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EEPROM Corruption during Power Down

Started by shabidali May 16, 2007
Hello,

We are working with MSP430fg4616 & 2.5V Microchip I2C Serial EEPROM.
Need to store critical data at the time of Power Down.
Using a Reset Chip also.
Randomly sometimes after power down random data of EEPROM is found
corrupted.

Any pointers please.

Beginning Microcontrollers with the MSP430

You did not provide any clue of why you think your EEPROM corrupted
during power down. May be you mean that:

(a) You used MSP430 to write something to the EEPROM
(b) You turned off the power
(c) You turned on the power
(d) You useed MSP430 to read the EEPROM and something changed
(e) And you concluded that the EEPROM corrupted between (b) and (c)

I think your conclusion may be incorrect. May be the EEPROM was not
written correctly to begin with. May be it was modified
unintentionally afterwards. May be it was not read correctly. May be
it was damaged.

Assuming that the EEPROM is not damaged, it is possible but very
unlikely that it losses its contents.
Did you power it down for many years?
Did you subject it to high temperature?
Did you use it for hundreds of thousands of times?
How many EEPROMs did you try? How many of them failed?

--- In m..., "shabidali" wrote:
>
> Hello,
>
> We are working with MSP430fg4616 & 2.5V Microchip I2C Serial EEPROM.
> Need to store critical data at the time of Power Down.
> Using a Reset Chip also.
> Randomly sometimes after power down random data of EEPROM is found
> corrupted.
>
> Any pointers please.
>
Make sure to observe maximum write cycle time spec. Using acknowledge
polling is a good way to do this.

Also, do not try to read eeprom immediately after a write, without
observing the write time spec.

If power drops before write is completed, there will be trouble.

I believe ti is also true that the eeprom may draw more current during a
write (check data sheet), so this is a consideration, as well.

You could try paralleling an electrolytic across the eeprom power supply
and see if the problem goes away; this would indicate that it is a power
supply issue.

Also, lack of corruption when the power down is not occurring may be a
clue pointing to power down issues; I have found in the past in my
debugging that when I set through the eeprom write cycles (not running
at full speed), the problem goes away; this indicates timing issues.

Mark