The PIC16C84 has the interupt at org 4
I don't see you saving the registers after going into interupt and returning
the registers when returning (you should have a RETFIE, not a return)
_w    equ    10
_status    equ    11

org 4
Interrupt
movwf    _w                ;save work
movf     STATUS, w
bcf        STATUS, RP0    ;puts the pic register in a know page (optional)
movwf    _status        ;save status

bcf    INTCON, 1    ;clear INTF in INTCON register
bcf    INTCON, 2    ;ckear TOIF in INTCON register

Do your other interupt code here

RETFIE                    ;puts the PC at Top of Stack (where the interupt came
from)





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 Schdfer <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
> >