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  1. #1
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    TMS320F280049C: Unwanted pulse on GPIO during Power On/OFF

    Hello,

    I'm using TMS320F280049C micro-controller (Texas).

    While testing its GPIO behavior during power on/off, I found a high to low transition on GPIO pin ,on every power on/off

    I'm checking the waveform on GPIO pin of micro-controller itself.

    I have used the same code provided by texas for GPIO initialization (C2000 examples)

    //Initialization code as follows:-

    GpioCtrlRegs.GPAPUD.bit.GPIO3 = 0; //Enable pull-up on GPIO3

    GpioDataRegs.GPASET.bit.GPIO3 = 1; //Load output Latch

    GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 0; //GPIO3= GPIO3

    GpioCtrlRegs.GPADIR.bit.GPIO3 = 1; //GPIO3=output

    Attatchment:- Waveform during Power On/off.Click image for larger version. 

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  2. #2
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    Re: TMS320F280049C: Unwanted pulse on GPIO during Power On/OFF

    What you're seeing is perhaps due to the output going tri-state. Do you see this behavior on every pin? If not, what is different about what is connected to this pin? Is there a capacitance? Maybe you need a pull-down resistor on the pin.



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  3. #3
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    Re: TMS320F280049C: Unwanted pulse on GPIO during Power On/OFF

    Hi,

    What is connected to the pin?

    As a general recommendation: don't leave it floating. You can't expect any level from a floating signal, because it is not defined.
    And, because a floating signal is high impedance it can be influenced from any signal nearby.

    Maybe you just see coupling effects from another signal.

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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