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Re: Redboot hanging during boot on EP9302
- From: Andrew McKay <amckay at iders dot ca>
- To: Jonathan Larmour <jifl at eCosCentric dot com>
- Cc: eCos developers <ecos-devel at ecos dot sourceware dot org>
- Date: Wed, 21 Jan 2009 16:31:48 -0600
- Subject: Re: Redboot hanging during boot on EP9302
- References: <49765D66.6090801@iders.ca> <497684C5.8020900@eCosCentric.com>
Jonathan Larmour wrote:
Hi Andrew,
You misaddressed this to ecos-devel-owner instead of ecos-devel. I've
CC'd it to ecos-devel for you in case anyone can help.
Thanks, silly me.
For what it's worth, in the 9 times out of 10 it works, is it solid?
Might it be worth trying out the eCos "heaptest" test (perhaps
increasing the iterations) to verify the stability of SDRAM in case the
timings are marginal?
It appears after sending this I ran across the problem. I double checked the
Errata for the EP9302 Rev2 part and found something wrong with the SDRAM controller.
From Cirrus' Errata sheet:
----------------------------------------------------------------------------
When the SDRAM controller is configure for PRECHARGE ALL commnd, the actual
sequence is not always issued to the SDRAM device(s).
Workaround:
Do a read from each SDRAM bank so that a PRECHARGE command is issued ot each
bank of the SDRAM device. This will satisfy the required SDRAM initialization
sequence.
Due to the effectiveness and simplicity of the software workaround, no silicon
fix is planned.
----------------------------------------------------------------------------
I made modifications as necessary to the SDRAM init code and all is well it appears.
Thanks for your time,
Andrew McKay