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From: Arun Dharankar <ADharankar@ATTBI.Com>
To: linuxppc-embedded@lists.linuxppc.org
Subject: Re: Problem: SDRAM configuration and refresh
Date: Tue, 11 Jun 2002 23:03:04 -0400
References: <20020611192251.WCYS2751.rwcrmhc52.attbi.com@rwcrwbc57>
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Greetings!

Thanks to anyone who might have attempted to
help out! The problem turned out to by too low
SDRAM refresh interval.

Best regards,
-Arun.


On Tuesday 11 June 2002 03:22 pm, adharankar@attbi.com wrote:
> Greetings,
>
> I am trying to getup a Scout based board with
> 64MB SDRAM, and could use any recommendations
> to fix this problem:
>
> If I set the refresh-enable bit in the PSDMR,
> the chipselect for flash and other devices
> vanishes: consequently, this startup code
> ends up executing junk. At this point if I try
> to look at the flash from the BDI2000, the
> flash cannot be seen.
>
>
>
> On the other hand, if I initialize the SDRAM
> without setting this refresh-enable bit, ppcboot
> (the code using it) comes up and am able to run
> commands etc. However, the problem now is that
> without the SDRAM refresh we run into memory
> corruption problem (mtest will fail) and a system
> hang.
>
> Its interesting to note that as long as memory
> is accessed frequently (say via mtest), the
> corruption is not see at that address. Also, an
> idle system almost hangs in a very short time,
> whereas an active one with mtest will continue on.
>
>
>
> Best regards,
> -Arun.
>


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