6 Apr
2012
6 Apr
'12
12:41 p.m.
For a "modern" keyboard, I'd recommend
something like Jim Brain's
adapter that has a silicon crossbar switch. We've been over that sort
of thing on the list before, but the design constraints are that the
scan routine runs every clock 'tick' (16.67ms on any C= NTSC machine)
and strobes the matrix in a few uS, plus in the case of the C-64, the
keyboard shares lines with the joysticks, so any keyboard adapter
should play nice with those lines in particular. I don't think many
people did in-the-box hacks with the keyboard scan lines, so as long
as the IRQ scan routine works and the joysticks work, that would be a
successful emulator. There are several techniques to do it; a silicon
crossbar switch is a low-effort one.
I still believe I can do that with a fast microcontroller. As soon as I
can put my dirty hands into one I'll jack it up to the logic analyser and
play with that.
Unfortunately,
I'm in the middle of a huge confusion, where a job was
cancelled, I have to move from my apartament until monday and have no
money
and no job :) I think it will take some time :)
That's unfortunate. I hope
some good news comes your way.