A modified arduino library for DS3231 RTC
This is a fork of the Adafruit library https://github.com/adafruit/RTClib, which I extended for DS3231 only by integrating some additional commands found in Jack Christensen's library https://github.com/JChristensen/DS3232RTC. I added commands for reading temperature and for using DS3231 alarms, that I needed for implementing wake-up of arduino on interrupt after entering the sleep state.