> But I don't know if a crystal will stretch that far - anyone ??? You can stretch a crystal to twice its tolerance usually (for crystals in the 2MHz-20MHz range) in a normal oscillator circuit. That is usually +/-100 ppm or +/-100Hz/MHz or +/-0.01%. With some circuits the frequency can be stretched much more but there will be problems. Peter -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu