Neil Bradley wrote...

>In there I believe lies my problem. The oscillator I'm going to use is a
>40Mhz part rather than the onboard *4Mhz* part. Supposedly (according to
>the data sheet), the part runs all the way down to DC, with the exception
>of the PLL option (which I'm not using).

You substituted a 40 MHz crystal for the onboard 4 MHz crystal???

If that's what you did, that may be the problem: the maximum
crystal frequency for the 18Fxx2 parts is 25 MHz.  Above that
frequency, you must use a lower frequency crystal and engage the
4X PLL clock option.  I'm in the middle of several 18F252
projects right now, both using a 10 MHz resonator with the PLL to
give a 40 MHz internal clock rate.  They work fine.

But as far as I know, you CANNOT just hook up a 40 MHz crystal to
the PIC and get reliable operation.

Dave D.

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