Alarm and Interrupt Support

Due to hardware limitations, RTC alarms and interrupts are not supported on this device. This limits funtionality and turns RTC into a more traditional timer. Daylight savings time (DST) is still supported. Instead of using alarms, DST conditions are checked every time the HAL reads or writes to the hardware clock. Upon entering DST, the hardware clock is incremented by an hour, and upon exiting DST it is decremented by an hour.