Help me out..

[mister_e]

to read a PS2 keyboard, you need something like...

                '
                '   PS2 Keypad signal
                '   -----------------
        DEFINE  PS2_SCLK        PORTC
        DEFINE  PS2_SCLK_BIT        1
        DEFINE  PS2_SDATA       PORTC
        DEFINE  PS2_SDATA_BIT       0

        '   
        '       Variables definition
        '       ====================
        KeyPS2      var BYTE                ' Store pressed key


    ' some code here


                '
                '       Keypad scan routine
                '       ===================
ReadPS2:        '
                '       data is packed in a 11 Bit format
                '           Start, 8 bit data(LSB first), 1 parity, 1 stop.
                '
                '       data is available on the falling edge of the clk
                '
        gotsync=0                           ' No synch received

    ScanIt:    
        ASM
            CHK?RP  PS2_SCLK
            CALL    SkipPulse               ; Skip the start bit
            CLRF    _BitCounter             ; clear bit counter

    ReadLoop
            BTFSC   PS2_SCLK,PS2_SCLK_BIT   ; wait for clk falling edge
            GOTO    $-1                     ;
            ENDASM
        
        @   MOVE?TB PS2_SDATA,PS2_SDATA_BIT,_SDATA
        KeyPS2.0[BitCounter]=SDATA          ; Save current bit value
        
        ASM
            BTFSS   PS2_SCLK,PS2_SCLK_BIT   ; wait for clk falling edge   
            GOTO    $-1                     ;
            
            INCF    _BitCounter,F           ; increment bit counter
            
            MOVLW   8                       ;
            XORWF   _BitCounter,W           ; check if = 8 (end)
            BTFSS   STATUS,Z                ;
            GOTO    ReadLoop                ; if not read again

            CALL    SkipPulse               ; skip parity
            CALL    SkipPulse               ; skip stop bit
            GOTO    GetOut                  ; get out of here to test the 
                                            ;     actual result
    
    SkipPulse
            BTFSC   PS2_SCLK,PS2_SCLK_BIT   ; wait for falling edge
            GOTO    $-1                     ;
            
            BTFSS   PS2_SCLK,PS2_SCLK_BIT   ; wait for rising edge
            GOTO    $-1                     ;
            
            RETURN                          ; Bye bye!
            
    GetOut            
        ENDASM

Then, you need to build a HUGE lookup table and + conditions to fit the PS2 ScanCode which is store in KeyPS2 variable.

The above don't check the parity, don't check the validity of the Start bit... it's just a plain and starter version.... sorry if it's mostly in ASM..

In PBP it should be something close to...

ReadPS2:
        FOR COUNTERBIT=0 TO 10
            WaitFallingEdge: if sclk then waitfallingedge
            KEY.0[COUNTERBit]=SDATA
            WaitRisingEdge: if sclk=0 then waitrisingedge
            NEXT
        KEY=(KEY>>1)&$ff          
        return

there's few other example here and there in the forum. Melanie also draw the whole PC ScanCode table.

at least
http://www.picbasic.co.uk/forum/show...ghlight=ps2%2A
http://www.picbasic.co.uk/forum/show...ight=scan+code

[Joann]

Thank you Steve, for your concern i will give it a try and get back to you, mostly to use ps2 keyboard is good for the moving sign display as it serves as stand alone with out pc,when you plug the key board you just hit any funtion key like f1 to enter data,f2 to delete,and f3 to store the data etc, that will be fine for me .

[Joann]

hello steve ,
i have try it without success.
anymore idea.

[T.Jackson]

hello steve ,
i have try it without success.
anymore idea.

Perhaps you could post a schematic of what you have done? This may help others in helping you since the suggested code you have been offered is to be known as working.

Best Regards,

Trent Jackson