, and 2).
The Intel 8237 DMA controller, except for the Command and Request registers and the

Rotate and Mask functions. The Mode register is partially supported.

The Intel 8272 or 82077 diskette drive controllers.
The Intel 8042 keyboard controller at addresses 0060h and 0064h.
All video standards using VGA, EGA, CGA, MDA, and Hercules modes.
The parallel printer ports (Parallel 1, Parallel 2, and Parallel 3) in compatibility mode.

Use the following information to develop application programs for personal computer
products. Whenever possible, use BIOS as an interface to hardware to provide maximum
compatibility and portability of applications among systems.

Hardware Interrupts

Hardware interrupts are level-sensitive in systems using PCI bus architecture and are
edge-triggered in systems using the personal computer type I/O architecture. The interrupt
controller clears its in-service register bit when the interrupt routine sends an End-of-Interrupt
(EOI) command to the controller. The EOI command is sent regardless of whether the
incoming interrupt request to the controller is active or inactive.

In systems using level-sensitive interrupts, the interrupt-in-progress latch is readable at an
I/O-address bit position. This latch is read during the interrupt service routine and might be
reset by the read operation or it might require an explicit reset.

Note: For performance and latency considerations, designers might want to limit the

number of devices sharing an interrupt level.

50 Chapter 5. System Compatibility

The interrupt controller in systems using level-sensitive interrupts requires that the interrupt
request be inactive at the time the EOI command is sent; otherwise, a new interrupt request
will be detected. To avoid this, a level-sensitive interrupt handler must clear the interrupt
condition (usually by a read or write operation to an I/O port on the device causing the
interrupt). After processing the interrupt, the interrupt handler:

1. Clears the interrupt

2. Waits one I/O delay

3. Sends the EOI

4. Waits one I/O delay

5. Enables the interrupt through the Set Interrupt Enable Flag command

In systems using level-sensitive interrupts, hardware prevents the interrupt controllers from
being set to the edge-triggered mode. In systems using edge-triggered interrupts, hardware
prevents the interrupt controllers from being set to the level-sensitive mode.

Hardware interrupt IRQ9 is defined as the replacement interrupt level for the cascade level
IRQ2. Program interrupt sharing is implemented on IRQ2, interrupt 0Ah. The following
processing occurs to maintain compatibility with the IRQ2 used by IBM Personal Computer
products:

1. A device drives the interrupt request active on IRQ2 of the channel.

2. This interrupt request is mapped in hardware to IRQ9 input on the second interrupt

controller.

3. When the interrupt occurs, the system microprocessor passes control to the IRQ9

(interrupt 71h) interrupt handler.

4. This interrupt handler performs an EOI command to the second interrupt controller and

passes control to the IRQ2 (interrupt 0Ah) interrupt handler.

5. This IRQ2 interrupt handler, when handling the interrupt, causes the device to reset the

interrupt request before performing an EOI command to the master interrupt controller
that finishes servicing the IRQ2 request.

Chapter 5. System Compatibility 51

Diskette Drives and Controller

The following figures show the reading, writing, and formatting capabilities of each type of
diskette drive.

Figure 34. 5.25-Inch Diskette Drive Reading, Writing, and Formatting Capabilities

Diskette Drive Type

5.25-inch diskette drive:
Single sided (48 TPI) RWF — —
Double sided (48 TPI) RWF RWF —
High capacity (1.2 MB) RWF RWF RWF

R = Read W = Write F = Format

Figure 35. 3.5-Inch Diskette Drive Reading, Writing, and Formatting Capabilities

Diskette Drive Type 720 KB Mode 1.44 MB Mode 2.88 MB Mode

3.5-inch diskette drive:

1.44 MB drive RWF RWF —

2.88 MB drive RWF RWF RWF

R = Read W = Write F = Format

160/180 KB
Mode

320/360 KB
Mode

1.2 MB
Mode

Notes:

1. Do not use 5.25-inch diskettes that are designed for the 1.2MB mode in either a 160/180
KB or 320/360 KB diskette drive.

2. Low-density 5.25-inch diskettes that are written to or formatted by a high-capacity 1.2 MB
diskette drive can be reliably read only by another 1.2 MB diskette drive.

3. Do not use 3.5-inch diskettes that are designed for the 2.88 MB mode in a 1.44MB
diskette drive.

Copy Protection

The following methods of copy protection might not work in systems using the 3.5-inch 1.44
MB diskette drive.

Bypassing BIOS routines:

– Data transfer rate: BIOS selects the proper data transfer rate for the media being

used.

– Diskette parameter table: Copy protection, which creates its own diskette parameter

table, might not work in these drives.

Diskette drive controls:

– Rotational speed: The time between two events in a diskette drive is a function of

the controller.

52 Chapter 5. System Compatibility

– Access time: Diskette BIOS routines must set the track-to-track access time for the

different types of media that are used in the drives.

– ‘Diskette change’ signal: Copy protection might not be able to reset this signal.

Write-current control: Copy protection that uses write-current control does not work,

because the controller selects the proper write current for the media that is being used.

Detailed information about specific diskette drives is available in the

Hardware Interface Technical Reference—Common Interfaces

technical references.

Hard Disk Drives and Controller

Reading from and writing to the hard disk is initiated in the same way as in IBM Personal
Computer products; however, new functions are supported. Detailed information about
specific hard disk drives and hard disk drive adapters is available in the

System/2 ATA/IDE Fixed Disk Drives Technical Reference

Software Compatibility

To maintain software compatibility, the interrupt polling mechanism that is used by IBM
Personal Computer products is retained. Software that interfaces with the reset port for the
IBM Personal Computer positive-edge interrupt sharing (hex address 02Fx or 06Fx, where
is the interrupt level) does not create interference.

Software Interrupts

With the advent of software interrupt sharing, software interrupt routines must daisy chain
interrupts. Each routine must check the function value, and if it is not in the range of function
calls for that routine, it must transfer control to the next routine in the chain. Because
software interrupts are initially pointed to address 0:0 before daisy chaining, check for this
case. If the next routine is pointed to address 0:0 and the function call is out of range, the
appropriate action is to set the carry flag and do a RET 2 to indicate an error condition.

IBM Personal System/2

and in separate option

IBM Personal

.

x

Chapter 5. System Compatibility 53

Machine-Sensitive Programs

Programs can select machine-specific features, but they must first identify the machine and
model type. IBM has defined methods for uniquely determining the specific machine type.
The machine model byte can be found through Interrupt 15H, Return System Configuration
Parameters function ((AH)=C0H). See the

BIOS Interface Technical Reference

Computer products.

BIOS Compatibility

The personal computer systems support BIOS interfaces as described in the

System/2 and Personal Computer BIOS Interface Technical Reference

IBM Personal System/2 and Personal Computer

for a listing of model bytes for other IBM Personal

IBM Personal

.

54 Chapter 5. System Compatibility

Chapter 6. Bus Architecture

Bus Architecture Descriptions ................................... 56

ISA Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

PCI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

PCI Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

PCI Peripheral Devices ................................... 57

Expansion-Bus Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Bus Voltage Levels ....................................... 59

Copyright IBM Corp. June 1996 55

Bus Architecture Descriptions

This section gives an overview of input/output (I/O) buses and explains how advanced I/O
buses can improve performance.

ISA Bus

A computer
the computer.
microprocessor has an external bus, called the
information between the microprocessor and main memory. The local bus has the same bus
width (64 bits) as the microprocessor and operates at the same external speed.

Another computer bus, the
microprocessor or memory and the I/O (peripheral) devices. While microprocessor-bus
performance has improved rapidly, improvements in I/O-bus performance have not equalled
those of microprocessors and some peripheral devices, such as video and disk controllers.
Regardless of how fast the microprocessor and other components are, data transfers
between them must pass through the I/O bus.

The computer has two I/O buses: the
used in IBM and IBM-compatible computers for many years. PCI is one of the advanced I/O
bus standards developed by the computer industry to keep up with performance
improvements of microprocessor buses and advanced peripheral devices. Although
advanced designs can match the performance of the microprocessor bus only up to a point,
they do achieve higher throughput by speeding up the I/O bus and widening its data path.
PCI is intended to add to, but not replace, the capability provided by the ISA bus. In fact,
most personal computers today need only three PCI connections: one for video, one for the
disk controller, and one for a network adapter or other optional device.

One of the most widely used and successful bus architectures is the AT bus, also called the

industry standard architecture (ISA) bus

operates at a speed of 8 MHz. It can transfer up to 8 MB of data per second between the
microprocessor and an I/O device. Practical performance ranges between 4 MB to 8 MB per
second.

bus

is a pathway of wires and signals that carry (or transfer) information inside

Information

includes data, addresses, instructions, and controls. The

I/O bus

microprocessor bus

or

expansion bus

ISA bus

, or the I/O channel. The ISA bus is a 16-bit bus that

, carries information between the

and the

PCI bus

or

local bus

. ISA is the standard I/O bus

, that carries

The ISA bus continues to be popular because so many adapters, devices, and applications
have been designed and marketed for it. ISA is adequate for users of DOS applications in a
stand-alone environment, or for DOS network requestors with moderate performance
requirements.

Although the ISA bus is widely used and is suitable for many applications, it cannot transfer
data fast enough for today's high-speed microprocessors and I/O devices. For example, the
ISA bus might not provide for the performance needs of video devices and applications with
high resolution and high-color content. Also, ISA might not be capable of handling the
throughput required by some fast hard disks, network controllers, or full-motion video
adapters.

56 Chapter 6. Bus Architecture

The ISA bus is buffered to provide sufficient power for the 98-pin connectors, assuming two
low-power Schottky (LS) loads per slot. The signal assignments and pin assignments for the
I/O channel connectors are shown in Figure 18 on page 30.

PCI Bus

The PCI bus connects to the microprocessor local bus through a buffered bridge controller.
A

bridge

receive all their data and control information through the PCI controller. The PCI controller
looks at all signals from the microprocessor local bus and then passes them to the ISA
controller, or to peripheral devices connected to the PCI bus. However, the PCI bus is not
governed by the speed of the microprocessor bus. PCI can operate at speeds as fast as 33
MHz, slow down, or even stop if there is no activity on the bus, all independent of the
microprocessor’s operations. This independence is a distinguishing feature of PCI that
allows the microprocessor to do other work while the I/O bus is busy. Microprocessor
independence also makes PCI adaptable to various microprocessor speeds and families and
allows consistency in the design and use of PCI peripheral devices across multiple computer
families.

PCI Performance

One of the most significant features of PCI is its 32-bit data path, which is twice the width of
the ISA data path. With a 32-bit data path, the PCI bus can transfer more information per
second than the ISA bus with its 16-bit data path. Also, PCI operates at higher speeds of up
to 33 MHz. Depending on the mode of operation and computer components used, the PCI
bus can transfer data at speeds up to 132 MB per second. While many factors can reduce
practical performance, achieving just half or a third of the PCI maximum theoretical
throughput far exceeds the practical performance of the ISA bus at 4 MB to 8 MB per
second.

translates signals from one bus architecture to another. PCI and ISA devices

PCI Peripheral Devices

The wider data path and higher throughput make PCI a more suitable bus for today's
high-speed microprocessors and I/O devices. Higher throughput translates into higher
performance of peripheral devices, such as higher video resolutions, more colors, and
quicker screen refreshes. The use of PCI architecture enhances the performance of the
monitor and the storage devices. Both the video controller and the IDE drive controller are
connected to the PCI bus on the system board. Thus, the peripheral devices that have the
greatest demand for higher performance are supported by the benefits of PCI architecture.

Expansion-Bus Features

The bit-width of the I/O bus determines the type of adapters the computer supports. The
shared slots handle 16-bit ISA adapters and 32-bit PCI adapters. The dedicated ISA slots
handle 16-bit ISA adapters only. The width of the I/O bus does not affect software
compatibility.

Chapter 6. Bus Architecture 57

The PC 730 riser card has three shared PCI and ISA slots; the PC 750 riser card has three
shared PCI and ISA slots and two dedicated ISA slots.

You can have up to three adapters in the PC 730 and up to five adapters in the PC 750.
Each PCI connector and the ISA connector directly below it share an expansion-slot opening
at the back of the computer that can be used by only one adapter at a time. This means
that you can install either a PCI adapter or an ISA adapter in a shared slot, but not both.

Shared

Slot 3

Shared

Slot 2

Shared

Slot 1

Shared

Slot 3

Shared

Slot 2

Shared

Slot 1

PCI

ISA

PCI

ISA

PCI
ISA

ISA 5
ISA 4
PCI

ISA
PCI

ISA
PCI

ISA

ISA/PCI Riser Card for PC 730

(On other side)

PCI connectors support both 3.52-volt and 5-volt adapters. A separate power cable connects
to the back of the riser card to supply 3.52-volt power.

PCI devices receive data through the PCI controller. The PCI controller looks at all signals
from the microprocessor local bus, then passes them to the ISA controller or to peripherals
connected to the PCI bus.

58 Chapter 6. Bus Architecture

ISA/PCI Riser Card for PC 750

The signal assignments and pin assignments for the PCI connectors are shown in Figure 19
on page 31. For additional information, see the
the PCI Special Interest Group.

Bus Voltage Levels

Four voltage levels are provided for I/O adapters. The maximum available values (for each
slot) are as follows:

+5 V dc (+5%, −4.5%) at 2.0 A

−5 V dc (+10%, −9.5%) at 0.100 A
+12 V dc (+5%, −4.5%) at 0.175 A

−12 V dc (+10%, −9.5%) at 0.100 A

The

I/O CH RDY signal is available on the I/O channel to allow operation with slow I/O or

memory devices. I/O CH RDY is held inactive by an addressed device to lengthen the
operation. For each clock cycle that the line is held inactive, one wait state is added to the
I/O or DMA operation.

Two voltage levels are provided for PCI bus adapters. The maximum available values (for
each slot) are as follows:

+5 V dc (+5%, −4.5%) at 7.576 A
+3.52 V dc (+2.5%, −2.5%) at 4.00 A

PCI Local Bus Specification

, published by

Chapter 6. Bus Architecture 59

60 Chapter 6. Bus Architecture

Appendix A. Error Codes

The following figures list the POST error codes and beep error codes for the computer.

POST Error Codes

POST error messages appear when POST finds problems with the hardware during
power-on or when a change in the hardware configuration is found. POST error messages
are 3-, 4-, 5-, 8-, or 12-character alphanumeric messages. An x in an error message can
represent any number.

Figure 36 (Page 1 of 2). POST Error Messages

Code Description

101 Interrupt failure
102 Timer failure
103 Timer-interrupt failure
104 protected mode failure
105 last 8042 command not accepted –keyboard failure
106 System board failure
108 Timer bus failure
109 low MB chip select test
110 System board parity error 1 (system board parity latch set)
111 I/O parity error 2 (I/O channel check latch set)
112 I/O channel check error
113 I/O channel check error
114 external ROM checksum error
115 DMA error
116 System board port read/write error
120 Microprocessor test error
121 Hardware error
151 Real time clock failure
161 Bad CMOS Battery
162 CMOS RAM checksum/configuration error
163 Clock not updating
164 CMOS RAM memory size does not match
167 Clock not updating
175 Riser card or system board error
176 System cover has been removed
177 Corrupted administrator password
178 Riser card or system board error
183 Administrator password has been set and must be entered
184 Password removed due to checksum error
185 Corrupted boot sequence
186 System board or hardware security error
189 More than three password attempts were made to access system
201 Memory date error
202 Memory address line error 00-15
203 Memory address line error 16-23
221 ROM to RAM remapping error
225 Unsupported memory type installed or memory pair mismatch
301 Keyboard error
302 Keyboard error

Copyright IBM Corp. June 1996 61

Figure 36 (Page 2 of 2). POST Error Messages

Code Description

303 Keyboard to system board interface error
304 Keyboard clock high
305 No keyboard +5 V
601 Diskette drive or controller error
602 Diskette IPL boot record not valid
604 Unsupported diskette drive installed
605 POST cannot unlock diskette drive
662 Diskette drive configuration error
762 Math coprocessor configuration error
11xx Serial port error (xx = serial port number)
1762 Hard disk configuration error
1780 Hard disk 0 failed
1781 Hard disk 1 failed
1782 Hard disk 2 failed
1783 Hard disk 3 failed
1800 PCI adapter has requested an unavailable hardware interrupt
1801 PCI adapter has requested an unavailable memory resource
1802 PCI adapter has requested an unavailable I/O address space, or a defective

1803 PCI adapter has requested an unavailable memory address space, or a
1804 PCI adapter has requested unavailable memory addresses

1805 PCI adapter ROM error
1962 Boot sequence error
2401 System board video error
8601 System board - keyboard/pointing device error
8602 Pointing device error
8603 Pointing device or system board error
12092 Level 1 cache error (Processor chip)
12094 Level 2 cache error
16101 Riser card battery is dead
I9990301 Hard disk failure
I9990305 No operating system found

adapter
defective adapter

62 Appendix A. Error Codes

Beep Codes

For the following beep codes, the numbers indicate the sequence and number of beeps. For
example, a “2-3-2” error symptom (a burst of two beeps, three beeps, then a burst of two
beeps) indicates a memory module problem. An x in an error message can represent any
number.

Figure 37. Beep Codes

Beep Code Probable Cause

1-1-3 CMOS write/read failure
1-1-4 BIOS ROM checksum failure
1-2-1 Programmable interval timer test failure
1-2-2 DMA initialization failure
1-2-3 DAM page register write/read test failure
1-2-4 RAM refresh verification failure
1-3-1 1st 64 K RAM test failure
1-3-2 1st 64 K RAM parity test failure
2-1-1 Slave DMA register test in progress or failure
2-1-2 Master DMA register test in progress or failure
2-1-3 Master interrupt mask register test failure
2-1-4 Slave interrupt mask register test failure
2-2-2 Keyboard controller test failure
2-3-2 Screen memory test in progress or failure
2-3-3 Screen retrace tests in progress or failure
3-1-1 Timer tick interrupt test failure
3-1-2 Interval timer channel 2 test failure
3-1-4 Time-of-Day clock test failure
3-2-4 Comparing CMOS memory size against actual
3-3-1 Memory size mismatch occurred

Appendix A. Error Codes 63

64 Appendix A. Error Codes

Appendix B. Notices and Trademarks

References in this publication to IBM products, programs, or services do not imply that IBM
intends to make these available in all countries in which IBM operates. Any reference to an
IBM product, program, or service is not intended to state or imply that only that IBM product,
program, or service may be used. Subject to IBM’s valid intellectual property or other legally
protectable rights, any functionally equivalent product, program, or service may be used
instead of the IBM product, program, or service. The evaluation and verification of operation
in conjunction with other products, except those expressly designated by IBM, are the
responsibility of the user.

IBM may have patents or pending patent applications covering subject matter in this
document. The furnishing of this document does not give you any license to these patents.
You can send license inquiries, in writing, to:

IBM Director of Licensing

IBM Corporation

500 Columbus Avenue
Thornwood, NY 10594
U.S.A.

Trademarks

The following terms are trademarks of the IBM Corporation in the United States or other
countries or both:

AT Personal Computer AT
IBM Mwave
Personal System/2 PS/2

Copyright IBM Corp. June 1996 65

The following terms are trademarks of other companies:
Hercules Hercules Computer Technology

Intel Intel Corporation
Matrox Matrox Electronic Systems, Ltd.
Motorola Motorola, Incorporated
National Semiconductor National Semiconductor Corporation
PCMCIA Personal Computer Memory Card International Association
Pentium Intel Corporation
S3 S3 Incorporated
Sound Blaster Creative Technology Ltd.
VESA Video Electronics Standards Association

Microsoft, Windows, and Windows NT, are trademarks or registered trademarks of Microsoft
Corporation.

66 Appendix D. Notices and Trademarks

Index
Numerics

16550-UART 39

A

adapters, adding 58
address map

DMA 12

system memory 8
advanced power management 21
altitude 19, 20
answering machine 40
APM 21
AT bus 56
AT-compatible mode (parallel port) 42
audio subsystem 5

B

baud rate 39
beep codes 63
bidirectional mode (parallel port) 42
BIOS data areas 8
bus

AT 56

ISA 56

PCI 57
bus architecture 4
bypassing BIOS 52

C

cables 19, 20
cache memory 47
CMOS RAM 4
compatibility

hardware 50
component maximum current 17
connector

diskette drive 28

display 43

hard disk drive 29

infrared 37

ISA bus 30

connector

controller

copy protection 52
current, electrical 19, 20

(continued)

memory 34
mouse 38
parallel port 41
PCI (peripheral component interconnect) 31
PCMCIA 25
power supply 33
serial port controller 39

diskette drive 5, 52
keyboard/auxiliary-device 5
parallel 5
serial 5

D

data collaboration 40
depth, system unit 19, 20
description

AT bus 56
diskette drive connector 28
display connector 43
hard disk drive connector 29
I/O channel 56
ISA bus 56
keyboard and auxiliary-device controller

connector 38
parallel port connector 41
PCI (peripheral component interconnect)

connector 31
PCI connector 31
power supply 15
power supply connectors 33
system board memory connector 34

direct memory access (DMA) channel

assignments 14

diskette drive

change signal 53
compatibility 52
connector 28
controller 5
signals 28

Copyright IBM Corp. June 1996 67

diskette drive

write current 53
diskette drives 52
display connector signal and pin assignments 43
DMA

I/O address map 12
DMA (direct memory access) channel

assignments 14

(continued)

E

ECP (extended capabilities port) 42
ECP/EPP 42
edge-triggered interrupts 50
electromagnetic compatibility 19, 20
enhanced parallel port (EPP) 42
environment, operating 19, 20
EPP (enhanced parallel port) 42
error codes, POST 61
expansion bus 56
extended capabilities port (ECP) 42

F

fault, overvoltage 18
fax 40
features 2
flash ROM 4
frequency 19, 20
frequency, input power 15

H

hard disk drive

compatibility 53

connector 29

controller 53

signals 29
hard disk drive connector signal and pin

assignments 29
hardware compatibility 50
hardware interrupts 50
heat output 19, 20
height, system unit 19, 20
humidity 19, 20

I

I/O

features 36

I/O address map

DMA 12
I/O channel (ISA) description 56
infrared (IR) connector 37
input power

frequency 15

requirements 15

voltage 15
interrupt request assignments 13
ISA bus connector signal and pin assignments 30

J

jumper

locations (system board) 7

K

keyboard and auxiliary-device controller

connector 38

keyboard and auxiliary-device signal and pin

assignments 38
keyboard cable 19, 20
keyboard signal and pin assignments 38

L

L1 cache 47
L2 cache 47
level-sensitive interrupts 50
load currents 17
local bus 56

M

machine-sensitive programs 54
Matrox Millennium adapter 24
measurements, system unit 19, 20
memory

cache 47
connector 34
error in 8
L1 cache 47
L2 cache 47
map, system 8

68 Index

memory

messages, POST error 61
microprocessor

microprocessor upgrade socket 4
modem 40
modes, power management 21

(continued)

RAM 8, 46
system memory map 8

features 4

O

outputs, power supply 17
overview 2
overvoltage fault 18

P

parallel port 5
parallel port connector 41
parallel port connector signal and pin

assignments 41
password
PC Cards 25
PCI connector signal and pin assignments 31
Pentium microprocessor 4
physical specifications

PC 350 20
polling mechanism 53
port

parallel 5

serial 5
POST 8
POST error codes 61
power

cable 19, 20

consumption 21

description 15

for components 17

load currents 17

management modes 21

output protection 18

outputs 17

specifications 19, 20
power supply connectors 33
protection, power supply 18
PS/2-compatible mode (parallel port) 42
publications, related viii

R

RAM (random access memory) 4, 8, 46
random access memory (RAM) 4, 8, 46
related publications viii
reserved

areas ix
riser card 58
RT/CMOS RAM

error in 8

S

SCSI (small computer system interface) 25
serial port 5
serial ports 39
short circuit 18
signals

diskette drive 28

hard disk drive 29
SIMMs (single inline memory modules) 46
single inline memory modules (SIMMs) 46
size, system unit 19, 20
small computer system interface (SCSI) 25
socket, microprocessor upgrade 4
software

compatibility 53

interrupts 53
speaker phone 40
specifications

physical 19, 20
standard mode (parallel port) 42
system

description 2

memory maps 8

specifications 19, 20

timers 5
system board

devices 4

diskette drive connector 28

display connector 43

features 4, 7

hard disk drive connector 29

keyboard and auxiliary-device controller

connector 38
memory connector 34
parallel port connector 41
PCI (peripheral component interconnect)

connector 31

Index 69

system board

power supply connectors 33
video feature connector 35

(continued)

T

temperature 19, 20
timers, system 5

U

UART (universal asynchronous

receiver/transmitter) 39
unidirectional mode (parallel port) 42
universal asynchronous receiver/transmitter

(UART) 39

V

video

feature connector 35
local-bus 4
Matrox Millennium adapter 24
subsystem 4

voltage, input power 15

W

warning, reserved areas ix
wave (.WAV) files, playing 40
weight, system unit 19, 20
width, system unit 19, 20
write current, diskette 53

70 Index

IBM

Part Number: 52H3381

Printed in U.S.A.

52H3381