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Re: question about EB55


"Greg Holdren" <greghol@sbcglobal.net> writes:

> ----- Original Message -----
> From: Roman Jordan <RomanJordan@gmx.de>
> To: Ecos Discuss <ecos-discuss@sources.redhat.com>
> Sent: Sunday, August 03, 2003 1:57 PM
> Subject: [ECOS] question about EB55
> 
> 
> > Hi,
> > i have downloaded the ecos image for the atmel eb55 board. The ram
> > version is running fine. But i have a question about flashing the rom
> > version of redboot. I do not want to delete the angel bootloader.
> > If i read the manual at page 93 (pdf page 195) i read the following.
> > Download the ram version, switch the jumper to position user. This will
> > invert the address line A20. In my opinion angel is then located at
> > 0x0110.0000. The free flash space is located at 0x0100.0000. I hope this
> > is correct.
> > Now i load the rom-srec file to ram. After this the manual says, write
> > the downloaded rom image to adresse 0x0110.0000. Is this really correct?
> > The jumper is already in the user position. I think there is angel now.
> >
> > I think i have to write the rom image at the address 0x0110.0000 and
> > then switch the jumper jp1 to user position.
> 
> 
> This procedure works for the EB40A and the EB55. I have used it and it works
> on both boards.
> 
> http://sources.redhat.com/ecos/docs-latest/ref/at91.html
> 
> The jumper should be in STD mode the whole time because you need angle to
> communicate with the board. Switch jumper to USER and reboot once the flash
> is programmed with redboot.ROM.
> 

To underline this. We discovered, the hard way, that the jumper/switch
on these boards only apears to affect read cycles. Any write cycles to
the flash continue to go to the original addresses. So writing to
0x01000000 with the jumper in USER mode actually writes to the Angel
half of the flash.

The only really safe way to program these boards is to load a RAM
RedBoot from Angel, run it, load a ROM RedBoot into memory, and then
program that into the flash at 0x01100000.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com      The eCos and RedBoot experts


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