File wiring_shift.c

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/*
  Copyright (c) 2014 Arduino.  All right reserved.

  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <Arduino.h>
#include <stdint.h>

uint8_t shiftIn(pin_size_t ulDataPin, pin_size_t ulClockPin, BitOrder ulBitOrder) {
    uint8_t value = 0;
    uint8_t i;

    for (i = 0; i < 8; ++i) {
        digitalWrite(ulClockPin, HIGH);

        if (ulBitOrder == LSBFIRST) {
            value |= digitalRead(ulDataPin) << i;
        } else {
            value |= digitalRead(ulDataPin) << (7 - i);
        }

        digitalWrite(ulClockPin, LOW);
    }

    return value;
}

void shiftOut(pin_size_t ulDataPin, pin_size_t ulClockPin, BitOrder ulBitOrder, uint8_t ulVal) {
    uint8_t i;

    for (i = 0; i < 8; i++) {
        if (ulBitOrder == LSBFIRST) {
            digitalWrite(ulDataPin, !!(ulVal & (1 << i)));
        } else {
            digitalWrite(ulDataPin, !!(ulVal & (1 << (7 - i))));
        }

        digitalWrite(ulClockPin, HIGH);
        digitalWrite(ulClockPin, LOW);
    }
}