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With three USB3.2 and two Gigabit Ethernet ports, for all Variants of CM4





I am a CM4 duino basic expansion board, an expansion board that can be used with Raspberry Pi Compute Module 4, and supports 5V DC power supply with Typc-C interface. Onboard HDMI interface, one CSI interface and one USB interface, standard arduino interface, etc...

Precautions for use

1: Do not plug and unplug any device except USB and HDMI when powered on.
2: Type C interface can be used as a power supply or as a USB interface to burn images (need to use BOOT switch to switch).
3: In order to ensure the normal power supply of CM4, please do not connect other devices when using the Type C interface to burn the image.
4: When CM4 is in normal use, it needs to provide a 5V 2A power supply for CM4. Otherwise, there may be problems such as automatic shutdown, frequency reduction, and so on.
5: USB2.0 is closed by default, if you want to open it, you need to add dtoverlay=dwc2,dr_mode=host in config.txt.

Product Size

Compute_Module 4
Compute Module 4 IO Board 5.png

What's on board


Label Name Description
1 Power supply/burning interface 5V/2A power supply, can also be used as an eMMC burning interface
2 USB 2.0 interface USB 2.0 interface, support various USB devices to be inserted
3 HDMI port HDMI port, supports 4K 30fps output
4 BOOT switch button ON: Compute Module 4 boots to USB Type-C port
OFF: Compute Module 4 boots to eMMC or Micro SD card
5 CM4 Connector Applies to all versions of Compute Module 4
6 CAM Interface MIPI CSI Camera Interface
7 User LED LED blinks and sparkles
8 ADC Chip 8-bit ADC, I2C interface, 8-channel ADC chip ADS7830
9 User Button Button Module
10 GPIO Arduino interface GPIO
11 Function Switch For details, please refer to the function pin description
12 M.2 Interface A module that supports NVME SSD solid state or other PCIE channels
13 Micro SD Card Slot For inserting a Micro SD card with the system to start the Compute Module 4 Lite


Hardware Connection

CM4 Duino Spec 01.jpg


Do not plug or unplug any device while it is powered on!

Writing Image


The USB port is disabled by default on the CM4 to save power. If you need to start, you need to add the following to the config.txt file:


After restarting:

If you use the latest Raspberry Pi OS (image after October 30, 2021) USB2.0 is OTG mode by default, CM4 will report an error:

 config failed, hub doesn't have any ports! (err -19)

However, USB can still be used. If you want to remove this error, remove otg_mode=1 in [cm4] of config.txt, and add dtoverlay=dwc2, dr_mode=host (USB cannot be recognized without adding it).
CM4 Burn EMMC 12.png


Basic introduction

The ADS7830 is a single-supply, low-power, 8-bit data acquisition device with a serial I2C interface and an 8-channel multiplexer. The analog-to-digital (A/D) converter has a track-and-hold amplifier and an internal asynchronous clock.
The ADS7830 has a resolution of 8 bits, a total of 8 inputs, and a maximum sampling rate of 70KSPS.
It can be set to differential mode and single-ended input, and the program defaults to single-ended input.
The I2C address is: 0x48

Download Program

Open the Raspberry Pi terminal and execute the following command:

sudo apt-get install p7zip-full
7z x -O./
cd CM4-duino-code


Run the demo, the program supports python2/3.

# python2
sudo python
# python3
sudo python3

As shown in the figure below, A0-A7 are 7 analog input channels:
Note: A total of 8 ADCs are collected from 0-7. If the channel is suspended, the value of the channel will float up and down, and the data will be invalid.

LED usage

A programmable LED is onboard:
Using GPIO6:

Button usage

Onboard 2 buttons USER1 USER2:
USER1 uses GPIO4, USER uses GPIO5, and USER2 can choose whether it is the reset of CM4 through the resistor, and the default connected GPIO5.

Functional pin description


Label Name Description
1 BT-DIS Disable Bluetooth, only support core board with wireless module
2 WIFI-DIS Disable WIFI, only support core board with wireless module
3 IO-VREF IO logic voltage selection
4 RUN/GL-EN Reset or shutdown CM4
5 CFG CFG pin function select 3.3V or A6
6 USER User button Function selection, D5 or RST
7 I2C ADDR ADC function module I2C address selection, default address: 0x48


Note: The following is a general description of CM4, specific devices are different: this module does not have a DSI interface, and only HDMI0, and CSI0.

Configuration file

CSI and DSI are disabled by default. When using the camera and DSI, it will occupy three I2C devices: I2C-10, I2C-11, and I2C-0.

  • Open a terminal and run the following commands:
sudo apt-get install p7zip-full -y
7z x CM4_dt_blob.7z -O./CM4_dt_blob
sudo chmod 777 -R CM4_dt_blob
cd CM4_dt_blob/
# If using two cameras and DSI1 execute
sudo dtc -I dts -O dtb -o /boot/dt-blob.bin dt-blob-disp1-double_cam.dts
# In the use of any DSI, HDMI1 no image output, even if you do not connect the DSI screen as long as the corresponding file compiled, that HDMI1 no output
# If you need to restore, delete the corresponding dt-blob.bin can be: sudo rm -rf /boot/dt-blob.bin 
#Execution is complete, power off and restart CM4

New Version (Bullseye)

Camera Config

  1. Execute the following commands to edit "/boot/config.txt" file.
    sudo nano /boot/config.txt
  2. Block or remove the automatic camera detection statement:
  3. Add the driver of the camera you are using, here I take IMX219 as an example and connect it to CAM0, and attach the adapter.
    Model CAM0 Set Sentence CAM1 Set Sentence
    OV9281 dtoverlay=ov9281,cam0 dtoverlay=ov9281,cam1
    IMX290/IMX327 dtoverlay=imx290,clock-frequency=37125000,cam0 dtoverlay=imx290,clock-frequency=37125000,cam1
    IMX378 dtoverlay=imx378,cam0 dtoverlay=imx378,cam1
    IMX219 dtoverlay=imx219,cam0 dtoverlay=imx219,cam1
    IMX477 dtoverlay=imx477,cam0 dtoverlay=imx477,cam1
    IMX708 dtoverlay=imx708,cam0 dtoverlay=imx708,cam1
    • If you are using the official Raspberry Pi camera and only one camera is connected, there is no need to set the config file. If it is not an official camera, set the "dtoverlay" statement without the "cam" suffix.
    • CM4-NANO - only CAM0 is used, so you only need to add "dtoverlay=imx219,cam0".
    4. Press Ctrl+o to save the file and then press Enter. CM4-NANO-B004.png
    5. Ctrl+x to exit the editor.
    6. Reboot the Raspberry Pi.
    sudo reboot

Camera Test

  1. Enter the camera detection command, you can see that the camera is detected by now.
    libcamera-hello --list-cameras


  2. Display the camera screen on the desktop.
  3. libcamera-hello -t
  4. Taking photos.
    libcamera-jpeg -o test.jpg
  5. Record a video of 10s.
    libcamera-vid -t 10000 -o test.h264
  6. Other Commands
    Check whether the camera is detected:
    libcamera-hello --list-cameras

    Open the corresponding cameras:

    libcamera-hello  --camera 1
    libcamera-hello  --camera 0

    Take a photo:

    libcamera-jpeg -o test.jpg
    #Add --camera to specify a camera 

Old Version (Buster)

Camera Config

    1. Execute the following command to enter the Raspberry Pi configuration.
    sudo raspi-config

    2. Choose Interfacing Options and enter.
    3. Choose Camera:
    4. Choose to enable the camera interface.
    5. The system prompts as follows:
    6. Back to the main interface, select Finish.
    7. Reboot the system.

    Camera Test

    raspistill -o image.jpg
    • Test the recording function:
    raspivid -o video.h264 -t 10000
      • Where -t 10000 means recording for 10 seconds, users can adjust according to their own needs.
      • Please refer to CSI.



Demo codes

3D Drawing




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