RickW wrote:
With the keyboard switches getting very old now, frequently one needs replacing and the source for them is not good.Has anyone designed a ps-2 keyboard adpater for the Aplle II or II+?
I have followed this thread and there are many good points there, here are some of my thoughts:
I have sometimes thought of making such an interface with a small controller, not for the Apple but for my Video Genie (TRS-80 Model I clone). It would emulate the scan matrix with i/o pins as well as sending the keys on a normal serial line.
The matrix emulation would detect the row lines by interrupt (from an or of them) and do a read of the row lines and present the row accordingly. Th microcontroller would have to be fast enough for the Z80 memory cycle to be fullfilled. The keyboard side is no problem, there are numerous examples of how to bit bang the PS/2 master.
Another approach would be a dual port ram device where the controller fills keyboard data into the ram and the Z80 reads it out as the keyboard matrix.
I normally use an external keyboard through a device driver on the Video Genie but many games and the rom can't use it so I need to have both keyboards.
Something similar might be made for the Apple. Knut