NXP's PCF85063 CMOS Real-Time Clock/Calendar (RTCs) are real-time clocks and calendar optimized for low power consumption. An offset register allows fine-tuning of the clock. All addresses and data are transferred serially via the two-line bidirectional I2C-bus or a Serial Peripheral Interface (SPI-bus). Maximum data rate is 400kbit/s for the PCF85063A and PCF85063TP. Maximum data rate on the PCF85063B is 7Mbit/s. The register address is incremented automatically after each written or read data byte. Typical applications include digital still cameras, digital video cameras, printers, copy machines, mobile equipment, and battery powered devices.