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MSP430F5436A: P2 external interrupt is not working in some time.

hui zhao
Prodigy 100 points
Part Number: MSP430F5436A


Hello,

currently I set the P2.6 to external interrupt with rising edge to trigger the controller and run the interrupt program.

The rising edge cannot trigger the P2.6 even I use the oscilloscope to capture the wave on the P2.6, but sometimes it can work properly. 

so what should I do for investigate this issue?

Thanks

  • 0
    Guru 100705 points

    How do you tell that the interrupt isn't triggering? A breakpoint in the ISR? Or some action that the ISR is expected to do? Also: Is there any bounce in your signal?

    There are a number of ways to cause pin interrupts to be intermittent. It would probably be quicker if you could post the ISR and the configuration code.

  • 0 in reply to Bruce McKenney
    Prodigy 100 points

    Hello Bruce,

    Thanks for your questions. I am a hardware designer, have no source code for sharing and cannot use breakpoint to monitor the status. but I want to figure it out from the hardware point of view. the channel 2 is the external signal for triggering the ISR. there is a spike on the signal. it is 3.5V (the Vcc of MCU is 3.3V) and duration is smaller than 20mS. my question is whether this spike can impact the trigger circuit and make it work improperly.

    any further questions just let me know.

  • 0 in reply to hui zhao
    Guru 100705 points

    Absolute Max on a pin is Vcc+0.3, so 3.6V in your case. 3.5V is not out of spec. [Ref datasheet (SLAS655H) Sec 8.1]

    The minimum pulse to trigger an interrupt is 20nsec, so 20msec is actually quite long. [Ref datasheet Sec 8.8]

  • 0 in reply to hui zhao
    TI__Mastermind 26535 points

    Hi Hui,

    I think it is more likely a software issue if the interrupt can not be triggered. As Bruce suggested, it is under the spec and should not make impact on interrupt triggering.

    The simplest way is use a demo code, with only setting a gpio interrupt and in the interrupt user can toggle another gpio. Then it is easy for user to check whether it still have the issue.

    B.R.

    Sal

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