This is a multi-part message in MIME format. ------=_NextPart_000_04F5_01C8BC05.44273E20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > Maybe it's important to add that it's a dsPIC (30F5011 to be exact) > and that I want it to be precise Mario, if you want short- and long-term accuracy, may I suggest the attached circuit. You can get 1 minute per year stability. By my reckoning that's about 1 part in 12,000,000, or keeping a 32k crystal stable to 0.0026Hz In a back-up situation with a 12V SLA, I use 150k/22k as a voltage divider to get ~1.7V for the clock driver and a 5V LDO to power the CMOS and a 12F675 time-keeper. 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