> -----Original Message----- > From: piclist-bounces@mit.edu On Behalf Of alan smith > Sent: Friday, February 04, 2005 1:25 PM > > So....not to get off topic but back to topic... > > Ignoring for the moment the discussion about the UARTs > that has gone on... > > I take it that the internal oscillators that Mchip has > internal are just as good as putting an external > crystal and associated parts. A cheap low quality crystal @ 25degC is accurate to +/-0.01% the internal oscillator of the PIC18F1220 is specified as +/-2% a huge difference in accuracy. For async serial comms I agree with what Wouter said in an earlier post on this thread: "I dunno how you meant this, but in my opinion 3% is the maximum error I would accept in the whole chain: sender, electronics, receiver. The error in the internal oscillator *and* the error listed for the baudrate divisor add up to the error at the sender, which I would not allocate more than 1%." With +/-2% error in the internal oscillator (+/-5% over temperature), I would not use it in a commercial product. However the typical error from the spec sheet is +/-1% so, for a hobby project it should be OK. Paul Hutch -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist