Logic level of the CAMx_PWDN on Jetson Orin Nano Devkit

Issue Overview

The discussion revolves around the voltage levels of the CAMx_PWDN pins connected to the J20 and J21 connectors on the Nvidia Jetson Orin Nano Devkit. Users are experiencing confusion regarding whether the CAMx_PWDN_LS pins output a voltage level of 1.8V or 3.3V.

Symptoms and Context

• Symptoms: Users are uncertain about the voltage levels of the CAMx_PWDN pins, leading to potential misconfigurations in their projects.
• Context: The issue arises during hardware setup and integration, particularly when interfacing with camera modules that rely on the correct voltage levels for power down functionality.
• Specifications: The Jetson_Orin_Nano_DevKit_Carrier_Board_Specification indicates a 1.8V level, while schematic documents suggest a 3.3V output from the SN74LV1T125 buffer.
• Frequency of Issue: This confusion appears to be a common concern among users, indicating a lack of clarity in documentation.
• Impact: Misunderstanding the voltage levels could lead to hardware damage or malfunctioning of connected components, severely impacting user experience.

Possible Causes

• Documentation Discrepancies: Conflicting information in the specifications and reference design files can lead to confusion regarding voltage levels.

• Hardware Design Choices: The use of a buffer (SN74LV1T125) that operates at 3.3V may imply that connected devices should also expect this higher voltage level.

• Misinterpretation of Pins: Users may misinterpret pin functionalities, mistaking input pins for output pins and vice versa.

Troubleshooting Steps, Solutions & Fixes

Step-by-Step Troubleshooting

1. Verify Documentation:

   • Cross-reference the Jetson_Orin_Nano_DevKit_Carrier_Board_Specification with the Reference Design Files to identify discrepancies.

2. Check Pin Configuration:

   • Confirm the configuration of J20 and J21 pins using a multimeter or oscilloscope to measure actual voltage levels at CAMx_PWDN_LS.

3. Review Schematic Diagrams:

   • Examine the schematic diagrams closely to understand how CAMx_PWDN is routed and its expected behavior.

Commands and Procedures

• To gather system information related to pin configurations, use:

  # Check GPIO pin status (example command)
  cat /sys/class/gpio/gpioX/value
  

  Replace X with the appropriate GPIO number corresponding to J20/J21 pins.

Isolation Methods

• Test with different camera modules or configurations to see if they respond correctly when powered down using both voltage levels.

• Temporarily disconnect other peripherals to ensure they are not affecting voltage readings.

Potential Fixes

• If it is confirmed that CAMx_PWDN_LS outputs 3.3V:

  • Ensure all connected devices are rated for 3.3V operation to prevent damage.

• If users require 1.8V operation:

  • Consider using a level shifter or voltage regulator that can convert 3.3V signals down to 1.8V.

Documentation and Updates

• Regularly check for updates in Nvidia’s official documentation regarding the Jetson Orin Nano Devkit, especially concerning hardware specifications and pin functionalities.

Best Practices

• Always verify pin functionalities before connecting external hardware.

• Maintain updated knowledge on any changes in specifications or design documents from Nvidia.

Unresolved Aspects

While several users have confirmed that CAMx_PWDN_LS operates at 3.3V, further clarification from Nvidia regarding documentation consistency is needed to prevent future confusion among users.