The interrupt vector's at H'04'.
Are you sure your software simulation is hitting the btfsc instruction?

Cheers,
Ben

Mathew Cohen wrote:
> 
> I believe that this is the interupt vector location for the 16f84. In
> software simulation it seems to work. If this is not the case than could
> someone please set me straight. Also it ahs been brought to my attention
> that I seem to have left the global interupt bit low this is probably why
> the code does not work .
> Can someone test it thanks.
> 
> Regards
> 
> Mathew Cohen
> 
> ----- Original Message -----
> From: Martin SchŠfer <Schaefer@ELEKTRONIK21.DE>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Wednesday, October 20, 1999 10:21 PM
> Subject: Re: Why doesn't this code work ???
> 
> > 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
> >