Keyestudio Mega 2560 R3 is a microcontroller board based on the ATMEGA2560-16AU , fully compatible with ARDUINO MEGA 2560 R3. It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, 1 ICSP header, and a reset button. The built-in ICSP port can burn the firmware for ATMEGA2560-16AU directly. This chip is burnt the firmware well before leaving the factory, therefore, we hardly use it. We can power on by USB wire, DC head and Vin GND pins. To facilitate wiring, a 0.5 m USB wire is provided for you.