AVR-Chat

*sigh*

  OK.    I suppose now I am going to have to go and read every data
sheet on Atmel's website, so I don't stick my foot in my mount again
like this.

  Query:  are these PLLs used with external crystal or clock sources to
multiply the clock frequency, or are they there for other purposes?
Whyt use an expensive PLL circuits for chips that don't run any faster
than 20 Mhz (except for that one, sweet 48 Mhz chip they just brought
out)?  It's not like a 4 or 5 Mhz cyrstal costs any less than a 20 Mhz
crystal, so why would they bother?

Tom.


On Thu, 2005-10-06 at 20:07 -0300, Hugo Oliveira wrote:
> Hi Tom,
> 
> AT90PWM3, does have a PLL, It is used for the CPU clock and for the
> PSC (PWM controllers).
> 
> Regards
> Hugo
> 
> On 10/6/05, Thomas Keller <tkeller1@neb.rr.com> wrote:
> > On Wed, 2005-10-05 at 17:43 +0100, David Collier wrote:
> > > If I run this chip off a 32KHz XTAL.. does it multiply up
> internally,
> > > or does it actually RUN at 32KHz???
> >
> >  AVR microprocessors do not contain PLLs in their clock circuitry.
> > They run at whatever frequency the clock is running at, unless you
> > choose to divide that frequency in those chips which support clock
> > division (which I believe includes the entire line of AVR chips).
> >
> > Tom
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> 
> 
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