Hello  David.
I think can help you in some thing. The best way to do a long timer is
really using INT of TMR0.
Place the prescaler 1/256 . I used a 4 mhz clock.
Enable INT of TMR0, then use some Regs. to get the time.
See the codes that you get an time aprox. 2:00hs. For 24hs it places more
some other Regs.
;Make a macro
t_2hs:   macro
              movlw d'15 '
              movwf cont_1sec       ;Its will give aprox 1sec
              movlw D'60 '
              movwf cont_1min       ;its will give aprox 1min.
              movlw d'180 '              ;thats is the min. here is 180min.
= 2hs
              movwf cont_h_min
              endm

              org 0x004
              btfss INTCON,T0IF     ;Int tmr0 ok
              retfie
              bcf INTCON,T0IF         ;clr the flag
;Here it begins the time of approximately 2:00hs
              decfsz cont_1sec,1
              retfie
              movlw d'15 '
              movwf cont_1sec         ;carry the values of 1sec again
              decfsz cont_1min,1
              retfie
              movlw d'60 '                  ;carry the values of 1min again
              movwf cont_1min
              movlw d'15 '
              movwf cont_1sec
              decfsz cont_h_min,1     ;Dec.the min.
              retfie
              ; here, do what you want

Excuse my English and I do not the C codes.
Regards
Lu’s F.

-----Mensagem Original-----
De: David Williams <davidw2@MORGAN.UCS.MUN.CA>
Para: <PICLIST>
Enviada em: Segunda-feira, 4 de Outubro de 1999 15:45
Assunto: 24 hour timer


> Hello,
>
> I've got to set a pin every 24 hours plus or minus 10 minutes.  I need the
> timer to work while I'm doing a bunch of other things (I guess this means
> I've got to use interrupts).  Anyway, anyone have any ideas how to set up
> a 24 hour count?  C code is preferred.
>
> Thanks,
> Dave