> It does have one "absolute" voltage reference- for the BOD- and note that it's a fairly tight spec on those devices (+/-50mV compared to +/-300mV on some other devices). Just a WAG. But the best suggestion I have seen so far. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body