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Original UNO R3 + Adafruit Motor Shield V2
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Original UNO R3 + Adafruit Motor Shield V2

by Trooper553 on Mon Nov 20, 2017 2:57 pm

It’s been a few years since I bought my youngest UNO and the four of them are of the same vintage. I’m building a dfrobot Devastator and propose using one of the UNO s and an Adafruit Motor Shield and I notice a a small difference. The Motor Shield has the last two connectors on the digital/PWM side headers marked as SDA and SCL. The old UNO has the headers but they’re not marked. A check on Amazon shows the more recent versions of the UNO, in particular the Genuino, have these headers marked. My question is: Are the unmarked headers on the old UNO functional or do I have to buy a more recent version to get the connectivity which is offered through the Motor Shield.

Thanks in anticipation,

553

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Re: Original UNO R3 + Adafruit Motor Shield V2

by adafruit_support_bill on Mon Nov 20, 2017 3:11 pm

The one without the extra pins is a pre-R3 model. Starting with R3, all standard footprint Arduinos have 2 extra pins on each size of the board.

But for the motor shield, it is irrelevant. The motor shield was originally designed for the older UNO boards and does not require the 2 extra pins to work with them (On and UNO, SDA and SCL share pins A4 and A5).

One potential issue when using the shield on an older board is that the extra pins on the shield are exposed. To avoid short circuits, check to make sure that they don't make contact with any components when plugged into your UNO.

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Re: Original UNO R3 + Adafruit Motor Shield V2

by Trooper553 on Mon Nov 20, 2017 3:59 pm

Thank you for the very prompt reply. I recall from a couple of old projects I did using A4 and A5 with SCL and SDA so was a bit puzzled when these appear to be duplicated in the opposite corner of UNO.

With that cleared up it looks like the project has one less hurdle in it.

Once again, thanks for the assistance

553

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Posts: 2
Joined: Mon Nov 20, 2017 2:34 pm

Please be positive and constructive with your questions and comments.