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Re: [ECOS] MBX hal clock settings



Jamie Guinan <guinan@bluebutton.com> writes:

> I was studying the MPC823 clocks, and I noticed what
> appears to be a small error.
> 
> In packages/hal/powerpc/mbx/v1_2_3/src/mbx.S, the setting
> for the PLPRCR register at 50MHz uses 0x5fa in the MF
> (multiplication factor) field.  Doing the math, I get,
> 
>   50*1000*1000 / 0x5fa = 32,786

Interesting, I get 32680 as the nearest value here.  But never mind...

> The crystal is suppoed to be 32,768 (not 86), so I belive
> the appropriate value should be 0x5f5.
> 
>   50*1000*1000 / 0x5f5 = 32,768
>
> There is actually some remainder there, but with 0x5f5
> the frequency is low by 28.8Khz versus over by 135KHz
> with 0x5fa (assuming the crystal is accurate).

Yup; I agree, I've patched our sources, this will take effect as and
when... (next week for anoncvs users)

Of course, this gives us a performance hit... we were successfully
overclocking!  ;-)
 
> (I didn't consider this a "support issue" so I just posted
>  here - let me know if there is a better place to report
>  bugs like this).

Small issues/typos like this, posting here works fine.

Thanks!
	- Huge

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