Allows to use the RTC functionalities. For Arduino Zero, MKRZero and MKR1000 only.
With this library you can use the RTC peripheral of an Arduino Zero or MKR1000 in order to program actions related to date and time.

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This library is compatible with the samd architecture so you should be able to use it on the following Arduino boards:

Compatibility Note

Note: while the library is supposed to compile correctly on these architectures, it might require specific hardware features that may be available only on some boards.


To use this library, open the Library Manager in the Arduino IDE and install it from there.


This library allows an enables an Arduino based on SAMD architectures (es. Zero, MKRZero or MKR1000 Board) to control and use the internal RTC (Real Time Clock). A real-time clock is a clock that keeps track of the current time and that can be used in order to program actions at a certain time. Most RTCs use a crystal oscillator (like in the Arduino Zero) whose frequency is 32.768 kHz (same frequency used in quartz clocks and watches). Namely this the frequency equal to 2^15 cycles per second and so is a convenient rate to use with simple binary counter circuits. Furthermore the RTC can continue to operate in any sleep mode, so it can be used to wake up the device from sleep modes in a programmed way. Every time the board is powered, the RTC is reset and starts from a standard date. To keep the time and the RTC running it is necessary to keep the board powered. A button sized lithium battery or any battery in the 3V range, connected through a diode to the 3.3V pin, is enough to keep RTC alive if the CPU is put in sleep mode before the standard USB or VIN power is disconnected.

To use this library

#include <RTCZero.h>