Quadrotor

/*

  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

  $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $

*/

#include "wiring_private.h"

uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {

        uint8_t value = 0;

        uint8_t i;

        for (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)

{

        uint8_t i;

        for (i = 0; i < 8; i++)  {

                if (bitOrder == LSBFIRST)

                        digitalWrite(dataPin, !!(val & (1 << i)));

                else        

                        digitalWrite(dataPin, !!(val & (1 << (7 - i))));

                digitalWrite(clockPin, HIGH);

                digitalWrite(clockPin, LOW);                

        }

}