>We code-protect our chips, so a readback & compare to a "master" >chip is not an option. The checksum is just a way to help ensure >that we are really putting the right stuff in the chip. I think >this is the same thing you are wanting to do. One free guess why one of the MPLAB options is to put the checksum into the ID Locations (2000-2003 on 16 series). -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist