Each pin has an internal pull up resistor which can be turned on and off using digitalwrite w a value of high or low respectively when the pin is configured as an input. In addition to the specific functions listed below the digital pins on an arduino board can be used for general purpose input and output via the pinmode digitalread and digitalwrite commands.
Arduino Spi Tutorial Communication Between Two Arduino As
Arduino Uno R3 Directly Supply Regulated 5v To 5v Pin
Arduino Uno Pin Diagram Specifications Pin Configuration
Schematic And Input Output Pins Explain For Arduino Uno R3
Arduino Nano Pin Diagram Features Pin Uses Programming
