Jetson Orin Nano HDMI DDC Pin Configuration Confusion

Issue Overview

The discussion centers around a confusion regarding the pin configuration for the Jetson Orin Nano, specifically pin 100, which is reported to serve dual purposes in different documentation. Users have encountered discrepancies between two official documents: the Jetson_Orin_NX_Orin_Nano_Pin_Descriptions.xlsx, which states that pin 100 is designated as HDMI_DDC_SCL (I2C Serial Clock Line), and the Jetson_Orin_NX_series_and_Orin_Nano_series_Pinmux_Config_Template.xlsm, which lists it as HDMI_DDC_SDA (I2C Serial Data Line). This inconsistency leads to confusion among users trying to utilize this pin for HDMI communication.

The issue arises during setup when users attempt to connect devices that rely on accurate pin assignments. The conflicting information can lead to incorrect wiring, resulting in failure to establish proper communication with HDMI devices. This problem has been noted by multiple users, indicating a consistent confusion that impacts their development experience.

Possible Causes

• Documentation Errors: The discrepancies in the official documents may stem from oversight or miscommunication within Nvidia’s technical writing teams.
• User Misinterpretation: Users may misinterpret the documentation due to unclear descriptions or lack of context regarding pin functionalities.
• Hardware Variability: Different versions of hardware or carrier boards may have variations in pin configurations that are not adequately documented.

Troubleshooting Steps, Solutions & Fixes

1. Verify Documentation:

   • Cross-reference both documents mentioned to confirm the pin designation.
   • Check for any errata or updates from Nvidia regarding the pin assignments.

2. Testing Pin Functionality:

   • Use a multimeter to test pin 100 for continuity and functionality as both SCL and SDA.
   • If possible, connect a known good HDMI device and observe if it responds correctly when using either designation.

3. Community Feedback:

   • Engage with the Nvidia forums or other developer communities to gather insights from other users who may have faced similar issues.
   • Document any successful configurations reported by other users for future reference.

4. Contact Nvidia Support:

   • If the issue persists, reach out to Nvidia’s technical support for clarification on the pin assignments.
   • Provide detailed descriptions of your findings and any tests conducted.

5. Firmware/Software Updates:

   • Ensure that your Jetson Orin Nano is running the latest firmware and software updates, as these may resolve underlying issues related to hardware recognition and functionality.

6. Best Practices for Future Development:

   • When designing circuits involving the Jetson Orin Nano, consider implementing a testing phase where pin functionalities are verified before finalizing connections.
   • Maintain a log of any discrepancies found during development for personal reference and community sharing.

7. Documentation Links:

   • Regularly check Nvidia’s developer site for updates on documentation related to the Jetson Orin Nano and its peripherals.

8. Unresolved Aspects:

   • The definitive resolution regarding whether pin 100 serves as SCL or SDA remains unclear, necessitating further investigation and clarification from Nvidia.

By following these steps, users can better navigate the confusion surrounding pin 100 on the Jetson Orin Nano and ensure successful integration with HDMI devices.