From: "Jinx" Sent: Tuesday, October 18, 2005 1:52 AM >> Leaving an input floating can fry the chip? > > http://www.piclist.com/techref/logic/xtrapins.htm > > The author says (about a floating input) - > > "The power loss due to rapid switching of a tri-stated input pin > may be significant. Disclamer: I do not have hard data on this, > but I believe I'm correct. Rapid switching will not fry the chip" > > That is unproven AFAIK, but maybe Microchip have documentation. > In either case, as you know, best not to let pins float I know it's best not to let pins float, but this was due to a wire that broke loose. So far it's the only thing I can see being wrong, but I can't see how it can damage the chip, and you seem to be saying it shouldn't too. >> > Is there any other damage ? eg moisture, corrosion > > I was thinking more of the board There's no damage I can see beyond the wire and resistor broken loose (it was a temporary modification and I was finally going to redo it more cleanly nad neatly with the permanent parts). There's no visible corrosion, etc. > Now, that's assuming the problem you have is noise. What > other components are there ? motor ? relay ? solenoid ? or > maybe even lighting ? There's about 1 amp of LED's being driven off the PSU controlled through transistors from the PIC. There are diodes between the transistor and the power rails. It might be causing a fair bit of ripple, but I don't think a negative voltage on any pin is possible. Jason -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist