I can't imagine the two oscillators getting along very well, but I could be wrong. The safest be would be to take the oscillator output (wired as per normal for one PIC), and buffer this through a 74HC14 or vaguely similar, and feed it's output to the clock in on the other PIC. I've done this with the 8051 types, and it works a charm... Till later, Scott. Û¼¡`¡¼Û¿,üü,¿Û¼¡`¡¼Û¿,üü,¿ Scott May. Hydrographic Support 1345 Ipswich Road Rocklea. Ph +617 3892 5610 Fax +617 3848 5191 scott.may@dnr.qld.gov.au scott@smartdata.com.au Û¼¡`¡¼Û¿,üü,¿Û¼¡`¡¼Û¿,üü,¿ -----Original Message----- From: William Ruehl [mailto:wruehl@SNET.NET] Sent: Friday, 25 June 1999 10:11 To: PICLIST@MITVMA.MIT.EDU Subject: Dual PICs one Xtal. PICsters, What is the best way to have two 16F84's on the same board share the same crystal? Can the chips share the crystal in parallel? or is there a more elegant approach? Bill Ruehl