84 lines
2.2 KiB
C
84 lines
2.2 KiB
C
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/*
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* wiringShift.c:
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* Emulate some of the Arduino wiring functionality.
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*
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* Copyright (c) 2009-2012 Gordon Henderson.
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***********************************************************************
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* This file is part of wiringPi:
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* https://projects.drogon.net/raspberry-pi/wiringpi/
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*
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* wiringPi is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* wiringPi 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
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with wiringPi. If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************
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*/
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#include <stdint.h>
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#include "wiringPi.h"
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#include "wiringShift.h"
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/*
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* shiftIn:
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* Shift data in from a clocked source
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*********************************************************************************
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*/
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uint8_t shiftIn (uint8_t dPin, uint8_t cPin, uint8_t order)
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{
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uint8_t value = 0 ;
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int8_t i ;
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if (order == MSBFIRST)
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for (i = 7 ; i >= 0 ; --i)
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{
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digitalWrite (cPin, HIGH) ;
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value |= digitalRead (dPin) << i ;
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digitalWrite (cPin, LOW) ;
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}
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else
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for (i = 0 ; i < 8 ; ++i)
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{
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digitalWrite (cPin, HIGH) ;
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value |= digitalRead (dPin) << i ;
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digitalWrite (cPin, LOW) ;
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}
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return value;
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}
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/*
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* shiftOut:
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* Shift data out to a clocked source
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*********************************************************************************
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*/
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void shiftOut (uint8_t dPin, uint8_t cPin, uint8_t order, uint8_t val)
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{
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int8_t i;
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if (order == MSBFIRST)
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for (i = 7 ; i >= 0 ; --i)
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{
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digitalWrite (dPin, val & (1 << i)) ;
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digitalWrite (cPin, HIGH) ;
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digitalWrite (cPin, LOW) ;
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}
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else
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for (i = 0 ; i < 8 ; ++i)
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{
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digitalWrite (dPin, val & (1 << i)) ;
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digitalWrite (cPin, HIGH) ;
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digitalWrite (cPin, LOW) ;
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}
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}
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