mirror of
https://github.com/RobTillaart/Arduino.git
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191 lines
4.2 KiB
C++
191 lines
4.2 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: 0.1.9
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// PURPOSE: I2C PCF8574 library for Arduino
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// URL: http://forum.arduino.cc/index.php?topic=184800
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//
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// HISTORY:
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// 0.1.9 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 ints 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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#include <Wire.h>
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PCF8574::PCF8574(const uint8_t deviceAddress)
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{
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_address = deviceAddress;
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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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void PCF8574::begin(uint8_t val)
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{
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Wire.begin();
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PCF8574::write8(val);
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}
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// removed Wire.beginTransmission(addr);
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// with @100KHz -> 265 micros()
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// without @100KHz -> 132 micros()
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// without @400KHz -> 52 micros()
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// TODO @800KHz -> ??
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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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#if (ARDUINO < 100)
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_dataIn = Wire.receive();
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#else
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_dataIn = Wire.read();
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#endif
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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 || n > 7) return;
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_dataOut >>= n;
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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 || n > 7) return;
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_dataOut <<= n;
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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;
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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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_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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//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);
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PCF8574::read8();
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PCF8574::write8(temp);
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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 rtn = PCF8574::read(pin);
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PCF8574::write8(temp);
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return rtn;
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}
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//added 0.1.08 Septillion
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void PCF8574::setButtonMask(uint8_t mask){
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_buttonMask = mask;
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}
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//
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// END OF FILE
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//
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