Writing to flash problems

Chris AtLee catlee at canada.com
Sat May 4 03:51:50 EDT 2002


Hello again,

After figuring out how to unlock my flash partition, I've been
experimenting with writing to it.  Erasing the partition seems to work
perfectly.

I have a file which contains 2 characters:
12

First I erase the partition with eraseall /dev/mtd3

Then I write data to the partition with
mtd_debug write /dev/mtd3 0 2 data

I retrieve the data with
mtd_debug read /dev/mtd3 0 2 data.new

The contents of data.new is 2 characters:
11

Now, if I repeat the process (without erasing) with the data 22, the new
contents of data.new is 00.

So to me it looks like I have two problems: writing to the words
themselves is not functioning, and the only way to set bits to 1 is by
erasing ('0' == '1' & '2').  In fact, this is in the documentation for
the flash: "If users attempt to program "1"s, the memory cell contents
do not change and no error occurs."

So it looks like I need to erase before writing to fix my second
problem.  I've tried putting in an erase command in do_write_oneword,
but I get timeout errors.

I'd really appreciate any pointers!

Thanks,
Chris




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