Regarding the register values for the SDRAM intialization.
akohlsmith-linuxbios at benshaw.com
Mon Dec 30 09:23:01 CET 2002
> I am porting the northbridge 82845e for my motherboard. While coding
> raminit.inc file, I took the file from the 82830 chipset directory and
> modified as per the requirement of the 82845e chipset. Now I want to know,
> How to get the register value of the regsiters, like DRB DRAM ROW BOUNDARY
> REGISTER and etc. Do I need to read these regsiter value from the system
> using normal BIOS? I could not find much details about the values in the
> specification. Is my assumption is correct?
At least on the 430tx, the DRB is programmed with the highest amount of memory
in each row, in 4MB chunks.
In my particular case, I have one single 64M dual-sided SODIMM in Row 0. So
my DRB0 has a value of 0x10 (16*4 = 64) and DRB1-5 have the same value since
they are not adding any memory.
Realistically you should be using a memory detection algorithm to try and find
out how much memory is at each row and then programming the DRB registers
correctly. I have never done this, though.
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