LPS22HH: Temperature and Pressure Monitor (I3C)


This sample periodically reads pressure from the LPS22HH MEMS pressure sensor and displays it on the console.


This sample uses the LPS22HH sensor controlled using the I3C interface. It has been tested using the LPS22HH on the evaluation board STEVALMKI192-V1 connected to the I3C header on NXP MIMXRT685-EVK.


Building and Running

This project outputs sensor data to the console. It requires an LPS22HH sensor (for example, the one on evaluation board STEVALMKI192-V1).


If CONFIG_LPS22HH_TRIGGER is enabled, the trigger is using I3C In-Band Interrupt (IBI) to signal new data being available. Since IBI is initiated by the sensor, it will take over the I3C bus. Therefore, when flashing a new image, a power cycle is needed to reset the sensor so that it will not generate IBIs anymore. Or else the I3C controller will not be able to be initialized, resulting in the sample not being able to communicate with the sensor.

Building on mimxrt685_evk_cm33 board

west build -b mimxrt685_evk_cm33 samples/sensor/lps22hh_i3c

Board Preparations


On the board NXP MIMXRT685-EVK, the I3C pins are exposed on the J18 header, where:

  • SCL is on pin 1

  • SDA is on pin 2

  • Internal pull-up is on pin 3 (which is connected to pin 2 already)

  • Ground is on pin4


A LPS22HH sensor needs to be connected to this header. For example, the evaluation board STEVAL-MKI192V1 can be used. This needs to be prepared so that the LPS22HH sensor has address 0x5D (i.e. 0xBA, left-shifed).

Sample Output

Configured for triggered collection at 1 Hz
Observation: 1
Pressure: 97.474 kPa
Temperature: 22.19 C
Observation: 2
Pressure: 97.466 kPa
Temperature: 22.21 C
Observation: 3
Pressure: 97.473 kPa
Temperature: 22.21 C
Observation: 4
Pressure: 97.455 kPa
Temperature: 22.21 C

<repeats endlessly every second>