Can the GPIO toggle speed of the SPE system reach 408MHz in Orin Nano?

Issue Overview

Users in the forum are experiencing challenges related to the GPIO toggle speed of the Nvidia Jetson Orin Nano Dev board, particularly concerning whether it can reach a frequency of 408MHz. The following symptoms and contexts have been reported:

• Symptoms: Users report that they are unable to achieve the desired GPIO toggle speed, with maximum speeds observed around 270kHz, significantly lower than the expected 408MHz.

• Context: The issue arises during attempts to configure GPIO settings for high-frequency toggling, specifically when using the Sensor Processing Engine (SPE) for output. Users have expressed frustration as this limitation affects their applications that require higher toggle rates.

• Hardware/Software Specifications: The discussions involve the Orin Nano Dev board, with users attempting to configure GPIO through Linux commands and various drivers.

• Frequency of Issue: This appears to be a common issue among multiple users, indicating a systemic limitation or configuration challenge.

• Impact on User Experience: The inability to achieve the desired toggle speed hampers users’ projects that rely on precise timing and control, such as PWM signal generation.

Possible Causes

Several potential causes for the issue have been identified:

• Hardware Limitations: The SPE may have inherent limitations on GPIO toggle speeds due to its architecture or design constraints.

• Software Bugs or Conflicts: There may be bugs within the drivers or software handling GPIO operations that restrict performance.

• Configuration Errors: Incorrect settings or parameters in the GPIO configuration could lead to suboptimal performance.

• Driver Issues: The driver used for GPIO may not support high-speed toggling or might need updates or modifications.

• Environmental Factors: Power supply issues or temperature variations could affect performance stability.

• User Errors or Misconfigurations: Users might not be utilizing the correct commands or configurations needed to achieve higher speeds.

Troubleshooting Steps, Solutions & Fixes

To address the GPIO toggle speed issue on the Nvidia Jetson Orin Nano Dev board, users can follow these troubleshooting steps and solutions:

1. Verify Permissions:

   • Ensure you are running commands with root privileges. Use sudo when attempting to write to /sys files.
   • Example command:

     sudo echo 1 > /sys/class/gpio/export
     

2. Check Current Settings:

   • Use cat commands to check existing GPIO settings before making changes.
   • Example command:

     cat /sys/class/gpio/gpioX/value
     

3. Update Driver Settings:

   • Investigate if there are driver updates available that might improve GPIO performance.
   • Check Nvidia’s developer forums for any patches or updates specific to Orin Nano.

4. Use PWM Instead of GPIO:

   • Consider implementing PWM directly in Linux instead of simulating it with GPIO. This can yield better results for high-frequency signals.
   • Follow these steps for PWM configuration:

     echo 1 > /sys/kernel/debug/bpmp/debug/clk/pwm7/state
     busybox devmem 0x032e0000 32 0x804d0000
     

5. Explore Alternative Methods:

   • If GPIO does not meet requirements, consider using UART or SPI interfaces for generating waveforms.
   • Configure UART baud rate appropriately; it can reach up to 12.75Mbps.
   • Example command for UART configuration:

     stty -F /dev/ttyUSB0 115200 cs8 -cstopb -parenb
     

6. Testing Different Configurations:

   • Experiment with different configurations and hardware setups (e.g., testing with other pins or boards) to isolate the issue.

7. Consult Documentation:

   • Refer to Nvidia’s Technical Reference Manual (TRM) for detailed information on hardware capabilities and limitations regarding GPIO and PWM functionalities.

8. Community Support:

   • Engage with community forums for shared experiences and solutions from other users who have faced similar issues.

9. Consider Hardware Alternatives:

   • If persistent issues remain, consider using external hardware like CPLDs or FPGAs for precise waveform generation, which can provide deterministic timing without software overhead.

10. Documentation Links:

    • Keep an eye on Nvidia’s official documentation and forums for any updates related to driver improvements or new features that could enhance performance.

By following these steps, users should be able to diagnose and potentially resolve their issues with GPIO toggle speeds on the Orin Nano Dev board. Further investigation may be required if problems persist despite these efforts.