Config/Connections for using 4-pin Oscillators

[Megahertz]

It seems that output pin pf the crystal will be connected to the OSC1 pin with an appropriate capacitor also grounding the OSC1 pin. For 20 MHz I can suggest similar values to 15-20 pf which you used before.

[RossWaddell]

Thanks Megahertz. If I still have to use a 22pF cap then I haven't saved myself as much in the way of components as I'd hoped. I had hoped to find a better choice than resonators which aren't as accurate.

[Megahertz]

If accuracy is not on top of your list, why don't you just put a resistor from 5V to OSC1 pin and a capacitor from OSC1 pin to Gnd.

[RossWaddell]

You misunderstood me - accuracy is of paramount importance, which is why I don't want to use a resonator (which also saves on components but isn't accurate enough)

[Darrel Taylor]

TTL oscillators do not require any additional components.

Connect it to OSC1/CLKIN on the 1825 and use ECH mode ...
--> ECH: External Clock, High-Power mode (4-32 MHz): device clock supplied to CLKIN pin

That frees up the OSC2/CLKOUT pin for general I/O.

On the 629 and 683 there is only one EC mode, but it works the same as ECH on the 1825.

[RossWaddell]

Thanks Darrel!