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Wake up from LPM3 with application of VCC?

Adam Garrison1
Intellectual 580 points
Other Parts Discussed in Thread: MSP430F5335

We’re working with the MSP430F5335. We want to determine whether it’s possible to wake from LPM3 or (preferably) LPM3.5 with application of VCC. Also, if there are any code snippets that can be shared on setting up the MSP for LPM3 or 3.5, that would be welcome as well.

Thank you,

Adam

  • 0
    TI__Mastermind 25045 points

    Hi Adam,

     Unfortunately I'm not following your request,

    Adam Garrison1 said:
    wake from LPM3 or (preferably) LPM3.5 with application of VCC

    Could you please give us more information??

    Do you want to wake up from lpm3 after you apply VCC to one of the GPIO's??

     

      Regards,

       David

  • 0 in reply to DavidL
    Intellectual 580 points
    That would be one strategy. I was thinking more along the lines of if VCC goes from <2.2 to >3V, the device wakes up from LMP3 or LPM3.5.

    Adam
  • 0 in reply to Adam Garrison1
    TI__Intellectual 1330 points
    Hi Adam,
    You could for example use Comparator B. Set one input to a fixed reference voltage and the other input you could divide with a voltage divider to compare it against your reference voltage. Please note, a voltage divider can consume a lot of power, so take care of our resistor values.
    If your Vcc rises above a selected voltage, the comparator crates an interrupt and will wakeup your device.

    Before somebody will shout at me, well, there are for sure some other possibilities… that’s just one idea.

    Best regards,
    Tobias
  • 0 in reply to Tobias Oschmann
    Guru 74080 points
    You could also use a simple pin interrupt. Then you should set your resistor divider slightly above the minimum threshold voltage of the input Schmitt trigger. But the way Tobias has mentioned has an advantage: The voltage you compare against is fixed and does not depend on manufacturing tolerances between different devices as much.

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