Subject: 750GX

From: Kevin Diggs <[email-masked]>
Date: Fri, 06 Jun 2008 11:43:28 -0700

Hi,

	In the 750GX data sheet (750GX_ds2-17-05.pdf), page 45 has Table 5-1 
that describes the PLL range field. It goes something like this:

	PLL_RNG	   range
	  00	600 - 900
	  01	900 - 1000
	  10	500 - 600

Anyone have any thoughts as to what the correct values are for 600 and 900?

	I think I have this working. I was setting the range to 1 for all 
frequencies because I did:

	if(freq<600)

instead of

	if(freq<600000)

when building my frequency table.

	This cpufreq stuff definitely messes up the repeatability of my 
bogomazes value.

kevin

P.S.:  I'd be interested in various theories as to what this does?

P.P.S.:  On page 341 of the 750GX user manual It says:

	"Turning the non selected PLL off results in a modest power savings ..."

	Regarding what goes on in idle_6xx.S, wouldn't this likely save more 
power than switching to a lower frequency (to clock mostly nothing since 
the processor is going into doze or nap)?