/*
  wiring_shift.c - shiftOut() function
  Part of Arduino - http://www.arduino.cc/

  Copyright (c) 2005-2006 David A. Mellis

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA
*/

#include "Arduino.h"

uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) 
{
	uint8_t value = 0;
	
	for (uint8_t i = 0; i < 8; ++i) 
	{
		digitalWrite(clockPin, HIGH);
		if (bitOrder == LSBFIRST)
			value |= digitalRead(dataPin) << i;
		else
			value |= digitalRead(dataPin) << (7 - i);
		digitalWrite(clockPin, LOW);
	}
	return value;
}

void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val)
{
	for (uint8_t i = 0; i < 8; i++)  
	{
		if (bitOrder == LSBFIRST) 
		{
			digitalWrite(dataPin, val & 1);
			val >>= 1;
		} else 
		{	
			digitalWrite(dataPin, (val & 128) != 0);
			val <<= 1;
		}
		digitalWrite(clockPin, HIGH);
		digitalWrite(clockPin, LOW);		
	}
}
