PCF8563 Real-time clock/calendar (I2C)
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 address and data are transferred serially via a two-line bidirectional I2C-bus. Maximum bus speed is 400 kbits/s. The built-in word address register is incremented automatically after each written or read data byte.