Apple Desktop Computer manual USB Devices, Open Firmware

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P R E F A C E

USB Devices

For more information about USB on the Macintosh computer, developers should refer to Apple Computer’s Mac OS USB DDK ATI Reference. Information is also available on the World Wide Web, at:

http://developer.apple.com/dev/usb/

For full specifications of the Universal Serial Bus, developers should refer to the USB Implementation Forum on the World Wide Web, at:

http://www.usb.org/developers/index.html

Open Firmware

Three Technotes provide an introduction to Open Firmware on the Macintosh platform. They are:

TN 1061: Open Firmware, Part I, available on the Technote web site at

http://developer.apple.com/technotes/tn/tn1061.html

TN 1062: Open Firmware, Part II, available on the Technote web site at

http://developer.apple.com/technotes/tn/tn1062.html

TN 1044: Open Firmware, Part III, available on the Technote web site at

http://developer.apple.com/technotes/tn/tn1044.html

The New World software architecture described in Chapter 5, “Software,” follows some of the standards defined by the Open Firmware IEEE 1274-1995 specification and the CHRP binding.

The basis for the bootinfo file format and use is the document PowerPCMicroprocessor Common Hardware Reference Platform (CHRP) System binding to: IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration) Firmware. A bootinfo file contains Open Firmware script, a description, information for individual operating systems, icons, along with other information. A bootinfo file can be extended to contain non-Open Firmware information, such as “Trampoline” code and the ToolBox ROM Image.

Other Open Firmware references of possible interest include:

IEEE 1275-1994 Standard for Boot (Initialization, Configuration) Firmware: Core Requirements and Practices

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Contents Apple iMac Computer Page Contents RAM Expansion Devices and PortsRtas SoftwareRtas NV-RAM Appendix Abbreviations IndexFigures and Tables Page About This Developer Note Contents of This NoteATA Devices PowerPC G3 MicroprocessorSupplemental Reference Documents Mac OSOpen Firmware USB DevicesE F a C E Introduction Features Shows a front view of the computer Case and External FeaturesFront view 2Side view showing I/O bay System Software Compatibility IssuesUSB Ports and Devices Main RAM Expansion ModulesVideo RAM Expansion Modules Page Architecture Architecture Backside Cache Processor moduleG3 Microprocessor Controller IC Main Logic BoardMemory Controller and PCI Bridge Built-in Modem USB ControllerVideo Display Subsystem Infrared Link Module Devices and Ports USB Ports USB ConnectorsGND Transfer Types SupportedADB Compatibility USB Compatibility IssuesUSB Controller Serial Port CompatibilityMacintosh-To-Macintosh Connections USB Storage DevicesKeyboard Layout KeyboardKeyboard and USB MouseVideo Display Hard Disk DriveSound System Infrared Communication LinkExternal Sound Input Sound InputsSound Outputs Built-in MicrophoneHeadphone Jacks Sound SpecificationsExternal Sound Output Total harmonic distortion Internal Modem Ethernet PortPage RAM Expansion Placing the Computer Face Down Removing the Logic Board AssemblyExpansion Slots Unfastening the Cables Removing the bottom coverRAM Expansion Removing the Retaining Screws 3Logic board assembly handle and retaining screwsRemoving the EMI Shield Removing the Logic Board AssemblyLocations of the Expansion Slots 6Locations of the RAM expansion slots Main RAM ExpansionElectrical Design of RAM SO-DIMMs Mechanical Design of RAM SO-DIMMsSdram Devices Configuration of RAM SO-DIMMs Address Multiplexing RAM SO-DIMM Electrical LimitsVideo RAM Expansion Page Software Why Make This Change? What Has Changed Features of the New Approach Data Structures and Files PerformanceRAM Footprint User ExperienceBoot ROM Contents Rtas Mac OS ndrv DriversToolbox Image File Contents ToolBox ROM Image NewWorld Boot ProcessTrampoline Code Interrupt Handling What Is DifferentRAM Footprint Outmoded ResourcesStartup Disk Control Panel NanoKernelMachine Identification Open Firmware and the Device TreeInterrupt Layout Software Abbreviations Chrp NMI Page Index Nvram X, Y, Z Allen Watson