PC Keyboard question

[HatchetHand]

Sorry for the delay, I have been working on trying different things. I am starting the PC with a regular keyboard and then swaping it with the PIC replacement.

I have tried a 16F627A and I have moved back to the 16F688

Below is the code I am testing, I am sending the data twice trying to send it both LSB and MSB first. Sometimes I get a beep from the PC when I change the PauseUS delay and other times I do not.

' PIC 16F688
' PortC.5 - Data
' PortC.4 - Clk
' PortA.2 - Switch in, normal low, active high
' PortA.4 - LED Out, high if switch pressed

' Circuit description
' 10K pull up on PortC.5 - Data
' 10K pull up on PortC.4 - Clk
' 10K pull up on /MCLR
' 10K pulling down on switch input, PortA.2

'Goal of program, to send a chracter to the PC keyboard port when switch is pressed
@ device INTRC_OSC_NOCLKOUT
INCLUDE "modedefs.bas"
DEFINE SHIFT_PAUSEUS 25
DEFINE OSC 8 ' 8 Mhz

TRISA = %00000100 ' Set PORTA.2 to input, all others are output
TRISC = %00000000 ' set PORTC to outputs
CMCON0 = 7 ' turn off comparitors
ANSEL = %00000000 ' set all as digital ports, analog off
WPUA = %00000000

char var word
breakcode var word

clkout var portc.4
switch1 var portA.2
ledout1 var portA.4
dataout var portc.5

'char = %10101101010 ' 'CR' mode 0
'breakcode = %11000011110 '/F0H mode 0
char = %01010110101
breakcode = %01111000011

'----- Main Loop --------------------------------
Start: ' loop start
low ledout1 ' turn off LED
if switch1 = 1 then ' check switch, if pushed then LED on and Char our
pause 50
if switch1 =1 then
high ledout1 ' LED on
shiftout dataout,clkout,4,[char\11]
shiftout dataout,clkout,4,[breakcode\11]
shiftout dataout,clkout,4,[char\11]
PAUSE 1
shiftout dataout,clkout,5,[char\11]
shiftout dataout,clkout,5,[breakcode\11]
shiftout dataout,clkout,5,[char\11]
endif
endif
goto start ' restart loop
'----- Main Loop --------------------------------

I have tried the character to send and the breakcode both ways, but they respond the same.

I see the characters and clock on the scope, all six characters come across but nothing on the PC.

I am driving the keyboard direct from the chip, no transistors. Do you think the open-collector could be an issue with the driving? Could the Clock and the timing be an issue?

I would think that something would appear with both combinations of send's but i seem to be going in circles.

USB would be great but it's not an option, I am not talking to a Windows OS. I have to use the PS/2 port to send data to the terminal.

Any thoughts would be great, my goal is to send about 24 pre-defined single characters on switches to the port. I have been

Thanks,
HH

[Kamikaze47]

2 problems that i can see:

First, looks like ur clock is too fast. PS2 keyboards generate a clock between 10khz-16khz. I'd be changing the shift pause to:

DEFINE SHIFT_PAUSEUS 40

Second, The "mode 0" as you call it is the only one with any chance of working, but "%10101101010" corresponds to a scancode of $AD which as far as i can tell is not a valid scancode.

Try using these:

char = %10001110000 '$1C = 'a'
breakcode = %11000011110 '$F0

shiftout dataout,clkout,4,[char\11]
shiftout dataout,clkout,4,[breakcode\11]
shiftout dataout,clkout,4,[char\11]


Something else you may want to try is this:

shiftout dataout,clkout,4,[char\11]
pauseus 100
shiftout dataout,clkout,4,[breakcode\11]
pauseus 100
shiftout dataout,clkout,4,[char\11]
pauseus 100

*edit* Check out this page for all the scancodes: http://www.computer-engineering.org/...cancodes2.html