RTC DS3231
#include <DS3231.h>




Note: the DS3231 also contains a Non-Volatile Ram, ATMEL732 24C32 flash memory.
The RTC's I2C address is 0X68, the NvRam's address is 0X57.
Vcc: 3.3 - 5Volts.
DS3231

DS3231 uses an I2C interface