Orin Nano Won’t Detect Arduino /dev/ttyUSB* or /dev/ttyACM*

Issue Overview

Users have reported issues with the Nvidia Jetson Orin Nano Dev board not detecting Arduino devices after upgrading to Jetpack 6 (Ubuntu 22.04). The primary symptoms include the absence of /dev/ttyACM* or /dev/ttyUSB* entries when running ls /dev/tty*, indicating that the system is not recognizing the connected Arduino. This issue arises during setup and while attempting to use Arduino devices, specifically an Arduino Mega clone utilizing a CH340 serial converter.

Symptoms:

• No detection of Arduino devices via USB.
• Output of dmesg shows USB device recognition but no driver association.
• Running lsusb identifies the USB device but does not link it to a serial port.

Context:

• The issue occurs after updating to Jetpack 6, which may have altered driver configurations or removed necessary drivers.
• Users have attempted various fixes, including disabling the brltty service and adding themselves to the dialout group, which are common steps for resolving serial communication issues.

Hardware/Software Specifications:

• Board: Nvidia Jetson Orin Nano
• OS: Ubuntu 22.04 with Jetpack 6
• Arduino Model: Arduino Mega clone with CH340 serial converter

Frequency:

The issue seems consistent across multiple users who have upgraded to Jetpack 6.

Impact:

This problem significantly hampers the user experience, particularly for those relying on Arduino integration for projects, leading to frustration and halted development.

Possible Causes

1. Hardware Incompatibilities:

   • The CH340 driver may not be included or properly configured in the new Jetpack version.

2. Software Bugs or Conflicts:

   • Jetpack 6 may contain bugs affecting USB device recognition or driver loading.

3. Configuration Errors:

   • Incorrect udev rules or group settings could prevent proper device detection.

4. Driver Issues:

   • Missing or misconfigured drivers for the CH340 serial converter can lead to detection failures.

5. Environmental Factors:

   • Power supply issues or faulty USB cables may also contribute to connectivity problems.

6. User Errors:

   • Misconfigurations in user permissions or group memberships can prevent access to serial devices.

Troubleshooting Steps, Solutions & Fixes

1. Verify Group Membership:

   • Ensure your user is added to the dialout group (do not add to tty):

     sudo usermod -aG dialout <your_username>
     

   • Reboot after making changes to group memberships.

2. Check Driver Configuration:

   • Verify if the CH340 driver is available:

     zcat /proc/config.gz | grep 'CH341'
     

   • If it returns # CONFIG_USB_SERIAL_CH341 is not set, you need to build this driver.

3. Install Missing Drivers:

   • Follow these steps to build and install the CH340 driver if it’s missing:

     # Set up build environment
     mkdir -p "${HOME}/build/kernel"
     export TOP="/usr/src/sources/kernel/kernel-<version>"
     export TEGRA_KERNEL_OUT="${HOME}/build/kernel"
     
     # Configure kernel
     cd $TOP
     make O=$TEGRA_KERNEL_OUT nconfig
     # Enable CONFIG_USB_SERIAL_CH341 as a module
     
     # Build and install modules
     make O=$TEGRA_KERNEL_OUT Image
     make O=$TEGRA_KERNEL_OUT modules
     make O=$TEGRA_KERNEL_OUT INSTALL_MOD_PATH=$TEGRA_MODULES_OUT modules_install
     
     # Copy module to appropriate directory
     sudo cp $TEGRA_KERNEL_OUT/drivers/usb/serial/ch341.ko /lib/modules/$(uname -r)/kernel/drivers/usb/serial/
     sudo depmod -a
     sudo reboot
     

4. Disable brltty Service:

   • Ensure that brltty is disabled as it can interfere with USB serial devices:

     sudo systemctl stop brltty.service
     sudo systemctl disable brltty.service
     

5. Test Connection:

   • After rebooting, connect your Arduino and check for device recognition:

     ls /dev/ttyUSB*
     

6. Monitor Kernel Messages:

   • Use dmesg --follow when plugging in the Arduino to observe any relevant logs that indicate success or failure in device detection.

7. Alternative Workaround:

   • If issues persist, consider using a genuine Arduino board, which may utilize a different serial converter that is recognized without additional configuration.

8. Documentation and Updates:

   • Regularly check Nvidia’s official documentation for updates related to Jetpack and kernel customization that may address these issues in future releases.

Unresolved Aspects

• Users have indicated that they are uncertain about kernel customization processes and whether they need to reflash their Jetson Orin Nano after building a new driver.
• Further investigation may be required into whether Nvidia will include necessary drivers by default in future Jetpack releases, as this has been a point of contention among users.