pic as ps/2 keyboard

[NavMicroSystems]

see:
here
and
here

[mischl]

thank you ralph for the reply

what i'm not sure :
- i need no external hardware, or?
- i can realise the software with shiftout?

[NavMicroSystems]

mischl,

this is probably the link you are after

[mischl]

ralph, thanks for the help.

i've looked for many sites and found asm as well bs examples. i read a lot about protocols and test my own code. because i have several problems and i'm a bit confused my question : has anybody else a piece of code which send at-keyboard commands to pc host?

if it is only a piece to test, it would me helps a lot

thanks for a support

[JEC]

I had a PS/2 KB emulator running a few weeks ago. I don't have the code right in front of me, but I wrote it all in PBP.

You can use the SHIFTOUT command with no problems - just tell shiftout to only send 9 bits instead of 16.

Don't forget to calculate the parity bit (odd) and tack it on at the end.

Clock and data both idle high, so make sure you use pullup resistors.

I'll dig around and see if I can find the code later this afternoon.

John

[JEC]

Here's a code snippet to transmit PS/2 data:

In this case, dataout is an array of bytes I may want to send to the computer.

Odd parity is NOT the value of all bits XOR'ed together.

Good luck!

John


* * *
for x = 0 to 7
if dataout[x] <> 0 then
sendthis = dataout[x]
parity = not(sendthis.0 ^^ sendthis.1 ^^ sendthis.2 ^^ sendthis.3 ^^ sendthis.4 ^^ sendthis.5 ^^ sendthis.6 ^^ sendthis.7)
sendthis = sendthis << 1 'move over to insert start bit
sendthis.0 = 0 'start bit
sendthis.9 = parity
sendthis.10 = 1 'stop bit
shiftout kbddata,kbdclk,4,[sendthis\11]
dataout[x] = 0
endif
next x

[mischl]

hello john

thanks for your support.

i work with a similar code. so i have some additional questions :

- which osc speed do you use? - i have a 16f876 with 4M
- have you defined a shift_pauseus? - i try it . around 40us seems best
- how long do you wait until you send the release code (F0) after the button press comand? - i don't wait
- how looks your hardware setup? - 2 transistors at portc with pull up works at best. nod good because i get different chars... when i only take pullups instead the transisitors, after connect the keyboard it wouldn't be initialized.
- what are you doing at the booting from the pc?

best regards