Orin Nano UART2 with dev kit carrier board?

Issue Overview

Users are experiencing difficulties in accessing multiple UART interfaces on the Nvidia Jetson Orin Nano Dev Kit. Specifically, they are inquiring about the possibility of assigning UART2 to spare pins on the 40-pin header of the dev kit carrier board. The main symptoms include:

• Confusion regarding the availability and routing of UARTs on the board.
• Users are attempting to utilize all three UARTs but find that only UART0 (debug serial port) and UART1 are accessible.
• The issue arises during setup and configuration, particularly when trying to expand UART functionality while using other M.2 slots for different peripherals (e.g., SSDs and Wi-Fi modules).
• The problem appears to be consistent, as multiple users have reported similar limitations.

The impact on user experience is significant, as it restricts the ability to interface with multiple devices simultaneously, which is critical for various applications.

Possible Causes

• Hardware Routing Limitations: The routing of UART interfaces is fixed, with UART2 being designated as a debug port and not available on the 40-pin header.

• M.2 Slot Configuration: The use of M.2 slots for other peripherals (like SSDs or Wi-Fi) can limit access to certain UART interfaces, particularly if they occupy slots that might otherwise be used for UART connections.

• Software Configuration: Users may not be aware of the fixed hardware configurations and might assume that reassigning UART functions is possible through software.

• User Misunderstanding: There may be a lack of clarity regarding which UARTs are available and how they can be utilized based on the hardware design.

Troubleshooting Steps, Solutions & Fixes

1. Verify Available UARTs:

   • Check the documentation for the Nvidia Jetson Orin Nano Dev Kit to confirm which UARTs are available and their designated functions.
   • Use commands like dmesg | grep tty in the terminal to list active serial ports.

2. Check Hardware Configuration:

   • Ensure that any M.2 slots being used do not conflict with UART access. If using an SSD in one slot, confirm that it does not disable access to other UARTs.

3. Testing with Different Configurations:

   • Remove any peripherals connected via M.2 slots temporarily to see if this allows access to additional UARTs.
   • Test configurations by connecting different devices to the available UARTs to confirm functionality.

4. Reconfigure Pin Assignments (if applicable):

   • While it appears that reconfiguring pins for additional UART access may not be supported due to hardware limitations, consult any relevant Nvidia documentation or community forums for potential workarounds or updates.

5. Refer to Community Discussions:

   • Engage with threads like "OrinNX: How to check UART is working?" for additional insights and troubleshooting tips from other users facing similar issues.

6. Documentation Links:

   • Review Nvidia’s official documentation regarding the Jetson Orin Nano Dev Kit for specific details about pin assignments and hardware configurations.
   • Check for firmware updates or driver updates that might improve device compatibility or functionality.

7. Best Practices:

   • Always refer to the latest hardware documentation before making assumptions about device capabilities.
   • When configuring multiple peripherals, plan layouts carefully to avoid conflicts in pin assignments or resource usage.

8. Unresolved Aspects:

   • Further investigation may be needed into potential firmware updates that could allow more flexible pin assignments in future iterations of the hardware.
   • Users should continue monitoring community forums for any new developments or solutions proposed by Nvidia or other developers.

By following these steps, users can better understand their limitations regarding UART access on the Nvidia Jetson Orin Nano Dev Kit and explore potential solutions or workarounds effectively.