Re: [ECOS] at91rm9200 Booting/using serial dataflash only, removingparallel flash

[Savin Zlobec <savin at elatec dot si>]

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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