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Following chapters are introducing digital input/output which are basic functions of microcontroller. Input/output pins are microcontroller contacts. They are so called “legs”. Digital signal is received and transmitted through them. If pin is configured as input, the status of switches or simple sensors connected to pin can be received. When pin is configured as output, it can be used to light LED-s or control electrical equipment.
Almost all typical microcontroller pins allow executing easier input-output functions, although often these pins have alternative functions. Before addressing the alternative functions, witch are covered in separate chapters, it would be useful to get to know the pins by studying their basic functions.