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Just to make sure I don't set my board on fire, is there any information out there about the maximum current per pin/pin group on an Arduino Micro?

This page states I can get 40mA per pin, but are there limits on group of pins?

As stated here, there are pin groups which should not exceed 100mA. But could not find anything about that in the ATmega32u4 datasheet, or any other Arduino Micro related websites.

Peter Bloomfield
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debgz
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1 Answers1

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It's in the notes in section 29.2:

  1. Although each I/O port can sink more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed:
    ATmega16U4/ATmega32U4:
    1.)The sum of all IOL, for ports A0-A7, G2, C4-C7 should not exceed 100 mA.
    2.)The sum of all IOL, for ports C0-C3, G0-G1, D0-D7 should not exceed 100 mA.
    3.)The sum of all IOL, for ports G3-G5, B0-B7, E0-E7 should not exceed 100 mA.
    4.)The sum of all IOL, for ports F0-F7 should not exceed 100 mA.
    If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test condition.
  2. Although each I/O port can source more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed:
    ATmega16U4/ATmega32U4:
    1)The sum of all IOH, for ports A0-A7, G2, C4-C7 should not exceed 100 mA.
    2)The sum of all IOH, for ports C0-C3, G0-G1, D0-D7 should not exceed 100 mA.
    3)The sum of all IOH, for ports G3-G5, B0-B7, E0-E7 should not exceed 100 mA.
    4)The sum of all IOH, for ports F0-F7 should not exceed 100 mA.

Note that the device will likely not fail if these are exceeded, but the rest of the numbers in the table may no longer apply.

Ignacio Vazquez-Abrams
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