> BTW, the best accuracy I've got with bresenham methode was +/- 2 > sec/month. Could be better ? > > best regards, Vasile > This represents an error of about 0.8 ppm. This is pretty amazing, given that crystals are generally rated an order of magnitude or 2 worse than 1ppm. (or are you using an oven, etc). Bob Ammerman RAm Systems -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.