A1200 Keyboard to PS/2 or other interface..

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Since page 34 there has been a discussion regarding interfacing an A1200 keyboard to FPGA boards with Amiga implementations.

The problem is that the A1200 keyboard is passive matrix connected to an microcontroller on the motherboard. That may not be reused easily. And if it fails there's no firmware sources..

Suggestions has been on Keyrah etc..
My personal suggestion is just to use another microcontroller like Atmel AVR, STM32 etc.. with the A1200 keyboard matrix in one end and PS/2 or similar in the other. If the controller just sends deterministic data. It can all be corrected inside the FPGA.

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This picture should make it obvious how Keyrah works:




green cable
close-up
picture of keyboard with connector


Anyway using this description and a microcontroller. While comparing with a working A1200's keyboard MCU's output it should be a piece of cake.

Two obstacles may pop up:
 * Undocumented shift/Alt combinations.
 * Special flat 31-pin connector pressed onto PCB pads.

A1200 matrix -> MCU -> PS/2 -> FPGAarcade/Minimig etc..

PS/2 gives drop-in replacement and keeps things simple and standardized.

@psxphill, "I heard the A1000 & A500 keyboard MCUs are going to be decapped.", how do you mean?, reading out the binary code?

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@delshay, Where do you connect the A500 keyboard to the A1200 ?

@psxphill, It's likely more work to extract the binary from the obsolete MCU than to make a fresh C implementation which would be better as it can be compiled for any MCU of choice.. As a effective countermeasure to manufactor EOL suprises..

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@Kolla, Plz produce a clear picture with A1200 keyboard and Keyrah wired together in the same picture of suitable pixel size..

@psxphill, Why is the A500 MCU better than the A1200 one ?

Still think it's faster to do some black-box reverse stuff

Now when a assembler listing with good comments is available. That would be really useful..!

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Which a NEW software can reduce the effects off..