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ICM42688

Product Overview​

The ICM42688 is a 6-axis IMU (3-axis gyroscope + 3-axis accelerometer) that connects to RDK development boards via I2C. The driver registers separate gyroscope and accelerometer IIO devices, making it easy to read angular velocity and linear acceleration raw values independently.

Supported Platforms

This document applies to RDK X5 / RDK X5 Module. System image 3.4.1 or later is recommended.

Installation​

Hardware Connection​

The example below uses the RDK stereo camera connection (you do not have to use a stereo camera; this only demonstrates using the sensor on the module):

rdk_x5_icm4288_hw_connect.png

  1. Connect the ICM42688 module to the RDK X5 MIPI connector according to the product manual.
  2. Ensure the module power supply and I2C address do not conflict.

Software Configuration​

Run sudo srpi-config in a full-screen terminal:

  1. Go to 3 Interface Options → I6 IMU

rdk_x5_icm42688_srpiconfig_1.png

rdk_x5_icm42688_srpiconfig_2.png

  1. Select the ICM42688 option (refer to the menu display)

rdk_x5_icm42688_srpiconfig_3.png

  1. Select Finish, confirm, and reboot

rdk_x5_bmi088_srpiconfig_9.png

rdk_x5_bmi088_srpiconfig_10.png

Uninstallation​

  1. Go to srpi-config → 3 Interface Options → I6 IMU
  2. Select UNSET
  3. Power off the board and remove the module

Operation​

1. Check IIO Devices​

ls /sys/bus/iio/devices/

2. Read Sensor Data​

In the examples below, iio:device1 and iio:device2 numbers depend on actual registration results. Confirm via the name node first:

cat /sys/bus/iio/devices/iio:device1/name
cat /sys/bus/iio/devices/iio:device2/name

Expected example output:

root@ubuntu:~# cat /sys/bus/iio/devices/iio:device1/name
icm42688-gyro
root@ubuntu:~# cat /sys/bus/iio/devices/iio:device2/name
icm42688-accel

rdk_x5_icm42688_iio_cat_1.png

Read raw data:

cat /sys/bus/iio/devices/iio:device2/in_accel_x_raw
cat /sys/bus/iio/devices/iio:device1/in_anglvel_x_raw

rdk_x5_icm42688_iio_cat_2.png

rdk_x5_icm42688_iio_cat_3.png

If you can read the correct name and *_raw values for each axis, the ICM42688 is working properly.

Troubleshooting​

  • Device numbers differ from examples: Use ls /sys/bus/iio/devices/ and cat .../name to identify actual nodes, then replace device1/device2 in the commands.
  • Empty reads or errors: Confirm ICM42688 is enabled in srpi-config and the board has been rebooted; check I2C wiring and address.

For fusion applications such as stereo IMU cameras, see Stereo IMU Camera.

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