IBM 770 User Manual

05L1739
S05L-1739-00

Note

Before using this information and the product it supports, be sure to read the
general information under Appendix C, “Notices” on page C-1.

First Edition (December 1997)

The following paragraph does not apply to the United Kingdom or any country
where such provisions are inconsistent with local law: INTERNATIONAL

BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION “AS IS”
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states
do not allow disclaimer of express or implied warranties in certain transactions;
therefore, this statement may not apply to you.

This publication could include technical inaccuracies or typographical errors. Changes
are periodically made to the information herein; these changes will be incorporated in
new editions of the publication. IBM may make improvements or changes in the
products or the programs described in this publication at any time.

Requests for technical information about IBM products should be made to your IBM
Authorized Dealer or your IBM Marketing Representative.

 Copyright International Business Machines Corporation 1997. 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Section 1. System Overview . . . . . . . . . . . . . . . . . . . 1-1

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

System Board Devices and Features ............... 1-3

System Board I/O Address Map .................. 1-5

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Performance Specifications . . . . . . . . . . . . . . . . . . . 1-7

Physical Specifications . . . . . . . . . . . . . . . . . . . . . . 1-8

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . 1-9

Acoustical Readings . . . . . . . . . . . . . . . . . . . . . . . 1-9

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Output Protection . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Voltage Sequencing . . . . . . . . . . . . . . . . . . . . . . . 1-11

Power Supply Connector .................... 1-11

Battery Pack . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Section 2. System Board . . . . . . . . . . . . . . . . . . . . . 2-1

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Cache Memory Operation .................... 2-2

Cacheable Address Space .................... 2-3

Bus Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Keyboard/Mouse Connector . . . . . . . . . . . . . . . . . . . . . 2-4

Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Scan Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Keyboard ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Displayable Characters and Symbols .............. 2-7

Hard Disk Drive Connector ..................... 2-8

External Bus Connector ....................... 2-9

UltraBay II Connector ....................... 2-12

Diskette Drive and Controller ................... 2-15

Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

ROM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . 2-16

RAM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

System Memory Map ...................... 2-17

System Board Memory for the DIMM Connectors ..... 2-18

 Copyright IBM Corp. 1997 iii

RT/CMOS RAM . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

Miscellaneous System Functions and Ports .......... 2-29

Nonmaskable Interrupt (NMI) ................. 2-29

System Control Port A (Hex 0092) .............. 2-30

System Control Port B (Hex 0061) .............. 2-31

Power-On Password . . . . . . . . . . . . . . . . . . . . . . 2-32

Other Passwords . . . . . . . . . . . . . . . . . . . . . . . . 2-32

Selectable Drive-Startup Sequence .............. 2-33

Hardware Compatibility . . . . . . . . . . . . . . . . . . . . . . 2-34

Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

Section 3. Subsystems . . . . . . . . . . . . . . . . . . . . . . 3-1

Video Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Video Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Modem Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

ThinkPad Modem . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

MIDI Port Function ........................ 3-5

Sound Blaster Support Function ................ 3-5

Telephony (Modem) Function .................. 3-6

Audio Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

MIDI Port Function ........................ 3-7

Sound Blaster Support Function ................ 3-7

Audio Port Specifications ..................... 3-8

Infrared (IR) Subsystem ....................... 3-9

IRQ Level and DMA Channel .................. 3-9

Enhanced Video Subsystem ................... 3-10

Video Port Specification .................... 3-10

PCMCIA Subsystem . . . . . . . . . . . . . . . . . . . . . . . . 3-11

Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

IDE Channel on the UltraBay II .................. 3-14

MIDI/Joystick Port . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

MIDI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Joystick Interface . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Appendix A. System Resources . . . . . . . . . . . . . . . . A-1

Appendix B. System Management API (SMAPI) BIOS

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

Header Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Calling Convention . . . . . . . . . . . . . . . . . . . . . . . . . . B-6

Parameter Structure . . . . . . . . . . . . . . . . . . . . . . . B-6

Calling Convention Pseudo Code ............... B-10

Return Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-11

Function Description . . . . . . . . . . . . . . . . . . . . . . . . B-12

iv

System Information Service .................. B-12

System Configuration Service ................. B-22

Power Management Service .................. B-29

Event Bit Definition ....................... B-34

Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-53

Function Declaration . . . . . . . . . . . . . . . . . . . . . . B-57

Installation Check . . . . . . . . . . . . . . . . . . . . . . . . B-58

BIOS Call . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-62

Appendix C. Notices . . . . . . . . . . . . . . . . . . . . . . . . C-1

Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2

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

v

vi

Figures

1-1. Model and Submodel Bytes ............... 1-2

1-2. System Board Devices and Features .......... 1-3

1-3. System Board I/O Address Map ............. 1-5

1-4. Performance Specifications . . . . . . . . . . . . . . . . 1-7

1-5. Physical Specifications . . . . . . . . . . . . . . . . . . 1-8

1-6. Electrical Specifications . . . . . . . . . . . . . . . . . . 1-9

1-7. Acoustical Readings . . . . . . . . . . . . . . . . . . . . 1-9

1-8. Power Supply Maximum Current ........... 1-10

1-9. Voltage Pin Assignments for the 56W AC Adapter . 1-11

1-10. Lithium-ion Battery Pack Specifications ........ 1-12

2-1. Keyboard and Mouse Signals .............. 2-4

2-2. Keyboard/Mouse Connector Pin Assignments ..... 2-4

2-3. Key Numbers for the 84-Key Keyboard ......... 2-5

2-4. Key Numbers for the 85-Key Keyboard ......... 2-6

2-5. Key Numbers for the External Numeric Keypad .... 2-7

2-6. Hard Disk Drive Connector Pin Assignments ..... 2-8

2-7. 240-Pin External Bus Connector Pin Assignments . 2-11

2-8. UltraBay II Connector Pin Assignments ........ 2-13

2-9. Diskette Drive Read, Write, and Format Capabilities 2-15

2-10. System Memory Map .................. 2-17

2-11. DIMM Adapter Card Memory Connector Pin

Assignments . . . . . . . . . . . . . . . . . . . . . . . 2-18

2-12. RT/CMOS RAM Address Map ............. 2-19

2-13. RT/CMOS Address and NMI Mask Register (Hex

0070) . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

2-14. RT/CMOS Data Register (Hex 0071) ......... 2-20

2-15. Real-Time Clock Bytes (Hex 000–00D) ........ 2-22

2-16. Status Register A (Hex 00A) .............. 2-22

2-17. Status Register B (Hex 00B) .............. 2-23

2-18. Status Register C (Hex 00C) .............. 2-24

2-19. Status Register D (Hex 00D) .............. 2-24

2-20. Diagnostic Status Byte (Hex 00E) ........... 2-25

2-21. Diskette Drive Type Byte (Hex 010) .......... 2-26

2-22. Diskette Drive Type Bits 7–4 .............. 2-26

2-23. Hard Disk Type Byte (Hex 011) ............ 2-26

2-24. Hard Disk Drive Type 2 (Bits 7–4) ........... 2-26

2-25. Hard Disk Drive Type 3 (Bits 3–0) ........... 2-26

2-26. Hard Disk Drive Type Byte ............... 2-27

2-27. Equipment Byte . . . . . . . . . . . . . . . . . . . . . 2-27

2-28. Installed Diskette Drive Bits .............. 2-27

2-29. Display Operating Mode Bits .............. 2-27

 Copyright IBM Corp. 1997 vii

2-30. System Control Port A (Hex 0092) .......... 2-30

2-31. System Control Port B (Hex 0061, Write) ...... 2-31

2-32. System Control Port B (Hex 0061, Read) ...... 2-31

2-33. Error Codes . . . . . . . . . . . . . . . . . . . . . . . . 2-35

3-1. BIOS Video VGA Modes ................. 3-3

3-2. Video BIOS Extended Modes—Trident 9397 ...... 3-4

3-3. PCMCIA PC Card Slot Pin Assignments ....... 3-12

viii

Preface

This technical reference contains hardware and software interface
information specific to the IBM ThinkPad 770 computer. This
technical reference is intended for those who develop hardware and
software products for the computer. Users should understand
computer architecture and programming concepts.

This publication consists of the following sections and appendixes:

Section 1, “System Overview,” describes the system, features,
and specifications.

Section 2, “System Board,” describes the system-specific
hardware implementations.

Section 3, “Subsystems,” describes the hardware functions
specific to the ThinkPad 770 computer.

Appendix A, “System Resources,” describes the available
system resources for the computer and docking stations.

Appendix B, “System Management API (SMAPI) BIOS
Overview,” describes the system software interface built into the
system, called the System Management Application Program
Interface (SMAPI) BIOS, which controls the system information,
system configuration, and power management features of the
ThinkPad computer.

Appendix C, “Notices,” contains special notices and trademark
information.

An index is also included.

Attention

The term
should not be 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. Read the register first and
change only the bits that must be changed.

 Copyright IBM Corp. 1997 ix

Reserved

describes certain signals, bits, and registers that

x Preface

Section 1. System Overview

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

System Board Devices and Features ............... 1-3

System Board I/O Address Map .................. 1-5

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Performance Specifications . . . . . . . . . . . . . . . . . . . 1-7

Physical Specifications . . . . . . . . . . . . . . . . . . . . . . 1-8

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . 1-9

Acoustical Readings . . . . . . . . . . . . . . . . . . . . . . . 1-9

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Output Protection . . . . . . . . . . . . . . . . . . . . . . . . 1-11

Voltage Sequencing . . . . . . . . . . . . . . . . . . . . . . . 1-11

Power Supply Connector .................... 1-11

Battery Pack . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

 Copyright IBM Corp. 1997 1-1

Description

The IBM ThinkPad 770 computer (hereafter called the

computer

or the

computer

) is notebook-size computer that feature

ThinkPad

the AT bus architecture. Each computer supports one UltraBay II
and one internal hard disk drive. The ThinkPad 770 computer also
supports an internal CD-ROM drive or an internal DVD drive as an
option.

Programs can distinguish the foregoing computer model from other
ThinkPad models by reading the system ID:

 Interrupt 15H

 Function code (AH)=23H and (AL)=10H.
 Returns
(AL)=27H

The system microprocessor contains an internal cache and cache
controller.

Figure 1-1 lists the model bytes, submodel bytes, and system clock
speed of the system board for each model.

Model Model Byte

(Hex)

770 FC 01 33 MHz

Figure 1-1. Model and Submodel Bytes

Submodel Byte
(Hex)

System Clock

For a listing of the other systems, refer to the

IBM Personal

System/2 and Personal Computer BIOS Interface

1-2 System Overview

.

System Board Devices and Features

Figure 1-2 lists the system board devices and their features. The

IBM Personal System/2 Hardware Interface Technical Reference

describes devices common to PS/2 products by type number.

Device Type Features
Microprocessor – Intel Pentium processor with the MMX

External cache – 512 KB (write back)
System timers 1 Channel 0: system timer

ROM subsystem – 128 KB by 4 banks (1 KB equals 1024 bytes)
RAM subsystem – 32 to 256 MB (1 MB equals 1,048,576 bytes)
CMOS RAM

subsystem
EEPROM

subsystem
Video subsystem – XGA video functions:

– 128 bytes CMOS RAM with real-time

– 1 K bits

technology

 200 or 233 MHz
 32 KB on-chip cache

Channel 1: refresh generation
Channel 2: tone generator for speaker

clock/calendar + 4 K byte NVRAM

 Up to 65,536 colors on the TFT XGA

(1024x768) LCD

 Up to 16,777,216 colors on an external

monitor

See “Video Subsystem” on page 3-2 for more
details on the video subsystem.

DMA controller 1 Seven DMA channels (AT compatible:)

Four 8-bit channels and three 16-bit channels

Figure 1-2 (Part 1 of 2). System Board Devices and Features

System Overview 1-3

Device Type Features
Interrupt controller 1 15 levels of system interrupts

Keyboard/auxiliary
device controller

Diskette drive
controller

Serial controller
port

Parallel controller
port

Expansion bus
adapter (PCI-bus)

PCMCIA** slots – Conforms to the standards for:

Modem subsystem – Is driven by:

Infrared subsystem – Supports:

Universal serial bus
(USB)

1 Internal keyboard

2 Supports:

2 EIA-232-E interface (16550 compatible)

1 Programmable as parallel port 1, 2, or 3

– Supports externally attached devices:

– Supports:

(interrupts are edge-triggered)
TrackPoint

Auxiliary device connector
Password security

 3.5-in. diskette (1.44 MB)
 3.5-in. diskette (1.2 MB)
 3.5-in. diskette (720 KB)

Programmable as serial port 1, 2, 3, or 4
One 9-pin, D-sub connector

IEEE P1284-A compatible
Supports bidirectional input and output
Enhanced Parallel Port (EPP) compatible
Extended Capabilities Port (ECP) compatible

 SelectaDock docking system

 Port replicator

 CardBus

 Two Type I or II PC cards
 One Type III PC card

 MDSP 3780i

 SRAM 32 Kb by 40 bits

 Crystal Audio

 Voice band CODEC for modem

 Internal DAA

 Internal omnidirectional microphone

 ThinkPad IR/SIR/D-ASK (500 KHz) IR

 USB input and output devices

Figure 1-2 (Part 2 of 2). System Board Devices and Features

1-4 System Overview

System Board I/O Address Map

Figure 1-3 is the I/O address map.

Address (Hex) Device

0000–001F DMA Controller (0–3)
0020, 0021 Interrupt Controller (master)
0022–002F Reserved
0040–0043 System Timer 1
0048–004B Reserved
0060 Keyboard, Auxiliary Device
0061 System Control Port B
0062, 0066 Slave Controller
0064 Keyboard, Auxiliary Device
0070, 0071 RT/CMOS and NMI Mask
0072, 0073 Extended RT and CMOS
0074, 0075, 0076 Reserved
0081–0083, 0087 DMA Page Registers (0–3)
0089–008B, 008F DMA Page Registers (4–7)
0092 System Control Port A
0096 Reserved
0098 System Flash ROM Control Register (DCR

00A0, 00A1 Interrupt Controller (slave)
00B2–00B3 Power Management Register
00C0–00DF DMA Controller (4–7)
00F0–00FF Reserved
0130–013F ThinkPad Modem
0170–0177 Secondary IDE Registers
01F0–01F7 Primary IDE Registers
0201 Joystick Port
0220–0233 Audio Subsystem - Sound Blaster
0240–0253 Audio Subsystem - Sound Blaster
026E, 026F Super I/O Configuration Registers
0260–0273 Audio Subsystem - Sound Blaster
0278–027A Parallel Port 3
027B–027F Reserved
0280–0283 Audio Subsystem - Sound Blaster
02E8–02EF Serial Port 4
02E8–02EF IR Port 4
02F8–02FF Serial Port 2
02F8–02FF IR Port 2
0300–0303 MIDI Port 1
0310–0313 MIDI Port 2
0320–0323 MIDI Port 3

2282)

Figure 1-3 (Part 1 of 2). System Board I/O Address Map

System Overview 1-5

Address (Hex) Device

0330–0333 MIDI Port 4
0350–035F ThinkPad Modem
0376, 0377 Secondary IDE Registers
0378–037A Parallel Port 2
037B–037F Reserved
0388–038B Audio Subsystem - FM Synthesizer
0398–0399 Reserved
03B4, 03B5, 03BA Video Subsystem
03BC–03BE Parallel Port 1
03C0–03C5 Video Subsystem
03C6–03C9 Video DAC
03CA, 03CC, 03CE, 03CF, Video Subsystem
03D4, 03D5, 03DA,
03D8–03DA
03E0–03E1 PCMCIA Interface (DCR 2959)
03E8–03EF Serial Port 3
03E8–03EF IR Port 3
03F0–03F5, 03F7 Diskette-Drive Controller
03F6, 03F7 Primary IDE Registers
03F8–03FF Serial Port 1
03F8–03FF IR Port 1
0530–0537 Audio - WSS 1
0538–053F Audio Control Port 1
0604–060B Audio - WSS 2
0770–077F ThinkPad Modem
0CF8–0CFB PCI Configuration Address Register
0CFC–0CFF PCI Configuration Data Register
0DB0–0DBF ThinkPad Modem
0D38–0D3F Audio Control Port 2
0E80–0E87 Audio - WSS 3
0E88–0E8F Audio Control Port 3
0F40–0F47 Audio - WSS 4
0FF0–0FF7 Audio Control Port 4
15E8–15EF Power Management Register
2120–21FF Reserved
23C0–23C7 Reserved
46E8 Video Subsystem Enable
EF00–EF37 Power Management Register
EFA0–EFAD SMBus IO Space Register
F104 Reserved

Figure 1-3 (Part 2 of 2). System Board I/O Address Map

1-6 System Overview

Specifications

Figure 1-4 to Figure 1-7 on page 1-9 list the specifications for the
computers.

Performance Specifications

Device/Cycle

Microprocessor 200 or 233

L1 cache (64bit)

read/write hit

L2 cache (64bit) (for not all

models)

read hit (back-to-back)
write hit (back-to-back)

Memory (64bit) (see Note)

read, page hit
read, raw miss
read, page miss

posted write

write retire rate from

write buffer

Note:

The cycle times shown for access to system
board RAM are based on 70 ns EDO memory.

Clock Counts
(66 MHz)

MHz
1 CPUCLK
90 ns (60 ns)

90 ns (60 ns)

240 ns
285 ns
345 ns
90 ns
135 ns

Figure 1-4. Performance Specifications

System Overview 1-7

Physical Specifications

Size

Width: 313.0 mm (12.3 in.)
Depth: 240.0 / 254.0 mm (9.45 / 10.00 in.)
Height: 56.0 mm (2.20 in.)

Weightñ (approximate value)

Air Temperature

Humidity

Maximum altitudeò: 3,048 m (10,000 ft) in unpressurized conditions
Heat output: 56 W
Acoustical readings (see Figure 1-7 on page 1-9)
Electrical (see Figure 1-6 on page 1-9)
Electromagnetic compatibility: FCC class B

ñ With battery pack installed.
ò This is the maximum altitude at which the specified air temperatures apply. At

higher altitudes, the maximum air temperatures are lower than those specified.

3.4 kg (7.4 lb)

3.5 kg (7.7 lb)

System on (without diskette)

5.0°C to 35.0°C (41°F to 95°F)

System on (with diskette)

10.0°C to 35.0°C (50°F to 95°F)

System off

5.0°C to 43.0°C (41°F to 110°F)

System (without diskette)

8% to 95%

System (with diskette)

8% to 80%

Figure 1-5. Physical Specifications

1-8 System Overview

Electrical Specifications

(56 W)
Input voltageñ

(V ac)
Frequency (Hz) 50/60
Inputò (kVA) 0.13

ñ Range is automatically selected; sine wave input is required.
ò At maximum configuration.

100–240

Figure 1-6. Electrical Specifications

Acoustical Readings

L
Operate Idle Operate Idle Operate Idle
770 4.40 3.90 35.0 30.0 30.0 25.5
770 (with

SelectaDock
III)

Notes:

L

WAd

L

pAm

<L

pA>m

Operate Shows the value while using the hard disk drive.
All measurements made in accordance with ANSI S12.10 and reported in

conformance with ISO 9296.

in bels L

WAd

4.60 4.30 37.5 34.0 31.0 28.0

Is the declared sound power level for the random sample of
machines.

Is the mean value of the A-weighted sound pressure levels at the
operator position (if any) for the random sample of machines.

Is the mean value of the A-weighted sound pressure levels at the
1 meter position for the random sample of machines.

in dB <L

pAm

pA>m

in dB

Figure 1-7. Acoustical Readings

System Overview 1-9

Power Supply

The power supply converts the ac voltage to dc voltage and provides
power for the following:

 System board set
 Diskette drive

 Hard disk drive
 CD-ROM drive
 Auxiliary devices
 Keyboard
 LCD panel
 PCMCIA cards
 DVD drive

Voltages

The power supply generates six different dc voltages: VCC5M,
VCC3M, VCC12, and VCCSW. Figure 1-8 shows the maximum
current for each voltage.

Output Voltage (V dc) Current (A)

VCC5M +5.0 5.80
VCC3M +3.3 6.00

VCC12 +12.0 0.50

VCCSW +5.0 0.01

Figure 1-8. Power Supply Maximum Current

1-10 System Overview

Output Protection

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

If an overvoltage fault occurs in the power supply, the power supply
latches all dc outputs into a shutdown state before any output
exceeds 135% of the nominal value of the power supply.

Voltage Sequencing

When power is turned on, the output voltages reach their operational
voltages within 2 seconds.

Power Supply Connector

The following connector is used with the AC adapter. The total
power capacity of this connector must not exceed 4.0 A.

Refer to Figure 1-9 for the appropriate adapter pin assignments.

Pin Voltage

1 +7.0 V dc to +17.0 V dc (depending on charging conditions)
2 Ground

Figure 1-9. Voltage Pin Assignments for the 56W AC Adapter

Battery Pack

The ThinkPad computer uses a lithium-ion (Li-ion) battery pack that
meets the following electrical specifications:

System Overview 1-11

Nominal Voltage +10.8 V dc
Capacity (average) 4.5 ampere hours (AH)
Protection Overcurrent protection

Overvoltage protection
Overdischarge protection
Thermal protection

Figure 1-10. Lithium-ion Battery Pack Specifications

1-12 System Overview

Section 2. System Board

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Cache Memory Operation .................... 2-2

Cacheable Address Space .................... 2-3

Bus Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Keyboard/Mouse Connector . . . . . . . . . . . . . . . . . . . . . 2-4

Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Scan Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Keyboard ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Displayable Characters and Symbols .............. 2-7

Hard Disk Drive Connector ..................... 2-8

External Bus Connector ....................... 2-9

UltraBay II Connector ....................... 2-12

Diskette Drive and Controller ................... 2-15

Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

ROM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . 2-16

RAM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

System Memory Map ...................... 2-17

System Board Memory for the DIMM Connectors ..... 2-18

RT/CMOS RAM . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

RT/CMOS Address and NMI Mask Register (Hex 0070) 2-20

RT/CMOS Data Register (Hex 0071) ........... 2-20

RT/CMOS RAM I/O Operations .............. 2-21

CMOS RAM Configuration ................. 2-25

Miscellaneous System Functions and Ports .......... 2-29

Nonmaskable Interrupt (NMI) ................. 2-29

System Control Port A (Hex 0092) .............. 2-30

System Control Port B (Hex 0061) .............. 2-31

Power-On Password . . . . . . . . . . . . . . . . . . . . . . 2-32

Other Passwords . . . . . . . . . . . . . . . . . . . . . . . . 2-32

Selectable Drive-Startup Sequence .............. 2-33

Hardware Compatibility . . . . . . . . . . . . . . . . . . . . . . 2-34

Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

 Copyright IBM Corp. 1997 2-1

Description

This section describes the microprocessor, connectors, memory
subsystems, and miscellaneous system functions and ports for the
ThinkPad computers.

Microprocessor

The ThinkPad 770 uses the Intel Pentium 200 or 233 MHz
processor with the MMX technology.

The Processor has a 32-bit address bus and a 64-bit data bus. It is
software-compatible with all previous microprocessors. The
Processor has an internal, split data and instruction, 32KB write-back
cache. It includes pipelined math coprocessor functions and
superscalar architecture (two execution units).

Cache Memory Operation

In addition to the 32 KB of internal Level 1 (L1) cache memory in the
microprocessor, the system board of the ThinkPad 770 computer
contains an additional 256 KB of external Level 2 (L2) cache
memory.

The cache memory in the Intel Pentium microprocessor and the L2
external cache memory enable the microprocessor to read
instructions and data much faster than if the microprocessor had to
access system memory. When an instruction is first used or data is
first read or written, it is transferred to the cache memory from main
memory. This enables future accesses to the instructions or data to
occur much faster.

The cache is disabled and empty when the microprocessor comes
out of the reset state. The cache is tested and enabled during the
power-on self-test (POST).

The cache memory in the Intel Pentium microprocessor is loaded
from system memory in 32-byte increments, each referred to as a

cache line

reference to any byte contained in a cache line results in the entire
line being read into the cache memory (if the data was not already in
the cache). When the microprocessor gives up control of the system
bus, the cache memory enters “snoop” mode and monitors all write

2-2 System Board

. A cache line is aligned on a paragraph boundary. A

and read operations. If memory data is written to a location in the
cache and the cache line is in the “modified” state, the corresponding
cache line is written back to system memory and invalidated.

When the microprocessor performs a memory read, the data address
is used to find the data in the cache. If the data is found (a hit), it is
read from the cache memory and no external bus cycle occurs. If
the data is not found (a miss), an external bus cycle is used to read
the data from system memory. If the address of the missed data is
in cacheable address space, the data is stored in the cache memory
and the remainder of the cache line is read.

When the microprocessor performs a memory write, the data
address is used to search the cache. If the address is found (hit),
the data is written to the cache and no external bus cycle is used to
write the data to system memory. (If the address of the write
operation was not in the cache memory but was in cacheable
address space, the data is read back into the cache memory and the
remainder of the cache line is read.)

Cacheable Address Space

Cacheable address space is defined as system memory that resides
on the system board (0–640 KB and 1 MB–256 MB). Cacheability of
system memory is up to 64 MB in the L2 cache. Nothing in address
range hex A0000–BFFFF, I/O address space, or memory in any AT
slot is cached.

ROM address space (hex C0000–C9FFF and F0000–FFFFF) is L1
cacheable for
range is already in cache memory and the address range is written
to, the cached line is invalidated and is read again from RAM, where
the BIOS is shadowed.

Bus Adapter

When the computer is attached to the ThinkPad SelectaDock III
docking system, the PCI adapters or AT-bus adapters can be used
through the docking system.

code read operations only

. If data in this address

System Board 2-3

Keyboard/Mouse Connector

Each ThinkPad computer has a keyboard/mouse connector, where
the IBM mouse, keyboard, or numeric keypad is connected.

Signals

The keyboard and mouse signals are driven by open-collector drivers
pulled to 5 V dc through a pull-up resistor. Figure 2-1 lists the
signals.

Sink current 1 mA Maximum
High-level output voltage 5.0 V dc minus pullup Minimum
Low-level output voltage 0.5 V dc Maximum
High-level input voltage 2.0 V dc Minimum
Low-level input voltage 0.8 V dc Maximum

Figure 2-1. Keyboard and Mouse Signals

Connector

The keyboard/mouse connector uses a 6-pin, miniature DIN
connector.

56

34

12

Pin I/O Signal Name

1 I/O Mouse Data
2 I/O Keyboard Data
3–Ground
4–+5 V dc
5 I/O Mouse Clock
6 I/O Keyboard Clock

Figure 2-2. Keyboard/Mouse Connector Pin Assignments

Note: The maximum current for +5 V dc (pin 4) is 0.5 A for both the

mouse and the numeric keypad.

2-4 System Board

Scan Codes

Figure 2-3 shows the key numbers assigned to keys on the 84-key
keyboard (for the U.S. and Japan). Figure 2-4 on page 2-6 shows
the key numbers assigned to keys on the 85-key keyboard (for
countries other than the U.S. and Japan). For scan codes assigned
to each numbered key, refer to the

Interface Technical Reference

IBM Personal System/2 Hardware

.

Figure 2-3. Key Numbers for the 84-Key Keyboard

System Board 2-5

Figure 2-4. Key Numbers for the 85-Key Keyboard

Keyboard ID

The keyboard ID consists of 2 bytes: hex 83AB (the built-in keyboard
with the external numeric keypad) or hex 84AB (the built-in keyboard
only). Interrupt 16H, function code (AH)=0AH, returns the keyboard
ID.

2-6 System Board

Figure 2-5 shows the key numbers assigned to keys on the external
numeric keypad. For scan codes assigned to each numbered key,
refer to the

Reference

IBM Personal System/2 Hardware Interface Technical

.

90 95

91

96

92

97

93

98

99

100

101

102

103

104

105

106

108

Figure 2-5. Key Numbers for the External Numeric Keypad

Displayable Characters and Symbols

For displayable characters and symbols that are keyable from the
keyboard, refer to the

Technical Reference

IBM Personal System/2 Hardware Interface

.

System Board 2-7

Hard Disk Drive Connector

The hard disk drive connected to the system board is removable.
Figure 2-6 shows the pin assignments for the connector on the
system board.

Pin Signal I/O or Feature Pin Signal I/O or Feature

1 DetectIn O 31 GND Ground
2 Jumper A NC 32 NC NC
3 Jumper B O 33 -PDREQ I
4 Jumper C O 34 GND Ground
5 Jumper D O 35 -PDIOW O
6 RSTDRV O 36 GND Ground
7 GND Ground 37 -PDIOR O
8 PDD7 I/O 38 GND Ground

9 PDD8 I/O 39 PIORDY I
10 GND Ground 40 CSEL O
11 PDD6 I/O 41 -PDACK O
12 PDD9 I/O 42 GND Ground
13 GND Ground 43 IRQ14HDD I
14 PDD5 I/O 44 -IOCS16 I
15 PDD10 I/O 45 PDA1 O
16 GND Ground 46 -PDIAGHDD O
17 PDD4 I/O 47 GND Ground
18 PDD11 I/O 48 PDA0 O
19 GND Ground 49 PDA2 O
20 PDD3 I/O 50 -CS1P O
21 PDD12 I/O 51 -CS3P O
22 GND Ground 52 -DASPHDD I
23 PDD2 I/O 53 GND Ground
24 PDD13 I/O 54 VCC5B Vcc
25 GND Ground 55 VCC5B Vcc
26 PDD1 I/O 56 VCC5B Vcc
27 PDD14 I/O 57 VCC5B Vcc
28 GND Ground 58 Reserved NC
29 PDD0 I/O 59 -HDDDETECTI
30 PDD15 I/O 60 GND Ground

Figure 2-6. Hard Disk Drive Connector Pin Assignments

2-8 System Board