setDirections.c

/*
 * @file count.c
 *
 * @author Andy Lindsay
 *
 * @version 0.85
 *
 * @copyright Copyright (C) Parallax, Inc. 2012.  See end of file for
 * terms of use (MIT License).
 *
 * @brief count function source, see simpletools.h for documentation.
 *
 * @detail Please submit bug reports, suggestions, and improvements to
 * this code to editor@parallax.com.
 */
 
#include "simpletools.h"                         // Include simpletools function defs
 
void set_directions(int endPin, int startPin, unsigned int pattern)
{
  if(endPin < startPin)                       // Handle reverse pin size
  {
    int temp = startPin;
    startPin = endPin;
    endPin = temp;
  }
  unsigned int andMask = -1;
  andMask <<= (31 - (endPin-startPin));
  andMask >>= (31 - endPin);
  andMask = ~andMask;
  unsigned int orMask = pattern << (startPin);
  DIRA = (DIRA & andMask) | orMask;
}