Dwight Elvey
Veteran Member
That's how I remember the O1 keyboard--simple passive matrix scanned by the CPU.
Probably the simplest way with an MCU would be a dual-ported 256 bit SRAM. The MCU would write a location corresponding to the (X,Y) address of the key and the Osborne would read it. Since PC keyboards have both a "make" and "break" signal, that simplifies knowing when to write.
Hi Chuck
I see from the code, one could run this based on the 60Hz timing. It would be eazy to sync up to the first row address and provide the needed data in time for the read. I don't think an external RAM is even needed. I believe the it can all be done in code, with no additional hardware, like a multi port RAM being there.
Dwight