Sources for 8b TTL keyboards (Keytronics)
Jim Brain
brain at jbrain.com
Fri Dec 5 15:09:43 CST 2008
Roy J. Tellason wrote:
>> Why bother? AVRs and PICs are cheap and easy to work with (in
>> particular, an AVR with SPI can be programmed with little more than a
>> parallel port and a handful of resistors). Code for handling AT-
>> style keyboards abounds. One DIP--that's all that it takes.
>>
>
> Because I don't know a darn thing about any of that current stuff?
>
> This was only a couple or three logic parts, from what I can remember, not
> all that much...
>
Not to weigh in on one side or the other, but I have prewritten routines
in AVR C that will scan up to a 16x8 matrix and output PS/2 codes. In
the other direction, I have prewrriten routines to accept incoming PS/2
data and output either RS232 or parallel ASCII codes, with support to
trigger an IRQ on keypress. My code runs on an ATMEGA8, which is a 28
.300" DIP unit or a ATMEGA16/32, which is a 40 pin .600 DIP.
Jim
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