[SunHELP] Re: Another possibly unanswerable question about AXI memory (fwd)

[Robert Novak]

On Fri, 7 Sep 2001 dhansen at zebra.net wrote:

> > I have two pieces of HB56SW3272ESK-5 "256MB Buffered EDO DRAM DIMM
> > but in my Ultra AXi board they
> > show up as 128MB sticks. I checked the bank layout and my configuration
> > matched the AXi manual's admonitions...
> 
>    Your first problem is that those are 50ns chips.

Okay. I didn't know if that would be a problem. I haven't run into 50ns vs
60ns issues on the smaller pieces (32MB and 64MB) that I'm aware of.

>  Have you done any kind of troubleshooting yet? Like remove
> the original pair and see if your new pair still behave the
> same way. What does POST reveal? 

I have tried different banks, with and without other banks of RAM (256MB
sticks, 64MB sticks), and they show up as 128MB each alone in either bank,
with a pair of 256s in the other 11bit bank, and with a pair of 64s in the
other 11bit bank.

POST reveals that they are detected as 11-bit column width in each
condition. This was the case with or without other memory.

	Probing Memory
	Group Info[0000.0000.0000.0003] : 0000.0000.0000.0000
	Group Info[0000.0000.0000.0002] : 0000.0000.0000.01a0
	Group Info[0000.0000.0000.0001] : 0000.0000.0000.0000
	Group Info[0000.0000.0000.0000] : 0000.0000.0000.0190
	Using 11-bit Column Addressing
	Done
	Clearing Memory... including Unix Retained Memory...Done
	MEM BASE = 0000.0000.3000.0000
	MEM SIZE = 0000.0000.1000.0000
	11-Column Mode Enabled
	
	Probing Memory Group #0 128 + 128 : 256 Megabytes
	Probing Memory Group #2 256 + 256 : 512 Megabytes
	
My remaining guesses are that either the 50ns vs 60ns is a firm
requirement on this size, or there's a single bank vs dual bank issue. I
guess I'll keep saving up for a directly certified option for the 256s,
and use these in my Ppro boxes.
	
> Have you tried calling/emailing Hitachi Semiconductor to verify column
> width on those chips? It would be nice if they work (I could use some
> in mine), but so far it doesn't look like they match the required
> specs.

I haven't, no. I'm a bit pessimistic about the likelihood of getting an
answer on a three year old product from such a big company. 

Thanks for the response. 

--Rob
Robert Novak, Indyramp Consulting * rnovak at indyramp.com * indyramp.com/~rnovak
        "And it's been a long December and there's reason to believe
           Maybe this year will be better than the last...." -- counting crows