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| Alternatives to Atmel dataflash for custom AT91SAM9G20 board http://www.at91.com/samphpbb/viewtopic.php?f=9&t=19543 |
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| Author: | pingswept [ Fri Sep 10, 2010 4:15 am ] |
| Post subject: | Alternatives to Atmel dataflash for custom AT91SAM9G20 board |
Hello all, I've been working on this AT91SAM9G20 board for a few weeks now, and it's working pretty well. I can run U-boot and run Linux, thanks to earlier help from this forum. I now want to add a serial dataflash chip to store AT91Bootstrap, but it seems that the Atmel dataflash chips are scarce, and leadtimes are 4-6 months, which to me means "We have no idea." Are there other serial Flash chips that are known to work with the AT91SAM9G20? The SST25VF032B looks like a decent candidate to me. Cheers, Brandon |
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| Author: | falingtrea [ Fri Sep 10, 2010 7:29 pm ] |
| Post subject: | Re: Alternatives to Atmel dataflash for custom AT91SAM9G20 board |
I hand wired a SST25VF080B serial flash chip to my 9G20 board. I was able to get it to work but had to use a specific bootstrap verison to do it. Also, the page size setting for the SST part listed in the SAM-BA code is wrong. The SST parts only support byte write so the "page size" needs to be set to 1, not 256 See the topic linked below for what I had to do to get it to run the bootstrap from serial flash and everything else from NAND Flash. http://www.at91.com/forum/viewtopic.php/f,9/t,19337/ |
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| Author: | pingswept [ Fri Sep 10, 2010 8:35 pm ] |
| Post subject: | Re: Alternatives to Atmel dataflash for custom AT91SAM9G20 board |
Hi Tim, Let me see if I understand you right. You modified and recompiled SAM-BA so you could load AT91Bootstrap to the SST25VF080B attached to SPI0_NCS1. At this point, ROMBoot would find AT91Bootstrap, load it to RAM, and execute it, but when it got to the step of reading U-boot out of NAND Flash, it hung because the NAND Flash hadn't been initialized by ROMBoot. You then modified AT91Bootstrap so that it correctly initialized the NAND Flash, and then the full ROMBoot - AT91Bootstrap - U-boot chain worked. Is that right? Cheers, Brandon |
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| Author: | falingtrea [ Mon Sep 13, 2010 7:19 pm ] |
| Post subject: | Re: Alternatives to Atmel dataflash for custom AT91SAM9G20 board |
Actually there are at least two different versions of the bootstrap file. One is in the bootstrap file that contains bootstrap code for all of the AT91 boards. This version of bootstrap has minimal support in order to keep the file size small. http://www.atmel.com/dyn/products/tools ... ol_id=4093 The other bootstrap code can be found as part of the software package supplied for each processor. This version of the bootstrap is more full featured, and worked without modification to boot NAND Flash from a serial Flash memory. http://www.atmel.com/dyn/products/tools ... ol_id=4343 |
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| Author: | pingswept [ Tue Sep 14, 2010 4:28 pm ] |
| Post subject: | Re: Alternatives to Atmel dataflash for custom AT91SAM9G20 board |
OK, that makes sense. Thanks for the clarification. I'll have a board for testing in a couple of weeks; I'm sure I'll be back then with more questions. Thanks, Brandon |
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