Quote Originally Posted by Darrel Taylor View Post
That would cause the loss of up to 17 of the anticipated 125 cycles you would get during the 1ms period.
Which is not a deal-breaker as X-10 receivers only look for 48 cycles during a window that extends from ZC+250uS to ZC+900uS. Still, one should follow X-10's recommendations to start the 120kHz burst within ZC+100uS. You're already losing some of that window as the PIC is late detecting ZC on rising edges (assuming the ZC detector given in AN236).