I don't use the 877 yet but applying the same logic as you do to an F84 TMR0, wouldn't you just load TMRH/L with EC77h (60535 or -5000) and let it count up 5000 instruction cycles to 0000h (65536) or does TMR1 on an 877 work differently ? -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu