This is basically the arduino.cc sample turned into a library for easier reusability. It's not perfect but it does the job. void clockWrite(byte year, byte month, byte day, byte wday, byte hours, byte ...

It also uses a DS3231 real-time clock module as a backup, keeping accurate time even when a network connection is unavailable. Time is displayed via a 60-pixel ring of WS2812B addressable LEDs.

Arduino Core for SAM D21 extensions to support fine grained power management, especially for the modules ADC, EIC, RTC and TC. Also supports reading Vcc, Vcore and internal temperature. - jnsbyr/ar ...