The I2C communication between the nRF52832 and the MAX30102 is not working

[jjjjunnn]

Hello, everyone. I am an undergraduate student majoring in Mechanical Engineering in South Korea.

I am currently working on a research project to develop a PPG sensor using the nRF52832 and the MAX30102 via I2C communication. Let me explain my setup in detail.

I am using an nRF52 DK and a custom PCB that I designed. I connect the DK to my PCB (power and GPIO pins), and I flash Zephyr-based firmware through VS Code.

Now, I will describe the PCB configuration.

As mentioned in the title, the MCU is an nRF52832 and the connected sensor is a MAX30102. The GPIO connections between the MCU and the sensor are:

• INT: P0.19

• SDA: P0.20

• SCL: P0.20

I chose these pins in order to minimize the PCB size as much as possible, so I would appreciate your understanding.

The current issue is that I2C communication between the MCU and the sensor does not work at all. I already changed the pin configuration in the overlay file, and the pull-up resistors are properly connected, but I2C still fails.

I checked the RTT logs in VS Code. The MCU clearly attempts I2C transactions, but there is no response from the sensor—communication never happens.

Please help me. I have been stuck on this problem for two months.

If you need any additional information, please leave a comment and I will respond immediately.

Thank you.

[jjjjunnn]

There was a typo in my previous message. The correct pin assignments are:

• INT: P0.19

• SDA: P0.20

• SCL: P0.21

Please note this correction.

[Michal]

Hello,

Did you run any sample using I2C to test the communication at all?

Have you tried using a logic analyzer or an oscilloscope to see if there is any I2C signal being sent at all?

Best regards,

Michal

[jjjjunnn]

I have been continuously checking the logs via RTT, and I confirmed that there is no I2C communication occurring with the sensor at all. Could you clarify what you mean by the “sample program”?

[Michal]

jjjjunnn said:

I have been continuously checking the logs via RTT, and I confirmed that there is no I2C communication occurring with the sensor at all.

That is not measuring the I2C bus. Please show me the logs at least though.

jjjjunnn said:

Could you clarify what you mean by the “sample program”?

There are a bunch of NCS samples and applications. Which NCS version are you on by the way?

You could look at one of the Zephyr I2C samples: https://docs.nordicsemi.com/bundle/ncs-3.1.1/page/zephyr/samples/index.html#inter-integrated_circuit_i2c_bus

Try to make a minimal program based on it (or use one of those directly) to get the I2C communication working at all.

Best regards,

Michal

[jjjjunnn]

I have checked all I2C buses. The SDA and SCL lines are detected normally, but no device address connected to the sensor is showing up at all. I am currently developing the code using nRF Connect SDK v2.5.2. Thank you.