OpenCM9.04 is an open-source controller that runs under 32bit ARM Cortex-M3.

All hardware and software are disclosed.


All Dynamixels can be controlled when using the accessory set of 485 expansion board.

Uses USB Cable (Micro-B) to download programs onto the board.

JTAG / SWD terminal can be used to run commercial developmental programs.


Various programming tools are optional.

 - ROBOTIS integrated programming software, RoboPlus

 - Open Source development tool, Arduino IDE

 - Open Source Library, DYNAMIXEL2Arduino

※ OpenCM IDE is no longer supported. 

Package Components
1x20 PIN Header Socket2
1x20 BOXHeader Socket2
Micro USB Cable 11
Instruction Manual1
H/W Specifications
CPUSTM32F103CB (ARM Cortex-M3)
Operation Voltage5V ~ 16V
Recommended Voltage

5V for USB

7.4V for DYNAMIXEL XL Series (LB-040 3.7V x 2)

(485 Expansion Board recommended to control DYNAMIXELs requiring 12V or higher)

External I/O26
Analog In(ADC)10 (12bit)
Flash128 Kbytes
SRAM20 Kbytes
USB1 (2.0 Full Speed)
TTL port (3Pin)4 (XL-320 exclusive)
External Sensor(5 Pin)4 (ROBOTIS Sensor can be used)
Dimensions27 mm X 66.5 mm
Compatible Products


* Users must attach connectors. 

* All DYNAMIXEL products can be used when OpenCM485 Expansion Board is used.


Wireless Communication : ZIG-110A, BT-110A, BT-210, BT-410

Infrared receiver OIR-10 (Not available when using RoboPlus



External Sensor : ROBOTIS Sensors

Parts Name

The OpenCM 485 Expansion Board, which supports TTL and RS-485, can be used to control all types of DYNAMIXELs, such as AX, MX, X and P-Series.

When using the OpenCM9.04-C to control the DYNAMIXEL, a separate power supply must be supplied to the DYNAMIXEL.


RoboPlus can be used when the board is connected to the PC via USB Downloader LN-101 or BT-210.

(PC must have Bluetooth device for Bluetooth connection)


ROBOTIS OpenCM IDE can be used only via Micro 5PIN USB Cable.

The RoboPlus and ROBOTIS OpenCM IDE CANNOT be used simultaneously.

The firmware must be changed depending on the software to be used.

(Please refer to the e-Manual for change the firmware)