Datasheet

All these features make this board the preferred choice for the emerging IoT battery-powered projects in a
compact form factor.
The USB port can be used to supply power (5V) to the board.The Arduino MKR1000 is able to run with or
without the Li-Po battery connected and has limited power consumption.
The MKR1000 Wifi module supports certificate SHA-256.
Warning: Unlike most Arduino & Genuino boards, the MKR1000 runs at 3.3V. The maximum voltage
that the I/O pins can tolerate is 3.3V. Applying voltages higher than 3.3V to any I/O pin could
damage the board. While output to 5V digital devices is possible, bidirectional communication with
5V devices needs proper level shifting.