VBUS DETECT on USB0

Issue Overview

Users are exploring the implementation of a basic USB 2.0 port on the Nvidia Jetson Orin Nano, specifically focusing on the VBUS_DETECT circuit associated with USB0. The main symptoms reported include confusion regarding the functionality and design of the VBUS_DETECT circuit as outlined in the Jetson Orin Nano product design guide.

The context of this issue arises during the setup phase for utilizing USB0 as a recovery port. Users are attempting to understand how the VBUS_DETECT circuit operates, particularly how it interacts with a MOSFET and whether it effectively serves its intended purpose as a level shifter.

Relevant specifications mentioned include the need for level shifting of VBUS to accommodate the GPIO pin levels, which are noted to be at 1.8V. The issue appears to be consistent among users who are implementing similar setups, indicating a common area of confusion.

The impact of this problem primarily affects developers’ ability to correctly implement and troubleshoot USB connectivity features on the Jetson Orin Nano, potentially leading to delays in project development.

Possible Causes

• Misunderstanding of Circuit Functionality: Users may not fully grasp how the VBUS_DETECT circuit operates, leading to incorrect assumptions about its design and function.

• Documentation Clarity: The product design guide may lack detailed explanations or diagrams that adequately illustrate the operation of the VBUS_DETECT circuit.

• Level Shifting Requirements: Users may not be aware of or may misinterpret the level shifting requirements for interfacing between 5V and 1.8V systems.

• Component Configuration: Incorrect configuration or selection of components (e.g., MOSFETs) could lead to improper functioning of the VBUS_DETECT circuit.

Troubleshooting Steps, Solutions & Fixes

1. Review Product Design Guide:

   • Carefully read through the relevant sections of the Jetson Orin Nano product design guide that discuss VBUS_DETECT and level shifting requirements.
   • Pay close attention to diagrams and specifications regarding GPIO levels.

2. Understand MOSFET Functionality:

   • Research how MOSFETs operate in level shifting applications. Ensure that you understand how connecting VBUS to the gate can facilitate level shifting from 5V to 1.8V.
   • Confirm that the selected MOSFET is suitable for this application (e.g., check its threshold voltage).

3. Circuit Analysis:

   • Analyze the provided circuit diagram to clarify how VBUS_DETECT is implemented and verify if it meets your design requirements.
   • Consider using simulation software to model the circuit behavior under different conditions.

4. Consult Community Resources:

   • Engage with forums or community groups focused on Nvidia Jetson products for insights from other developers who have implemented similar features.
   • Share specific questions or concerns regarding your implementation for targeted advice.

5. Test Circuit Functionality:

   • Set up a prototype of your VBUS_DETECT circuit and test its functionality with actual hardware.
   • Measure voltage levels at various points in the circuit to ensure proper operation during USB connection events.

6. Document Findings:

   • Keep detailed notes on your understanding and any adjustments made during troubleshooting, which can help future users facing similar issues.

7. Seek Clarification from Nvidia Support:

   • If confusion persists, consider reaching out directly to Nvidia support for clarification regarding the design guide or specific implementation questions.

By following these troubleshooting steps and solutions, users can better understand and implement the VBUS_DETECT functionality on their Nvidia Jetson Orin Nano devices, ensuring successful setup and operation of USB connectivity features.