55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
/*
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wiring_shift.c - shiftOut() function
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Part of Arduino - http://www.arduino.cc/
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Copyright (c) 2005-2006 David A. Mellis
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General
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Public License along with this library; if not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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Boston, MA 02111-1307 USA
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$Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
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*/
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#include "wiring_private.h"
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uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {
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uint8_t value = 0;
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uint8_t i;
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for (i = 0; i < 8; ++i) {
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digitalWrite(clockPin, HIGH);
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if (bitOrder == LSBFIRST)
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value |= digitalRead(dataPin) << i;
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else
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value |= digitalRead(dataPin) << (7 - i);
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digitalWrite(clockPin, LOW);
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}
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return value;
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}
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void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t val)
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{
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uint8_t i;
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for (i = 0; i < 8; i++) {
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if (bitOrder == LSBFIRST)
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digitalWrite(dataPin, !!(val & (1 << i)));
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else
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digitalWrite(dataPin, !!(val & (1 << (7 - i))));
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digitalWrite(clockPin, HIGH);
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digitalWrite(clockPin, LOW);
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}
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}
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