15.9.1.2.1 Initialization Code

Create an rtc_module struct and add to the main application source file, outside of any functions:
struct rtc_module rtc_instance;
Copy-paste the following setup code to your application:
void configure_rtc_calendar(void)
{
    /* Initialize RTC in calendar mode. */
    struct rtc_calendar_config config_rtc_calendar;
    rtc_calendar_get_config_defaults(&config_rtc_calendar);

    struct rtc_calendar_time alarm;
    rtc_calendar_get_time_defaults(&alarm);
    alarm.year   = 2013;
    alarm.month  = 1;
    alarm.day    = 1;
    alarm.hour   = 0;
    alarm.minute = 0;
    alarm.second = 4;

    config_rtc_calendar.clock_24h     = true;
    config_rtc_calendar.alarm[0].time = alarm;
    config_rtc_calendar.alarm[0].mask = RTC_CALENDAR_ALARM_MASK_YEAR;

    rtc_calendar_init(&rtc_instance, RTC, &config_rtc_calendar);

    rtc_calendar_enable(&rtc_instance);
}