The Mega 2560 is an update for Mega, which it replaces.
The board is a microcontroller board based on the ATmega2560-16AU .It has 54 digital input/output pins (of which 14 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, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Mega is compatible with most shields designed

Product Summary:

• CH340G replace the Atmega 8U2/16U2 
  

Specifications:

• Microcontroller: ATmega2560
  
• Clock Speed:16 MHz
  
• EEPROM: 4 KB
  
• SRAM: 8 KB
  
• Flash Memory: 256 KB of which 8 KB used by bootloader
  
• Operating Voltage: 5V
  
• Input Voltage (recommended): 7-12V
  
• Analog Input Pins: 16
  
• Digital I/O Pins: 54 (of which 14 provide PWM output)
  
• DC Current for 3.3V Pin: 50 mA
  
• DC Current per I/O Pin: 40 mA
  
• Size: 100*55mm