Sugestions for keyboard raw mode

From: Jim Brain (
Date: 2006-03-07 00:49:33

Trying to finish up projects on my desk, and am almost finished with C=Key.

It looks like, due to the way my project board is laid out, that I can 
support sending raw keycodes from a PC keyboard to the 64/128.

My idea was/is:

wait for special "doorknock" codes on PORTA (knocks would include bits 
that can't be set via joysticks and also include 2+ bits low).
Switch into raw mode.  when keycode comes in, set on PORTA and bring 
RESTORE line low to create NMI
Use 1 bit of PORTB to trigger an IRQ in the interface.  If triggered, 
read data from PORTA

Code to do this is trivial, though it suffers if someone uses the 
joysticks during that time.  I could implement serial protocol or 
something more exotic, but I'd rather not if its not necessary.

Thus, I thought I'd inquire for any safeguards/other ideas here.  All I 
have access to is the 16 lines of the KB port and RESTORE (on a 64, 
lowest common denominator)


Jim Brain, Brain Innovations                      
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!

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