Been trying to get a timer to fire off on my 16F870 for a while now...

I tried TMR0 since I had experience setting it on from my 16F84a.  Here
are the steps I take:

Set up TMR0 configuration stuff, prescalar, etc. (watchdog disabled of
course)
Enable T0 interrupt
Enable Global Interrupts

wait for the magic to happen.  nothing.  is there something I'm missing
on the 16F870 to get a timer to go off?  My code worked fine on my 16F84
so I just changed it to fit a 870...

So I nuked that code, and tried to use TMR1 since it was 16 bit and
would be a bit slower to work with.  Here's my setup (I saved the code
this time! :)

*snip*

  movlw 0x24                                    ; W <- 0010 0100
  movwf T1CON                                   ; set T1CON (PS=4,
Internal OSC)
  clrf TMR1H                                    ; clear timer
  clrf TMR1L                                    ; clear timer
  BANK1                                         ; bank1 macro
  bsf PIE1,TMR1IE                               ; enable TIMER1
interrupt
  BANK0
  bsf INTCON,GIE                                ; enable global
interrupts

*snip*

 org 4

ISR
  movwf W_TEMP                                  ; Copy W to TEMP
register
  swapf STATUS,w                                ; Swap status to be
saved into W
  clrf STATUS                                   ; bank 0, regardless of
current bank, Clears IRP,RP1,RP0
  movwf STATUS_TEMP                             ; Save status to bank
zero STATUS_TEMP register
  movf PCLATH,w                                 ; Only required if using
pages 1, 2 and/or 3
  movwf PCLATH_TEMP                             ; Save PCLATH into W
  clrf PCLATH                                   ; Page zero, regardless
of current page

  incf EIGHTTEEN,f                              ; counter++
  movlw 18
  subwf EIGHTTEEN,w
  btfss STATUS,C                                ; if EIGHTTEEN < 18
    goto ISR_DONE                               ; do nothing
  incf MINUTES                                  ; otherwise do this

ISR_DONE
  movf PCLATH_TEMP,w                            ; Restore PCLATH
  movwf PCLATH                                  ; Move W into PCLATH
  swapf STATUS_TEMP,w                           ; Swap STATUS_TEMP
register into W
  movwf STATUS                                  ; Move W into STATUS
register
  swapf W_TEMP,f                                ; Swap W_TEMP
  swapf W_TEMP,w                                ; Swap W_TEMP into W
  bcf PIR1,TMR1IF                               ; handle TMR1 flag
  retfie

*snip*

and nothing happens, MINUTES never gets incremented, nor does TMR1H/L as
I've outputted them as well...

Any thoughts?  This is confusing me as this should be totally simple!

All hail PICLIST :)

Thanks... -- Nick Veys

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