To operate the RTC, follow these steps:
- 1.Configure the RTC-internal prescaler by
writing the PRESCALER bit field in the Control A register (RTC.CTRLA).
- 2.Set the Compare value in the Compare register (RTC.CMP), and/or the Overflow value in
the Top register (RTC.PER).
- 3.Enable the desired Interrupts by writing to the respective Interrupt Enable bits (CMP,
OVF) in the Interrupt Control register (RTC.INTCTRL).
- 4.Enable the RTC by writing a '1' to the RTC Enable bit (RTCEN) in the Control A register
(RTC.CTRLA).