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....