Radxa CM3J + WaveShare CM4-IO-BASE-B
Preparation
If you are using the WaveShare CM4-IO-BASE-B IO board for the first time, be sure to read the official user manual for the CM4-IO-BASE-B from WaveShare.
- Radxa CM3J Core Board + WaveShare CM4-IO-BASE-B
- CM3J Core Board
- WaveShare CM4-IO-BASE-B IO Board


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To start the Radxa CM3J + WaveShare CM4-IO-BASE-B IO board, the following items are also required:
- DC 5V/3A Adapter.
- An HDMI cable and a display that supports HDMI, with a recommended resolution of 1080P or higher. A 4K display will provide the best experience.
- A set of USB mouse and keyboard, with common USB input devices supporting plug-and-play.
- An Ethernet cable, as an internet connection is required for system updates.
It is recommended to use the official Radxa PD 30W Adapter as the power adapter.
Assembly
- Installing the Core Board
- Removing the Core Board
First, align the four mounting holes on the core board with the four mounting holes on the io board. Then, gently press down one side to about halfway, followed by pressing the other side to halfway as well. After confirming that all slots are aligned, press down each side to the bottom in sequence.
Note: When pressing, do not forcefully press down on the suspended area in the middle, as this may cause stress on the PCB, leading to component loosening or damage, such as DDR loosening or resistor breakage.
Use tools similar to the ones shown below to pry open from the two corners as indicated in the image. Do not use your hands or tools to force it open from the middle or just one side.
Choose Boot Method
Please refer to the Install System section to choose the method for booting your system according to your needs.
Wiring and Powering On
- Insert the SD card with the operating system flashed (using SD card boot as an example).

- Connect the HDMI0 output port of the WaveShare CM4-IO-BASE-B IO Board to an HDMI display using an HDMI cable.

- Connect the USB mouse and keyboard to any USB 2.0 port on the WaveShare CM4-IO-BASE-B IO Board.

- Connect the Ethernet cable to the Ethernet port.

- Plug the power adapter into the power interface of the WaveShare CM4-IO-BASE-B IO Board. When the device is powered on, the green power indicator on the core board will light up.

The system takes approximately 40 seconds to boot up after powering on. Once the system successfully starts, the green indicator light on the core board will change from a steady light to a blinking state.
Login to the System
After the system boots, the HDMI display shows the desktop.

Log in using the username radxa
and the password radxa
.