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Topic: Pin on top of power header (Read 666 times) previous topic - next topic


There is an unmarked pin on the power header on my Arduino Uno - Is this meant to be unmarked, and what does it do?


There isn't on mine.  You need to say which revision of the board - is this an official
Uno board?

A photo (whole board) would be useful...
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


As per product description for the Arduino Uno v3 (http://arduino.cc/en/Main/ArduinoBoardUno):

- 1.0 pinout: added SDA and SCL pins that are near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. In future, shields will be compatible with both the board that uses the AVR, which operates with 5V and with the Arduino Due that operates with 3.3V. The second one is a not connected pin, that is reserved for future purposes.

So yes, if you have a Uno v3, it is a unused pin

Have fun,


Thanks. Bit pointless, though. Why not ass it on the future revision?

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