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Re: at91rm9200 Booting/using serial dataflash only, removingparallel flash
- From: Savin Zlobec <savin at elatec dot si>
- To: Damian Slee <damian at commtech dot com dot au>
- Cc: eCos Discussion <ecos-discuss at ecos dot sourceware dot org>
- Date: Mon, 14 Feb 2005 09:51:08 +0100
- Subject: Re: [ECOS] at91rm9200 Booting/using serial dataflash only, removingparallel flash
- References: <B967C997C2BE2D48A6BBE14078F79BD6287161@ntserver.commtech.com.au>
Damian Slee wrote:
Hi,
given the errata problem with the at91rm9200 #37, where booting from
external parallel flash requires 20ns flash. As a result people are
using small eeproms or dataflashes to boot from instead, then switching
to parallel flash. which then boots redboot and so on.
i'm thinking about using a big serial dataflash only, with large amounts
of sdram.
I think someone has done this with the eb55 atmel board? Was a while
ago tho.
I've used DataFlash with AT91M55800A (the AT91 SPI and DataFlash drivers
were written and tested on this uC). I didn't got around using JFFS2 on
it (buffering
and block size issues) - now that this is solved (in JFFS2 CVS) it
should work just
fine.
The following app note descibes this with u-boot. anyone tried it? any
issues anyone can think off?
http://www.atmel.com/dyn/resources/prod_documents/doc6067.pdf
So does this mean i need a small boot loader like romboot.bin (see pdf)
that gets loaded to internal SRAM first, which will then load RedBoot
(RAM?) from the dataflash into SDRAM, which will then load my
application from dataflash into SDRAM?
Yes. You can get the 1 stage boot loader (romboot) sources from
http://www.teest.com/at91 .
savin
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