My advice would be, "if it ain't broke make it run faster until it breaks"

On 5/17/05, Mark Scoville <mscoville@unicontrolinc.com> wrote:
>=20
> My 64MHz test failed at 5.00V
>=20
> I tried at 3.70V and it looks like it IS running. It seems to be running =
a
> little faster. It really is running a little faster - I checked my SPI=20
> clock
> line with a scope... however... It does not appear to be running at 64MHz=
.
> Maybe 41.8MHz... I'm not sure how reliable it is - but it is running. On
> this particular chip it looks like maybe the PLL can't phase lock much=20
> above
> 40MHz? The OSCCON lock bit indicates that the PLL is locked - but it=20
> doesn't
> look like it to me.
>=20
> Interesting stuff... but I would never try this in production.
>=20
> -- Mark
>=20
> > -----Original Message-----
> > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
> > Of Electron
> > Sent: Tuesday, May 17, 2005 12:32 PM
> > To: Microcontroller discussion list - Public.
> > Subject: RE: [PIC]: PIC18F at 44.5MHz. Anybody has experiences to share=
?
> >
> >
> >
> > At what voltage were you running it? :)
> >
> >
> > At 11.09 2005.05.17 -0400, you wrote:
> > >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=20
> 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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> > >> View/change your membership options at
> > >> http://mailman.mit.edu/mailman/listinfo/piclist
> > >>
> > >>
> > >
> > >
> > >
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> >
>=20
> --
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