From: Andre Fachat (afachat_at_gmx.de)
Date: 2004-05-20 18:38:07
Hi Jim,
what do you mean by 8x8 crossboard switch?
I have emulated the C64 keyboard with my CS/A65 system, so I have
the schematics for a keyboard emulator at
http://www.6502.org/users/andre/csa/index.html
It uses a 256 byte RAM array that the emulating CPU
writes to and the C64 reads from, using the CIA output
as addresses. So it's similar to the EPROM version,
but I can use shift/ctrl etc keys as well.
But probably this is more hardware than you wanted...
However, If you use not a 64k EPROM (8 bit input from
CIA and 8 bit char code), but, say a 256k EPROM you can
emulate control keys as well: 8 bit input from CIA,
8 bit char/key code, 1 bit=shift, 1 bit=ctrl
-> 18bit input -> 256k
If you use a 1M EPROM, you could even use left/right shift,
ctrl and C= keys :-) and any combination thereof.
It can still not handle two other keys pressed simultaniously.
(The RAM solution I used above can)
I guess it's just a matter of your requirements.
Andre
On Thu, May 20, 2004 at 01:26:29AM -0500, Jim Brain wrote:
> >
> >I am trying to build a keyboard eliminator that does not require a cross
> >point switch to "emulate" the 64/128 keyboard. However, in the event my
> >idea does not pan out, anyone know a part number for a 8x8 or so switch
> >that is not as big as the 40 pin monster on 64-KEYB?
> >
> >I'd like a plan B so my idea doesn't evaporate....
> >
> >Jim
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