RTC module (Real Time Clock) based on chip DS3231. It has a 32Kb AT24C32 EEPROM memory to store user data, I2C interface, temperature compensated crystal oscillator (TCXO), 32.768 kHz square wave output pin, 3.3 to 5.5 volt power supply . The RTC allows you to count the seconds, minutes, hours, day, date, month and year with correction for leap years up to 2100. It can operate in 12 or 24 hour modes, with indication of the hours before the hours (AM) and of those afternoon (PM). Thanks to an internal back-up system, it can keep data in memory even in the absence of current. Shown in all the applications where it is necessary to have a precise temporal reference. Button battery not included.

• Power supply: da 3,3 a 5,5 volt
• RTC: DS3231
• Precision watch (0°C to +40°C): 2 ppm
• Calendar and alarm clock: sì
• Square wave output: 32.768 Hz
• Temperature sensor precision: 3°C
• EEPROM: AT24C32 (capacità di memoria 32Kb)
• EEPROM addressing: A0 / A1 / A2 (default con ponticelli aperti: 0x57)
• Interface: I2C @400 kHz
• Dimensions (mm): 38x22x14
• Weigth: 8 grammi
• Wiring instructions with Arduino UNO:
  SCL → A5
  SDA → A4
  VCC → 5V
  GND → GND

• DS3231 RTC
• DS3231 Datasheet
• 24C32 Datasheet
• DS3231 Demo code
• AT24C32 Demo code