I understand that A-B plug used to be common but they could have switched to micro without issues.

My questions:

  • Why does Arduino use USB A-B plug, instead of A to micro USB plug?
  • What are the challenged Arduino would be facing if they switched to micro USB?

Note: By "Arduino" I'm referring to Arduino models that do not come with a micro USB port such as the most common Uno & Mega.

  • 2
    Are you talking about any particular Arduino? Dec 25, 2014 at 11:53
  • 1
    Arduino leonardo has a micro USB. What is your question?
    – jfpoilpret
    Dec 25, 2014 at 12:30
  • 1
    Just a legacy thing. Micro usb didn't even exist until april 2007.
    – Gerben
    Dec 25, 2014 at 15:46
  • UNO was first released in 2010 I think.
    – jfpoilpret
    Dec 25, 2014 at 19:10
  • Obviously I'm referring to Arduino models that do NOT come with a micro USB here. But I will edit nonetheless. Thanks.
    – Phil
    Dec 26, 2014 at 11:25

1 Answer 1


Please note that this answer is based on speculation and some common sense rather than on insider information:

If you take look at the hardware index, you'll notice that significant parts of the layout (drill holes, pin spacing, and position and type of the USB jack) haven't changed between the Arduino Extreme and the current Arduino UNO R3), while other improvements have been made. For changes between the UNO R2 and R3, please see Arduino UNO FAQ at adafruit (link provided by jfpoilpret).

It is thus reasonable to me that keeping the USB jack was a deliberate design decision: Improve if possible, but keep the layout changes to a minimum and allow for maximum backwards compaptibility.

But again, this is just the guess of a user!

  • I am not sure, even including your comment, that it would consitute a serious answer to the question, it looks more like a lead to follow and check.
    – jfpoilpret
    Dec 25, 2014 at 17:09
  • 1
    Then you should improve your answer by changing the question into something like "It is probably for backward compatibility between UNO revisions". You could even refer to learn.adafruit.com/arduino-tips-tricks-and-techniques/… which mentions backward comaptibility albeit it does not explicitly mention USB socket compatibility. Merry Christmas to you too!
    – jfpoilpret
    Dec 25, 2014 at 17:28
  • 1
    That makes absolute sense @KlausWarzecha, thanks! And thank you as well jfpoilpret !
    – Phil
    Dec 26, 2014 at 11:50
  • 1
    Durability is also a factor. The big standard USB-B is a lot more durable than Micro-USB. Though in practice it probably doesn't make such a huge difference, you don't connect/disconnect your Arduino THAT often. But I guess its one of the components that could die first, if you don't built a bad circuit with your UNO, the connector could indeed die first after years and years of usage.
    – timonsku
    Dec 26, 2014 at 15:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.