This library deals with the operation of the library for the sensor SHT21. The library provides basic functions for communications between MCU and SHT21. The main routine are placed in the file SHT21.c. In the file SHT21.h are located definitions of functions and commands. The main function (main.c) is the example of using this library. The Main function uses libraries form the project NUCLEO-F411-I2C-HD44780. In the main function is exmaple of using SHT21. Basic loop performs measurements of temperature and humidity. Temperature and humidity obtained from the sensor are displayed on the display HD44780.

• The first function is sht21_soft_reset(). This function performs a software reset SHT21 and set to default.
• Other functions are sht21_read_user_reg() and sht21_write_user_reg() to perform read and write user registry, which sets the measurement accuracy of temperature and humidity. For more information about the user registry download this document.
• The last two functions begin acquiring data from sensors SHT21. The collected data is then performed to calculate the temperature and relative humidity. This functions are called sht21_get_humidity() and sht21_get_temperature().