CCS811 Gas sensor doesn't communicate with nRF9160

[nrgunarat]

Hi,

I am using the nRF9160 to read data from the CCS811 gas sensor, and logs data on LTE Monitor. I am using the BME280 sensor to read temperature and pressure values and both CCS811 and BME280 sensors share the same GPIO pins and use I2C to communicate. So for I can read data from the BME280 sensor, but not the CCS811 sensor.

I am using a Windows laptop and as the software version, I am using nRF Connect v3.3.0, Programmer v1.4.2, and LTE Link Monitor v1.1.1. To generate the merged.hex file, I have been using the Segger Embedded Studio V4.52 version. I am directly using the sample CCS811 code from the NCS folder to Build and Run the solution. I really appreciate it if anyone can help.

Looking forward to a reply.

Thank you,

Nilupa

[Didrik Rokhaug]

Hi.

Do you have a logic analyzer or an oscilloscope you can use to get a waveform of the communication between the nRF9160 and the CCS811?

We are aware of a compatibility issue between Zephyr's I2C driver and the nRF9160's TWIM peripheral. This issue causes a STOP/START condition between each byte sent, which will cause a different behavior in the slave than without the STOP/START condition.

This limitation is also documented in Zephyr, see the note in the i2c_transfer documentation: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/peripherals/i2c.html#_CPPv412i2c_transferP6deviceP7i2c_msg4u8_t5u16_t

We are looking into ways to work around this limitation, but I would like to see a waveform of the communication so that we can confirm that this is the issue you are having.

Best regards,

Didrik