Ultimate Guide to Arduino Mega 2560 Pinout, Specs & Schematic The Vcc voltage value can be negative or positive to the GND pin. I2C Pins on Arduino Mega? It is the two-wire serial communication protocol. It stands for Inter-Integrated Circuits. The I2C uses two lines to send and receive data: a serial clock pin uses (SCL) and a serial data (SDA) (SDA) pin. SCL-It stands for Serial Clock. It is defined as Schematics - Micro Bit It also provides a Connected Device Class that allows a serial port interface to be used across the USB. The interface processor also contains an on-board regulator that steps down the USB voltage to 3 suitable for powering the rest of the micro:bit, and you can draw 120mA V1 /300mA V2 from this processor regulator. A TVS device is fitted to