I'm looking for a complete pinout of the Arduino Ethernet R3. I've found one here which is low quality, and seems not complete (where are the digital I/O pins?).

enter image description here

BTW, it was not a good idea for Arduino to name this board "Arduino Ethernet", as this is pretty useless for searching online :-(

  • 4
    ... What? The digital I/O pins are the cyan ones... Jan 18, 2015 at 15:19
  • 1
    The pinout is Arduino Uno compatible, except for pins 10-13
    – Omer
    Jan 18, 2015 at 15:30
  • Clicking on the image on Arduino's site reveals a much higher resolution version. Jan 18, 2015 at 17:08
  • @AnnonomusPenguin: Not sure what you mean. The low quality I 'complain about' is for the image in the question (board with pinout, not an image of the board itself), which is not on the Arduino site. Thanks anyway.
    – mins
    Jan 18, 2015 at 18:59

2 Answers 2


That's a better one from :


This one also presents the Arduino Ethernet R3 board and has the extra I2C pins (SCK=A5,SDA=A4) next to the AREF pin.

enter image description here


The formal Arduino.cc website mentions, somewhat obscurely, that the Arduino Ethernet is pin compatible with Arduino Uno:

The Revision 3 of the board introduces the standardized 1.0 pinout

Except for pins 10-13:

Pins 10, 11, 12 and 13 are reserved for interfacing with the Ethernet module and should not be used otherwise. This reduces the number of available pins to 9, with 4 available as PWM outputs.

The other difference is the onboard LED is connected to pin 9 rather than the Uno's pin 13:

On most other arduino boards, this LED is found on pin 13. It is on pin 9 on the Ethernet board because pin 13 is used as part of the SPI connection.

You can use any Arduino Uno pinout diagram as a reference, the one you have found seems to be pretty elaborated.

  • 1
    Except that it does: "The Revision 3 of the board introduces the standardized 1.0 pinout..." Jan 18, 2015 at 15:57

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