• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 82 subscribers
  • Views 310 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

THE GPIO input issue for TMS320F28027

Ashutosh Pailwan1
Expert 2480 points


Dear,

The GPIO 12 pin is connected to pushbotton switch with resistor in series and then conected to ground

I had configured GPIO12 as input pin with internal pull up.

Moreover, it is configured for external interrupt from high to low trnasistion.

However, when I the switch is closed  the waveform at GPIO pin is indicating negative 2.4 volt to 1.64 volt pulse of duration 200 msec each side. i.e 2.4 msec last for 200 msec and 1.64Volt drops down to 0.8volt within 200 msec

Question.

1. Why there is negative trnasition to -2.4 Volt

2. Wont it dmagae my mircontroller as each pin is configured to withstand upto -0.3 volt only.

3. Why positive voltage trnasition is 1.64 volt only.

Enclosed is the drawing

waeform and circuit drawing.pdf

  • 0
    Guru 192875 points

    Hi Ashutosh,

    Ashutosh Pailwan1 said:
    However, when I the switch is closed  the waveform at GPIO pin is indicating negative 2.4 volt to 1.64 volt pulse of duration 200 msec each side. i.e 2.4 msec last for 200 msec and 1.64Volt drops down to 0.8volt within 200 msec

    There's something wrong in your hardware configuration. It should not go down to negative voltage at all.

    Ashutosh Pailwan1 said:
    1. Why there is negative trnasition to -2.4 Volt

    Check your hardware

    Ashutosh Pailwan1 said:
    2. Wont it dmagae my mircontroller as each pin is configured to withstand upto -0.3 volt only.

    Offcourse this negative voltage will damge the GPIO!

    Ashutosh Pailwan1 said:
    3. Why positive voltage trnasition is 1.64 volt only.

    Again, check your hardware.

    Regards,

    Gautam