My thought was to get the original code and examine it to determine if there is anything non-obvious being done in the code. Plus, I assume (dangerous), that Apple did some testing and optimizing to get the timing of the debounce and such to the best values. Extracting/reverse engineering those timings would be useful in a recreation.
Of course, if one builds a replacement keyboard with a different brand/model of keyswitch, those values may not be so useful any more.
Personally, I don't care to recreate the Mac Plus keyboard in an authentic way -- meaning that I don't feel any need to use an 8049 or 8021 as the microcontroller. I do think it would be fun to create new keyboards or adapt old favorite keyboards using a more modern and accessible MC and an adaptation of the old code.
It might be possible to get a perfectly acceptable result by examining the signals from the keyboard, but there is also some value in examining the old code, if for no other reason than to confirm that there's nothing important in there that would be missed or overlooked by just examining the signals. Plus, I think hacking the code out of the OTPROM would be fun.
And why else are we fiddling with these out of date machines, if not for fun?
I have about a dozen brand new (well, never used) Apple IIe Platinum keyboards from when Sun was clearing out stuff. It might be interesting to convert one or more of those into Mac Plus Keyboards. I haven't looked to see if they have a MC on board or just a switch matrix. From the look of the cable, I suspect it's just a switch matrix, but I'm not going on much evidence.
Of course, if one builds a replacement keyboard with a different brand/model of keyswitch, those values may not be so useful any more.
Personally, I don't care to recreate the Mac Plus keyboard in an authentic way -- meaning that I don't feel any need to use an 8049 or 8021 as the microcontroller. I do think it would be fun to create new keyboards or adapt old favorite keyboards using a more modern and accessible MC and an adaptation of the old code.
It might be possible to get a perfectly acceptable result by examining the signals from the keyboard, but there is also some value in examining the old code, if for no other reason than to confirm that there's nothing important in there that would be missed or overlooked by just examining the signals. Plus, I think hacking the code out of the OTPROM would be fun.
And why else are we fiddling with these out of date machines, if not for fun?
I have about a dozen brand new (well, never used) Apple IIe Platinum keyboards from when Sun was clearing out stuff. It might be interesting to convert one or more of those into Mac Plus Keyboards. I haven't looked to see if they have a MC on board or just a switch matrix. From the look of the cable, I suspect it's just a switch matrix, but I'm not going on much evidence.