DP Multiplexed Pins with I2C6 for Jetson Orin Nano

Issue Overview

Users are experiencing challenges with utilizing additional I2C channels on the Nvidia Jetson Orin Nano Dev board. Specifically, they are inquiring about the feasibility of using DisplayPort (DP) multiplexed pins for I2C communication, in addition to the four dedicated I2C channels that the board provides.

Symptoms and Context

• Users are unsure if the DP pins can be repurposed for I2C communication.
• The issue arises during the design phase when users require a total of five I2C channels for their applications.
• There is a lack of clarity on how to configure these pins if they are to be used for I2C.
• The problem is consistent among multiple users who need additional I2C channels beyond what is natively supported.

Hardware and Software Specifications

• Hardware: Nvidia Jetson Orin Nano Dev board
• Software: Not explicitly mentioned, but likely involves standard Linux-based operating systems used with Jetson boards.

Impact on User Experience

The inability to utilize additional I2C channels can significantly hinder project development, particularly for users requiring multiple sensor integrations or device communications. This limitation affects overall system functionality and can lead to delays in project timelines.

Possible Causes

• Hardware Incompatibilities: The DP pins may not support I2C communication due to hardware design limitations.

• Configuration Errors: Users may not have the correct configuration settings or pin mappings to enable I2C on the DP pins.

• Driver Issues: There may be a lack of driver support for utilizing DP pins as I2C ports.

• User Errors: Misunderstandings regarding the capabilities of the Jetson Orin Nano could lead to incorrect assumptions about pin usage.

Troubleshooting Steps, Solutions & Fixes

1. Verify Pin Configuration:

   • Refer to the official Jetson Orin Nano Design Guide to confirm pin functionalities.
   • Check if the DP pins can be configured as general-purpose I2C ports.

2. Use an I2C Switch:

   • If five I2C channels are required, consider using an I2C switch to expand available channels.
   • An example of an I2C switch is the TCA9548A, which allows multiple devices to communicate over a single bus.

3. Testing Configuration Changes:

   • If attempting to use DP pins as I2C, ensure that any necessary changes in configuration files (e.g., device tree overlays) are made.
   • Example command to check current device tree settings:

     sudo cat /proc/device-tree/ | grep i2c
     

4. Isolation Testing:

   • Test with different configurations by connecting only one device at a time to identify any conflicts or issues.
   • Use a logic analyzer or oscilloscope to check if signals are being transmitted correctly on the intended pins.

5. Documentation and Firmware Updates:

   • Regularly check Nvidia’s developer forums and documentation for updates regarding pin usage and potential firmware upgrades that may enhance functionality.
   • Ensure that your development environment is up-to-date with the latest drivers and software packages.

6. Best Practices:

   • Always refer to the official documentation before making hardware modifications or configurations.
   • Keep backup configurations of your system settings before making changes.

Recommended Approach

Using an I2C switch has been suggested by multiple users as a viable solution for projects requiring more than four I2C channels. This method allows for flexible design without needing extensive modifications to existing hardware setups.

Unresolved Aspects

While several solutions have been proposed, there remains uncertainty regarding specific configurations required to enable DP pins for I2C communication. Further investigation into Nvidia’s documentation or community forums may be necessary for definitive guidance on this issue.