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MSP430F149: Power off and restart sometimes unsuccessful

Jason yu
Intellectual 430 points
Part Number: MSP430F149

i used the chip to measure the AD voltage，AD pin measures the voltage of a battery pack through a resistor divider，The working environment requires that the battery pack needs to be directly on the circuit board

In other words, the AD pin of the chip always has a voltage.When I was doing tests, I often found that the chip failed to restart after power off.Is it due to the voltage on the AD pin?Or is there any other reason?How can I solve it?

The reset pin has a voltage of about 240mv after the chip is powered off，This voltage is due to the AD pin voltage, because after removing the battery pack measured by AD, the voltage is gone.

thanks for your answer

  • 0
    Genius 3255 points
    I ran into the same problem ~7 years ago. The ESD clamping diodes at the inputs of the MSP430 basically mean that any input can become a power supply to the chip. So most likely your problem is not really that the chip is not restarting, but rather that the chip is never turning off due to the voltage from A0.

    To resolve this, I would recommend that you place a high-side switch between your battery pack and the voltage divider that is controlled by your power ON/OFF circuitry.
  • 0 in reply to Mike Tooma
    Intellectual 430 points

    Hi,Mike

    you think the chip is never turning off,but why it is not work when i power on again,by the way,it works well if i restating by out button.

    best regards

  • 0 in reply to Jason yu
    Genius 3255 points
    The voltage from the battery pack is placing all kind of voltages at your circuit. As you mentioned, it could cause the reset voltage to never go below the reset threshold. Or, it could send the MCU into an unknown state. Or it could cause the oscillator circuitry in the MCU to never start properly, etc..
    The point here is that you have a problem in your circuit that could cause multiple issues. The best way to resolve it is by removing the effects of the battery pack by placing a barrier like a high-side switch.

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