Regarding the original apple2 and apple2plus "two part" keyboard, it uses a GI AY-5-3600 custom mask 931 part (which does internal keycode->ascii translation), which has not been completely dumped or decapped yet. Someone at VCF-east I spoke to had done a partial table of it by hand and was planning to use an arduino or similar to dump the full table out of it. This mask 931 part uses the mask option where pins 1, 2 and 3 are internal oscillator, pin 4 is AKO and pin 5 is B10. (B10 is incorrectly called "BIO" on parts of the datasheet, it's an extra data output bit to the computer side).

The Apple IIe and IIc use the AY-5-3600-PRO part, which was a mask sold by GI which is well-documented on datasheets (intended to use an external EPROM for keycode->ascii translation, as apple did in this case), so we know what the mask contents are for every possible key combination. The AY-5-3600-PRO has pins 1, 2 and 3 masked for internal oscillator, pin 4 is LO/RO and pin 5 is AKO


Last edited by Lord Nightmare; 09/09/19 07:11 PM. Reason: fix BIO/B10 with explanation

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