3 Replies Latest reply on Aug 20, 2013 12:31 AM by ki.leung

    PC (Program Counter) corruption after power off

    sebastian.seczkowski
              After 2 weeks of work the chip suddenly failed after power off. PC jumps to strangle locations. The whole flash is write protected. The only thing I occasionally write is EEPROM.   
        • 1. Re: PC (Program Counter) corruption after power off
          user_1377889

          As far as I know, most devices fail when they are switched On!

             

          I would suggest to read-out the flash and compare it with the desired hex. When you have debugging capabilities integrated to your board you even may inspect the memory contents.

             

           

             

          Bob

          • 2. Re: PC (Program Counter) corruption after power off
            user_14586677

            Suspect as always is tranients on I/O pins that inject charge into the

               

            substrate, and potentially corrupt FLASH cells. Or transients on Vdd

               

            that exceed gate ox breakdown. Best way of detecting a condition like

               

            this is a DSO set to trigger on something like this -

               

             

               

            Vss - .7V >  Vtrig > Vdd + .7V

               

             

               

            and look at key interface pins talking to loads than can generate

               

            transients, like a relay, a MOSFET driving a relay (transient feedback

               

            thru Cgd). Set up jig to cycle power, and enable DSO on signal that

               

            triggers power up and down.

               

             

               

            This is vary tedious to find, patience is a virtue.

               

             

               

            Also in general power supply sequencing, make sure PSOC comes up

               

            before any I/O loads do. If you cannot guarentee that make sure all pins

               

            clamped by zener arrays, avaialable from On Semi, Vishay, Fairchild to

               

            name a few.

               

             

               

            Regards, Dana.

            • 3. Re: PC (Program Counter) corruption after power off
              ki.leung

              How do you find the PC corrupted?

                 

              Would there be some cases where your EEPROM value is out of your expected range and your program perform not as you expected?