Editing File:Apple IIGS Hardware Reference 1989.pdf (section)

== Summary ==
'''Apple IIGS Hardware Reference''', second edition, "for Apple IIGS and 1 MB Apple IIGS" (Apple Computer, Inc., 1989; Addison-Wesley).

Apple's own hardware reference for the [[Apple IIGS]]. The source this wiki cites for:
* Processor speed '''selectable between 1.024 MHz and 2.8 MHz'''; FPI DRAM refresh '''reduces the effective speed of programs in RAM by about 8 per cent'''; programs in ROM run at the full 2.8 MHz.
* Memory: 128K of fast (FPI) RAM plus 128K on the Mega II side, 256K in total, '''1 MB on the 1 MB logic board'''; 128K of ROM (256K on the 1 MB board); '''up to 4 MB of expansion RAM and up to 1 MB of expansion ROM'''.
* Super Hi-Res: 320 or 640 pixels across, 200 lines, 16 colours per line chosen from 4096; a 320-mode pixel can be any of 16 palette colours, a 640-mode pixel one of only 4, with the 16 palette colours split into four groups of four.
* Sound: '''Ensoniq 5503 Digital Oscillator Chip''', 32 independent oscillators, 64K of dedicated sound RAM, interfaced through the Sound GLU. Sound leaves the machine through the built-in speaker, the external speaker jack, or the '''7-pin molex connector J-25''' on the main logic board. Separating the oscillators into up to eight channels requires '''external demultiplexer hardware''' on that connector - the built-in output is a single mixed channel.
* The 1 MB logic board's differences: the new ADB microcontroller with sticky keys and keyboard mouse, text page 2 shadowing, the cold-boot bit in the Speed register, and the fact that it '''no longer supports the built-in (Apple IIe style) keyboard - only ADB keyboards'''.
* The built-in real-time clock with a backup battery, accessible through the Control Panel.

This is the searchable (OCR text layer) edition scanned by the Internet Archive.