[ECOS] Serial EEPROM/flash?

[ECOS] Serial EEPROM/flash?

[Paul D. DeRocco]

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.

-- 

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com 


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Re: [ECOS] Serial EEPROM/flash?

[Andrew Lunn]

On Sat, Aug 11, 2007 at 10:06:21PM -0700, 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.

Is this a DataFlash device? There is a device driver for such devices
in the V2 branch.

       Andrew

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RE: [ECOS] Serial EEPROM/flash?

[Paul D. DeRocco]

> From: Andrew Lunn [mailto:andrew@lunn.ch] 
> 
> Is this a DataFlash device? There is a device driver for such 
> devices in the V2 branch.

Ahah! I was looking in the public CVS, which I fetched recently, and it
doesn't appear to have it. But the eCosPro version, which I use at work,
does have it. Thanks.

-- 

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com 


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Re: [ECOS] Serial EEPROM/flash?

[Andrew Lunn]

On Sun, Aug 12, 2007 at 02:14:24AM -0700, Paul D. DeRocco wrote:
> > From: Andrew Lunn [mailto:andrew@lunn.ch] 
> > 
> > Is this a DataFlash device? There is a device driver for such 
> > devices in the V2 branch.
> 
> Ahah! I was looking in the public CVS, which I fetched recently, and it
> doesn't appear to have it. But the eCosPro version, which I use at work,
> does have it. Thanks.

It is in the public version, in the V2 branch.

   Andrew

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Re: [ECOS] Serial EEPROM/flash?

[Gary Thomas]

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.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

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