I2c_1 not showing the slave address

Technical Support
1

Hello Toradex.
We are using verdin development board along with imx8m plus SoM. I flash the SoM with torizon os v.5.7.0 with evaluation containers(PREEMT_RT). After that i tried to access general purpose i2c bus .i.e i2c1 but it is not showing any internal chips address like temperature sensor,eeprom etc.we connected sodium 12,14,jumpers also.We used i2c tools for testing.
Thanks & Regards.
Raj Kumar.

2

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Hello,

To address the issue of I2C 1 not showing the slave addresses on your Verdin development board with the iMX8M Plus SoM running Torizon OS v5.7.0, please follow these steps:

  1. Verify Hardware Connections: Ensure that the SODIMM pins 12 and 14 (assuming these correspond to the I2C1 SDA and SCL lines on your SoM) are correctly connected and that there are no loose connections. Also, verify that the jumpers are correctly placed to enable I2C1.

  2. Check I2C Bus Activation: Ensure that I2C1 is enabled within the device tree. For Torizon, the device tree might be pre-compiled, but you can customize it using the TorizonCore Builder Tool. Verify that the I2C1 bus is not disabled in the device tree.

  3. Use I2C Tools: Since you’ve already used I2C tools without success, ensure you’re using the correct command syntax, such as i2cdetect -y 1 to scan for devices on I2C bus 1. If no devices are showing up, it could indicate a hardware issue or misconfiguration.

  4. Check for Kernel Messages: Look at the kernel dmesg log for any messages related to I2C1. Use the command dmesg | grep i2c to filter relevant messages. This can provide clues if the bus is not being initialized correctly or if there are errors during operation.

  5. Evaluate Power Supply and Grounding: Ensure that the devices you are trying to communicate with are correctly powered and share a common ground with the SoM. Incorrect power supply levels or grounding issues can prevent successful communication.

  6. Software Configuration: Verify that the PREEMPT_RT patch or any other evaluation containers you are using do not interfere with the I2C operation. Although unlikely, real-time configurations can sometimes alter system behavior.

  7. Update and Test: Ensure your Torizon OS and all containers are up to date. Although you are using v5.7.0, it’s good practice to check for any updates or patches that might address known issues.

If after these steps the I2C bus still does not show any slave addresses, it might be necessary to delve deeper into the hardware setup or consider testing with a minimal software configuration to rule out software-related issues.

Best regards,
Toradex AI Assistant

Please, also check if these links can help you solve your problem:

Basic Linux Commands | Toradex Developer Center.

3

Hi @RajKumar ,
Please always give the details of your query.
eg.
What device tree changes you have done
What do you mean by internal chip address and where it is not showing?
Are you using external temperature senor and EEPROM ? If yes, where have you conected?

5

Hi sahil,

I haven’t flash any device tree in above scenario.I just flashed the torizon os v 5.7.0 and try to see the i2c1 bus using i2c command line tools in linux i.e i2c-tools.we followed below link from toradex website for access How to use I²C on Torizon OS | Toradex Developer Center

Sorry for the confusion, i am trying to access verdin development v1.1c board temperature sensor which is 0x4f on i2c_1 bus but it is not showing any address on the bus.

hope your clear now!
Thanks & Regards,
Raj Kumar.

6

can you guide me how to verify this one .

7

Hi @RajKumar ,
Can you share the steps you have done and the results/error you got?