Bill Kuncicky wrote: >Jan-Erik Soderholm wrote: > > > > >>>What is your oscillator config ? >>> >>> >>Any 100 nF cap near the PIC ? >>Any I/O pins configurated as inputs but left unconnected ? >>How is MCLR connected ? >>Anything else you haven't told us ? >> >> > > >. >1. The oscillator config is a 10 MHz resonator, between OSC1 and OSC2. >Center pin grounded, and of course the resonator has built-in 22 pf >capacitors to ground. > > but these caps are only useful to the resonator tank, and will have no bearing on any other oscillation in the system. >2. There were not any 100 nf caps from Vdd to Vss. I have now put them in, >as suggested by Olin Lathrop. > > > PICs (nor any other uP) are not designed to run properly without bypass caps. People leave them out to their peril. Olin called it right; this is the fix. >3. All unused I/O pins are configured as output. > >4. MCLR is tied through a 10K resistor to +5 volts. > > 22K is ok, too, if you need to. >5. I have told you everything that I think is significant, but of course >Murphey's Law says that I have forgotten to tell you something crucial. :-) > > Murphy was an optomist >I'm going to let it run awhile with the 100 nf capacitors put in and see if >it fails again. > >(Since no one told me whether or not this sounded like oscillation, I guess >it must have). > > Absolutely classic symptoms. We've all been there. >Bill > > -- Note: To protect our network, attachments must be sent to attach@engineer.cotse.net . 1-520-850-1673 USA/Canada http://beam.to/azengineer -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist