pic as ps/2 keyboard

[ultiblade]

Update:

Ok messed up some of the scancode's. I can now send normal characters
by sending the reversed scancode with shiftout

For example : if i send 0x15 = 00010101, LSB first = 10101000 = "q" on screen, that's perfect. I tried other codes and they work also.

There was an error with the parity calculator also, so i skipped that ....

But now, i want to use Left-shift + q, which, when looking at the scancode
table this would be 0x12 for left shift, 0x15 for "q", 0xF0 for release, 0x15 for release "q" and 0xF0 and 0x12 for release left shift.

Doing this results in an F10 being received ??

Here's the code :

sendthis = %01001000 'left shift       
test = 1 'parity bit
gosub calsub
                         
sendthis = %10101000 'q 
test = 0
gosub calsub
                  
sendthis = %00001111 'Release       
test = 1
gosub calsub

sendthis = %10101000 'q
test = 0
gosub calsub

sendthis = %00001111 'Release 
test = 1
gosub calsub  
  
sendthis = %01001000 'left shift        
test = 1
gosub calsub
       
goto start       


calsub:
    sendthis = sendthis << 1 'move over to insert start bit  
    sendthis.0 = 0 'start bit
    sendthis.9 = test 'parity
    sendthis.10 = 1 'stop bit
    shiftout kbddata,kbdclk,1,[sendthis\11]
return

Best regards, UB

[mister_e]

not sure but i think you have to send some other code(s) + sendthis as well.

[ultiblade]

Mister_e,

I found some source code in basic stamp, the author claims it works.
Apart from the fact that everything is inverted (he inverts the inputs in his
schematic using transistors) i can't find anything other tahn my code ?

' -----[ Program Description ]----------------------------------------
'
' This simple program shows how to connect a BASIC Stamp II to the AT
' keyboard port on a PC and to send characters when one of three buttons
' is pressed. Please read KEYBTST.TXT for more information about it's
' limitations and for a simple schematic.

' -----[ Constants ]--------------------------------------------------
'
datpin      con 0   'Keyboard Data
clkpin      con 1   'Keyboard Clock
btn00       con 2   'Button 0
btn01       con 3   'Button 1
btn02       con 4   'Button 2

' -----[ Variables ]--------------------------------------------------
'
temp        var B2  'Temp variabel
char        var W2  'Variabel containing the character
breakcode   var W3  'Variabel containing "Breakcode"
extcode     var W4  'Variabel containing "Extended charcode"

' -----[ Initialization ]---------------------------------------------
'

'Set pin 0 and 1 as outputs, rest as inputs 
 Dirl= %00000011

'Set datpin and clkpin default to high (1)
 low datpin
 low clkpin

'Define breakcode
'           s--DATA--PS (s=start, DATA=LSB First, P=parity, S=stop)
 breakcode=%11111000000 '/F0H
'Define extcode
'         s--DATA--PS (s=start, DATA=LSB First, P=parity, S=stop)
 extcode=%11111100010 '/E0H

' -----[ Main Code ]--------------------------------------------------
'

start:

temp=0
pause 1000
button btn00,0,255,100,temp,1,button00
button btn01,0,255,100,temp,1,button01
button btn02,0,255,100,temp,1,button02

goto start

' -----[ Test Characters ]--------------------------------------------
'
'      s--DATA--PS (s=startbit, DATA=LSB First, P=paritybit, S=stopbit)
'char=%10110101110 '/SPACE
'char=%11100011110 '/a
'char=%11010010100 '/CR
'char=%11011001110 '/b
'char=%11100101110 '/t
'char=%10100101100 '/r
'char=%10011101110 '/d
'char=%10101111100 '/F1
'char=%11111000110 '/INS

button00:
'Assign char a character with startbit, parity and stopbit. OBS inverted !
'     s--DATA--PS (s=startbit, DATA=LSB First, P=paritybit, S=stopbit)
char=%11100011110 '/a
gosub sendchar
goto start

button01:
'Assign char a character with startbit, parity and stopbit. OBS inverted !
'     s--DATA--PS (s=startbit, DATA=LSB First, P=paritybit, S=stopbit)
char=%11010010100 '/CR
gosub sendchar
goto start

button02:
'Assigne char a character with startbit, parity and stopbit. OBS inverted !
'     s--DATA--PS (s=startbit, DATA=LSB First, P=paritybit, S=stopbit)
char=%11111000110 '/INS
gosub sendextchar
goto start

' -----[ Subroutines ]------------------------------------------------
'
sendchar
  'Send character
  shiftout datpin,clkpin,1,[char\11]
  'Send breakcode + character
  shiftout datpin,clkpin,1,[breakcode\11]
  shiftout datpin,clkpin,1,[char\11]
return

sendextchar
  'Send extcode + character
  shiftout datpin,clkpin,1,[extcode\11]
  shiftout datpin,clkpin,1,[char\11]
  'Send extcode + breakcode + character
  shiftout datpin,clkpin,1,[extcode\11]
  shiftout datpin,clkpin,1,[breakcode\11]
  shiftout datpin,clkpin,1,[char\11]
return

' -----[ End ]--------------------------------------------------------

Best regards, UB

[mister_e]

YEAH as i thought... it's all there... sequence of char, breakcode and extcode. I knew something was missing.

[ultiblade]

Thanks guys, for thinking this over with me ....

Above code does seem to work !

Best Regards,
UB

[mister_e]

[T.Jackson]

Out of interest - I wonder what the requirements would be to get a PC to boot with a PIC attached rather than the actual keyboard. Anyone done this?