Xtal transistor oscillator driving 2 PIC micros - 4 MHz

Thread Starter


Joined Jan 6, 2004
Initially I implemented a 4 MHz clock driving 2 PIC micros, using 2 inverters, one of them as a buffer (74HC04). To avoid the waste of space (the other 4 gates do nothing) I tried a transistor oscillator and buffer from an ARRL book but couldn't have it working. In my implementation space is at a premium.
Can anyone show me a really working circuit?
BTW: input should be a 4 MHz square wave or kind of a sine wave? If so, what pk to pk value? No experience on this.
Thanks for any help.


Joined Apr 20, 2004

The clock should be a square wave. Also, the clock oscillator that hqmjr mentions may be had in 1/2 size packages for tight spaces.


Joined Oct 11, 2004
I don't know which PIC you are using. If it has two pins OSCin and OSCout with the xtal between them and a cap from each to ground, then the 'in' pin will be high Z and the 'out' pin low Z.

You can then wire direct from the OSCout of the first PIC to the OSCin of the second one.