CSI Diff Pair Polarity Swap on Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users have reported confusion regarding the polarity of the D1 diff pair on CSI0 and the D0 diff pair on CSI1 when interfacing with cameras on the Nvidia Jetson Orin Nano Dev board. The issue arises from discrepancies between the new design guide (version 1.0) and the previous version (0.99), specifically indicating that these diff pairs have swapped polarity.

Symptoms include:

• Inability to interface cameras correctly.
• Uncertainty about whether hardware modifications are necessary or if adjustments can be made via software.

The problem typically occurs during the initial setup phase or while attempting to connect compatible cameras. Users are concerned about whether they need to modify their carrier boards or if they can rely on software configurations. The impact of this issue is significant, as it directly affects camera functionality, which is crucial for many applications utilizing the Orin Nano.

Possible Causes

• Hardware Incompatibilities: If the carrier board is not designed to accommodate the polarity swap, it may lead to improper camera operation.

• Software Bugs or Conflicts: Incompatibilities between the device tree settings and the actual hardware configuration can result in errors.

• Configuration Errors: Incorrect settings in the device tree may prevent proper communication with the camera.

• Driver Issues: Outdated or incompatible drivers may not handle polarity swaps correctly.

• User Errors: Misconfigurations by users when setting up their devices can lead to these problems.

Each of these causes could result in an inability to properly interface with cameras, leading to frustration and wasted time during development.

Troubleshooting Steps, Solutions & Fixes

1. Verify Hardware Configuration:

   • Check if your carrier board supports the polarity swap as indicated in the new design guide.
   • Ensure that all connections are secure and correctly oriented.

2. Adjust Device Tree Settings:

   • Modify the device tree configuration to reflect any necessary polarity swaps.
   • Locate the relevant device tree source file, such as:

     $public_sources/kernel_src/hardware/nvidia/platform/t23x/p3768/kernel-dts/cvb/tegra234-camera-rbpcv2-imx219.dtsi
     

   • Set the lane_polarity parameter according to your configuration:
     • For a polarity swap on CSIx_D0 only:

       lane_polarity = "1";  // 0001
       

     • For swaps on CSIx_D1 and CSI(X+1)_D0:

       lane_polarity = "6";  // 0110
       

3. Update Drivers:

   • Ensure that you are using the latest drivers for your Nvidia Jetson Orin Nano.
   • Check Nvidia’s official documentation for any updates related to camera interfaces.

4. Test with Different Configurations:

   • If possible, test with different cameras or configurations to isolate whether the issue lies with a specific component.
   • Use known working setups as a reference point.

5. Consult Documentation:

   • Refer to Nvidia’s official documentation for guidance on camera interfacing and device tree modifications.
   • Look for community forums or support channels for additional insights or solutions shared by other users.

6. Best Practices:

   • Always back up your device tree configurations before making changes.
   • Document any modifications made for future reference or troubleshooting.

7. Unresolved Aspects:

   • Further investigation may be needed regarding how different camera models respond to these polarity changes and whether additional software updates will be required in future releases.

By following these steps, users can effectively address issues related to CSI diff pair polarity swaps on their Nvidia Jetson Orin Nano Dev boards, ensuring successful camera integration and functionality.