On Thu, 13 Feb 2014 18:52:13 -0000 "Dom S" wrote: > "Totally a stab in the dark but make sure you have adequate decoupling on= =20 > the > microcontroller. >=20 > I had issues with a product that had a 0.1uf decoupling cap a little too = far > from the power pins of the controller for comfort - it would randomly res= et > and occasionally randomly accessed parts of the program it shouldn't. Thanks for the repeat, Dom! I have an RF background, so RF decoupling is one of my OCD themes... There is a 100nF cap at less than 3mm from the supply pins, another one where the= =20 supply enters, and a 47uF cap for good measure. The problem is not while running. I've had it running, deliberately with lo= ng cables, for days without any issue. The problem is clearly with on/off switching. In fact, I thing the 47uF cap might be detrimental - the slow idscharge may be causing strange effect in the pic. Again, cheers, John --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .