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Christian

Posted Sun Oct 13, 2019 6:45 pm

Amiga 1000 US (NTSC) keyboards use an earlier version of the 6570 keyboard controller.

The code in the -033 (A1000 US keyboards) differs from the -036 (all other Amiga keyboards except A1200 and A2000 Cherry which use Motorola and Intel micro controllers respectively) in the following ways:
- Does not flash caps lock when CTRL-Amiga-Amiga is pressed
- Does not implement partial n-key rollover. (Note: only early A500, as well as A2000, A3000, CDTV, CD32 and early A4000 keyboards have full n-key rollover. Membrane keyboards generally don't)
- Slight timing differences on the communication protocol
- Doesn't implement scanning the for the extra keys added later on

The 6570-036 can be used in US A1000 keyboards to replace the original 6570-033. The chip is pin compatible and does not need an adapter. However, Commodore switched keyboard clock (kclk) and keyboard data (kdat) pins (thanks to Upsnowman on Amibay who pointed this out) on the 6570-036. All that is required is to cross jumper wires J3 and J4 (these have a ferrite bead on my keyboard). Keyboard works great now, all keys accounted for.

Note: be careful with the orientation of the 6570 - it's upside down when viewed from the front of the keyboard.

Change (when using -036 in place of -033)

J3 o--------o
J4 o--------o

to

J3 o---\
J4 \---o

and

J3 /---o
J4 o----/

Easiest to do by doing the crossover on the upper and lower side of the PCB - or use insulated wire to avoid short circuits.

User avatar
Christian

Posted Sun Oct 13, 2019 6:47 pm

My ASCII art is not coming through properly. I'll take a picture in the next days.





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