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Following chapters are introducing most basic microcontroller function: digital input/output. Input/output pins are microcontroller contacts. They are so called “legs”. Through them digital signal is received and transmitted. 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 these pins have also alternate functions. Before addressing to the alternate functions, witch are covered in separate chapters, it would be useful to get to know the pins by studying their basic functions.