Greetings to all. A friend has started building a circuit with a 18F4550 and a 20 MHz 3 pin ceramic resonator. Is a resonator accurate enough to allow USB communication or does he need a quartz? Peter van Hoof -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist