mirror of
https://github.com/RobTillaart/Arduino.git
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265 lines
6.0 KiB
C++
265 lines
6.0 KiB
C++
//
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// FILE: PCF8574.cpp
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// AUTHOR: Rob Tillaart
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// DATE: 02-febr-2013
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// VERSION: 0.3.3
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// PURPOSE: Arduino library for PCF8574 - 8 channel I2C IO expander
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// URL: https://github.com/RobTillaart/PCF8574
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// http://forum.arduino.cc/index.php?topic=184800
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//
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// HISTORY:
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//
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// 0.3.3 2021-12-23 update library.json, license, readme, minor edits
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// 0.3.2 2021-07-04 fix #25 add setAddress()
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// 0.3.1 2021-04-23 Fix for platformIO compatibility
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// 0.3.0 2021-01-03 multiWire support - inspired by mattbue - issue #14
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// 0.2.4 2020-12-17 fix #6 tag problem 0.2.3
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// 0.2.3 2020-12-14 fix #6 readButton8 ambiguity
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// 0.2.2 2020-12-07 add Arduino-ci + start unit test + _wire->h in PCF8574.h
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// 0.2.1 2020-06-19 fix library.json
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// 0.2.0 2020-05-22 #pragma once; refactor;
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// removed pre 1.0 support
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// added begin(dsa, scl) for ESP32
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// added reverse()
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//
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// 0.1.9 2017-02-27 fix warning about return in readButton8()
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// 0.1.08 2016-05-20 Merged work of Septillion
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// Fix/refactor ButtonRead8() - see https://github.com/RobTillaart/Arduino/issues/38
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// missing begin() => mask parameter
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// 0.1.07 2016-05-02 (manually merged) Septillion
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// added dataOut so a write() doesn't read first,
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// possibly corrupting a input pin;
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// fixed shift comment, should read 1..7;
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// added begin() to be sure it's in a known state,
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// states could be different if uC is reset and the PCF8574 isn't;
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// added buttonRead() and buttonRead8()
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// which only effect the output while reading
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// 0.1.06 (intermediate) added defined errors + refactor rotate
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// 0.1.05 2016-04-30 refactor, +toggleMask, +rotLeft, +rotRight
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// 0.1.04 2015-05-09 removed ambiguity in read8()
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// 0.1.03 2015-03-02 address int -> uint8_t
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// 0.1.02 replaced integers with uint8_t to reduce footprint;
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// added default value for shiftLeft() and shiftRight()
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// renamed status() to lastError();
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// 0.1.01 added value(); returns last read 8 bit value (cached);
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// value() does not always reflect the latest state of the pins!
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// 0.1.00 initial version
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//
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#include "PCF8574.h"
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PCF8574::PCF8574(const uint8_t deviceAddress, TwoWire *wire)
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{
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_address = deviceAddress;
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_wire = wire;
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_dataIn = 0;
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_dataOut = 0xFF;
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_buttonMask = 0xFF;
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_error = PCF8574_OK;
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}
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#if defined (ESP8266) || defined(ESP32)
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bool PCF8574::begin(uint8_t dataPin, uint8_t clockPin, uint8_t value)
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{
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_wire = &Wire;
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if ((dataPin < 255) && (clockPin < 255))
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{
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_wire->begin(dataPin, clockPin);
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} else {
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_wire->begin();
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}
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if (! isConnected()) return false;
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PCF8574::write8(value);
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return true;
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}
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#endif
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bool PCF8574::begin(uint8_t value)
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{
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_wire->begin();
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if (! isConnected()) return false;
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PCF8574::write8(value);
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return true;
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}
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bool PCF8574::isConnected()
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{
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_wire->beginTransmission(_address);
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return ( _wire->endTransmission() == 0);
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}
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bool PCF8574::setAddress(const uint8_t deviceAddress)
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{
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_address = deviceAddress;
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return isConnected();
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}
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uint8_t PCF8574::getAddress()
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{
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return _address;
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}
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// removed _wire->beginTransmission(_address);
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// with @100 KHz -> 265 micros()
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// without @100 KHz -> 132 micros()
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// without @400 KHz -> 52 micros()
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// TODO @800 KHz -> ??
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uint8_t PCF8574::read8()
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{
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if (_wire->requestFrom(_address, (uint8_t)1) != 1)
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{
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_error = PCF8574_I2C_ERROR;
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return _dataIn; // last value
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}
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_dataIn = _wire->read();
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return _dataIn;
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}
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void PCF8574::write8(const uint8_t value)
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{
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_dataOut = value;
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_wire->beginTransmission(_address);
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_wire->write(_dataOut);
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_error = _wire->endTransmission();
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}
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uint8_t PCF8574::read(const uint8_t pin)
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{
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if (pin > 7)
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{
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_error = PCF8574_PIN_ERROR;
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return 0;
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}
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PCF8574::read8();
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return (_dataIn & (1 << pin)) > 0;
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}
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void PCF8574::write(const uint8_t pin, const uint8_t value)
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{
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if (pin > 7)
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{
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_error = PCF8574_PIN_ERROR;
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return;
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}
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if (value == LOW)
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{
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_dataOut &= ~(1 << pin);
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}
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else
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{
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_dataOut |= (1 << pin);
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}
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write8(_dataOut);
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}
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void PCF8574::toggle(const uint8_t pin)
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{
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if (pin > 7)
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{
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_error = PCF8574_PIN_ERROR;
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return;
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}
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toggleMask(1 << pin);
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}
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void PCF8574::toggleMask(const uint8_t mask)
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{
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_dataOut ^= mask;
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PCF8574::write8(_dataOut);
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}
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void PCF8574::shiftRight(const uint8_t n)
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{
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if ((n == 0) || (_dataOut == 0)) return;
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if (n > 7) _dataOut = 0; // shift 8++ clears all, valid...
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if (_dataOut != 0) _dataOut >>= n; // only shift if there are bits set
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PCF8574::write8(_dataOut);
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}
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void PCF8574::shiftLeft(const uint8_t n)
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{
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if ((n == 0) || (_dataOut == 0)) return;
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if (n > 7) _dataOut = 0; // shift 8++ clears all, valid...
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if (_dataOut != 0) _dataOut <<= n; // only shift if there are bits set
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PCF8574::write8(_dataOut);
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}
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int PCF8574::lastError()
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{
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int e = _error;
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_error = PCF8574_OK; // reset error after read, is this wise?
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return e;
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}
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void PCF8574::rotateRight(const uint8_t n)
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{
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uint8_t r = n & 7;
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if (r == 0) return;
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_dataOut = (_dataOut >> r) | (_dataOut << (8 - r));
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PCF8574::write8(_dataOut);
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}
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void PCF8574::rotateLeft(const uint8_t n)
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{
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rotateRight(8 - (n & 7));
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}
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void PCF8574::reverse() // quite fast: 14 shifts, 3 or, 3 assignment.
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{
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uint8_t x = _dataOut;
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x = (((x & 0xAA) >> 1) | ((x & 0x55) << 1));
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x = (((x & 0xCC) >> 2) | ((x & 0x33) << 2));
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x = ((x >> 4) | (x << 4));
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PCF8574::write8(x);
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}
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//added 0.1.07/08 Septillion
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uint8_t PCF8574::readButton8(const uint8_t mask)
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{
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uint8_t temp = _dataOut;
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PCF8574::write8(mask | _dataOut); // read only selected lines
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PCF8574::read8();
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PCF8574::write8(temp); // restore
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return _dataIn;
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}
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//added 0.1.07 Septillion
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uint8_t PCF8574::readButton(const uint8_t pin)
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{
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if (pin > 7)
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{
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_error = PCF8574_PIN_ERROR;
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return 0;
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}
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uint8_t temp = _dataOut;
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PCF8574::write(pin, HIGH);
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uint8_t value = PCF8574::read(pin);
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PCF8574::write8(temp);
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return value;
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}
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// -- END OF FILE --
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