in order to read or write the option register in bank 1, select the
appropriate bit(s) in the mirrored status register.  you can use option_reg
instead of option as defined in p16c63.inc

ex.

bsf     status, rp0   ; 083h, 5
                      ; Select Bank 1
movlw   b'00001111'   ; Program WDT to 128 * .018ms = 2.3 seconds
movwf   option_reg    ; 081h
bcf     status, rp0   ; 083h, 5
                      ; Select Bank 0

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Trond Georg Andersen
Sent: Wednesday, May 06, 1998 5:32 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: Watchdog Timer


I think you need to make sure you are on the right page to write to the
OPTION register.
trond
>
> I'm trying to use the watchdog timer on a PIC16C63.
>
> How do I turn it on?
>
> So far I'm able to write to the options register as follows:
>
> movlw   b'00001111'   ; Program WDT to 128 * .018ms = 2.3 seconds
> movwf   81h
>
> Note: For some reason I couldn't write to OPTION, the assembler did not
> recognize this word.
>
> I have a main loop in my program where I plan on inserting a
>
> CLRWDT
>
> to reset the watchdog....unless I"m missing a real obvious one, I can't
> figure out how to start this
> thing ticking!!
>
> Thanks in advance....