text: #ifndef COMMON_H_INCLUDED
  #define COMMON_H_INCLUDED
  
  /***********************************************************************
   * 
   * Common functions and defines.
   * ATmega328P (Arduino Uno), 16 MHz, AVR 8-bit Toolchain 3.6.2
   *
   * Copyright (c) 2019 Tomas Fryza
   * Dept. of Radio Electronics, Brno University of Technology, Czechia
   * This work is licensed under the terms of the MIT license.
   *
   **********************************************************************/
  
  /**
   *  @file  common.h
   *  @brief Common functions and defines.
   *
   *  @copyright (c) 2019 Tomas Fryza
   *  Dept. of Radio Electronics, Brno University of Technology, Czechia
   *  This work is licensed under the terms of the MIT license.
   */
  
  /* Define ------------------------------------------------------------*/
  /** @brief Define address of data direction register of port _x. */
  #define DDR(_x) (*(&_x - 1))
  
  /** @brief Define address of input register of port _x. */
  #define PIN(_x) (*(&_x - 2))
  
  #endif /* COMMON_H_INCLUDED */
  