Sources for 8b TTL keyboards (Keytronics)

Jim Brain brain at
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.


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