Martin McCormick wrote: > How about a correction factor which adjusts itself based on the >temperature? At 25 C, no correction and then increasing correction as >the temperature deviates from 25 DEG C. If the change in temperature only affected the crystal, the results might be somewhat predictable and hence could be conpensated. Unfortunately, there are other factors such as the oscillator circuit, the crystal caps etc. We sprayed 'freeze mist' on a PIC running with a watch crystal and the frequency went UP!. If the crystal were the only factor the frequency should have gone down. -- Bob Fehrenbach Wauwatosa, WI bfehrenb@execpc.com