23.3.1.2 Configure RTC

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).