PC Keyboard question

[ultiblade]

Hi Hatchedhand,

I did this (PIC -> PC PS2) a while ago to simulate keystrokes. I used a simple 12F509
and it worked ....

See thread : http://www.picbasic.co.uk/forum/showthread.php?t=1611

Best Regards,

UB

[Kamikaze47]

Your other option is to use USB.

It is quite trivial to set up a PIC keyboard with USB PIC chip. When you plug it in, your OS detects it as a generic USB keyboard. Include the USB keyboard definitions file and its a matter of 1 or 2 lines of code to send keystrokes. Much easier than PS2.

[HatchetHand]

Attached is a program I have tried. I see data going out of the data pin and the clock on the scope. But I do not get anything on the dos screen (DOS 6.22).

I strobe the switch looking for a High, and then set and LED on when I get it, for some reason I do not see any data on the screen.

I have tried all of the modes for the shiftout command but nothing seems to work.

I am using pins +5 and Ground on the PCB connector, and then 1 and 5 on the connector. I have even jumpered 1-2 and 5-6 thinking I am looking at the wrong end of the cable. but nothig works.

Any help would be appreciated.



USB would be great, but I need PS/2.
Thanks,
HH





' PIC 16F688
' PortC.5 - Data
' PortC.4 - Clk
' PortA.2 - Switch in, normal low, active high
' PortA.0 - 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

INCLUDE "modedefs.bas"
DEFINE OSC 4 ' 4 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
char var word
breakcode var word

char = %11100011110 '/a
breakcode = %11111000000 '/F0H
'----- Main Loop --------------------------------
Start: ' loop start
low porta.0 ' turn off LED
if PORTA.2 = 1 then ' check switch, if pushed then LED on and Char our
high porta.0 ' LED on
call sendchar ' send characters
endif
goto start ' restart loop


sendchar:
char = %11100011110 '/a
shiftout portc.5,portc.4,4,[(char)\11] ' LSB first, Clk High
shiftout portc.5,portc.4,4,[(breakcode)\11]
shiftout portc.5,portc.4,4,[(char)\11]

char=%11010010100 '/CR
shiftout portc.5,portc.4,1,[(char)\11] ' MSB first, Clk low
shiftout portc.5,portc.4,1,[(breakcode)\11]
shiftout portc.5,portc.4,1,[(char)\11]

char=%11011001110 '/b
shiftout portc.5,portc.4,1,[char\11] ' MSB first, Clk low
shiftout portc.5,portc.4,1,[breakcode\11]
shiftout portc.5,portc.4,1,[char\11]

char=%11100101110 '/t
shiftout portc.5,portc.4,5,[(char)\11] ' MSB first, Clk high
shiftout portc.5,portc.4,5,[(breakcode)\11]
shiftout portc.5,portc.4,5,[(char)\11]

char=%10100101100 '/r
shiftout portc.5,portc.4,0,[(char)\11] ' LSB first, Clk low
shiftout portc.5,portc.4,0,[(breakcode)\11]
shiftout portc.5,portc.4,0,[(char)\11]


char=%10011101110 '/d
shiftout portc.5,portc.4,1,[char\11] ' MSB first, Clk low
shiftout portc.5,portc.4,1,[breakcode\11]
shiftout portc.5,portc.4,1,[char\11]

pause 100
return

[Kamikaze47]

I think your problem is that a normal keyboard will initialize with the PC at boot up. This involves the PC sending different commands to the keyboard, and the keyboard responding to them.

You might want to try plugging in a standard keyboard, boot the PC, and while its still on, unplug the keyboard and plug in your pic and see if it works then.

Heres an example of the 2 way communication that happens as the keyboard inits:

    Keyboard: AA  Self-test passed                ;Keyboard controller init
    Host:     ED  Set/Reset Status Indicators 
    Keyboard: FA  Acknowledge
    Host:     00  Turn off all LEDs
    Keyboard: FA  Acknowledge
    Host:     F2  Read ID
    Keyboard: FA  Acknowledge
    Keyboard: AB  First byte of ID
    Host:     ED  Set/Reset Status Indicators     ;BIOS init
    Keyboard: FA  Acknowledge
    Host:     02  Turn on Num Lock LED
    Keyboard: FA  Acknowledge
    Host:     F3  Set Typematic Rate/Delay        ;Windows init
    Keyboard: FA  Acknowledge
    Host:     20  500 ms / 30.0 reports/sec
    Keyboard: FA  Acknowledge
    Host:     F4  Enable
    Keyboard: FA  Acknowledge
    Host:     F3  Set Typematic Rate/delay
    Keyboard: FA  Acknowledge
    Host:     00  250 ms / 30.0 reports/sec
    Keyboard: FA  Acknowledge

The above is copied from: http://www.computer-engineering.org/ps2keyboard/

[Kamikaze47]

Also, the PS2 keyboard protocol expects data in the order shown below and the data is valid when the clock is low.

First Bit Sent -> Last Bit Sent
Start(0), Data0, Data2, Data3, Data4, Data5, Data6, Data7, Parity, Stop(1)

To press A you need to send $1C and then to release you need to send $F0, $1C

Which means the code for A is "0 00011100 0 1", but if you store that into a word variable it will be stored as 0000000001110001 which wont help us much becuase the first bit we want to send is bit10. So if you store the code for A in reverse like this:

char = %10001110000 '/a

you can then send the LSB first and you will get the correct bits in the correct order. It then follows that:

breakcode = %11000011110 '/F0

[Kamikaze47]

Not meaning to flood this thread, but just spotted something else:
"call sendchar" should be "gosub sendchar" as call is only for routines written in assembly.

[Luciano]

Hi,

You can use a built-in feature of Windows if the PC has an unused serial port.
This feature lets you send any kind of keystroke to the PC via serial port.

* * *

Use an Alternative Input Device Instead of a Keyboard or Mouse

SerialKeys is accessibility feature designed for people who have difficulty
using the computer's standard keyboard or mouse. SerialKeys provides support
so that alternative input devices, such as single switch or puff and sip
devices can be plugged into the computer's serial port.

https://www.microsoft.com/windowsxp/...erialkeys.mspx

How to Set Up and Use SerialKeys in Windows:
http://support.microsoft.com/?kbid=260517

Best regards,

Luciano