> I am using the 16F84 to construct my programme to run on the 508 when I
have
> debugged. I have got this....
>
>  movlw b'00000111' ;Set option reg
>  movwf 081h

you need to either access the option register using the OPTION command

    movlw    b'00000111' ;Set option reg
    option

or change to bank 1 when you write to the option register

    bsf    status,rp0
    movlw  b'00000111' ;Set option reg
    movwf  081h
    bcf    status,rp0

> .
>  movlw .1
>  movwf 01h
> .
> .
>  movf 01h,1
>  btfss 03,2
>  goto $-2
> I am using MPLAB SIM to run my programme but TMR0 does not increment so I
> get stuck in this loop. Is there a bit I should be setting somewhere?

No, there are no other bits to set AFAIK.
The movf  01h,1 causes the tmr0 register not to change which is why it gets
stuck. I've never tried to check tmr0 this way so I don't know what is
happening there.

A better way to check for tmr0 reaching zero is to poll the timer0 interrupt
flag.

 LIST P = PIC16F84
 INCLUDE <P16F84.INC>

   org 0

   movlw   b'00000111' ;Set option reg
   option
   clrf    INTCON      ;note that GIE and T0IE are cleared

testloop
   btfss   INTCON,2
   goto    testloop

stop
   goto    stop

   end


James Hillman

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics