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MSP430FR5887: After power off and restart, sampling disorder

Timsen
Expert 1660 points
Part Number: MSP430FR5887

Dear all：

        I used MSP430FR5887 to design the magnet-free sensor. When my program was just written, I ran sample OK.But then the power went off and the sampling went haywire.

The power supply is 3V, I use the voltage regulator to supply 3V, and this is also the case after the power failure and restart.
What's the reason, please?It doesn't seem to be a hardware problem. Is there something wrong with my software?

Thank you！

  • 0
    TI__Mastermind 49692 points

    Hello Timsen,

    Thanks for your post. One of our team members will be looking into your post and replying shortly.

    Regards,

    James

  • 0 in reply to James Evans
    TI__Expert 7015 points

    Hi, Timsen, 

    I want to double check with you about the failed case: When you power on and programming with sample code, the board worked well. But immediately, the 3v power dropped and the FR5887 restart. Then the power dropped again and MCU restart again. Right? 

    What is the code example? What is the peripheral you used in the code example and what is the external circuit driving by MCU? If no external circuit connected to MCU and the only simple code examples run such as the "msp430fr69xx_1.c", will the failed case occur? 

    From the datasheet, the MCU will reset when 3v power drop to VSVSH- (1.75v~1.85v). Do you have tested the how much drop for the power supply for the failed case? We need to find the components which consume big current so as to cause the 3v power dropped. 

    Thanks, 

    Lixin 

  • 0 in reply to Lixin Chen1
    TI__Genius 14165 points

    Hi Timsen,

    if you do a sensor design I assume you have a voltage signal connected to any GPIO pin right?

    Did you check that during power down all GPIOs were powered off as well? Otherwise you might have supplied your device via ESD diodes of the GPIO which can cause malfunctions. This is a hot topic especially if you're using an LDO which might not be able to sink power.

    There are some people who do not consider this in a right way therefore I wrote an Apps Note some time ago: Feel free to check if this might cause your problem:
    www.ti.com/lit/an/slaa689/slaa689.pdf

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