In USA long term mains drift is _very_ close to zero. The power grid will deliberately adjust the mains frequency to compensate for previous errors. Mains driven clocks keep good time nearly indefinitely (barring power failure, which is very rare except for local problems due to storms, etc.) [And California's problems due to stupidity :-) ]. Bob Ammerman RAm Systems (contract development of high performance, high function, low-level software) ----- Original Message ----- From: Vasile Surducan To: Sent: Thursday, February 22, 2001 3:26 AM Subject: Re: [PIC] Timer Tribulations > On Wed, 21 Feb 2001, Tony Nixon wrote: > > > You will find that the clock will drift one way or the other depending > > on temperature, so using the mains as a frequency source is much more > > accurate. > > You are certainly joking ! Or in your country mains frequency drift is > under 0.5% ... > > Vasile > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics