CPU operation =
[(PLLDB+1)*Crystal_frequency/Prescaler]/Postscaler/2
So any input frequency change will reflect either
PLLDB or Prescaler or Postscale change. You will see
this change in the settings of PLL in Cpu.c file
Charlie
--- Hardeep Gida <hgida@hgid...> wrote:
> I thought that it would be in the _EntryPoint(),
but
> after some
> investigation I found that the PLL settings are
> being setup in that
> routine. I also thought that the value would be
> stored in some register,
> but after going through the manual, I couldn't find
> any registers that
> holds its value. That's why I'm thinking that maybe
> it's saved as a
> global variable somewhere?
>
> I know that you set the crystal's value in the bean
> (and it uses this
> value to correctly set the prescalers for all timer
> beans), but I still
> haven't been able to find in the C code how the
> program knows that the
> processor is using the 4MHz crystal.
>
> Thanks.
> Hardeep
> -----Original Message-----
> From: R.A.Imhoff [mailto:rimhoff@rimh...]
> Sent: Friday, December 02, 2005 11:52 AM
> To: Hardeep Gida
> Cc: motoroladsp@moto...
> Subject: Re: [motoroladsp] Crystal Oscillator
>
> Hello Hardeep,
>
> Processor Expert needs to know your cpu frequency in
> order to correctly
> set the prescalers for all timer beans you add to
> the project.
> If you add a bean to create an interrupt every 10
> ms, it needs to know
> how many clock cycles that corresponds to, which in
> turn depends on the
> crystal frequency.
>
> Best regards
> Robert
>
> On 02.12.2005, at 17:17, Hardeep wrote:
>
> > Hi,
> >
> > I am working with the DSP56858. In the CPU bean
> for my project, I can
> > select a value of crystal from 2MHz to 4MHz. Where
> in the program is
> > this crystal value being used? Is it being saved
> as a global variable?
> > If so, in which file would it be?
> >
> > Thanks.
> > Hardeep
> >
> >
> >
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
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> >
> >
> >
>
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