mirror of
https://github.com/RobTillaart/Arduino.git
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165 lines
3.2 KiB
C++
165 lines
3.2 KiB
C++
//
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// FILE: FastShiftOut.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.3.2
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// PURPOSE: ShiftOut that implements the Print interface
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// DATE: 2013-08-22
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// URL: https://github.com/RobTillaart/FastShiftOut
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#include "FastShiftOut.h"
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FastShiftOut::FastShiftOut(uint8_t dataOut, uint8_t clockPin, uint8_t bitOrder)
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{
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_bitOrder = bitOrder;
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pinMode(dataOut, OUTPUT);
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pinMode(clockPin, OUTPUT);
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// https://www.arduino.cc/reference/en/language/functions/advanced-io/shiftout/
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digitalWrite(clockPin, LOW); // assume rising pulses from clock
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#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
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uint8_t _port = digitalPinToPort(dataOut);
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_dataOutRegister = portOutputRegister(_port);
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_dataOutBit = digitalPinToBitMask(dataOut);
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_port = digitalPinToPort(clockPin);
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_clockRegister = portOutputRegister(_port);
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_clockBit = digitalPinToBitMask(clockPin);
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#else // reference implementation
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_dataPinOut = dataOut;
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_clockPin = clockPin;
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#endif
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}
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size_t FastShiftOut::write(uint8_t data)
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{
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if (_bitOrder == LSBFIRST)
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{
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return writeLSBFIRST(data);
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}
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return writeMSBFIRST(data);
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}
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/* experimental
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size_t write(const uint8_t \*buffer, size_t size)
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{
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size_t n = 0;
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if (_bitOrder == LSBFIRST)
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{
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for (size_t i = size; i > 0; ) // from end to begin ????
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{
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i--;
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n += writeLSBFIRST(buffer[i]);
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}
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}
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else
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{
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for (size_t i = 0; i < size; i++) // from begin to end..
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{
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n += writeMSBFIRST(buffer[i]);
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}
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}
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return n;
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}
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*/
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size_t FastShiftOut::writeLSBFIRST(uint8_t data)
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{
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uint8_t value = data;
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_lastValue = value;
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#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
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uint8_t cbmask1 = _clockBit;
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uint8_t cbmask2 = ~_clockBit;
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uint8_t outmask1 = _dataOutBit;
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uint8_t outmask2 = ~_dataOutBit;
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for (uint8_t m = 1; m > 0; m <<= 1)
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{
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uint8_t oldSREG = SREG;
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noInterrupts();
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if ((value & m) == 0) *_dataOutRegister &= outmask2;
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else *_dataOutRegister |= outmask1;
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*_clockRegister |= cbmask1;
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*_clockRegister &= cbmask2;
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SREG = oldSREG;
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}
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#else
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shiftOut(_dataPinOut, _clockPin, LSBFIRST, value);
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#endif
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return 1;
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}
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size_t FastShiftOut::writeMSBFIRST(uint8_t data)
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{
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uint8_t value = data;
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_lastValue = value;
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#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
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uint8_t cbmask1 = _clockBit;
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uint8_t cbmask2 = ~_clockBit;
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uint8_t outmask1 = _dataOutBit;
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uint8_t outmask2 = ~_dataOutBit;
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for (uint8_t m = 0x80; m > 0; m >>= 1)
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{
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uint8_t oldSREG = SREG;
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noInterrupts();
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if ((value & m) == 0) *_dataOutRegister &= outmask2;
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else *_dataOutRegister |= outmask1;
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*_clockRegister |= cbmask1;
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*_clockRegister &= cbmask2;
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SREG = oldSREG;
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}
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#else
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shiftOut(_dataPinOut, _clockPin, MSBFIRST, value);
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#endif
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return 1;
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}
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uint8_t FastShiftOut::lastWritten(void)
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{
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return _lastValue;
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}
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bool FastShiftOut::setBitOrder(const uint8_t bitOrder)
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{
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if ((bitOrder == LSBFIRST) || (bitOrder == MSBFIRST))
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{
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_bitOrder = bitOrder;
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return true;
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};
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return false;
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}
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uint8_t FastShiftOut::getBitOrder(void)
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{
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return _bitOrder;
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}
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// -- END OF FILE --
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