Tuesday, January 15, 2008

Next step linux from SD card

As everything runs smoothly out the of box using the 8Mb parallel flash for root fs and the 8Mb serial flash to mount /usr I think it will be a good idea to move one step forward and try to boot from a SD/MMC media card. I started this process yesterday.

Right now I'm busy to making a linux distribution ready to boot and run from SD card. The buildroot run was quit nice only a bit long. Finally after having the binaries ready I copied the TAR archive to the EXT2 formatted SD card (1GB) from SanDisk. I encountered already some problems with reading this card in the target board. When I changed the SD card to a 256Mb from Pretec the boot was much better but still not running. I subscript the www.avrfreaks.net forums and start an issue on these problems and can be followed clicking this link:

http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=58549&sid=d74366e69f9ec41056e5e77ecd6d1bee

The reason to make this run possible is partially due ti the fact that the original kernel is a 2.6.18
and is rather old so better to go for the latest 2.6.23 and partially to solved problems in the I2C driver. In my project with the NGW100 I just need the I2C functionallity to interface an extern I/O board. I also need the ethernet in some way but not yet sure what kind of protocol I should use. I did some test already in c using the socket/pthread and there seems to be no problem at all. the first thing that I want to do if I have a fully running linux on SD card is trying to play with the GPIO first from teh linux shell and finally in some c code using simple files attached to the device.

All for now. Till later when I have more (good) news.

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