DS3231 is a lowcost, precision I2C realtime clock with an integrated temperature compensated crystal oscillator (TCXO) and crystal. It includes a battery input to maintain timing when mains power is removed. Integrated crystals reduce component count and improve reliability in production lines. The monitor pin can be used as a manual input to generate an MP, in addition to the device's timing accuracy. The DS3231 also provides additional features that expand the system host's capabilities and options. It integrates a digital temperature sensor accessible via the I2C interface (in addition to time data). The temperature sensor accuracy is ±3 C. The DS3231 is available in commercial and industrial temperature ranges and comes in a 16pin 300 mil SO package. It stores seconds, minutes, hours, day of the week, date, month and year information. Months with less than 31 days are automatically adjusted, including corrections for leap years. The clock can operate in either 24hour or 12hour format with AM/PM indication. It provides two programmable calendar alarms and a programmable square wave output. Address and data are transmitted serially over the I2C bidirectional bus. A temperaturecompensated voltage reference and comparator monitor Vcc status, detect power supply failures, provide a reset output, and automatically switch to backup power when .