How to Save Data in uClinux

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Basically, if you want to use CFI-Flash, you may want to add MTD driver.

I am using JFFS2. It is easy to use, but consume a bit area for the file system itself.

You should be able to find the drive in the menuconfig selection.

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Hi nekojiru

Thank you for your replying.

I enable "Direct char device access to MTD Device"

After that, I write a small program to test it.

I try to open it

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fd = open("/dev/mtd0",O_RDWR);

if(fd<0){

printf("Cannot Open mtd0 Error Code = %d\n",fd);

}else{

printf("Open mtd0 Success\n");

ret = read( fd, buffer, 4);

if(ret > 0)

printf("PreData 0x%02x 0x%02x 0x%02x 0x%02x\n",buffer[0],buffer[1],buffer[2],buffer[3]);

else

printf("Reading Fail %d\n",ret);

buffer[0] = buffer[0] + 1;

buffer[1] = buffer[1] + 2;

buffer[2] = buffer[2] + 3;

buffer[3] = 0x30;

ret = write(fd,buffer, 4);

if(ret > 0)

printf("Write Success !!\n");

else

printf("Write Fail %d\n",ret);

ret = read( fd, buffer, 4);

if(ret > 0)

printf("Reading Data 0x%02x 0x%02x 0x%02x 0x%02x\n",buffer[0],buffer[1],buffer[2],buffer[3]);

else

printf("Reading Fail %d\n",ret);

}

close(fd);

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The Exec result is past below

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Open mtd0 Success

PreData 0xff 0x00 0x00 0x01

Write Success !!

Reading Data 0xff 0xff 0xff 0xff

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It seems I still can't read write to correct location.

I search Internet, and It seems I need to create the file systems

mkfs.jffs2 ****

However, do I need to create file system every time?

If I need to do it every time when I booting up, my file saved inside will been clear.

Then I still can't save it.

I am using Cyclone III (#define CONFIG_ALTERA_CYCLONE_III)

This is the booting up result when I added the MTD Support.

http://i53.tinypic.com/zmts2.jpg

Below is my setting for Flash

MTD Support Setting

http://i54.tinypic.com/20s6fpx.jpg

File System Setting

http://i52.tinypic.com/28vx8nk.png

Flash Tool

http://i52.tinypic.com/wlt92v.png