17.2.1.1 Prescaler

The prescaler divides the input frequency to create a time-based strobe (typically 1 Hz) for the calendar counter. The Alarm and Compare Registers, in conjunction with the calendar counter, facilitate 
time-matched events.

To properly operate in Calendar mode, (Clock mode: 1), the 26-bit prescaler must be programmed to generate a 1 Hz strobe to the RTC. In Binary mode, (Clock mode: 0), the prescaler can be programmed as required in the application.