> I'm trying to measure a frequency ... I would have replied in more detail except that you sent you message with quoted printable encoding. This makes it difficult to reply to with MSOE without looking like a mess. Anyway, check out the CCP module in capture mode. I've used this many time to measure frequency. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.