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Andres Cao
Andres Cao
Associate III
April 13, 2017
Question

STM32F4 Resetting itself (Nucleo 64)

  • April 13, 2017
  • 14 replies
  • 15399 views
Posted on April 14, 2017 at 00:58

Hi!

I have a Nucleo64-446RE and every 5/10 minutes the board resets itself.

I'm using the Virtual COM to send data to my PC and plot it (among many other things), and when the board resets I lose the Serial connection. I need to re-open it in order to plot again. If after this reset I want to program the microcontroller I get the ''Unable to reset target'' message for which I need to unplug and replug the USB(which is also powering the board). I'm using the System Workbench for STM32.

Here's an oscilloscope picture of the NRST pin (blue), which confirms the reset. The red trace is a 3.3V pin, which shows there are no power issues. 

0690X00000606kYQAQ.png

Can you please help me debug this reset?

As I understand, it can't be a Hard Fault because (I think) in that case the system wouldn't reset but end up in an infinite loop. I haven't implemented any of the error handlers, but I think they're implemented by default with weak attributes.

Watching the following image:

0690X00000606llQAA.png

From external sources:

  • Definitely I'm not pressing the reset button
  • The ST-LINK could be resetting. How likely is this, why would it? Given that Virtual Com connection is lost it could be the case, since if I press the reset button the Virtual Com connection is not lost.

From internal sources:

  • WWDG is not activated
  • IWDG is not activated
  • Red trace would prove it's not a power reset
  • There's no lower-power mode being used.
  • Software reset, this would be the only option. What causes a software reset?

Thank you very much in advance for all your input!

Cheers,

Andrés

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    14 replies

    Show previous replies
    AndyJT
    AndyJT
    Associate III
    November 28, 2018

    I had a similar issue developing on a 144 pin Nucleo-L496ZG.

    It would reset every 10 minutes or so. If debugging then I'd get an exception and breakpoint at the start of main. If not debugging (just powering through the onboard ST Link) then I'd keep hearing the USB virtual com port drop out on the PC.

    I seem to have cured this now by powering the Nucleo board off an external 5V supply connected to the Morpho pins. (Remember to swap jumper JP6 to the E5V setting and make sure JP1 is removed)

    Hope this helps.

      JKing.5
      JKing.5
      Visitor II
      March 30, 2019

      I have a total of four Dells. A PC and laptop both at home and at work. All exhibited the periodic reset. I stopped and disabled all Dell services on the home PC. My Nucleo has now been running for three hours without a reset. Can't wait to try it on the other Dells.

      Thank you to all who suggested the Support Assist and agent. It has been a frustrating issue.

      AMaci.16
      AMaci.16
      Associate
      August 7, 2019

      Thank you all guys, using STM32NucleoF411RE on a Dell Inspiron 3521 and almost quit on learning ST microcontrollers because of this periodical reset issue. Uninstalling Dell SupportAssist solved the problem.

      regards,

      Alberto M

        BBloc.1933
        BBloc.1933
        Visitor II
        December 3, 2019

        Thank you for all your work, I'm experiencing something very similar with the STM32L475xx Discovery IoT board. running on a dell precision 5520. It still resets my board even if I'm not debuggin, but as previously mentioned that would probably be solved by not using the st-link for the power. You have given me some areas to look into for the cause of the resets :D

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