Hmmm... I have a prototype 18F6585 based device on my desk. Just for grins I
tried changing the 10MHz xtal to 16MHz (Bumps clock from 40MHz to 64MHz) -
it didn't work for me :-(  If I can find an 11MHz xtal lying around I'll try
it at 44MHz.

-- Mark

> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
> Of Jinx
> Sent: Tuesday, May 17, 2005 9:27 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC]: PIC18F at 44.5MHz. Anybody has experiences to share?
>
>
> > > Does anybody have experiences to share about overclocking
> > > 40MHz-rated PIC18F parts to about 44.5MHz?
>
> Some time last year I posted about an 18F452 that I accidentally
> connected an 18.432MHz xtal to and then turned the PLL on. It
> did appear to run OK with some very simple timing tests at
> 73.728MHz but I would never expect to try that in production
> nd without a complete battery of tests on all the modules it's
> impossible to say whether it was a fully functional device at that
> speed
>
> Although you've been advised that 44.5MHz is out of spec, that
> doesn't necessarily mean it won't work reliably. Just that if it
> doesn't you've no one to blame but yourself. I don't know what
> Microchip's actual criteria are for specifications at the higher
> frequencies, but at the bottom end you probably can overclock
> parts. For example, a -04 part is guaranteed to run at 4MHz,
> but came from the same batch as -10 parts, and failed the 10MHz
> test. So it could run alright at 6MHz or 8MHz
>
> It might very well be the case that some 40MHz parts will run
> at 44.5MHz. You would have to sort out which ones will, and
> with the functions you're using
>
>
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