Phillip wrote: > So is the lesson I need to take away from all this is that in order to > realistically be able to alter my code in the field via a serial port I > will need to operate the PIC at 5V??? Not at all. However if you really want to support ICSP you need to make the rest of the circuit tolerate the PIC Vdd pin raised to 5.5V. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist