Power out reset interrupt

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Posted by Trevor Woods

on Jan 04 2013 13:56 PM

I am using the MSP430F5529 and I was wondering if there is an interrupt that fires when the power goes off and comes back on. Most of my program works dandy, but there is one peripheral (BQ76PL536) that needs to be reset and re-addressed on power on. I can do this in software, but it is used all over the place for different reasons and doing this would be a time-consuming affair that I am hoping to avoid.

Is there an interrupt that fires anywhere that would help me?

Thanks in advance!

MSP-TS430PN80USB w/ MSP430F5529

CCS Version: 5.2.1.00018

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Posted by chethu gowda

on Jan 05 2013 08:39 AM

Verified Answer

Verified by Trevor Woods

Genius3785 points

As per my knowledge no MCU will work without power :)

So you should have a hardware mechanism to detect the power loss along with a efficient capacitor / battery backup to aid your MCU to act in case of power fail detection.

Thanks & Regards,

cbn

Posted by Trevor Woods

on Jan 05 2013 14:59 PM

Intellectual390 points

I figure the only way to detect a power loss is with something like that. I was just hoping there was an easier way.

Thanks!

MSP-TS430PN80USB w/ MSP430F5529

CCS Version: 5.2.1.00018

Posted by Jens-Michael Gross

on Jan 06 2013 11:12 AM

Guru140085 points

On 5x/6x family, you can read the SYSRSTIV register to get the reason of the last reset. The register can be read multiple times and reports the reasons based on priority (not based on teh order they appeared), but the last one reported is always a BOR (brownout-reset = most likely a power cycle, or at least a significant drop of VCC)

So if you read this register on start of your application (until it returns 0) you'll see whetehr a BOR happened since last restart (or just a PUC due to a violation or a WDT timeout).

However, a low signal on the RST line will also report a BOR, even though there might be no fail on VCC.

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