Enable I2C Clock Stretching on Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties when attempting to interface the Adafruit 9DOF sensor, which utilizes the Bosch BNO055 IMU chip, with the Nvidia Jetson Orin Nano Dev board via I2C. The primary symptoms include:

• Constant Register Reads: Users report that while they can read constant registers successfully, all other data registers return zero.
• Context of the Issue: This problem occurs specifically when the sensor is connected to the Jetson board. In contrast, the same sensor works as expected when connected to an Arduino.
• Hardware Specifications: The discussion mentions the use of the Adafruit 9DOF sensor and its connection through I2C. The specific configuration of the Jetson board is not detailed, but it is implied that it is set up for general development tasks.
• Frequency of the Issue: The issue appears to be consistent for users attempting to read data from the BNO055 chip on the Jetson.
• Impact on User Experience: This problem severely limits functionality, as users cannot retrieve meaningful data from the sensor, affecting applications reliant on accurate IMU readings.

Possible Causes

Several potential causes have been identified for this issue:

• Clock Stretching Support: The BNO055 IMU chip utilizes clock stretching as part of its I2C communication protocol. If the Jetson does not support this feature, it could lead to incomplete or erroneous data reads.

• Hardware Incompatibility: There may be hardware-specific issues with the Jetson Orin Nano that affect I2C communication, particularly with certain sensors like the BNO055.

• Software Bugs or Configuration Errors: There could be bugs in the I2C driver or misconfigurations in the software stack that prevent proper communication with I2C devices.

• Driver Issues: Outdated or incompatible drivers may hinder proper operation of I2C devices on the Jetson platform.

Troubleshooting Steps, Solutions & Fixes

To address the issue of enabling I2C clock stretching and ensuring proper communication with the BNO055 chip, follow these troubleshooting steps:

1. Verify I2C Configuration:

   • Check if I2C is enabled on your Jetson board. You can do this by running:

     sudo i2cdetect -y 1
     

   • Ensure that your device is listed and responds correctly.

2. Check for Clock Stretching Support:

   • Investigate if your current kernel and driver support clock stretching. You may need to consult Nvidia’s documentation or community forums for specific kernel versions that include this feature.

3. Update Drivers and Firmware:

   • Ensure your Jetson board is running the latest software updates:

     sudo apt update
     sudo apt upgrade
     

   • Check for any firmware updates related to I2C drivers.

4. Modify Device Tree (Advanced):

   • If you have access to modify device tree settings, ensure that clock stretching is enabled in your device tree source file (DTS). This requires advanced knowledge of Linux kernel development.

5. Test with Different Configurations:

   • If possible, try connecting a different I2C device that also uses clock stretching to determine if the issue is specific to the BNO055 or more general.

6. Consult Documentation:

   • Refer to Nvidia’s official documentation regarding I2C communication and any specific notes about using external sensors.

7. Community Engagement:

   • Engage with community forums or support channels for additional insights or similar experiences shared by other users.

8. Fallback Solutions:

   • As a temporary workaround, consider using an Arduino as an intermediary between the Jetson and the BNO055 if immediate functionality is required while troubleshooting.

By following these steps, users should be able to diagnose and potentially resolve issues related to I2C clock stretching on their Nvidia Jetson Orin Nano Dev board when interfacing with the Adafruit 9DOF sensor. Further investigation may be necessary if problems persist after these steps are taken.