I2C Device Addresses on NVIDIA Jetson Orin Nano

Issue Overview

Users of the NVIDIA Jetson Orin Nano have observed three I2C addresses (0x50, 0x57, and 0x5f) on bus 0 and are seeking information about the devices or components these addresses correspond to. Understanding these addresses is crucial for developers working with the Jetson Orin Nano, as it impacts system configuration and potential use of these devices in projects.

Possible Causes

1. Standard system components: These addresses likely correspond to built-in hardware components of the Jetson Orin Nano.
2. EEPROM storage: Some addresses may be associated with EEPROM (Electrically Erasable Programmable Read-Only Memory) used for storing configuration data.
3. Display-related components: One address might be related to display interfaces like HDMI or DisplayPort.
4. Custom hardware: In case of a custom carrier board, these addresses could represent additional components added to the system.

Troubleshooting Steps, Solutions & Fixes

1. Identify the hardware setup:

   • Determine if you’re using the Jetson Orin Nano Developer Kit (p3768) or a custom board.
   • Check your JetPack version, as this may affect the I2C configuration.

2. Understand the standard I2C address assignments:

   • 0x50: This address is associated with the Jetson Orin Nano module EEPROM.
   • 0x57: This address is used for the carrier board EEPROM.
   • 0x5f: This address’s purpose is not explicitly stated in the provided information.

3. Examine EEPROM contents:
   Use the following command to view the contents of the EEPROM at address 0x50:

   i2cdump -y 0 0x50
   

   This reveals information such as the module’s part number and serial number.

4. Check for display-related information:
   If you switch to a different I2C bus, address 0x50 might be associated with HDMI or DisplayPort’s DDC wire for EDID (Extended Display Identification Data) queries.

5. Investigate unusual data:

   • Address 0x57 shows all 0xFF values, which might indicate an unprogrammed or inaccessible EEPROM.
   • Address 0x5f shows a repeating pattern with "DSA998" visible, which could be a device-specific identifier.

6. Consult Jetson documentation:
   Refer to the Jetson EEPROM Layout documentation for detailed information about EEPROM usage and structure on Jetson devices.

7. Use i2cdetect for a complete bus scan:

   i2cdetect -y 0
   

   This command will show all active I2C addresses on bus 0.

8. For custom boards:
   If you’re using a custom carrier board, consult your board’s documentation or manufacturer for information about additional I2C devices that may be present.

9. Analyze data patterns:

   • Look for readable strings or consistent patterns in the i2cdump output.
   • The "699-13767-00" string at address 0x50 likely represents a part number.

10. Use additional tools:
    Employ tools like i2cget and i2cset to read or write specific registers on these devices for further investigation.

11. Check for system-specific documentation:
    Look for any Jetson Orin Nano-specific documentation that might provide more details about these I2C addresses and their associated devices.

12. Monitor I2C traffic:
    Use a logic analyzer or oscilloscope to monitor the I2C bus and observe real-time communication with these devices.

By following these steps, you should be able to identify and understand the devices associated with the I2C addresses 0x50, 0x57, and 0x5f on your Jetson Orin Nano. Remember that the exact configuration may vary depending on your specific hardware setup and JetPack version.