Adafruit PCF8523 Real Time Clock Assembled Breakout Board

This is a great battery-backed real time clock (RTC) that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. Perfect for datalogging, clock-building, time stamping, timers and alarms, etc. Equipped withPCF8523RTC – it can run from 3.3Vor5V power & logic!Works great with anArduino using our RTC libraryor with aRaspberry Pi (or similar single board linux computer)PCB & header are includedPlugs into any breadboard, or you can use wiresTwo mounting holesWill keep time for 5 years or moreNote: This product does not come with a CR1220 coin cell battery.The PCF8523 is simple and inexpensive but not a high precision device.TECHNICAL DETAILSDimensions:Length: 25.8mm/1.02inWidth: 21.8mm/0.86inHeight: 5mm/0.2inWeight: 2.3g/0.09ozMounting holes are 2.2mm(0.086in) diameter, 25mm(0.98in) apartThis board/chip uses I2C 7-bit address 0x68