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Re: Serial EEPROM/flash?
- From: Gary Thomas <gary at mlbassoc dot com>
- To: "Paul D. DeRocco" <pderocco at ix dot netcom dot com>
- Cc: 'ecos-discuss' <ecos-discuss at ecos dot sourceware dot org>
- Date: Sun, 12 Aug 2007 16:19:29 -0600
- Subject: Re: [ECOS] Serial EEPROM/flash?
- References: <041001c7dc9e$87753f20$887ba8c0@PAULD>
Paul D. DeRocco wrote:
> Is there any driver available for serial EEPROM or flash devices like the
> AT24Cxxx (I2C) or AT25Fxxx (SPI) series parts? In particular, I want to use
> such a part with Redboot, so that I can store a boot script and other
> configuration data in it.
>
> This is for an AT91RM9200 system, which has an on-board boot ROM that can
> boot a 16KB program from serial EEPROM. I figure I'll write a small bit of
> code that sits in the beginning of the EEPROM; it will enable SDRAM, and
> load Redboot from the next piece of the EEPROM; the tail end of the EEPROM
> will hold the boot script and the configuration data. The application will
> boot from a much larger SD card.
>
> Do I need to write my own driver, or has anyone already done this? Or is
> there some reason it can't be done? The v2 flash docs imply that there's no
> requirement that the device actually be memory-mapped flash.
>
The PowerPC/MOAB target has just such a device, configured to
use as the backing store for 'fconfig' data. You can look at
how I did it on that platform and see how to adapt to yours.
Note that there are some special RedBoot CDL options to get
it configured to work this way, etc.
--
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Gary Thomas | Consulting for the
MLB Associates | Embedded world
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