http://www.piclist.com/piclist/2009/07/17/183137a.txt? Could this have been related to the Read - Modify - Write issue? I mean, could it be that the pin was just changed and it didn't have time to come up to the expected logic level when running at full speed, but single stepping introduced a (human) delay that permitted a slightly higher voltage to be reached and therefore seen differently? --- James Newton mailto:jamesnewton@massmind.org 1(949)743-1447 phone http://www.massmind.org/member/JMN-EFP-786 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist