More powerful ATMEGA16U2 expands the ISP FLASH. Besides traditional USB to serial port, it allows users to define other functions, for example, set the USB as mouse, keyboard, rocking lever, camera, etc; Compared with the 2011 version, this module adds to it SDA, SCL; IOREF port gives shield voltage reference; One extra port space is preserved in the left of IOREF for future use. Its reset circuit is also improved and more stable; Operating voltage: 5V; Input voltage (recommended): 7~12V; Input Voltage (limits): 6~20V; Digital I/O Pins: 54 (of which 14 provide PWM output; Analog input Pins: 16; DC current per I/O Pin: 40mA; DC current for 3.3V Pin: 50mA; Flash memory: 256KB of which 4KB used by bootloader; SRAM: 8KB; EEPROM: 4KB; Clock speed: 16MHz; A product for Arduino that works with official Arduino boards.