Hi Mathew,

why is your interrupt starting at H'03' ?

Mathew Cohen schrieb:

>   Hi All, Can someone tell me why the following code will not work. Is
> this the correct way to initilise the timer and use the timer overflow
> interupt. Thanks in advance Mathew Cohen               ORG
> H'50' Start
>  Call Initporta
>  Call Initportb
>  Call Initmr
>  GOTO
> Checkswitch ;-----------------------------------------------------------------
---------
> ORG H'03'
> TmrInterupt  BTFSC PORTB,7
>  call Initmr
>  goto toggleleds Initmr
>  CLRF TMR0
>  BSF STATUS,RP0 ;select bank 1
>  CLRF OPTION_REG
>  MOVLW B'00000111'
>  IORWF OPTION_REG,1
>  BCF INTCON,T0IF
>  BSF INTCON,T0IE  RETURN
> Initporta  BSF STATUS,RP0
>  MOVLW 0
>  TRIS PORTA
>  BCF STATUS,RP0
>  MOVLW 31
>  MOVWF PORTA  RETURN Initportb  BSF STATUS,RP0
>  MOVLW H'FF'
>  MOVWF TRISB
>  BCF STATUS,RP0
>  RETURN Checkswitch
>  BTFSS PORTB,7
>  BSF PORTA,4
>  BTFSC PORTB,7
>  BCF PORTA,4
>  GOTO Checkswitch
> toggleleds
>
>  BTFSS PORTA,1
>  goto LedsOFF
>  BTFSC PORTA,1
>  goto Ledson
>
> Ledson  MOVLW 15
>  MOVWF PORTA
>  CALL Initmr
>  GOTO Checkswitch
> LedsOFF
>
>  MOVLW 0
>  MOVWF PORTA
>  CALL Initmr
>  GOTO Checkswitch
>
>  END