pressure.c : Get pressure and temperature readings from the LPS25H pressure sensor.

humidity.c : Get relative humidity and temperature readings from the HTS221 humidity sensor.

This is a more complex procedure than the pressure sensor, above. Each HTS221 sensor is individually calibrated and the results stored in designated registers. These calibration registers are then read and the straight line equations for calibration (y = mx + c) determined. The measured ambient values are then converted to give the output humidity and temperature, by reference to these calibration linear equations.

led_matrix.c : Demonstrate control of the LED matrix using the mmap method to map the led device into memory.