Digital Arduino Pin Max Output

Discussion in 'UDOO X86' started by Manu Bedrossian, Oct 5, 2017.

  1. Manu Bedrossian

    Manu Bedrossian New Member

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    I'm a little confused on the documentation for the UDOO x86. For the arduino pinout information, it says that the digital I/O pins are 3.3 V, and 5 V compliant. What exactly does 'complaint' mean in this situation?

    My ultimate goal would be to use the digital pins to output 5 V to use for an LED.

    Any help would be much appreciated!
     
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  2. YellowGTM

    YellowGTM Member

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    I'm confused about this as well. My best guess is that, GPIO's that are designated as 3.3V have compliant trigger levels
    (logic low and logic high ) when interfacing with 5V devices.

    Here is a good link with an explanation: https://learn.sparkfun.com/tutorials/logic-levels/33-v-cmos-logic-levels

    As for driving an LED, be sure to add a series current limiting resistor that does not undercut the power capability of the
    pin you're using.
     
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  3. Manu Bedrossian

    Manu Bedrossian New Member

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    Thanks for the link! That's a great graphical explanation. Also, thanks for the heads up about the current limiting resistors for LED's. I've chosen LED packages with built in resistors for this very reason.
     
  4. Markus Laire

    Markus Laire Active Member

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    I've thought that 'compliant' means that in addition to high/low levels being appropriate for both 3.3V and 5V operation, pins can accept 5V input without damage. (But output is still always 3.3V)

    It would be nice to have exact definition of 'compliant'.
     
  5. ccs_hello

    ccs_hello UDOOer

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    Arduino 101 is native 3.3V operation.
    Output pins follow that rule. 0V for low and close to 3.3V for logical high.
    5V tolerant is for I/O pin used in input mode.
     

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