main clock frequency

Björn König bkoenig at
Thu Aug 16 16:00:48 UTC 2007

Wed, 13 Jun 2007 05:36:23 +0200 (CEST)
Björn König wrote:
> > in at91_pmc_attach you're assume a certain main clock frequency. Isn't it
> > reasonable to read this value from the main clock frequency register
if it
> > is available?

Tue, 12 Jun 2007 21:54:30 -0600 (MDT)
M. Warner Losh wrote:
> Yes.  I think that's reasonable.  I didn't do it because I didn't
> think of it at the time I wrote the code.

I talked with the hardware guys and they said that the content of the main
clock frequency register is always inaccurate and should not be used for
determining the main clock frequency if a quartz oscillator is present.
They said the register might be useful for calibration in case an RC
oscillator is connected.


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