DS3231 library for the Arduino.

  This library implements the following features:

   - read/write of current time, both of the alarms,
   control/status registers, aging register
   - read of the temperature register, and of any address from the chip.

  Author:          Petre Rodan <[email protected]>
  Available from:  https://github.com/rodan/ds3231
  License:         GNU GPLv3

  The DS3231 is a low-cost, extremely accurate I2C real-time clock 
  (RTC) with an integrated temperature-compensated crystal oscillator 
  (TCXO) and crystal.