The board is powered by Atmel’s SAMD21 MCU, which features a 32-bit ARM Cortex® M0+ core. One of its most important features is Atmel’s Embedded Debugger (EDBG), which provides a full debug interface without the need for additional hardware, significantly increasing the ease-of-use for software debugging. EDBG also supports a virtual COM port that can be used for device and bootloader programming.
![Zero](https://cdn-ak-scissors.b.st-hatena.com/image/square/709a0178281e972f8ca380bda274a2adb400ed87/height=288;version=1;width=512/https%3A%2F%2Fcontent.arduino.cc%2Fassets%2Farduino_logo_1200x630-01.png)