Over the weekend I got the new power monitior system put down on a breadboard. I am using one Arduino and one ADE7763 on a “motherboard”. On small daughter boards I am putting down a small PIC processor and an analog mux. Since the mux needs a negative voltage rail, I am also putting down a small charge pump voltage negater. The idea behind the daugther board was to allow me to add as many or as few as I wanted. They would plug into a stacked header (like Arduino shields) and bus over power ground the differential analog current signals and the clock and data lines that allow me to perform board selects using the PIC.
Everything was working when I noticed a small cloud of smoke. After shutting down power, I carefully checked everything and then started testing sections of the circuit one at a time. When I got to the PIC it was not working and would not respond to the programmer. No visible damage but the chip is dead. So what caused the problem? Do I have a design flaw? Did I nail the chip with ESD? Did I cause an inadvertant short?
Well, its off to buy a few replacement chips and do further testing before I commit this design to a board.