PS/2 and USB (in fallback) keyboard Adapter for Gradiente Expert

Hello!

In the past I've suffered very similar problems ie. with Daewoo CPC-50, but personally I solved it by software and attaching PS/2 keyboard to joystick port... Unfortunately I also know that this is not good solution outside of MSX-BASIC / MSX-DOS environment.

I also know that Leonardo Padial (RIP) used very much time to solve this problem with hardware and even sold some USB and PS/2 keyboard adapters for MSX users as cartridge... Needless to repeat that these skills lead to dead end ATM.

It is great if you have found a solution for Gradiente, but do you think you have possibility to expand your project to other MSX-models as well?

Thank you Louthrax and NYYRIKKI
The output of the circuit simulates open collector outputs, then yes, it can be connected together with existing keyboards without worries about contention of the signals.
As it is the circuit reads 4 bits from PPI, then for computers that provide the signal decoded there are 2 possibilities

• Use of a decimal encoder chip (74xx148).
• Use of a simplified diode matrix.

Either way some modification on the code is expected, either for adapting the keyboard layout or to expand the software matrix to accomodate up to 64 entries from the diode matrix. I

But don´t worry, I wrote the code with plenty of comments, so tweaking should be easy. I should put some words about tweaking the original article though :)