DMIC Interface Support on Jetson Orin Nano 8GB SOM: Clarification and Documentation Update

Issue Overview

The Jetson Orin Nano 8GB SOM has conflicting documentation regarding the number of DMIC (Digital Microphone) interfaces it supports. This inconsistency has led to confusion among users and developers. The issue spans across multiple official documents:

1. The datasheet (Section 1.9.3) states that the SOM supports 3x DMIC interfaces.
2. The Interface Comparison and Migration document (Table 11) lists only 2 pins (197 and 195) as DMIC capable.
3. The pinmux spreadsheet shows pin 124 as the only exposed DMIC pin.

This discrepancy in documentation has created uncertainty about the actual DMIC capabilities of the Jetson Orin Nano 8GB SOM, potentially affecting project planning and implementation for audio-related applications.

Possible Causes

1. Documentation Error: The conflicting information could be due to errors or outdated content in the various documents. This might have occurred during the product development or documentation process.

2. Hardware Revision Changes: It’s possible that different hardware revisions of the Jetson Orin Nano 8GB SOM had varying DMIC capabilities, leading to inconsistencies in documentation.

3. Misinterpretation of Pin Functionality: The pins listed in different documents might have multiple functions, with DMIC being a secondary or deprecated function, causing confusion in the documentation.

4. Software Support Limitations: While the hardware might support multiple DMIC interfaces, software or driver limitations could restrict the actual usable interfaces.

5. Incomplete Product Finalization: The documentation might reflect different stages of product development, with some documents not being updated to reflect the final product specifications.

Troubleshooting Steps, Solutions & Fixes

1. Official Clarification:
   The most crucial information comes from an official reply stating that DMIC is not supported on the Jetson Orin Nano 8GB SOM. This clarification supersedes all previous documentation.

2. Documentation Update:

   • The official documentation, including the datasheet, Interface Comparison and Migration document, and pinmux spreadsheet, will be updated to reflect the correct information.
   • Users should periodically check for updated documentation on the NVIDIA Developer website or through official channels.

3. Alternative Audio Input Solutions:
   Since DMIC is not supported, consider the following alternatives for audio input:

   • Use USB audio devices for digital audio input.
   • Utilize the onboard audio codec (if available) for analog audio input.
   • Explore I2S (Inter-IC Sound) interfaces if digital audio is required for your project.

4. Project Adaptation:

   • If your project was relying on DMIC functionality, you’ll need to redesign your audio input strategy.
   • Consider using USB-based microphones or audio capture devices as a straightforward alternative.
   • For projects requiring low-latency or high-quality audio input, investigate I2S-based solutions compatible with the Jetson Orin Nano.

5. Community Resources:

   • Stay engaged with the NVIDIA Developer forums for the latest updates and community-driven solutions.
   • Share your workarounds or alternative implementations to help other developers facing similar challenges.

6. Feedback to NVIDIA:

   • If DMIC support is crucial for your application, consider providing feedback to NVIDIA about the importance of this feature for future product iterations.
   • Use official channels or developer forums to submit feature requests or discuss the impact of this limitation on your projects.

7. Documentation Best Practices:

   • When working with Jetson products, always cross-reference multiple official documents and seek the most recent information.
   • If inconsistencies are found, reach out to NVIDIA support or community forums for clarification before making design decisions based on potentially outdated information.

By following these steps and being aware of the current limitations, developers can adapt their projects accordingly and find suitable alternatives for audio input on the Jetson Orin Nano 8GB SOM.