Microcontroler continually powers up and down.....is this a problem?

[treez]

Hello,

We are using a SAM3N00B microcontroller in our "special" emergency light application.

Whenever the battery is removed when the mains is ON, the microcontroller repeatedly powers down and powers back up again.......(once every 5 seconds)

Is this a problem? (does repeated power up and down damage the micro?)

Our new software engineer says it is a problem, but can't say why.


Its certainly not a problem from the point of view of the operation of the unit.

SAM3N00B datasheet
http://www.atmel.com/Images/doc11011.pdf

 

[tpetar]

You probably have bad power supply. When you have battery in device, battery acts as big capacitor and filter for spikes and ripples.

Without device circuit we can just assume.

If you dont have voltage regulation and filtering capacitors in circuit and 100nF near uC, you can expect unstable or dead uC.

 

[FvM]

Frequent power cycling has been reported as a fact, apparently we aren't meaned to understand why it is so. Maybe it's on purpose, maybe bad design.

But which problem does the software guy expect? Are you inviting to collective guessing? O.K. Writing to an eeprom would be the only reasonable explanation. Otherwise I assume erroneous believe.

 

[treez]

FvM,
You read my mind correctly on several counts.

..Yes the power cycling just happens and doesnt matter as long as the micro doesnt die.....the emrgency unit is useless without the battery, so what the micro does is not that important when battery is removed.

.and Yes we had to make sure the micro did not write to eeprom immediately on power up as otherwise the eeprom would ahve dies from continuous writes.

Ssounds to me like our "softy" is wide of the mark, so to speak?