Re: Atmel flash memory issue, maybe?

Thanks Sudip.

But is rewriting without erasing so bad that it will destroy the entire
flash chip?

--Vishnu

Sudip wrote:
Vishnu Swaminathan wrote:
Hello folks,

I am using Atmel flash AT49BV322DT in a custom dsp board i am building.
the dsp is a TI 320DM641. I have written test software that erases, writes
and reads from the flash.

When I send the sequence of erase commands to the flash, I am able to see
write signals on the scope. Shortly thereafter, I also see the Ready/Busy/
output from the flash go low, as expected. Same thing while writing. I cam
also read the data back from the flash. so far, so good.

yesterday, all of a sudden, after half a day's experimenting with flash
timing, the thing stopped working. the READY/BUSY signal would not respond
to any command sequence.

The only thing I can think of is that one must __ALWAYS__ do an erase
before a write. While exprimenting with flash timings, I performed quite a
few (8-10-20) writes. unfortunately, i did not scope the signals during
each write, so i do not know exactly when the thing stopped working.

So, my question is: do I always need to erase before reprogramming the
flash? Is this true of all flash memories?


Not the whole flash, but yes u have to erase those specific sectors
where you are going to rewrite. If you use any of flash writers, they
actually erase the required sectors before reprogramming.


tomorrow i am going to replace the chip.

Any help will be greatly appreciated.

Thanks!

--Vishnu

.

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