:: I've got an application where I need to CRC program memory and be :: as :: sure as I can be about it having a correct checksum - I know this isn't a checksum, but would some form of Hamming Code with self error correction not work? I never got around to trying this out in a Pic. Colin -- cdb, colin@btech-online.co.uk on 12/24/2009 Web presence: www.btech-online.co.uk Hosted by: www.1and1.co.uk/?k_id=7988359 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist