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Regarding interrupts internal pull-ups@TM4C123E6PMIR

Rama chandra
Prodigy 40 points

Hi,

We are using some GPIO as Interrupts to control keys(up,down, etc).  As per the data sheets GPIOs will have internal pull-ups enabled. Here the concern is when these GPIOs used as interrupts, internal pull-ups can be enabled or not. So that we can avoid external pull-ups.

Could you please clarify me on this concern.

Thanks,

Ramachandra

  • 0
    TI__Mastermind 18905 points

    Your question is a bit confusing.  A pull up has no bearing on an interrupt operation, as long as you are configuring the interrupt of the opposite direction of the pull up.  In fact, when using interrupts to detect voltage level, it is recommended to use pull ups/downs to put pin state in known idle state.  Otherwise, the pin state can float into an unknown level, and cause an unexpected interrupt. 

    For example:

    External pull on pin of 10k to 3.3V and/or internal pull up is enabled.... code configures GPIOIntTypeSet(uint32_t i32Port, uint8_t ui8Pins, uint32_t ui32IntType) for GPIO_LOW_LEVEL.  Pin is pulled to 0V by button press, then interrupt is set for pin as pin level is detected low.

    Lela