MEGA 2560 R3 Upgraded version CH340

The Mega 2560 is a microcontroller board based on the CH340. It has 54 digital input/output pins (15 of which can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16MHz crystal oscillator, a USB connector, a power connector, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; just connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started. The Mega is compatible with most shields designed for the Duemilanove or Diecimila.

The Mega 2560 is an update of the Mega, which it replaces.
The Mega2560 differs from all previous cards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the CH340 programmed as a USB-to-serial converter.
Revision 2 of the Mega2560 board has a resistor that pulls the 8U2 HWB line to ground, making it easier to put into DFU mode.

Revision 3 of the board has the following new features:

1.0 pinout: Added SDA and SCL pins that are near the AREF pin and two other new pins that are placed near the RESET pin, the IOREF that allows the shields to adapt to the voltage that provided by the board. In the future, shields will be compatible with both the board using the AVR, which operate at 5V, and the Due, which operate at 3.3V. The second is an unconnected pin, which is reserved for future use.

Stronger RESET circuit.

Atmega 16U2 replaces the 8U

Microcontroller - CH340

Working voltage - 5V

Input voltage (recommended) - 7-12V

Input voltage (limits) - 6-20V

Digital I/O pins - 54 (of which 15 with PWM output)

Analog input pins - 16

DC current per I/O pin - 40 mA

DC current for 3.3V pin - 50 mA

Flash Memory - 256 KB of which 8 KB used by bootloader

SRAM - 8 KB

EEPROM - 4 KB

Clock speed - 16MHz