Simon Nield wrote: >according to the manual the comf will indeed clear the prescaler, however the plan is that it also >effectively sets the lsb of the prescaler on the next clock edge. i guess i could have done movlw 0xff / movwf tmr0... same thing. Yes, but the same thing, from prescaler point of view, is already accomplished by the comf TMR0 instruction, as you described, on the foregoing line? /Morgan -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.