The RTC is an independent BCD timer/counter. It provides a time-of-day clock/calendar, two programmable alarms and a programmable periodic wake up timer.
Features
Time-of-day clock/calendar with subseconds, seconds, minutes, hours (12h/24h format), day (day of week), date (day of month), month, and year
Daylight saving compensation.
Two programmable alarms (interrupts).
Programmable wakeup timer (interrupt).
Digital calibration.
Runs regardless of device status i.e. also in low-power modes and reset