On Thu, 25 May 2017 10:46:14 +0100 Cristiano Cesaretto wrote: > Everything works well but occasionally some boards are not detected anymo= re > by the PC and I have to reflash the firmware again to make them work. I > haven't been able to find a cause for this. I had the same problem with a LED display a couple of years ago. Finally I determined that the problem was with the resident boot software in the PIC (not my own code). In some rare cases, the bootstrap code would execute the flash programming routine, and delete the actual firmware code. (This, in spite of several tricks to protect this from happening) When all was well-tested, I removed the bootstrap code, recompiled my own code to boot by itself, and the circuit never failed since (going on 3 years). 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 .