Apple Developer Note PowerBook G4 Service Manual

D e v e l o p e r N o t e

PowerBook G4

November 2002

Apple Computer, Inc.

© 2001, 2002 Apple Computer, Inc. All rights reserved.

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Simultaneously published in the United States and Canada.

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Contents

	Figures and Tables			7
Preface	About This Developer Note				9
	Contents of This Note			9
Chapter 1	Introduction		11
	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

Chapter 2 Architecture	21
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

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C O N T E N T S

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					33
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

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C O N T E N T S

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	71
RAM Expansion Slots 71
Getting Access to the Slots	71

Mechanical Design of RAM SO-DIMMs 73

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C O N T E N T S

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 Supplemental Reference Documents							79
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
Appendix B Abbreviations				87
Abbreviations and Standard Units						87
Other Abbreviations				88
Index	91

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Figures and Tables

Chapter 1	Introduction		11
	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
Chapter 2	Architecture		21
	Figure 2-1	Block diagram		22
	Table 2-1	Buses supported by the Uni-N IC					25
Chapter 3	Devices and Ports			33
	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

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F I G U R E S A N D T A B L E S

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		71
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

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P R E F A C E

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	9
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P R E F A C E

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.

10Contents of This Note

Apple Computer, Inc. November 2002

C H A P T E R 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: The PowerBook G4 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).

■Graphics IC and memory: The ATI Mobility Radeon 9000 graphics processor 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: 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).

■Battery bay: The computer has a 61 watt-hours battery bay.

■Power adapter: The computer ships with a 65 W power adapter with grounded plug.

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

New Features	11
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C H A P T E R 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 changes

Feature	Previous model	Current model
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	40 GB on 867 MHz and
	on 800 MHz, or 60 GB CTO	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	DVD-ROM/CD-RW Combo
	drive	drive or a DVD-R/CD-RW
		SuperDrive
Hard drive option	Additional CTO hard drive	No additional CTO hard
	support	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.

12Features

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C H A P T E R 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

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C H A P T E R 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.

14Features

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C H A P T E R 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	Display	Trackpad
	release button	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

Appearance

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C H A P T E R 1

Introduction

Figure 1-2 Back view showing I/O ports

			AirPort antenna
			window
Power			PC Card
adapter port	Sleep indicator light		eject button
			PC Card slot
	DVI-I port	Internal	Headphone
		modem port	jack
FireWire
port
Ethernet port	USB ports		Audio line-in connector
(10/100/1000Base-T)			TV out port

Peripheral Devices

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

16Peripheral Devices

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C H A P T E R 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

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C H A P T E R 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.

18System Software

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C H A P T E R 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

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C H A P T E R 1

Introduction

20System Software

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C H A P T E R 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
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C H A P T		E R 2
Architecture
Figure 2-1		Block diagram

PowerPC G4

L3

microprocessor

Connector to

cache

SO-DIMM

L2 cache: 256K

internal display

slots

memory bus

Max bus

AGP

Mobility

bus

Radeon 9000

Uni-N

graphics IC

memory

controller

CardBus slot

Ethernet

and PCI

PHY

connector

bus bridge

FireWire

PHY

CardBus

bridge

Boot

PCI bus

ROM

Connector to internal

Connector to

Ultra-ATA bus

DVD-ROM/CD-RW Combo

internal IDE

drive or DVD-R/CD-RW

disk drive

SuperDrive

ATA bus

Snapper

audio

Connector

Internal

to internal

KeyLargo

antenna

I/O device

speaker

and disk

connector

controller

RF

DSP and

and

MAC

IF

Wireless LAN module

USB

Data pump

PMU99

and DAA

power

Modem module

controller

S-video connector

DVI-I monitor connector

Ethernet port

FireWire port

Audio input jack

Headphone jack

USB port

USB port

Telephone connector

22Block Diagram and Buses

Apple Computer, Inc. November 2002

C H A P T E R 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

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C H A P T E R 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.

24Memory Controller and Bus Bridge

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C H A P T E R 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	32 bits	33 MHz
			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.

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

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C H A P T E R 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

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■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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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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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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