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Original question:

LP-MSPM0G3507: Brownout interrupt not going into NMI_Handler

LP-MSPM0G3507: BOR0 violation resulting in NMI instead of Reset

Paul K Joy
Prodigy 150 points

Part Number: LP-MSPM0G3507
Other Parts Discussed in Thread: MSPM0G3107

Tool/software:

Hi,

I am using MSPM0G3107 for my project.
I am not configuring BOR_THRESHOLD , so by default it is BOR0. I confirmed by getting the BOR level using DriverLib.

So issue is sometimes NMI handler is hit and when checking the mask it is BOR violation.
When I went through the data sheet when BOR0 violation happens, It is supposed to reset the mcu right, but my mcu is stuck at while(1) in the NMI handler.

The Vcc to MCU will not go below 2.5, because externally I am using a chip which itself cut of the supply when it goes below that.

  • 0
    TI__Expert 8275 points

    Hi Paul, for the supply voltage coming in, do you see any transients on the line? It is interesting this is only happening sometimes, but from the description of the issue, sounds like the BOR happens sometimes, but always results in the MCU jumping to the while(1) in the handler. Is that correct? If you are hitting an interrupt handler, sounds like you may still be going into BOR1/2/3 since it is not causing a reboot, but generating a SYSCTL violation signal.

    What does your BORCURTHRESHOLD value in the SYSSTATUS register?

  • 0 in reply to Brian Dempsey
    Prodigy 150 points

    As I already mentioned, I am not configuring any BOR thresholds, so by default it is BOR0. I have verified by reading also, it is BOR0.

    There is an external chip through which 3.3 v is coming into MCU, which cut offs below 2.5V. So there is no chance of transient in Supply voltage.

  • 0 in reply to Paul K Joy
    TI__Expert 8275 points

    Ok, thanks for confirming. I am running an example with the BOR set to BOR0 and reducing the voltage down below 2.5V and I am not seeing any NMI interrupt and the device reboots as expected. Can you swap devices and see if you get the same issue? If the voltage remains consistent I am not sure why you would even hit BOR0, but I am not able to see the same issue.

  • 0 in reply to Brian Dempsey
    Prodigy 150 points

    Hi ,

    BOR0- threshold is 1.55V right, if you drop voltage below 2.5 V, NMI interrupt will not hit.
    As per data sheet BOR reset happens when Vcc goes below BOR0- threshold.

    I request you to read my issue again.

  • 0 in reply to Paul K Joy
    Prodigy 150 points

    Any Update on this?

  • 0 in reply to Paul K Joy
    TI__Expert 8275 points

    Hi Paul, as I said, I am starting up the same device on my test setup and not seeing any NMI interrupts. It seems to be a code issue, but from the details you shared, I am not able to replicate the issue and therefore do not see any interrupts. Can you kindly provide feedback on my requests above if this is occurring with every device, or only one?