PCF85263AT RTC by Microrusty
PCF85263A Real-Time Clock (RTC) optimized for low power consumption
Features Calendar Automatic switching to battery on main power loss. Stop-watch (elapsed time counter). Stop-watch mode for elapsed time counting. From 100th seconds to 999999 hours Three time log registers triggered from battery switch-over as well as input driven events. Featuring clock output and two independent interrupt signals. Two alarms I2C interface Quartz crystal calibration. Provides year, month, day, weekday, hours, minutes, seconds and 100th seconds based on a 32.768 kHz quartz crystal
Using the Arduino IDE copy the follow program and paste in the IDE.
Connect the PCF85263AT to the Arduino uno.