Pullup resistor on input pin

Discussion in 'Embedded Systems and Microcontrollers' started by Dritech, Apr 17, 2015.

  1. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
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    I am using external interrupt 0 of the 8051 MCU which is connected to to switch. Do I have to use a pull-up resistor? Also, do I have to set the pin as input?
     
    Last edited: Apr 17, 2015
  2. MrChips

    Moderator

    Oct 2, 2009
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    It is best to start a new thread on a new topic.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    What processor?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Yes, the pin must be configured as input.

    A pullup resistor is required. Some microcontrollers have the pullup resistor as an optional feature. Check the datasheet of your MCU.
     
  5. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    I am using the 8051 MCU.
     
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Download and read the data sheet. It will spell out the requirements on a pin-by-pin basis.
     
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