On Fri, Jun 11, 2010 at 11:53 AM, Craig Stevens wrote: > Are you erasing the chip before programming? > Have you erased its clock calibration?heers PIC16C72A has no calibration part. And it is an OTP part, so no erase actually. You can blank check it. If it is not blank, pretty much you can not use it any more (not exactly right, since there are tricks to use it in certain cases, but that is just exception). -- Xiaofan http://mcuee.blogspot.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist