U2D2 UART Connector

Instead of using the micro-b USB port(it for computer connection), I want to connect the UART pins on the U2D2 to the Arduino.
Can I read and write data from the servos by sending data to the UART connector on the U2D2 using the serial pin of any Arduino ?


If this UART connector is not for this purpose, what is it for?

Can anyone help with this?

I am unclear about what you are trying to do. If you have an UNO R3, you need to use the Original DXL Shield to control the DXLs.

I use the U2D2 only when I want to control DXLs directly from PC or SBC via their USB ports, without needing any Arduino Shield. The U2D2 converts USB communications to the half-duplex UART communications that the DXLs need, via the 3-Pin (TTL) and 4-Pin (RS-485) connectors.

The UART connector on the U2D2 is controlled by the USB input port and provide full-duplex UART - usually to other ROBOTIS Controllers.


Essentially to make the U2D2 behave like an LN-101.

If you want to use the UART Port this way, you’ll also need to change an internal DIP switch


Thanks for your answer.

When U2D2 is connected to the computer via USB, it is used to communicate with a different device connected to the UART connector, in addition to the TTL servos connected to U2D2. As a result, no data can be sent or read to the Servos via the UART on the U2D2. In other words, the UART here does not control serial communication for TTL. Did I understand correctly?

You can check out the emanual page itself

It seemed to be an either/or situation to me: DXLs or other Robotis Controllers.

The UART output is one of three outputs for the U2D2 which has only 1 input which is the USB port.

Packets and comm. timing for Robotis controllers are very different from packets for DXLs anyway.

It is easier to help you if you just tell me what are your end goals and then I can offer option(s).

It is easier to help you if you just tell me what are your end goals and then I can offer option(s).

Thank you. My goal is to read and write from Dynamixel servos with Arduino. I only have U2D2 controls.

As you use the UNO-R3 (i.e. a 5V Arduino Board), you’ve got to use the Original Dynamixel Shield.

A word of caution, I have used the Dynamixel Shield and the newer UNO-R4 and they did not work for me. I have never tried the UNO-R3 so I can’t be certain - sorry! See this post

ROBOTIS has this video too