Apple Developer Note PowerBook G4 Service Manual

Developer Note

PowerBook G4

November 2002



Apple Computer, Inc.

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Every effort has been made to ensure that the information in this document is accurate. Apple is not responsible for typographical errors.

Apple Computer, Inc. 1 Infinite Loop Cupertino, CA 95014 408-996-1010

Apple, the Apple logo, AirPort, FireWire, iMac, Mac, PowerBook, and Macintosh are trademarks of Apple Computer, Inc., registered in the United States and other countries.

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Simultaneously published in the United States and Canada.

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Figures and Tables 7

Preface

Chapter 1

Chapter 2

About This Developer Note

Contents of This Note 9

Introduction

New Features 11 Features 12 Appearance 15 Peripheral Devices 16 System Software 17

Open Firmware 17 Computer Identification 18 Power-Saving Features 18

Reduced Processor Speed 18 Operating Modes 18

Architecture

Block Diagram and Buses 21

Block Diagram 21 Main ICs and Buses 23

Microprocessor and Caches 23

PowerPC G4 Microprocessor 23 Level 2 Cache 24 Level 3 Cache 24

 Apple Computer, Inc. November 2002

CONTENTS

Memory Controller and Bus Bridge 24

System RAM 25 Boot ROM 25 FireWire Controller 26 Ethernet Controller 26 Video Display Subsystem 26

I/O Controller 28

DMA Support 28 Interrupt Support 28 USB Interface 28 Ultra DMA/66 Interface 29 EIDE Interface 29 Modem Support 29 Sound Circuitry 30 Power Controller 30 AirPort Card Interface 31 CardBus Controller IC 31

Chapter 3

Devices and Ports

USB Ports 33

USB Connectors 33 USB Storage Devices 34

FireWire Port 35

FireWire Connector 35 FireWire Device Programming 37

Target Disk Mode 37 Ethernet Port 38 Internal Modem 40 AirPort Card 40

Data Security 41

AirPort Hardware 41

AirPort Software 42 Hard Disk Drive 42

Hard Disk Dimensions 42

Hard Disk Connector 44

Signal Assignments 45 ATA Signal Descriptions 46

 Apple Computer, Inc. November 2002

CONTENTS

DVD-ROM/CD-RW Combo Drive 48 DVD-R /CD-RW SuperDrive 49 Trackpad 50 Keyboard 50

Removing the Keyboard 50

Changing the Operation of the Keyboard 51

Keyboard Illustrations 51 Using the Fn Key 55 Using the Num Lock Key 55 The Function-Keys Checkbox 55 The Embedded Keypad 57

Other Control Keys 58 Flat-Panel Display 59 External Monitors 60

Dual Display and Mirror Mode 60 Analog Monitor Resolutions 61 Digital Display Resolutions 62

DVI-I Connector 62 External Video Port 64 Sound System 66

Sound Inputs 67

Built-in Microphone 67 Audio Input Jack 68 Modem Activity Sound Signals 68

Sound Outputs 68

Headphone Jack 68 Internal Speakers 69

Digitizing Sound 69

Chapter 4

Expansion Features

RAM Expansion Slots 71

Getting Access to the Slots 71

Mechanical Design of RAM SO-DIMMs 73

 Apple Computer, Inc. November 2002

CONTENTS

Electrical Design of RAM SO-DIMMs 73

SDRAM Devices 74 Configuration of RAM SO-DIMMs 75 Address Multiplexing 75

RAM SO-DIMM Electrical Limits 76 CardBus Slot 77

Appendix A

Appendix B

Supplemental Reference Documents

Apple Technical Notes 79 3D Graphics 79 PowerPC G4 Microprocessor 80 Velocity Engine (AltiVec) 80 Mac OS X 81 Mac OS 9.2.2 81 I/O Kit 82 Open Firmware 82 RAM Expansion Modules 83 PC Card Manager 83 ATA Devices 84 USB Interface 84 FireWire Interface 85 Digital Visual Interface 86 Wireless Networks 86

Abbreviations

Abbreviations and Standard Units 87 Other Abbreviations 88

Index

 Apple Computer, Inc. November 2002

Figures and Tables

Chapter 1

Chapter 2

Chapter 3

Introduction

Figure 1-1 Front view of the computer 15 Figure 1-2 Back view showing I/O ports 16 Table 1-1 Feature changes 12

Architecture

Figure 2-1 Block diagram 22 Table 2-1 Buses supported by the Uni-N IC 25

Devices and Ports

Figure 3-1 USB Type A port 34 Figure 3-2 FireWire connector 36 Figure 3-3 Maximum dimensions of the internal hard disk 43 Figure 3-4 Hard disk connector and location 44 Figure 3-5 Keyboard layout 52 Figure 3-6 Alternate operations of function and control keys 53 Figure 3-7 Embedded numeric keypad operation 54 Figure 3-8 DVI-I connector 63 Figure 3-9 S-video connector 65 Table 3-1 Pin assignments on the USB port 34 Table 3-2 Pin assignments on the FireWire connector 36 Table 3-3 Signals for 10Base-T and 100Base-T operation 38 Table 3-4 Signals for 1000Base-T operation 39 Table 3-5 Pin assignments on the ATA hard disk connector 45 Table 3-6 Signals on the ATA hard disk connector 46 Table 3-7 Types of media read and written by the DVD-ROM/CD-RW

drive 48

Table 3-8 Media read and written by the SuperDrive 49 Table 3-9 Setting the default behavior of the function keys 56

 Apple Computer, Inc. November 2002

FIGURES AND TABLES

Table 3-10 The function keys as control buttons 56 Table 3-11 Embedded keypad keys 57 Table 3-12 Control keys that change 58 Table 3-13 Picture sizes on the flat-panel display 59 Table 3-14 Picture sizes on an analog monitor 61 Table 3-15 Picture sizes on a digital display 62 Table 3-16 Main signals on the DVI-I connector 63 Table 3-17 MicroCross signals on the DVI-I connector 64 Table 3-18 Pin assignments for the S-video output connector 65 Table 3-19 Picture sizes for S-video output 66

Chapter 4

Expansion Features

Figure 4-1 Interior view showing RAM expansion slots 72 Table 4-1 Sizes of RAM expansion modules and devices 75 Table 4-2 Types of DRAM devices 76

 Apple Computer, Inc. November 2002

PREFACE

About This Developer Note

This developer note is a technical description of the PowerBook G4 computer. The note provides information about the computer’s internal design, input-output features, and expansion capabilities.

Note:

This developer note has been updated to include information about the

latest product features and configurations.

This developer note is intended to help hardware and software developers design products that are compatible with the Macintosh products described here. If you are not already familiar with Macintosh computers or if you would like additional technical information, you may wish to read the supplementary reference documents described in Appendix A (page 79).

Contents of This Note

The information in this note is arranged in four chapters and two appendixes.

■

Chapter 1, “Introduction” (page 11), introduces the PowerBook G4 computer

and describes its features.

Chapter 2, “Architecture” (page 21), describes the internal logic of the computer,

■

including the main ICs that appear in the block diagram.

Chapter 3, “Devices and Ports” (page 33), describes the standard I/O ports and

■

the built-in I/O devices.

Contents of This Note

 Apple Computer, Inc. November 2002

PREFACE

About This Developer Note

■

Chapter 4, “Expansion Features” (page 71), describes the expansion features of

interest to developers. It includes development guides for expansion-bay devices, the RAM expansion modules, and the PC Card slot.

■

Appendix A (page 79) contains links to supplemental reference documents.

Appendix B (page 87) is a list of the abbreviations used in this developer note.

■

Contents of This Note

 Apple Computer, Inc. November 2002

CHAPTER 1

1 Introduction

This chapter outlines the features of the PowerBook G4 computer, with emphasis on the changes from the previous models.

New Features

The features that have changed are listed here along with references to the sections that describe them. For a quick summary of the changes, see Table 1-1.

Processor:

■

running at a clock speed of 867 MHz or 1 GHz. For more information, see “PowerPC G4 Microprocessor” (page 23).

Graphics IC and memory:

■

operates on the AGP4x bus along with 32 or 64 MB of DDR RAM. For more information, see “Video Display Subsystem” (page 26).

■

Hard disk storage:

capacity of 40 or 60 GB. For more information and developer guidelines for alternative hard drives, see “Hard Disk Drive” (page 42).

■

Battery bay:

Power adapter:

■

plug.

SuperDrive (DVD-R/CD-RW drive):

■

G4 computer have a SuperDrive drive. For more information, see “DVD-R /

CD-RW SuperDrive” (page 49).

New Features

 Apple Computer, Inc. November 2002

The PowerBook G4 computer has a PowerPC G4 microprocessor

The ATI Mobility Radeon 9000 graphics processor

The computer comes with a built-in hard disk drive with a

The computer has a 61 watt-hours battery bay.

The computer ships with a 65 W power adapter with grounded

Some configurations of the PowerBook

CHAPTER 1

Introduction

■

Modem:

The computer has a built-in Apple 56 Kbps modem. The modem supports K56flex and V.92 modem standard. For more information, see

“Modem Support” (page 29).

■

AirPort Card standard:

An AirPort Card is standard in the 1 GHz model. See

“AirPort Card” (page 40).

Table 1-1

Feature Previous model Current model

Feature changes

Processor PowerPC G4 PowerPC G4

Processor clock speed 667 or 800 MHz 867 MHz or 1 GHz

Graphics IC ATI Mobility Radeon 7500 ATI Mobility Radeon 9000

Graphics memory 32 MB of DDR 32 or 64 MB of DDR

Hard disk drive 30 GB on 667 MHz, 40 GB

on 800 MHz, or 60 GB CTO

40 GB on 867 MHz and 60 GB on 1 GHz

AirPort Card Standard on 800 MHz only Standard on 1 GHz only

Battery bay 55.3 watt-hours battery bay 61 watt-hours battery bay

Power adapter 45 W power adapter 65 W power adapter

Removable media DVD-ROM/CD-RW Combo

drive

DVD-ROM/CD-RW Combo drive or a DVD-R/CD-RW SuperDrive

Hard drive option Additional CTO hard drive

support

No additional CTO hard drive support

Features

Here is a list of the features of the PowerBook G4 computer. Each feature is described in a later chapter, as indicated in the list.

Features

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

■

Processor:

The computer has a PowerPC G4 microprocessor running at a clock speed of 867 MHz or 1 GHz. For more information, see “PowerPC G4 Microprocessor” (page 23).

■

System bus:

The speed of the system bus is 133 MHz in all models.

Cache location and speed:

■

In addition to the L2 cache, which is internal to the

processor IC, the computer also has an L3 cache. See “Level 2 Cache” (page 24).

■

RAM:

The computer has two standard SO-DIMM expansion slots for SDRAM modules. The computer comes with 256 or 512 MB of SDRAM installed. See “RAM Expansion Slots” (page 71).

■

ROM:

The computer has 1 MB of boot ROM used by Open Firmware at startup. For information about the ROM, see “Boot ROM” (page 25). For information about Open Firmware, see “Open Firmware” (page 82).

■

Hard disk storage:

The computer comes with a built-in hard disk drive with a capacity of 40 or 60 GB. For more information and developer guidelines for alternative hard drives, see “Hard Disk Drive” (page 42).

■

Display:

The display is a 15.2 inch wide-screen TFT (1280 by 854 pixels) with a

resolution of 101.4 dpi. See “Flat-Panel Display” (page 59).

■

External monitor:

All configurations support an external video monitor, using the DVI-I connector for a digital video display and an S-video connector for a PAL or NTSC video monitor. (A VGA adapter and an S-video-to-composite adapter are included and an ADC adapter is available separately.) See “External Monitors” (page 60).

■

Graphics IC and memory:

The ATI Mobility Radeon 9000 graphics controller operates on the AGP4x bus along with 32 or 64 MB of video RAM. For more information, see “Video Display Subsystem” (page 26).

■

Battery bay:

The computer has a single battery bay. The battery uses lithium ion

cells and provides 61 watt-hours at 14.4 V (nominal).

■

Power adapter:

The computer comes with a 65 W power adapter with

grounded plug.

■

DVD-ROM/CD-RW Combo drive:

Some configurations have a built-in

DVD-ROM/CD-RW drive. See “DVD-ROM/CD-RW Combo Drive” (page 48).

■

SuperDrive (DVD-R/CD-RW drive):

Some configurations of the PowerBook G4 computer have a built-in DVD-R/CD-RW SuperDrive drive. For more information, see “DVD-R /CD-RW SuperDrive” (page 49).

Features

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

■

CardBus slot:

The computer has a CardBus slot that accepts one Type I or Type II PC card or a CardBus Card. For more information, see “CardBus Slot” (page 77).

■

USB ports:

The computer has two USB 1.1 ports for an external keyboard, a

mouse, and other USB devices, described in “USB Ports” (page 33).

■

FireWire port:

The computer has one IEEE-1394a high-speed serial FireWire port, which supports transfer rates of 100, 200, and 400 Mbps. For more information, see “FireWire Port” (page 35).

■

Target disk mode: The PowerBook G4 computer can act like a FireWire storage device connected to another computer. See “Target Disk Mode” (page 37)

■ Modem: The computer has a built-in modem with 56 Kbps data rate and V.92

support. For more information, see “Internal Modem” (page 40).

■ Ethernet: The computer has a built in Ethernet port with an RJ-45 connector for

10Base-T, 100Base-T, and 1000Base-T operation. For more information, see “Ethernet Port” (page 38).

■ AirPort Card: An AirPort Card wireless LAN module is standard on the 1 GHz

model and optional on the 867 MHz model. For more information, see “AirPort Card” (page 40).

■ Sound: The computer has a built-in microphone and stereo speakers as well as

a stereo headphone jack and a sound input jack. See “Sound System” (page 66).

■ Keyboard: The keyboard has an embedded numeric keypad and inverted-T

arrow keys. Some of the function keys are used to control the display brightness and speaker volume; the other function keys are programmable by the user. See “Keyboard” (page 50).

■ Trackpad: The integrated trackpad includes tap/double-tap and drag features.

For more information, see “Trackpad” (page 50).

■ Weight: The basic configuration weighs 2.4 kg (5.4 pounds).

■ Size: The computer is 341 mm (13.4 inches) wide, 241 mm (9.49 inches) deep,

and 26.3 mm (1.04 inches) thick.

Features

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

Appearance

Figure 1-1 is a front view of the PowerBook G4 computer. Figure 1-2 is a back view showing the I/O ports.

Figure 1-1 Front view of the computer

Sleep indicator light

Built-in speaker/ microphone

Function key

Trackpad

Appearance 15

 Apple Computer, Inc. November 2002

Display release button

Trackpad button

Power button

Security slot

Built-in speaker

AirPort antenna window

Slot-loading DVD-ROM /CD-RW Combo drive or DVD-R/CD-RW SuperDrive

CHAPTER 1

Introduction

Figure 1-2 Back view showing I/O ports

AirPort antenna window

Power adapter port

FireWire port

Ethernet port (10/100/1000Base-T)

Peripheral Devices

In addition to the devices that are included with the computer, several peripheral devices are available separately:

Sleep indicator light

DVI-I port

USB ports

Internal modem port

PC Card eject button

PC Card slot

Headphone jack

Audio line-in connector

TV out port

16 Peripheral Devices

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

■ The PowerBook G4 Rechargeable Battery is available separately as an additional

or replacement battery.

■ The Apple Portable Power Adapter, which comes with the computer, is also

available separately. The adapter can fully recharge a completely depleted battery in three hours or less while the computer is running, shut down, or in sleep mode.

■ The Apple DVI to ADC Adapter, which enables the PowerBook G4 computer to

support Apple’s ADC displays, is available separately.

■ The Apple Pro Keyboard, a full-featured USB keyboard, is available separately.

■ The Apple Pro Mouse, an optical USB mouse, is available separately.

■ The AirPort Base Station is available separately.

■ The AirPort Card is also available separately.

■ A power cable for use on airliners is also available. The airline power cable

should have a sense resistor of 24.3K ohms connected between the power plug's shell and ground. For more information, see “Power Controller” (page 30).

System Software

The PowerBook G4 computer comes with both Mac OS X version 10.2 and Mac OS

9.2.2 installed. Mac OS X is the default startup system. For the latest information, see the references listed in “Mac OS X” (page 81) and “Mac OS 9.2.2” (page 81).

Here are a few items of interest about the system software on the PowerBook G4 computer.

Open Firmware

System software on all current Macintosh models uses a design based on Open Firmware. With this approach, the ROM on the main logic board contains only the Open Firmware code needed to initialize the hardware and load an operating system. The rest of the system code is loaded into RAM from disk or from the network. For more information, see the references listed in “Open Firmware” (page 82).

System Software 17

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

Computer Identification

Rather than reading the box flag or the model string and then making assumptions about the computer’s features, applications that need to find out the features of the computer should use IORegistry calls to test for the features they require. IORegistry calls are part of the I/O Kit API. For more information, see the references listed at “I/O Kit” (page 82).

Asset management software that reports the kind of computer it is running on can obtain the value of the model property from the IOService plane of the IORegistry. For the PowerBook G4 computer, the value of the model property is PowerBook3,5.

Power-Saving Features

The PowerBook G4 computer has several profiles to save power. These profiles are labeled on the Energy Saver panel of System Preferences.

Reduced Processor Speed

Reduced processor speed allows the software to change the processor’s clock speed, slowing down to conserve power or speeding up when more speed is needed. The slower clock speed is 667 MHz and the L3 cache is turned off.

■ The system software uses a reduced processor speed to automatically conserve

power under the following conditions:

■ during system startup

■ when battery charge is low

■ when there is no battery installed

■

when using airline power

■ The user interface for the reduced processor speed is located in the options tab

under the Energy Saver panel in System Preferences.

Operating Modes

The power management protocols on the PowerBook G4 computer support two power-saving modes: idle and sleep.

18 System Software

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

■ Idle: The system is idling with the main processor stopped in a halted,

low-power state. All clocks are running; the system can return to running code within a few nanoseconds. Cache coherency is maintained in this state.

■ Sleep: The system is completely shut down, with only the DRAM state

preserved for quick recovery. All processors are powered off with their state preserved in DRAM. All clocks in the system are suspended except for the

32.768 kHz timebase crystal on the PMU99 IC.

The computer automatically enters Idle mode after several seconds of inactivity. If the computer is attached to a network, it is able to respond to service requests and other events directed to the computer while it is in Idle mode.

While it is connected to an AC power supply, the computer can also respond to network activity when it is in sleep mode. The user can enable this feature by selecting Wake-on-LAN in the Energy Saver control panel.

When operating on the battery in sleep mode, the computer consumes less than 1 watt of power, meeting the Energy Star power-saving standard. When operating on the power adapter in sleep mode, the combined computer and adapter consume 3 to 4 watts of power.

Important

Peripherals such as PCMCIA cards and USB devices that do not conform to the computer’s power management protocols prevent the computer from switching to sleep mode and so deny the user the benefits of this energy-saving mode. When such peripherals are attached to the computer, the operating system displays a dialog to inform the user that the computer no longer meets the Energy Star requirements.

System Software 19

 Apple Computer, Inc. November 2002

CHAPTER 1

Introduction

20 System Software

 Apple Computer, Inc. November 2002

CHAPTER 2

2 Architecture

This chapter describes the architecture of the PowerBook G4 computer. It includes information about the major components on the main logic board: the microprocessor, the other main ICs, and the buses that connect them to each other and to the I/O interfaces.

Block Diagram and Buses

This section is an overview of the major ICs and buses on the computer’s main logic board.

Block Diagram

Figure 2-1 is a simplified block diagram of the main logic board. The diagram shows the input and output connectors, the main ICs, and the buses that connect them together.

Block Diagram and Buses 21

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

Figure 2-1 Block diagram

SO-DIMM

slots

CardBus slot

connector

Connector to internal DVD-ROM/CD-RW Combo drive or DVD-R/CD-RW SuperDrive

Connector to internal antenna

and

Wireless LAN module

cache

memory bus

CardBus

bridge

ATA bus

DSP and

MAC

PMU99

power

controller

PowerPC G4

microprocessor

L2 cache: 256K

Max bus

Uni-N

memory

controller

and PCI

bus bridge

PCI bus

KeyLargo

I/O device

and disk

controller

Connector to

internal display

AGP

bus

Radeon 9000

graphics IC

Boot

ROM

Ultra-ATA bus

Snapper

audio

USB

Mobility

Ethernet

PHY

FireWire

PHY

Internal speaker connector

Data pump

and DAA

Modem module

Connector to internal IDE disk drive

S-video connecto

DVI-I monitor connector

Ethernet port

FireWire port

Audio input jack

Headphone jack

USB port

Telephone connector

22 Block Diagram and Buses

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

Main ICs and Buses

The architecture of the PowerBook G4 computer is designed around the PowerPC G4 microprocessor and two custom ICs: the Uni-N memory controller and bus bridge, and the KeyLargo I/O device controller. Those three ICs occupy the center of the block diagram.

The PowerPC G4 microprocessor is connected to the Uni-N memory controller and bus bridge IC by a MaxBus bus. The bus clock speed is 133 MHz. The Uni-N IC has other buses that connect with the KeyLargo IC, the main system RAM, and the graphics IC. The buses implemented by the Uni-N IC are summarized in Table 2-1, which is in the section “Memory Controller and Bus Bridge” (page 24).

The Uni-N IC is connected to the KeyLargo I/O controller IC by a 32-bit PCI bus with a bus clock speed of 33 MHz. That bus also connects to the Boot ROM and the CardBus controller. The KeyLargo IC has other buses that connect with the hard disk drive and the optical drive, the power controller IC, the sound IC, the internal modem module, and the wireless LAN module.

Each of the components listed here is described in one of the following sections.

Microprocessor and Caches

The microprocessor communicates with the rest of the system by way of a 64-bit MaxBus bus to the Uni-N IC. The microprocessor has a separate bus to its internal second-level cache.

PowerPC G4 Microprocessor

The PowerPC G4 microprocessor used in the PowerBook G4 computer has many powerful features, including an efficient pipelined system bus called MaxBus.

Features of the PowerPC G4 include

■ 32-bit PowerPC implementation

■ superscalar PowerPC core

Microprocessor and Caches 23

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

■ Velocity Engine (AltiVec technology): 128-bit-wide vector execution unit

■ dual 32 KB instruction and data caches

■ an on-chip level 2 (L2) cache consisting of 256 KB with a clock speed ratio of 1:1

■ high bandwidth MaxBus (also compatible with 60x bus)

■ fully symmetric multiprocessing capability

The PowerPC G4 microprocessor in the PowerBook G4 computer runs at a clock speed of 867 MHz or 1 GHz.

Level 2 Cache

The data storage for the L2 cache consists of 256 KB of fast static RAM that is built into the microprocessor chip along with the cache controller and tag storage. The built-in L2 cache runs at the same clock speed as the microprocessor.

Level 3 Cache

The data storage for the L3 cache is 1 MB of DDR SRAM running at a clock speed ratio of 5:1. The tag storage for the L3 cache is built into the microprocessor.

Memory Controller and Bus Bridge

The Uni-N memory controller and bus bridge IC provides cost and performance benefits by combining several functions into a single IC. It contains the memory controller, the PCI bus bridge, the Ethernet and FireWire interfaces, and the AGP interface.

Each of the separate communication channels in the Uni-N IC can operate at its full capacity without degrading the performance of the other channels.

24 Memory Controller and Bus Bridge

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

In addition to the four buses listed in Table 2-1, the Uni-N IC also has separate interfaces to the physical layer (PHY) ICs for Ethernet and FireWire, and an IIC (inter-IC control bus) interface that is used for configuring the memory subsystem.

Table 2-1 Buses supported by the Uni-N IC

Bus Destinations Width of data path Bus clock speed

MaxBus Microprocessor 64 bits 133 MHz

Memory System RAM 64 bits 133 MHz

PCI KeyLargo IC

and Boot ROM

AGP Graphics IC 32 bits 133 MHz

The microprocessor and the I/O controller IC are described in their own sections. The following sections describe the other subsystems that are connected to the Uni-N IC.

32 bits 33 MHz

System RAM

The memory subsystem in the PowerBook G4 computer supports two slots for 144-pin SO-DIMMs (small-outline dual inline memory modules). The data bus to the RAM and DIMM is 64 bits wide, and the memory interface is synchronized to the MaxBus bus interface at 133 MHz. See “RAM Expansion Slots” (page 71).

Boot ROM

The boot ROM is connected to the Uni-N IC by way of the high byte of the PCI bus plus three additional control signals: chip select, write enable, and output enable. The boot ROM is a 1 MB by 8 bit device.

Memory Controller and Bus Bridge 25

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

FireWire Controller

The Uni-N IC includes an IEEE 1394a FireWire controller with a maximum data rate of 400 Mbits (50 MB) per second. The Uni-N IC provides DMA (direct memory access) support for the FireWire interface.

The controller in the Uni-N IC implements the FireWire link layer. A physical layer IC, called a PHY, implements the electrical signaling protocol of the FireWire interface and provides the electrical signals to the port. For more information, see “FireWire Connector” (page 35).

Ethernet Controller

The Uni-N IC includes an Ethernet media access controller (MAC) that implements the link layer. The Uni-N IC provides DB-DMA support for the Ethernet interface.

The Ethernet controller in the Uni-N IC is connected to a PHY interface IC that provides the electrical signals to the port. The PHY is capable of operating in either 10Base-T, 100Base-T, or 1000Base-T mode: The actual speed of the link is automatically negotiated by the PHY and the bridge or router to which it is connected. For more information, see “Ethernet Port” (page 38).

The PHY supports Auto-MDIX, which allows the use of straight-through cables in crossover situations (and conversely). For more information, see “Ethernet Port” (page 38).

Video Display Subsystem

The video display subsystem contains the graphics controller IC along with either 32 MB of DDR memory in the 867 MHz computer or 64 MB of DDR memory (32 MB internal and another 32 MB external to the IC) in the 1 GHz computer. The graphics IC, an ATI Mobility Radeon 9000, contains 2D and 3D acceleration engines, front-end and back-end scalers, a CRT controller, and an AGP4x bus interface with bus master capability.

The features of the Mobility Radeon 9000 include

■ graphics processor clock speed of 200 MHz

■ memory clock speed of 200 MHz

■ support for 32 MB of DDR video memory with 64-bit interface

26 Memory Controller and Bus Bridge

 Apple Computer, Inc. November 2002

CHAPTER 2

Architecture

■ support for 64 MB of DDR video memory with 128-bit interface

■ 2D and 3D graphics acceleration

■ transform acceleration

■ lighting acceleration

■ video acceleration

■ support for MPEG decoding

■ support for video mirror mode

■ support for dual-display mode

■ S-video output for a TV monitor

■ support for programmable pixel and vertex shading

The interface between the graphics IC and the rest of the system is an AGP4x (accelerated graphics port, quadruple speed) bus on the Uni-N IC. To give the graphics IC fast access to system memory, the AGP bus has separate address and data lines and supports deeply pipelined read and write operations. The AGP bus has 32 data lines and a clock speed of 133 MHz.

The graphics IC uses a graphics address remapping table (GART) to translate AGP logical addresses into physical addresses. The graphics driver software can allocate memory in both the graphics SDRAM and the main memory.

The graphics IC supports the built-in flat-panel display and an external monitor. The external monitor can either mirror the built-in display or show additional desktop space (dual-display mode). For information about the displays and supported resolutions, see “Flat-Panel Display” (page 59) and “External Monitors” (page 60).

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CHAPTER 2

Architecture

I/O Controller

The I/O controller IC in the PowerBook G4 computer is a custom IC called KeyLargo. It provides the interface and control signals for the devices and functions described in the following sections.

Note: In the device tree, the I/O controller is named “mac-io”.

DMA Support

The KeyLargo IC provides DB-DMA (descriptor-based direct memory access) support for the following I/O channels:

■ Ultra DMA ATA interface to the the internal hard drive

■ modem slot interface to the built-in modem

■ IIS channel to the sound IC

The DB-DMA system provides a scatter-gather process based on memory resident data structures that describe the data transfers. The DMA engine is enhanced to allow bursting of data files for improved performance.

Interrupt Support

The KeyLargo IC has an interrupt controller (MPIC) that handles interrupts generated within the IC as well as external interrupts, such as those from the Ethernet and FireWire controllers.

USB Interface

The KeyLargo IC implements two independent USB controllers (root hubs), each of which is connected to one of the ports on the back panel of the computer. The use of two independent controllers allows both USB ports to support high data rate

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CHAPTER 2

Architecture

devices at the same time with no degradation of their performance. If a user connects a high-speed (12 Mbps) device to one port and another high-speed device to the other, both devices can operate at their full data rates.

The two external USB connectors support USB devices with data transfer rates of

1.5 Mbps or 12 Mbps. For more information about the connectors, see “USB Connectors” (page 33).

USB devices connected to the PowerBook G4 computer are required to support USB-suspend mode as defined in the USB specification. Information about the operation of USB-suspend mode on Macintosh computers is included in the Mac OS USB DDK API Reference. To obtain it, see the reference at “USB Interface” (page 84).

The USB ports on the PowerBook G4 computer comply with the Universal Serial Bus Speciﬁcation 1.1 Final Draft Revision. The USB controllers comply with the Open Host Controller Interface (OHCI) specification.

Ultra DMA/66 Interface

The KeyLargo IC provides an Ultra DMA/66 channel that is connected to the internal hard disk drive. The KeyLargo IC provides DB-DMA (descriptor-based direct memory access) support for the Ultra DMA interface.

The internal hard disk drive is connected as device 0 (master) in an ATA Device 0/ 1 configuration.

EIDE Interface

The KeyLargo IC provides an EIDE interface (ATA bus) that supports the Combo (DVD-ROM/CD-RW) drive, SuperDrive (DVD-R/CD-RW) drive, and the wireless LAN module. The Combo and SuperDrive drives are ATAPI drives and are device-selected as master in an ATA device configuration.

Modem Support

The internal modem is connected to an internal USB port. The KeyLargo IC provides DB-DMA support for the modem interface. The modem provides digital call progress signals to the Snapper sound circuitry.

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