This is a digital RTC - Real Time Clock made specifically to be used with the Arduino, Raspberry Pi and all other general-purpose microcontrollers which support the I2C interface. The RTC can be used to store and retrieve the current time. Once saved the RTC will use its inbuilt battery to keep time even when the Arduino or the external microcontroller is powered off. The module can keep time for long periods upto 2 years(depending on the battery you use).
The PCF8563 is a CMOS real-time clock/calendar optimized for low power consumption.
A programmable clock output, interrupt output and voltage-low detector are also provided.
All addresses and data are transferred serially via a two-line bidirectional I2C-bus. The maximum bus speed is 400 kbit/s. The built-in word address register is incremented
automatically after each written or read data byte.
1 x PCF8563 RTC Breakout Board