Atmega328 Vcc pin

A basic Arduino clone

I received a comment from “N00B” on my Build an Arduino Clone post pointing out a mistake I made by connecting 5V power to the pin #6 instead of pin #7 of the Atmega328 micro-controller.

He was right and I changed the text of the article from pin #6 to pin #7 but, what puzzled me is that the circuit I made for this article was actually using pin #6 to power the micro-controller.

I still have this circuit all wired up in my lab. I validated that it works as well powered on pin #6 as on pin #7. How can that be? Anyone can explain that one to me?


  1. Crashds
    November 29, 2013

    I’ve seen this before you can power a chip through an input, I’m pretty sure RFIDs use this (back powering) method to alleviate the need for an external power source.

    1. pchretien
      November 29, 2013

      Eh, thank you for your comment … I guess you’re right, there is so much work involved in the development of these micro-controllers, this behavior must be “by design”. I should try to find more info about that …


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