[tag added] Fig 16-1 in the datasheet seems to imply that a 4xPLL could be used on a 16MHz EC input to get 64MHz. I don't think it says you can't http://ww1.microchip.com/downloads/en/DeviceDoc/41675A.pdf If you can, then all processors could be clocked by one crystal module Joe ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2015.0.5863 / Virus Database: 4321/9474 - Release Date: 04/06/15 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .