I2C addresses display issues on Jetson Nanon

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

I am using a Jetson Nano to operate various sensors like pH, Conductivity, Temperature, Humidity as well as Carbon Dioxide by Atlas Scientific. We have made a customised PCB carrier board so that we can operate all the sensors via I2C protocol. There’s one port expander in I2C mode as well which is installed on the carrier board PCB which operates the relay modules.

Now my problem is, whenever I do i2cdetect -y -r 0 with 2-3 sensors, all the sensors as well as port expander addresses are displayed. Whenever I add more than 4 sensors, the I2C address of the port expander doesn’t show up at all. Its only visible when max 4 sensors are connected.

We thought it was an issue with the PCB carrier board, so tried with a completely new carrier board and the issue still persist the same but the pattern is different(when any one sensor is connected the port expander addresses doesn’t show up).

What might be the issue with it?

Note: I have tried using an ESP32 to do the same process and all the sensors including the port expander were displayed.

2

Hello,

Thanks for visiting the NVIDIA Developer forums! Your topic will be best served in the Jetson category.

I will move this post over for visibility.

Cheers,
Tom

5

What’s kind of port expander? It’s i2c MUX?

6

Hey! Thanks for reaching out. I am using PCF8574ADWR for the as port expander on the carrier board

7

I would suggest consult with vendor to check the HW design.

Thanks