Thomas
Presumably you are using a brownout detect of some sort to stop the
processor as the volts die. We were having a similar problem (with a
different Atmel chip) but fixed it by enabling the brownout detector &
setting it to 4V. As the volts dropped the program wandered wherever it
liked and often ended up corrupting the EEPROM.
If the problem really is the supply dying during a write, then the only fix
is to make sure you have enough on-board capacity (caps or battery) to hold
the supply up until the EEPROM write is complete.
Since the micro won't be drawing all of the 10mA (I guess) -  can you
separate the micro supply from the rest of the circuit using a diode and
use a cap to hold the micro supply up until the write is compete? - You may
need to supply the circuit at 5.6 V and then have 2 diodes splitting the
supplies to 5V for the micro & the "rest".


Richard P




Hello everyone,

I am using a data flash (ATMEL 45DB041B) to store voice information.  I
often get data corruption (I think the table of contents screws up) when I
power up and down the test board (I get data corruption about once every
100
tries)

Let say the MCU sends out a "program a page" command, and the data flash
starts to program a page (it takes about 10ms to program one page) and
during the time where the data flash is being programmed , the unit is
powered down.  Data corruption occurs!!!

Is there any way to overcome this problem?  Any work-around?  I tried to
put
the big cap at the data flash supply to retain its power (for 10ms), but
during the write operation, the data flash consumes lots of current (20
mA),
so it's too much for the cap.

Thank you in advance!
Thomas


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