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MSP430F149 power up failure

Other Parts Discussed in Thread: MSP430F149, MSP430F169, MSP430F249

I found that this chip on my product pcb, could fail when being powered up shortly after being powered down. And a reset signal could not bring it back to work. The only way to bring it back is to do another power cycle and wait longer before turning on the power.

Why this is happening? What is the status of the chip? And most important, what can I do to prevent this from happening?

btw, I have a reset monitor chip on pcb, but it does no good on this. A reset signal could not wake it up at all.

Thanks

  • An external reset monitor could be your solution. However, it must hold the nRST pin down before the MSP430 gets stuck until the power is good. Resetting it after it is already stuck does no good (you already knew this from the current situation).
  • Hi Xiao,

    the MSP430F149 is a relatively old and simple device. It does not have any Brownout or SVS circuitry.
    If your supply drops below the minimum allowed Vcc but not all the way down to 0V the MCU still tries to execute which can lead to a behavior as you described.

    To get rid of this behavior, you must take care that Vcc reaches 0V before you power up again. If this is something that you can't guarantee you could consider changing the MCU. The MSP430F169 is a pin compatible device from the same device family that is having a brownout. An even better choice might be the MSP430F249 which is having a SVS/SVM module as well.

    Thanks and best regards,
    Christoph

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