The DS3231 RTC chip features:   •  Accurate to within 2 minutes per year   •  Internal temperature compensated TCXO oscillator   •  32KHz square wave output   •  Additional programmable square wave output   •  24 hour or 12 hour with AM/PM   •  2 built-in alarms   •  Automatic number-of-days in the month   •  Automatic leap years   •  On-board AT24C32 EEPROM chip (32Kb, 4K Bytes) with adjustable I2C address   •  100KHz / 400KHz I2C bus communications   •  Complete with 3V 2032 battery   •  5V (Nano / Uno / Mega) Arduino compatible   •  3.3V Pi compatible version available upon request (for the same price)

Please see Maxim Integrated DS3231 datasheet for full specification.

+5V Operation Every manufacturer's DS3231 ZS-042 modules, when using them with a 5V Arduino, you should disable the "charging" components to protect against damage to the 3V battery

+3.3V Operation The charging components don't need to be disabled.

Please choose when ordering if you would like the components disabled for +5V use.