matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10182
Posted: 09:57pm 20 Jun 2018
I think this is possible by using the frequency as input to one of the PIC's timers and then reading the timer at intervals. I believe it could be done with a CFunction. Of course you will need a trivial circuit to convert the crystal output to a TTL signal as input to the timer