Mike B yahoo.com> writes: > Over the week of running I found a +/- drift of less than 84 seconds. Umm, that's about 150ppm. Is this in a temperature controlled environment ? Like a basement lab underneath an inhabited house ? RC clock drift is hard to find in the Microchip docs. AN588 is too old to be useful I think. thanks, Peter P. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist