Macintosh IIsi Developer Note
The Macintosh IIsi Computer Developer Note is Apple's hardware description of the Macintosh IIsi for card and software developers, published by Apple Developer Technical Publications, © 1990. The hosted file is a 108-page PDF distilled in March 1995. Apple describes it as covering "those features that are new or different from those of other Macintosh II–family computers", and warns that it "does not constitute a manual and is not complete".
The printed page numbers in the body do not match the contents list, so the page numbers below are positions in the PDF.
Contents
[edit | edit source]- Preface, supplemental reference documents (pp. 9-12)
- 1 Introduction: features, block diagram, compatibility (floppy disks, hard disks, memory, ADB, SCSI and SCC, sound, no on-board FPU, colour) (pp. 13-22)
- 2 Address Mapping: memory maps, 24-bit and 32-bit modes (pp. 23-30)
- 3 The Memory Interface: RAM interface and configurations, use of RAM by the video, DRAM timing, ROM interface and 64-pin ROM SIMM pinout (pp. 31-39)
- 4 The Video Interface: on-board video, monitor sense codes, timing, video connector and cable pinouts (pp. 40-53)
- 5 Input/Output Interfaces: SCC and SCSI, floppy connectors, VIA, sound, ADB microcontroller, clock and PRAM, soft power, reset and NMI, network booting, wakeup (pp. 54-69)
- 6 Expansion Interface: 68030 Direct Slot adapter and card design, connector pinout and signal loading, RAM access timing, NuBus adapter and pinout (pp. 70-100)
- 7 Software Overview: the IIsi ROM, system software (pp. 101-103)
- 8 Sound Input (pp. 104-107)
What it settles
[edit | edit source]- Memory: bank A is 1 MB soldered to the board (eight 256K × 4 DRAMs) and holds the video frame buffer; bank B is four SIMM sockets taking four identical SIMMs from 256K to 16 MB, for up to 65 MB. RAM must be 100 ns fast page mode (pp. 18, 32-36).
- ROM: the first production boards carry the 512K ROM on a ROM SIMM; later boards have it soldered, with the socket kept for upgrades (p. 38).
- Video: 12-inch and 13-inch RGB and 12-inch monochrome monitors at up to 8 bits per pixel, the 15-inch portrait monitor at up to 4; an unknown monitor halts the video (p. 41).
- The FPU is on the adapter cards only, and both adapters carry one (pp. 19, 70).
- Power control: a custom 68HC05 handles ADB, clock, PRAM, soft power and reset. The supply keeps a +5 V trickle output whenever it is plugged in. ADB pin 3 supplies +5 V through a 1 A fuse. The rear power switch can be locked on. Command-Control-Power is a hard reset and Command-Power an NMI (pp. 15, 62-66).
- Expansion: SE/30 direct-slot cards work if they run at 20 MHz and their ribbon cables are at least 220 mm long; the NuBus slot is at address $9 and takes any card size Apple specifies (pp. 71-72, 95).
- System software: 6.0.6 at introduction (p. 103).
What it does not contain
[edit | edit source]It gives no power supply ratings and no power budget for the slot, referring card designers to Designing Cards and Drivers for the Macintosh Family (p. 80). There are no schematics, no parts list, no capacitor or battery information and no service procedures; those are in Macintosh IIsi Service Source.
Pages that cite this document
[edit | edit source]- Macintosh IIsi: memory, video, ROM, slot, FPU and power-control details
- Macintosh IIsi General Maintenance: trickle supply, ADB fuse, ROM SIMM
- Macintosh IIsi Troubleshooting: monitor support, reset keys, FPU
- Macintosh IIsi Capacitor Replacement Guide: soft power
Many programming-book pages also link here from a standard "not a repair source" note; they do not cite it.
Download: Macintosh IIsi Developer Note.pdf