> I have a 18F252, programmed for HS, that works fine with a 20mhz xtal,
but I have tried two different 40mhz xtals without success.

As the manual states, 40 MHz Xtals or external input are not supported,
the only way to run at 40 MHz is to use the *4 PLL.

Wouter van Ooijen

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Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products

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