Grant Brown wrote:
> Hi list,
> 
> Starting to use a PIC18F45J10 for the first time.

Right, start with the datasheet, in particular the chapter
on the oscillator configurations. It's just a couple
of pages.

> I have a external 20Mhz crystal as the clock input and wish to run 
> the device at its maximum speed of 40Mhz

Not possible. The datasheet is perfectly clear on this.

Jan-Erik.
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