Haven't looked at it for some time, but doesn't he need to use a 6MHz XTAL with PLL to do USB? Or a 24MHz XTAL, I guess. 20 MHz won't work because the USB SIE requires a 24MHz clock, IIRC. -- Bob Ammerman ----- Original Message ----- From: "Peter van Hoof" To: Sent: Wednesday, October 28, 2009 9:58 PM Subject: [PIC] 18F4550 resonator for USB? > 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 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist