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Re: Frequency scaling on iPaq
- To: Cristiano Ligieri Pereira <cpereira at ics dot uci dot edu>
- Subject: Re: [ECOS] Frequency scaling on iPaq
- From: Nicolas Pitre <nico at cam dot org>
- Date: Wed, 6 Jun 2001 19:27:06 -0400 (EDT)
- cc: <ecos-discuss at sourceware dot cygnus dot com>
On Wed, 6 Jun 2001, Cristiano Ligieri Pereira wrote:
>
> have you tried it on eCos?
No.
> 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.
Then it should work. Be sure you adjust the ram timingsin the same order
i.e. whether you actually increase or decrease the clock frequency.
Double-checking the SDRAM parameters for each frequencies might be worth it
too.
> 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.
Normally it shouldn't matter if you slow down the flash access. The LCD and
PCMCIA timings might have to be recalibrated as well.
Nicolas