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FastShiftInOut.cpp
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FastShiftInOut.cpp
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//
// FILE: FastShiftInOut.cpp
// AUTHOR: Rob Tillaart
// VERSION: 0.2.0
// PURPOSE: Arduino library for (AVR) optimized shiftInOut (simultaneously)
// URL: https://github.com/RobTillaart/FastShiftInOut
#include "FastShiftInOut.h"
FastShiftInOut::FastShiftInOut(uint8_t dataIn, uint8_t dataOut, uint8_t clockPin, uint8_t bitOrder)
{
_bitOrder = bitOrder;
pinMode(dataIn, INPUT);
pinMode(dataOut, OUTPUT);
pinMode(clockPin, OUTPUT);
// https://www.arduino.cc/reference/en/language/functions/advanced-io/shiftout/
digitalWrite(clockPin, LOW); // assume rising pulses from clock
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
uint8_t _port = digitalPinToPort(dataIn);
_dataInRegister = portInputRegister(_port);
_dataInBit = digitalPinToBitMask(dataIn);
_port = digitalPinToPort(dataOut);
_dataOutRegister = portOutputRegister(_port);
_dataOutBit = digitalPinToBitMask(dataOut);
_port = digitalPinToPort(clockPin);
_clockRegister = portOutputRegister(_port);
_clockBit = digitalPinToBitMask(clockPin);
#else
_dataPinIn = dataIn;
_dataPinOut = dataOut;
_clockPin = clockPin;
#endif
_lastValue = 0;
_lastRead = 0;
}
uint8_t FastShiftInOut::write(uint8_t data)
{
if (_bitOrder == LSBFIRST)
{
return writeLSBFIRST(data);
}
return writeMSBFIRST(data);
}
uint8_t FastShiftInOut::lastWritten(void)
{
return _lastValue;
};
uint8_t FastShiftInOut::lastRead(void)
{
return _lastRead;
};
bool FastShiftInOut::setBitOrder(uint8_t bitOrder)
{
if ((bitOrder == LSBFIRST) || (bitOrder == MSBFIRST))
{
_bitOrder = bitOrder;
return true;
};
return false;
}
uint8_t FastShiftInOut::getBitOrder(void)
{
return _bitOrder;
};
uint8_t FastShiftInOut::writeLSBFIRST(uint8_t data)
{
uint8_t rv = 0;
uint8_t value = data;
_lastValue = value;
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
#if defined(FASTSHIFTINOUT_AVR_LOOP_UNROLLED) // AVR SPEED OPTIMIZED
uint8_t cbmask1 = _clockBit;
uint8_t inmask1 = _dataInBit;
uint8_t outmask1 = _dataOutBit;
uint8_t outmask2 = ~_dataOutBit;
volatile uint8_t* localDataInRegister = _dataInRegister;
volatile uint8_t* localDataOutRegister = _dataOutRegister;
volatile uint8_t* localClockRegister = _clockRegister;
// disable interrupts (for all bits)
uint8_t oldSREG = SREG;
noInterrupts();
if ((value & 0x01) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
// *localClockRegister |= cbmask1;
// if ((*localDataInRegister & inmask1) > 0) rv |= 0x01;
// *localClockRegister &= cbmask2; // ~_clockBit;
// following code is allowed as interrupts are disabled.
// so register can not change
uint8_t r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x01;
*localClockRegister = r; // reset it
if ((value & 0x02) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x02;
*localClockRegister = r; // reset it
if ((value & 0x04) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x04;
*localClockRegister = r; // reset it
if ((value & 0x08) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x08;
*localClockRegister = r; // reset it
if ((value & 0x10) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x10;
*localClockRegister = r; // reset it
if ((value & 0x20) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x20;
*localClockRegister = r; // reset it
if ((value & 0x40) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x40;
*localClockRegister = r; // reset it
if ((value & 0x80) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x80;
*localClockRegister = r; // reset it
SREG = oldSREG;
#else // AVR SIZE OPTIMIZED
uint8_t cbmask1 = _clockBit;
uint8_t inmask1 = _dataInBit;
uint8_t outmask1 = _dataOutBit;
uint8_t outmask2 = ~_dataOutBit;
volatile uint8_t* localDataInRegister = _dataInRegister;
volatile uint8_t* localDataOutRegister = _dataOutRegister;
volatile uint8_t* localClockRegister = _clockRegister;
uint8_t oldSREG = SREG;
noInterrupts();
uint8_t r = *localClockRegister;
for (uint8_t m = 1; m > 0; m <<= 1)
{
// write one bit
if ((value & m) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
// clock pulse HIGH
*localClockRegister |= cbmask1;
// read one bit
if ((*localDataInRegister & inmask1) > 0) rv |= m;
// clock pulse LOW
*localClockRegister = r;
}
SREG = oldSREG;
#endif // if (AVR)
#else // other platforms reference implementation
for (uint8_t i = 0; i < 8; i++)
{
// write one bit
digitalWrite(_dataPinOut, value & 0x01);
value >>= 1;
// clock pulse
digitalWrite(_clockPin, HIGH);
// read one bit
rv >>= 1;
if (digitalRead(_dataPinIn) == HIGH) rv |= 0x80;
// clock pulse
digitalWrite(_clockPin, LOW);
}
#endif
_lastRead = rv;
return rv;
}
uint8_t FastShiftInOut::writeMSBFIRST(uint8_t data)
{
uint8_t rv = 0;
uint8_t value = data;
_lastValue = value;
#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
#if defined(FASTSHIFTINOUT_AVR_LOOP_UNROLLED) // AVR SPEED OPTIMIZED
uint8_t cbmask1 = _clockBit;
uint8_t inmask1 = _dataInBit;
uint8_t outmask1 = _dataOutBit;
uint8_t outmask2 = ~_dataOutBit;
volatile uint8_t* localDataInRegister = _dataInRegister;
volatile uint8_t* localDataOutRegister = _dataOutRegister;
volatile uint8_t* localClockRegister = _clockRegister;
uint8_t oldSREG = SREG;
noInterrupts();
if ((value & 0x80) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
// *localClockRegister |= cbmask1;
// if ((*localDataInRegister & inmask1) > 0) rv |= 0x80;
// *localClockRegister &= cbmask2; // ~_clockBit;
// following code is allowed as interrupts are disabled.
// so register can not change
uint8_t r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x80;
*localClockRegister = r; // reset it
if ((value & 0x40) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x40;
*localClockRegister = r; // reset it
if ((value & 0x20) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x20;
*localClockRegister = r; // reset it
if ((value & 0x10) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x10;
*localClockRegister = r; // reset it
if ((value & 0x08) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x08;
*localClockRegister = r; // reset it
if ((value & 0x04) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x04;
*localClockRegister = r; // reset it
if ((value & 0x02) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x02;
*localClockRegister = r; // reset it
if ((value & 0x01) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
r = *localClockRegister;
*localClockRegister = r | cbmask1; // set one bit
if ((*localDataInRegister & inmask1) > 0) rv |= 0x01;
*localClockRegister = r; // reset it
SREG = oldSREG;
#else // AVR SIZE OPTIMIZED
uint8_t cbmask1 = _clockBit;
uint8_t inmask1 = _dataInBit;
uint8_t outmask1 = _dataOutBit;
uint8_t outmask2 = ~_dataOutBit;
volatile uint8_t* localDataInRegister = _dataInRegister;
volatile uint8_t* localDataOutRegister = _dataOutRegister;
volatile uint8_t* localClockRegister = _clockRegister;
uint8_t oldSREG = SREG;
noInterrupts();
uint8_t r = *localClockRegister;
for (uint8_t m = 0x80; m > 0; m >>= 1)
{
// write one bit
if ((value & m) == 0) *localDataOutRegister &= outmask2;
else *localDataOutRegister |= outmask1;
// clock pulse HIGH
*localClockRegister |= cbmask1;
// read one bit
if ((*localDataInRegister & inmask1) > 0) rv |= m;
// clock pulse LOW
*localClockRegister = r;
}
// reset interrupts flag to previous state
SREG = oldSREG;
#endif // if (AVR)
#else // other platforms reference implementation
for (uint8_t i = 0; i < 8; i++)
{
// write one bit
digitalWrite(_dataPinOut, value & 0x80);
value <<= 1;
// clock pulse
digitalWrite(_clockPin, HIGH);
// read one bit
rv <<= 1;
if (digitalRead(_dataPinIn) == HIGH) rv |= 1;
// clock pulse
digitalWrite(_clockPin, LOW);
}
#endif
_lastRead = rv;
return rv;
}
// -- END OF FILE --