The SM8578BV is a serial interface, real-time clock IC that uses a 32.768 kHz crystal oscillator for its reference timing. It comprises second-counter to year-counter clock and calendar circuits that feature automatic leap-year adjustment, alarm and timer interrupt functions, as well as oscillator stop, timer reloading, and other detection functions. Data is transferred to and from an external controller using a 3-wire serial interface. It is available in compact 8-pin VSOP packages, making it ideal for use in all types of portable, hand-held equipment.