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CCS/MSP430FR2311: 230V A.C. mains detection with microcontroller gets on RESET on switching

R & D
Intellectual 560 points
Part Number: MSP430FR2311
Other Parts Discussed in Thread: CC3200

Tool/software: Code Composer Studio

Dear all,

I am detecting 240 V AC mains using optocoupler. Here is my circuit.

enter image description here

When I am doing this my microcontroller resets every time I on/off the 230V AC circuit. I've seen response of the on & off switch in oscilloscope. It is looking like below image

enter image description hereBecause of this transient my controller gets reset as the same transient is being seen in the reset pin and power pin of the controller.

Can anyone help with how to reduce this transient. I've tried low pass filter at output side by adding 330Ohm resistor with 10uF capacitor. Did not worked.

Any help would be appreciated

Thanks

Abhishek

  • 0
    TI__Mastermind 27505 points
    Hi,
    It seems like it is causing by the 10uF capacitor. I suggest that you can remove that cap or replace it by a resistance.

    Best regards,
    Cash Hao
  • 0 in reply to Cash Hao11
    Intellectual 560 points
    Hello Cash Hao,

    Thanks for the prompt response. I'll check that and let you know in a while

    Thanks
    Abhishek
  • 0 in reply to R & D
    Intellectual 560 points
    Dear ,

    How can I have resistor over there? Either I can have capacitor or I'll need to open circuit it. As When 230 V AC mains is on optoisolator will be ON and I'll get GND at MSP430 and at Off Condition I'll get 3.3V at uC pin. 10k Resistor is pullup resistor which keeps uC to known state. If I have resistor over there it will create resistor divider and I won't get any output.

    I hope it may be clear enough.

    Thanks
    Abhishek
  • 0 in reply to R & D
    TI__Mastermind 27505 points
    Understand. But you can still just remove the cap. Right?

    Best regards,
    Cash Hao
  • 0 in reply to Cash Hao11
    Intellectual 560 points

    Dear


    We have tried removing it but still results are same. Actually I can't remove it as I want to detect A.C. mains On/Off and if I remove it instead of getting continuous signal what I am receiving is half sinewave from 0 to 3.3V. But still same transient are present.

    I've tried running this circuit on CC3200 eval board and Arduino (Atmega 328P). Texas Instruments ICs gets RESET when these type of transient occurs but Atmega don't.

    Thanks
    Best Regards
    Abhishek

  • 0 in reply to R & D
    TI__Mastermind 27505 points
    Hi Abhishek,
    It is related to the IC design. The IO pins have a relationship with the VCC in MSP430. I am not sure it is the same in CC3200. So that means, MSP430 will reset cause by the VCC fluctuation, and the VCC fluctuation was caused by the input IO signal. Hope this will help you solve your concerns.

    Best regards,
    Cash Hao

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