Arduino Mega 2560 Rev3

The Arduino Mega 2560 is a board with a microcontroller that is built around the ATmega2560 chip. The board includes 54 digital I/O pins (with 15 usable as PWM outputs), 16 analog inputs, 4 UARTs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. All required components to operate the microcontroller are included; just connect it to a computer using a USB cable or power it up using an AC-to-DC adapter or battery to begin.

Datasheet: https://docs.arduino.cc/resources/datasheets/A000067-datasheet.pdf