PLL with EXT oscillator

[Ron Marcus]

Is it possible to inject an external clock signal and use the PLL feature of the 18F processors? It looks like it is only available with HS and intosc modes.
Thanks,
Ron

[skimask]

Is it possible to inject an external clock signal and use the PLL feature of the 18F processors? It looks like it is only available with HS and intosc modes.
Thanks,
Ron

Yep, do it all the time. Use an external 10Mhz DIP oscillator directly into OSC1 using HS/PLL mode for the oscillator. Works great.

Incidentally, I've got a decent select of those DIP oscillators. I've gotten about 99% of the newer PIC18Fxxxx's to run off of 12Mhz external (48Mhz internal). The only ones that really fail are the older 18F452. A few newer types run well at 15Mhz (60Mhz internal), and a couple of my 18F4685's will run at 16Mhz (64Mhz) all day...and are still running...but nothing critical since they're not spec'd to run that fast.