> Date: Fri, 16 Nov 2007 10:06:43 -0800 > From: "Andre Abelian" > > Hi to all, > > I use pic18f4550 and I noticed that the pic looses it's program memory > I am not sure how many % but it is enough to see things are not working > and this is my 3rd time I started doing hardware trouble shooting and I > ended up > reprogramming pic fixed the problem. The only possibility is the part got > over heated while > soldering. any idea? > > thanks > > Andre > I've seen this happen a couple of times. In all cases there was a definite problem with the hardware or software. I just can't remember what exactly caused it (late night debugging sessions!) IIRC it was an input set to an output or some issue with the power supply. Holding up the supply with a cap can cause its own problems. I tried a similar circuit on a 12F683, if the circuit was switched on and off relatively quickly then the voltage could decay to a point between the minimum working voltage (loss of RAM) and the POR voltage, at which point Brown Out Reset is not guaranteed to work. In my case it certainly didn't! Its surprising how long a 12F683 can run from a fully charged 68uF cap. Cheers James -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist