[ECOS] Frequency scaling on iPaq

[Cristiano Ligieri Pereira]

I'm talking about the cpu-scale.c linux file, which is the one responsible
to scale the frequency.

------------------------------------------------------------
Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira

On Wed, 6 Jun 2001, Cristiano Ligieri Pereira wrote:

> 
> have you tried it on eCos? I'm doing exacly the same things that are done
> in the change_clock_speed() function execpt the function call to
> recalibrate_delay(void) since it deals with linux global variables.
> 
> Now the system frezzes and the LCD display shows nothing when I try to    
> scale lower than 162Mhz. Should I calibrate the FLASH timings as 
> well? Although it's not done in the linux source code.
> 
> Thanks,
> Cristiano.
> 
> 
> ------------------------------------------------------------
> Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira
> 
> On Tue, 5 Jun 2001, Nicolas Pitre wrote:
> > 
> > We had that problem under Linux and the solution you described is correct.
> > Look at the Linux code for reference.  It works fine on iPAQ.
> > 
> > Note that changing the PLL must be done  for long term power saving.  Since
> > the PLL requires quite a delay to stabilize when it is changed you can't use
> > CPU speed reduction for things like the idle loop.
> > 
> > 
> > Nicolas
> > 
> > 
> 
>