Memory settings

[Abraham vd M. <ab...@2d...>]

Hi!

1. This is actually a general ARM question I guess, but this is probably the
best list to ask. If you calculate the DRAM settings using the Intel
configuration thingy (http://appzone.intel.com/hcd/sa1110/memory/index.asp)
you get values for MDCNFG, SMCNFG, MDREFR, MDCAS00, MDCAS01, MDCAS02, and
MSC0, but blob also needs MSC1 and MECR. From the SA-1110 datasheet it seems
these are using for expansion memory, etc. which is optional. Can I just set
this to anything in blob? (I set it to zero and it seems to work, but I'm
not sure if this is wise)

2. Also what should I expect to go wrong when my settings don't match the
processor speed. I worked out above settings for 206.4MHz, but it seems to
work fine for any clock speed (I tried 59.0MHz and 221.2MHz). Is this safe
or not?

3. It seems that if the CPU runs at > 200MHz then the memory is accessed at
1/4 of the core cpu speed (for 100MHz SDRAM), but if the CPU runs < 200Mhz
it is 1/2 the core cpu speed, so at 206.4MHz you get 51.6Mhz, but at
191.7MHz you get 95.9MHz ram (almost twice as fast). Isn't it better to run
the CPU at a bit slower speed then or does the 20 odd Mhz make such a big
difference (in which case you should be running at 221.2MHz I guess).

My sincere apologies if some of the questions is off topic.

--=20

Regards
 Abraham

Rule #1:
	The Boss is always right.

Rule #2:
	If the Boss is wrong, see Rule #1.

__________________________________________________________
 Abraham vd Merwe - 2d3D, Inc.

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