Addimg SRAM to NGW100

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I'm after adding some external parallel (i.e. no SPI or TWI) SRAM / FRAM to my NGW100.

The hardware side of things is not a problem (address / data bus, read / write / etc), as there's clear examples in the AVR32 datasheet on how to wire things up.

What I'm not sure about is the best (or rather easiest !!) way to add this sram device to linux ??

Do I have to write a whole new device driver that adds the sram to the /dev tree via sysfs ? If so, how ??

Or are there existing places I can hook the new device into so it (mgaically !!) appears without any extra effort ?

I'm guessing it's a whole new driver ... but feel free to steer me in the right direction !!

Thanks
Mark

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http://avr32linux.org/twiki/bin/...

There's no reason to add external RAM, just replace the RAM IC with a larger one. See the link above to find out how. By the way, it's not practical to add an external parallel RAM to the NGW because the EBI isn't connected to the headers.

I like cats, too. Let's exchange recipes.

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Okay ... we've actually made our own custom board with 8bit parallel FRAM connected to the EBI.

Using U-Boot, I can read / write data, but I'm trying to work out how to read / write from within Linux.

Do I have to write my own device driver, or can I "register" the FRAM device with Linux in some way to let my apps use the extra memory ?

[Update]

I have ended up writing my own (very simple) device driver !!

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If you want to get Linux to recognize it as RAM for general usage, this is actually done in the bootloader which, in turn, tells Linux about it.

If you just want to use it as storage then yes you can write a simple character driver, use UIO to present that memory region to userspace or simply mmap() the appropriate bit of /dev/mem.

-S.