- •Contents
- •Figures and Tables
- •About This Developer Note
- •Contents of This Note
- •Supplemental Reference Documents
- •PowerPC G3 Microprocessor
- •Mac OS
- •ATA Devices
- •USB Devices
- •Open Firmware
- •Introduction
- •Features
- •Case and External Features
- •Compatibility Issues
- •System Software
- •Main RAM Expansion Modules
- •Video RAM Expansion Modules
- •USB Ports and Devices
- •Architecture
- •Processor module
- •G3 Microprocessor
- •Backside Cache
- •Memory Controller and PCI Bridge
- •Main Logic Board
- •I/O Controller IC
- •USB Controller
- •Video Display Subsystem
- •Built-in Modem
- •Infrared Link Module
- •Devices and Ports
- •USB Ports
- •USB Connectors
- •Transfer Types Supported
- •USB Compatibility Issues
- •ADB Compatibility
- •Serial Port Compatibility
- •Macintosh-To-Macintosh Connections
- •USB Storage Devices
- •USB Controller
- •Keyboard
- •Keyboard Layout
- •Keyboard and USB
- •Mouse
- •Hard Disk Drive
- •Video Display
- •Infrared Communication Link
- •Sound System
- •Sound Inputs
- •Built-in Microphone
- •External Sound Input
- •Sound Outputs
- •Internal Speakers
- •External Sound Output
- •Headphone Jacks
- •Ethernet Port
- •Internal Modem
- •RAM Expansion
- •The Expansion Slots
- •Removing the Logic Board Assembly
- •Placing the Computer Face Down
- •Removing the bottom cover
- •Unfastening the Cables
- •Removing the Retaining Screws
- •Removing the Logic Board Assembly
- •Removing the EMI Shield
- •Locations of the Expansion Slots
- •Main RAM Expansion
- •Mechanical Design of RAM SO-DIMMs
- •Electrical Design of RAM SO-DIMMs
- •SDRAM Devices
- •Address Multiplexing
- •RAM SO-DIMM Electrical Limits
- •Video RAM Expansion
- •Software
- •Why Make This Change?
- •What Has Changed
- •Features of the New Approach
- •Performance
- •RAM Footprint
- •User Experience
- •Data Structures and Files
- •Compatibility
- •Boot ROM Contents
- •POST Code
- •Open Firmware
- •Mac OS 'ndrv' Drivers
- •RTAS
- •Toolbox Image File Contents
- •Open Firmware Script
- •Trampoline Code
- •ToolBox ROM Image
- •NewWorld Boot Process
- •What Is Different
- •Interrupt Handling
- •Outmoded Resources
- •RAM Footprint
- •RTAS
- •NV-RAM
- •NanoKernel
- •Startup Disk Control Panel
- •Open Firmware and the Device Tree
- •Interrupt Layout
- •Abbreviations
- •Index

Developer Note
Apple iMac Computer
Developer Note
Technical Publications
© Apple Computer, Inc. 1998
Apple Computer, Inc.
© 1998 Apple Computer, Inc. All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, mechanical, electronic, photocopying, recording, or otherwise, without prior written permission of Apple Computer, Inc., except to make a backup copy of any documentation provided on
The Apple logo is a trademark of Apple Computer, Inc.
Use of the “keyboard” Apple logo
No licenses, express or implied, are granted with respect to any of the technology described in this book. Apple retains all intellectual property rights associated with the technology described in this book. This book is intended to assist application developers to develop applications only for
Every effort has been made to ensure that the information in this manual is accurate. Apple is not responsible for typographical errors.
Apple Computer, Inc. 1 Infinite Loop Cupertino, CA 95014
Apple, the Apple logo, Macintosh and Power Macintosh are trademarks of Apple Computer, Inc., registered in the United States and other countries.
iMac is a trademark of Apple Computer, Inc.
Adobe, Acrobat, and PostScript are trademarks of Adobe Systems Incorporated or its subsidiaries and
may be registered in certain jurisdictions.
Helvetica and Palatino are registered trademarks of
ITC Zapf Dingbats is a registered trademark of International Typeface Corporation.
PowerPC is a trademark of International Business Machines Corporation, used under license therefrom.
SRS is a registered trademark of SRS Labs, Inc., in the United States and selected foreign countries.
Simultaneously published in the United States and Canada.
Even though Apple has reviewed this manual, APPLE MAKES NO WARRANTY OR REPRESENTATION, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THIS MANUAL, ITS QUALITY, ACCURACY, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. AS A RESULT, THIS MANUAL IS SOLD “AS IS,” AND YOU, THE PURCHASER, ARE ASSUMING THE ENTIRE RISK AS TO ITS QUALITY AND ACCURACY.
IN NO EVENT WILL APPLE BE LIABLE FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY DEFECT OR INACCURACY IN THIS MANUAL, even if advised of the possibility of such damages.
THE WARRANTY AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHERS, ORAL OR WRITTEN, EXPRESS OR IMPLIED. No Apple dealer, agent, or employee is authorized to make any modification, extension, or addition to this warranty.
Some states do not allow the exclusion or limitation of implied warranties or liability for incidental or consequential damages, so the above limitation or exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.
Contents
| Figures and Tables |
| 7 |
|
|
| |
Preface | About This Developer Note |
| 9 | ||||
|
|
|
|
|
| ||
| Contents of This Note | 9 |
|
|
| ||
| Supplemental Reference Documents | 10 | |||||
| PowerPC G3 Microprocessor | 10 |
| ||||
| Mac OS | 10 |
|
|
|
|
|
| ATA Devices | 10 |
|
|
|
| |
| USB Devices | 11 |
|
|
|
| |
| Open Firmware |
| 11 |
|
|
| |
Chapter 1 | Introduction | 13 |
|
|
| ||
|
|
|
|
|
|
|
|
| Features | 14 |
|
|
|
|
|
| Case and External Features | 15 |
|
| |||
| Compatibility Issues | 18 |
|
|
| ||
| System Software |
| 18 |
|
|
| |
| Main RAM Expansion Modules |
| 19 | ||||
| Video RAM Expansion Modules |
| 19 | ||||
| USB Ports and Devices | 19 |
|
| |||
Chapter 2 | Architecture | 21 |
|
|
| ||
|
|
|
|
|
|
| |
| Processor module |
| 23 |
|
|
| |
| G3 Microprocessor | 23 |
|
|
| ||
| Backside Cache |
| 23 |
|
|
| |
| Memory Controller and PCI Bridge | 24 | |||||
| Main Logic Board |
| 24 |
|
|
| |
| I/O Controller IC | 24 |
|
|
| ||
| USB Controller |
| 25 |
|
|
| |
| Video Display Subsystem | 25 |
|
| |||
|
| 25 |
|
|
|
3
| Infrared Link Module | 26 |
|
| |||
Chapter 3 | Devices and Ports | 27 |
|
| |||
|
|
|
|
|
|
|
|
| USB Ports | 28 |
|
|
|
|
|
| USB Connectors | 28 |
|
|
| ||
| Transfer Types Supported |
| 29 |
| |||
| USB Compatibility Issues |
| 30 |
| |||
| ADB Compatibility | 30 |
|
| |||
| Serial Port Compatibility | 31 |
| ||||
| 31 | ||||||
| USB Storage Devices | 31 |
|
| |||
| USB Controller | 31 |
|
|
| ||
| Keyboard | 32 |
|
|
|
|
|
| Keyboard Layout | 32 |
|
|
| ||
| Keyboard and USB | 33 |
|
|
| ||
| Mouse | 33 |
|
|
|
|
|
| Hard Disk Drive | 34 |
|
|
| ||
| Video Display | 34 |
|
|
|
| |
| Infrared Communication Link | 35 |
| ||||
| Sound System | 35 |
|
|
|
| |
| Sound Inputs | 36 |
|
|
|
| |
| 36 |
|
| ||||
| External Sound Input | 36 |
| ||||
| Sound Outputs | 36 |
|
|
| ||
| Internal Speakers | 36 |
|
| |||
| External Sound Output |
| 37 |
| |||
| Headphone Jacks | 37 |
|
| |||
| Sound Specifications | 37 |
|
| |||
| Ethernet Port | 39 |
|
|
|
| |
| Internal Modem | 39 |
|
|
|
|
Chapter 4 RAM Expansion | 41 |
The Expansion Slots | 42 |
Removing the Logic Board Assembly | 42 |
4
Placing the Computer Face Down | 42 | |||
Removing the bottom cover | 43 |
| ||
Unfastening the Cables | 43 |
|
| |
Removing the Retaining Screws | 45 | |||
Removing the Logic Board Assembly | 46 | |||
Removing the EMI Shield | 46 |
|
| |
Locations of the Expansion Slots | 47 |
| ||
Main RAM Expansion | 48 |
|
|
|
Mechanical Design of RAM | 49 | |||
Electrical Design of RAM | 49 | |||
SDRAM Devices | 50 |
|
|
|
Configuration of RAM | 51 | |||
Address Multiplexing | 52 |
|
| |
RAM | 52 |
| ||
Video RAM Expansion | 53 |
|
|
|
Chapter 5 Software |
| 55 |
|
|
|
Why Make This Change? | 56 |
| |||
What Has Changed | 57 |
| |||
Features of the New Approach | 58 | ||||
Performance | 59 |
|
| ||
RAM Footprint | 59 |
| |||
User Experience |
| 59 |
| ||
Data Structures and Files | 59 | ||||
Compatibility | 59 |
| |||
Boot ROM Contents |
| 60 |
| ||
POST Code | 60 |
|
|
| |
Open Firmware | 61 |
|
| ||
Mac OS 'ndrv' Drivers | 61 |
| |||
RTAS | 61 |
|
|
|
|
Toolbox Image File Contents | 62 | ||||
Open Firmware Script | 62 |
| |||
Trampoline Code | 63 |
| |||
ToolBox ROM Image | 63 |
| |||
NewWorld Boot Process | 63 |
| |||
What Is Different | 64 |
|
|
5

| Interrupt Handling |
| 64 |
|
| ||
| Outmoded Resources | 65 |
|
| |||
| RAM Footprint | 65 |
|
|
| ||
| RTAS | 65 |
|
|
|
|
|
|
| 65 |
|
|
|
| |
| NanoKernel | 66 |
|
|
|
| |
| Startup Disk Control Panel | 66 |
| ||||
| Open Firmware and the Device Tree | 67 | |||||
| Interrupt Layout | 67 |
|
|
| ||
| Machine Identification | 67 |
|
| |||
Appendix | Abbreviations | 69 |
|
|
| ||
|
|
|
|
|
|
|
|
Index 73
6