Instruction/ maintenance manual of the product Desktop Computer Apple
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T echnical Publications © Apple Computer , Inc. 1998 De veloper Note Apple iMac Computer Developer Note.
Apple Computer , Inc. © 1998 Apple Computer , Inc. All rights reserved. No part of this publication may be repr oduced, stored in a retrieval system, or transmitted, in any form or by any means, mechanical, electronic, photocopying, r ecording, or otherwise, without prior written permission of Apple Computer , Inc.
3 Contents Figures and T ables 7 Pref ace About This Dev eloper Note 9 Contents of This Note 9 Supplemental Reference Documents 10 PowerPC G3 Micropr ocessor 10 Mac OS 10 A T A Devices 10 USB Devices .
4 Infrared Link Module 26 Chapter 3 De vices and P or ts 27 USB Ports 28 USB Connectors 28 T ransfer T ypes Supported 29 USB Compatibility Issues 30 ADB Compatibility 30 Serial Port Compatibility 31 M.
5 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.
6 Interrupt Handling 64 Outmoded Resources 65 RAM Footprint 65 R T AS 65 NV -RAM 65 NanoKernel 66 Startup Disk Control Panel 66 Open Firmware and the Device T ree 67 Interrupt Layout 67 Machine Identi.
7 Figur es and T ables Chapter 1 Introduction 13 Figure 1-1 F ront vie w 16 Figure 1-2 Side view sho wing I/O ba y 17 Chapter 2 Architecture 21 Figure 2-1 Block diag ram 22 Chapter 3 De vices and P or.
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9 PREF ACE About This Developer Note This developer note is a concise description of the iMac ™ computer , with the emphasis on the features that ar e new or differ ent from those of other Macintosh desktop computers.
10 PREF ACE Supplemental Refer ence Documents 0 For more information about the technologies mentioned in this developer note, you may wish to consult some of the following refer ences.
11 PREF ACE USB De vices 0 For more information about USB on the Macintosh computer , developers should refer to Apple Computer ’s Mac OS USB DDK A TI Refer ence .
12 PREF ACE IEEE Std 1275-1994 Standard for Boot (Initialization, Configuration) Firmware (V ersion 1.7) Open Firmware Recommended Practice: Device Support Extensions (V ersion 1.
13 CHAPTER 1 Intr oduction 1 Figure 1-0 Listing 1-0 T able 1-0.
CHAPTER 1 Introduction 14 F eatures The Apple iMac computer is a new consumer-oriented desktop computer . This chapter summarizes the features of this new computer and points out issues affecting compatibility . Featur es 1 Here is a list of the featur es of the iMac computer .
CHAPTER 1 Introduction Case and External Features 15 ■ Modem: The computer has a built-in modem with 56 Kbps data rate. For more information, see “Internal Modem” (page 39). ■ Ethernet: The computer has a built in Ethernet port for a 10Base-T and 100Base-TX operation with an RJ-45 connector .
CHAPTER 1 Introduction 16 Case and External Features Figure 1-1 F ront vie w The front of the case is dominated by the 15-inch display . The fr ont also includes, below the display , the following fea.
CHAPTER 1 Introduction Case and External Features 17 Figure 1-2 Side view sho wing I/O ba y Sound input port Sound output port Universal Serial Bus (USB) ports (2) Ethernet port Hole for reset button .
CHAPTER 1 Introduction 18 Compatibility Issues The back of the case contains the receptacle for the power cor d and a small folding handle for use in removing the access cover on the bottom of the case. The right side of the case, as viewed from the fr ont, contains the I/O bay behind a hinged cover .
CHAPTER 1 Introduction Compatibility Issues 19 Main RAM Expansion Modules 1 For expansion of main RAM, the iMac computer uses standard SO-DIMMs that contain SDRAM devices. These are similar to the SO-DIMMs used in the Macintosh G3 PowerBook Series. For more information, see “Main RAM Expansion” (page 48).
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21 CHAPTER 2 Ar chitectur e 2 Figure 2-0 Listing 2-0 T able 2-0.
CHAPTER 2 Architecture 22 The components at the heart of the iMac computer reside on two printed-cir cuit boards: the main logic boar d and the processor module. The Figur e 2-1 is a block diagram showing the major components on those boards. The components shown are described in the sections that follow .
CHAPTER 2 Architecture Processor module 23 Pr ocessor module 2 The processor module contains the high-speed components: ■ G3 micropr ocessor ■ 512 KB backside cache memory ■ main memory (minimum.
CHAPTER 2 Architecture 24 Main Logic Board processor ’s clock speed, rather than at the clock speed of the main system bus. In the iMac, the clock speed of the backside cache is half that of the micropr ocessor . The data storage for the backside L2 cache consists of 512 KB of fast static RAM on the processor module.
CHAPTER 2 Architecture Main Logic Board 25 ■ the built-in modem ■ the infrared link ■ the Ethernet port ■ the sound ASIC ■ the internal IDE hard drive ■ the internal CD-ROM drive ■ the power manager IC The Paddington IC is similar to the Heathrow IC used in the Power Macintosh G3 computers and Macintosh PowerBook G3 computers.
CHAPTER 2 Architecture 26 Main Logic Board Infrared Link Module 2 The infrared link module is a separate printed cir cuit board that is connected to SCC port B of the Paddington IC.
27 CHAPTER 3 Devices and Ports 3 Figure 3-0 Listing 3-0 T able 3-0.
CHAPTER 3 De vices and P orts 28 USB P orts This chapter describes both the built-in I/O devices and the ports for connecting external I/O devices. Each of the following sections describes an I/O port.
CHAPTER 3 De vices and P orts USB P orts 29 Figure 3-1 USB T ype A por t and connector The iMac computer provides 5-volt power at 500 mA for each of the two ports. The USB ports support both low-speed and high-speed data transfers, at up to 1.5 Mbits per second and 12 Mbits per second, respectively .
CHAPTER 3 De vices and P orts 30 USB P orts ■ Interrupt transfers, used for human interface device (HID) class devices such as keyboards and mice, as well as devices that r eport status changes, such as serial or parallel adaptors and modems. ■ Isochronous transfers, used for on-time delivery of data.
CHAPTER 3 De vices and P orts USB P orts 31 Serial P or t Compatibility 3 The first release of the MacOS USB DDK does not include a universal Serial/ USB shim that would allow processes that use the Communications T oolbox CRM to use a USB serial device.
CHAPTER 3 De vices and P orts 32 K eyboard Keyboar d 3 The Apple USB keyboard has a total of 82 keys, including 12 function keys, a numeric keypad and a set of 4 cursor-contr ol keys.
CHAPTER 3 De vices and P orts Mouse 33 K e yboard and USB 3 The Apple USB keyboard is designed to work with the iMac computer by way of the USB ports. The keyboard has a captive cable with a USB T ype A connector . The keyboard is a bus-power ed USB hub with two USB T ype A ports.
CHAPTER 3 De vices and P orts 34 Hard Disk Drive The mechanism inside the Apple USB mouse is similar to that in the Apple Desktop Bus Mouse II. The mouse ball is removeable for cleaning; the ring that allows access to the ball can be locked by inserting an unfolded paper clip into a small hole and turning the ring clockwise.
CHAPTER 3 De vices and P orts Infrared Communication Link 35 Infrar ed Communication Link 3 The iMac computer has a direct infrar ed (IR) communication link connected internally to serial port B. When the computer is placed within range of another device with an IR interface, it can send and receive serial data using the IrDA protocol.
CHAPTER 3 De vices and P orts 36 Sound System Sound Inputs 3 The sound system accepts inputs from thr ee possible sources: ■ built-in microphone ■ external stereo sound input jack ■ sound from i.
CHAPTER 3 De vices and P orts Sound System 37 ■ during power cycling Exter nal Sound Output 3 The external sound output jack is a 3.5-mm mini phone jack located in the I/O bay on the right side of the computer . It accepts a stereo miniplug-to-RCA cable adapter for connecting stereo equipment to the computer .
CHAPTER 3 De vices and P orts 38 Sound System T otal harmonic distortion plus noise (THD+N) as a percentage of full scale for various outputs are shown in T able 3-3. The signal-to-noise ratios (SNR) for various inputs and outputs are shown in T able 3-4.
CHAPTER 3 De vices and P orts Ethernet Port 39 Ethernet Port 3 The iMac computer has a built-in 10/100 Mbps Ethernet port. The user can connect it to either a 10Base-T or a 100Base-TX hub; the port will automatically sense which type of hub is connected.
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41 CHAPTER 4 RAM Expansion 4 Figure 4-0 Listing 4-0 T able 4-0.
CHAPTER 4 RAM Expansion 42 The Expansion Slots This chapter tells how to gain access to the expansion slots in the iMac computer and describes the two types of RAM expansion: main RAM expansion and video RAM expansion.
CHAPTER 4 RAM Expansion The Expansion Slots 43 Figure 4-1 Bottom view sho wing bottom cov er handle Removing the bottom co v er 4 The bottom cover is held in place by a retaining scr ew located on the bottom cover and accessible through the opening in the handle.
CHAPTER 4 RAM Expansion 44 The Expansion Slots Figure 4-2 Cables connected to the logic board assemb ly.
CHAPTER 4 RAM Expansion The Expansion Slots 45 Removing the Retaining Scre ws 4 A slot-shaped handle is located at the back end of the logic boar d assembly .
CHAPTER 4 RAM Expansion 46 The Expansion Slots Removing the Logic Board Assemb ly 4 W ith the r etaining screws r emoved and the cables positioned to the sides, the user can remove the logic boar d assembly by pulling upward on the handle, as shown in Figure 4-4.
CHAPTER 4 RAM Expansion The Expansion Slots 47 Figure 4-5 EMI shield Locations of the Expansion Slots 4 Figure 4-6 shows the location of the two main RAM expansion slots and the video RAM expansion slot. One of the main RAM expansion slots is on the bottom of the processor module and is normally occupied by the factory-installed SO-DIMM.
CHAPTER 4 RAM Expansion 48 Main RAM Expansion Figure 4-6 Locations of the RAM e xpansion slots Main RAM Expansion 4 The iMac computer has two RAM expansion slots that accommodate standard SO (small outline) DIMMs using SDRAM devices. IMPORT ANT RAM expansion SO-DIMMs for the iMac must use SDRAM devices.
CHAPTER 4 RAM Expansion Main RAM Expansion 49 T otal RAM capacity using devices currently available is 128 MB and is limited by the space available for the SO-DIMMs. The bottom slot can accommodate a 1.5-inch SO-DIMM. The top slot can accommodate a 2.
CHAPTER 4 RAM Expansion 50 Main RAM Expansion The JEDEC specification for the SO-DIMM defines a Serial Presence Detect (SPD) feature that contains the attributes of the module. SO-DIMMs for use in the iMac are r equired to have the SPD featur e. Information about the requir ed values to be stored in the pr esence detect EEPROM is in section 4.
CHAPTER 4 RAM Expansion Main RAM Expansion 51 Configuration of RAM SO-DIMMs 4 T able 4-1 shows the sizes of the RAM expansion modules that can be used in the iMac computer and the differ ent sizes of SDRAM devices that make up those modules. The iMac accepts either one or two SO-DIMMs.
CHAPTER 4 RAM Expansion 52 Main RAM Expansion Address Multiple xing 4 Signals A[0] – A[13] on each RAM SO-DIMM make up a 14-bit multiplexed address bus that can support several dif ferent types of SDRAM devices.
CHAPTER 4 RAM Expansion Video RAM Expansion 53 Active 1.2 A (8 devices at 150 mA each) Sleep 6 mA per bank The maximum current specified for active operation generally r ules out the use of 4-bit-wide SDRAM devices in a RAM expansion card. Such a car d would have 16 such devices, and the 1.
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55 CHAPTER 5 Softwar e 5 Figure 5-0 Listing 5-0 T able 5-0.
CHAPTER 5 Software 56 Wh y Make This Change? The Apple iMac computer is differ ent from pr evious Macintosh computers in that it has no single, large ROM that contains the toolbox softwar e, the 68K emulator , hardwar e initialization, and the nanokernel.
CHAPTER 5 Software Wh y Make This Change? 57 • Not changing the higher level software as often simplifies things for many groups inside Apple, including testing, system softwar e, software configuration management, developer support, and publications.
CHAPTER 5 Software 58 Wh y Make This Change? F eatures of the Ne w Approach 5 Because the iMac has new hardwar e features that ar e differ ent fr om other Macintosh computers, new software featur es are needed in addition to the NewW orld requirements for other Macintosh computers.
CHAPTER 5 Software Wh y Make This Change? 59 P erf ormance 5 Performance of an iMac computer using ROM in RAM should exceed performance measurements for other Macintosh computers with comparable CPUs and speeds due to improved interr upt handling with the New W orld approach.
CHAPTER 5 Software 60 Boot ROM Contents in RAM appears to be a ROM, the ROM-in-RAM approach is completely compatible with all application and system software. The Mac OS T oolBox image is kept in a file in the System Folder on the specified boot device.
CHAPTER 5 Software Boot ROM Contents 61 Failure to boot in POST causes the err or beep, optionally entering the Mini-Nub. Open Fir mware 5 The Open Firmware component of NewW orld is based on the CHRP version of Open Firmware, also known as Open Firmwar e 3.
CHAPTER 5 Software 62 T oolbo x Image File Contents R T AS is relocateable code; its location in RAM is determined by the OS, and it remains functional after the OS boots. Note R T AS is part of the system software. It is not needed by applications, which use operating system APIs.
CHAPTER 5 Software NewW orld Boot Process 63 T rampoline Code 5 The T rampoline code is the component of the NewW orld architectur e that handles the transition between Open Firmware and the T oolBox ROM Image.
CHAPTER 5 Software 64 What Is Diff erent 5. The Forth script transfers control to the T rampoline code, which functions as the transition between Open Firmware and the beginning of the Mac OS execution; 6.
CHAPTER 5 Software What Is Diff erent 65 that interrupt latency has been r educed to such an extent as to make it negligible. The other is that the interrupt handling code no longer r equires changes to support a new machine, unless it has new interrupt contr oller hardwar e.
CHAPTER 5 Software 66 What Is Diff erent variable-sized partitions that are used by Mac OS, Open Firmwar e, and any other client. PRAM resides in the Mac OS partition. The partitioning scheme is part of the CHRP specification. NanoK ernel 5 The previous version of the NanoKernel has code that is pr ocessor-specific to create data str uctures.
CHAPTER 5 Software What Is Diff erent 67 Once Open Firmware locates a startup device and successfully loads a Mac OS ROM, image it passes information about the chosen device in the bootpath variable.
CHAPTER 5 Software 68 What Is Diff erent T oolBox ROM Image, so sharing the same Box Flag is not an issue for those areas. IMPORT ANT Programs such as contr ol panels and installers that use Box Flag to verify that this is a valid CPU on which to execute need to be changed to verify the existence of the hardwar e they requir e.
69 APPENDIX Abbr eviations A Standard units of measur e used in this note include: Other abbreviations used in this note include: A amperes MB megabytes dB decibels Mbps megabits per second GB gigabyt.
APPENDIX A Abbre viations 70 CHRP Common Hardwar e Reference Platform CPU central pr ocessing unit CRM Communications Resource Manager CR T cathode ray tube, a video display device DAA data access ada.
APPENDIX A Abbre viations 71 NMI nonmaskable interrupt NV -RAM nonvolatile random-access memory OHCI Open Host Controller Interface OS operating system PCI Peripheral Component Interconnect, an indust.
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73 Index A A T A Device Software Guide 10, 34 A T A disk interface 34 A T A hard disk 34 A TI Rage IC 25 B backside cache 23 Boot ROM 57 contents 60–62 Box Flag 68 C cache, See backside cache case 1.
INDEX 74 K keyboard 32–33 L L2 cache 23 M machine ID 67 Macintosh ROM, why it’s changing 56–60 Mac OS 8.1 10 Mac OS ROM file 59 Mac OS ROM image 58 Mac OS T oolBox ROM 57 main logic board 24–.
INDEX 75 Run-T ime Abstraction Services. See RT AS S SDRAM device specifications 50 serial presence detect, on SO-DIMM 50 SGRAM 53 SO-DIMMs, for RAM expansion 48 address multiplexing on 52 configura.
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An important point after buying a device Apple Desktop Computer (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Apple Desktop Computer yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Apple Desktop Computer - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Apple Desktop Computer you will learn all the available features of the product, as well as information on its operation. The information that you get Apple Desktop Computer will certainly help you make a decision on the purchase.
If you already are a holder of Apple Desktop Computer, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Apple Desktop Computer.
However, one of the most important roles played by the user manual is to help in solving problems with Apple Desktop Computer. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Apple Desktop Computer along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
