6 Jan
2008
6 Jan
'08
3:49 p.m.
Enrico Lazzerini wrote:
1) a parallel keyboard: is it anybody could help me to transform a PS/2 or
AT keyboard in a parallel one? Even using the only internal matrix and using
a new keyboard encoder (I prefer less this way cause my limited free time).
In 1983 I used KR-2376 to create the correct character codes.
Fancy you should ask that. I just helped JP Hindin create such an
interface for his Flashwriter II board. It's an Atmel AVR ATMEGA8 uC
solution, but it decodes all the PS2/AT keyboard keystrokes (including
the funky extended ones and the really esoteric ones like Pause/Break).
Right now, the code will convert all the main KB keys, but has open
slots in the tables for stuff like function keys and END/HOME and the
like. They are easy to add, of course. The code also detects
CTRL/Alt/Del and creates an Interrupt (for RESET) on the IC.
Of course, I am sure there are other, more "vintage" ways to do this.
But, it's a single IC design at present. With a spot of effort, I could
probably remove the need for a crystal, so it would be a 4 part design
(1 cap, 1 pullup, 1 IC, one PS2 connector), as it is now a 7 part design
(crystal and 2 caps)
I can provide the source and the designs if desired.
Jim