From 2e46b2274742fed767fd2cbbef3ad218e54d64fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Tue, 25 Feb 2020 01:17:54 +0100
Subject: [PATCH 01/15] Added inverted input mode

---
 src/MCP23017.cpp | 255 +++++++++++++++++++++++++++++++++++++++++++++--
 src/MCP23017.h   | 221 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 468 insertions(+), 8 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 293675d..5175b36 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -1,197 +1,440 @@
 #include "MCP23017.h"
 
+
+
 MCP23017::MCP23017(uint8_t address, TwoWire& bus) {
+
 	_deviceAddr = address;
+
 	_bus = &bus;
+
 }
 
+
+
 MCP23017::~MCP23017() {}
 
+
+
 void MCP23017::init()
+
 {
+
 	//BANK = 	0 : sequential register addresses
+
 	//MIRROR = 	0 : use configureInterrupt 
+
 	//SEQOP = 	1 : sequential operation disabled, address pointer does not increment
+
 	//DISSLW = 	0 : slew rate enabled
+
 	//HAEN = 	0 : hardware address pin is always enabled on 23017
+
 	//ODR = 	0 : open drain output
+
 	//INTPOL = 	0 : interrupt active low
+
 	writeRegister(MCP23017_REGISTER::IOCON, 0b00100000);
 
+
+
 	//enable all pull up resistors (will be effective for input pins only)
+
 	writeRegister(MCP23017_REGISTER::GPPUA, 0xFF, 0xFF);
+
 }
 
-void MCP23017::portMode(MCP23017_PORT port, uint8_t value)
+
+
+void MCP23017::portMode(MCP23017_PORT port, uint8_t value, bool inverted)
+
 {
+
 	writeRegister(MCP23017_REGISTER::IODIRA + port, value);
+
+	if( inverted ){
+
+		writeRegister(MCP23017_REGISTER::IPOLA + port, value);
+
+	}
+
 }
 
-void MCP23017::pinMode(uint8_t pin, uint8_t mode)
+
+
+void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
+
 {
+
 	MCP23017_REGISTER iodirreg = MCP23017_REGISTER::IODIRA;
+
 	uint8_t iodir;
-	if(pin > 7)
+
+	if( pin > 7 )
+
 	{
+
 		iodirreg = MCP23017_REGISTER::IODIRB;
+
 		pin -= 8;
+
+	}
+
+
+
+	if( inverted && mode == INPUT ){
+
+
+
+	MCP23017_REGISTER reg;
+
+	uint8_t pol;
+
+	
+
+	if( pin < 8 ) {
+
+		pol = readRegister(MCP23017_REGISTER::IPOLA);
+
+	} else {
+
+		pol = readRegister(MCP23017_REGISTER::IPOLB);
+
 	}
 
+
+
+	pol = readRegister(reg);
+
+	pol |= _BV(pin);
+
+	writeRegister( reg, pol );
+
+	} 
+
+
+
 	iodir = readRegister(iodirreg);
-	if(mode == OUTPUT) iodir &= ~_BV(pin);
-	else iodir |= _BV(pin);
 
-	writeRegister(iodirreg, iodir);
+	if(mode == OUTPUT) {
+
+		iodir &= ~_BV(pin);
+
+	} else{
+
+		 iodir |= _BV(pin);
+
+	}
+
+	
+
+	writeRegister( iodirreg, iodir );
+
+	
+
 }
 
+
+
 void MCP23017::digitalWrite(uint8_t pin, uint8_t state)
+
 {
+
 	MCP23017_REGISTER gpioreg = MCP23017_REGISTER::GPIOA;
+
 	uint8_t gpio;
+
 	if(pin > 7)
+
 	{
+
 		gpioreg = MCP23017_REGISTER::GPIOB;
+
 		pin -= 8;
+
 	}
 
+
+
 	gpio = readRegister(gpioreg);
+
 	if(state == HIGH) gpio |= _BV(pin);
+
 	else gpio &= ~_BV(pin);
 
+
+
 	writeRegister(gpioreg, gpio);
+
 }
 
+
+
 uint8_t MCP23017::digitalRead(uint8_t pin)
+
 {
+
 	MCP23017_REGISTER gpioreg = MCP23017_REGISTER::GPIOA;
+
 	uint8_t gpio;
+
 	if(pin > 7)
+
 	{
+
 		gpioreg = MCP23017_REGISTER::GPIOB;
+
 		pin -=8;
+
 	}
 
+
+
 	gpio = readRegister(gpioreg);
+
 	if((gpio & _BV(pin)) == _BV(pin)) return HIGH;
+
 	return LOW;
+
 }
 
+
+
 void MCP23017::writePort(MCP23017_PORT port, uint8_t value)
+
 {
+
 	writeRegister(MCP23017_REGISTER::GPIOA + port, value);
+
 }
 
+
+
 void MCP23017::write(uint16_t value)
+
 {
+
 	writeRegister(MCP23017_REGISTER::GPIOA, lowByte(value), highByte(value));
+
 }
 
+
+
 uint8_t MCP23017::readPort(MCP23017_PORT port)
+
 {
+
 	return readRegister(MCP23017_REGISTER::GPIOA + port);
+
 }
 
+
+
 uint16_t MCP23017::read()
+
 {
+
 	uint8_t a = readPort(MCP23017_PORT::A);
+
 	uint8_t b = readPort(MCP23017_PORT::B);
 
+
+
 	return a | b << 8;
+
 }
 
+
+
 void MCP23017::writeRegister(MCP23017_REGISTER reg, uint8_t value)
+
 {
+
 	_bus->beginTransmission(_deviceAddr);
+
 	_bus->write(static_cast<uint8_t>(reg));
+
 	_bus->write(value);
+
 	_bus->endTransmission();
+
 }
 
+
+
 void MCP23017::writeRegister(MCP23017_REGISTER reg, uint8_t portA, uint8_t portB)
+
 {
+
 	_bus->beginTransmission(_deviceAddr);
+
 	_bus->write(static_cast<uint8_t>(reg));
+
 	_bus->write(portA);
+
 	_bus->write(portB);
+
 	_bus->endTransmission();
+
 }
 
 
+
+
+
 uint8_t MCP23017::readRegister(MCP23017_REGISTER reg)
+
 {
+
 	_bus->beginTransmission(_deviceAddr);
+
 	_bus->write(static_cast<uint8_t>(reg));
+
 	_bus->endTransmission();
+
 	_bus->requestFrom(_deviceAddr, (uint8_t)1);
+
 	return _bus->read();
+
 }
 
+
+
 void MCP23017::readRegister(MCP23017_REGISTER reg, uint8_t& portA, uint8_t& portB)
+
 {
+
 	_bus->beginTransmission(_deviceAddr);
+
 	_bus->write(static_cast<uint8_t>(reg));
+
 	_bus->endTransmission();
+
 	_bus->requestFrom(_deviceAddr, (uint8_t)2);
+
 	portA = _bus->read();
+
 	portB = _bus->read();
+
 }
 
+
+
 #ifdef _MCP23017_INTERRUPT_SUPPORT_
 
+
+
 void MCP23017::interruptMode(MCP23017_INTMODE intMode)
+
 {
+
 	uint8_t iocon = readRegister(MCP23017_REGISTER::IOCON);
+
 	if(intMode == MCP23017_INTMODE::OR) iocon |= static_cast<uint8_t>(MCP23017_INTMODE::OR);
+
 	else iocon &= ~(static_cast<uint8_t>(MCP23017_INTMODE::OR));
 
+
+
 	writeRegister(MCP23017_REGISTER::IOCON, iocon);
+
 }
 
+
+
 void MCP23017::interrupt(MCP23017_PORT port, uint8_t mode)
+
 {
+
 	MCP23017_REGISTER defvalreg = MCP23017_REGISTER::DEFVALA + port;
+
 	MCP23017_REGISTER intconreg = MCP23017_REGISTER::INTCONA + port;
 
+
+
 	//enable interrupt for port
+
 	writeRegister(MCP23017_REGISTER::GPINTENA + port, 0xFF);
+
 	switch(mode)
+
 	{
+
 	case CHANGE:
+
 		//interrupt on change
+
 		writeRegister(intconreg, 0);
+
 		break;
+
 	case FALLING:
+
 		//interrupt falling : compared against defval, 0xff
+
 		writeRegister(intconreg, 0xFF);
+
 		writeRegister(defvalreg, 0xFF);
+
 		break;
+
 	case RISING:
+
 		//interrupt falling : compared against defval, 0x00
+
 		writeRegister(intconreg, 0xFF);
+
 		writeRegister(defvalreg, 0x00);
+
 		break;
+
 	}
+
 }
 
+
+
 void MCP23017::interruptedBy(uint8_t& portA, uint8_t& portB)
+
 {
+
 	readRegister(MCP23017_REGISTER::INTFA, portA, portB);
+
 }
 
+
+
 void MCP23017::disableInterrupt(MCP23017_PORT port)
+
 {
+
 	writeRegister(MCP23017_REGISTER::GPINTENA + port, 0x00);
+
 }
 
+
+
 void MCP23017::clearInterrupts()
+
 {
+
 	uint8_t a, b;
+
 	clearInterrupts(a, b);
+
 }
 
+
+
 void MCP23017::clearInterrupts(uint8_t& portA, uint8_t& portB)
+
 {
+
 	readRegister(MCP23017_REGISTER::INTCAPA, portA, portB);
+
 }
 
+
+
 #endif
+
diff --git a/src/MCP23017.h b/src/MCP23017.h
index d467567..4d23052 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -1,218 +1,435 @@
 #pragma once
 
+
+
 #include <Arduino.h>
+
 #include <Wire.h>
 
+
+
 #define _MCP23017_INTERRUPT_SUPPORT_ ///< Enables support for MCP23017 interrupts.
 
+
+
 enum class MCP23017_PORT : uint8_t
+
 {
+
 	A = 0,
+
 	B = 1
+
 };
 
+
+
 /**
+
  * Controls if the two interrupt pins mirror each other.
+
  * See "3.6 Interrupt Logic".
+
  */
+
 enum class MCP23017_INTMODE : uint8_t
+
 {
+
 	SEPARATED = 0,	///< Interrupt pins are kept independent
+
 	OR = 0b01000000	///< Interrupt pins are mirrored
+
 };
 
+
+
 /**
+
  * Registers addresses.
+
  * The library use addresses for IOCON.BANK = 0.
+
  * See "3.2.1 Byte mode and Sequential mode".
+
  */
+
 enum class MCP23017_REGISTER : uint8_t
+
 {
+
 	IODIRA		= 0x00, 		///< Controls the direction of the data I/O for port A.
+
 	IODIRB		= 0x01,			///< Controls the direction of the data I/O for port B.
+
 	IPOLA		= 0x02,			///< Configures the polarity on the corresponding GPIO port bits for port A.
+
 	IPOLB		= 0x03,			///< Configures the polarity on the corresponding GPIO port bits for port B.
+
 	GPINTENA	= 0x04,			///< Controls the interrupt-on-change for each pin of port A.
+
 	GPINTENB	= 0x05,			///< Controls the interrupt-on-change for each pin of port B.
+
 	DEFVALA		= 0x06,			///< Controls the default comparaison value for interrupt-on-change for port A.
+
 	DEFVALB		= 0x07,			///< Controls the default comparaison value for interrupt-on-change for port B.
+
 	INTCONA		= 0x08,			///< Controls how the associated pin value is compared for the interrupt-on-change for port A.
+
 	INTCONB		= 0x09,			///< Controls how the associated pin value is compared for the interrupt-on-change for port B.
+
 	IOCON		= 0x0A,			///< Controls the device.
+
 	GPPUA		= 0x0C,			///< Controls the pull-up resistors for the port A pins.
+
 	GPPUB		= 0x0D,			///< Controls the pull-up resistors for the port B pins.
+
 	INTFA		= 0x0E,			///< Reflects the interrupt condition on the port A pins.
+
 	INTFB		= 0x0F,			///< Reflects the interrupt condition on the port B pins.
+
 	INTCAPA		= 0x10,			///< Captures the port A value at the time the interrupt occured.
+
 	INTCAPB		= 0x11,			///< Captures the port B value at the time the interrupt occured.
+
 	GPIOA		= 0x12,			///< Reflects the value on the port A.
+
 	GPIOB		= 0x13,			///< Reflects the value on the port B.
+
 	OLATA		= 0x14,			///< Provides access to the port A output latches.
+
 	OLATB		= 0x15,			///< Provides access to the port B output latches.
+
 };
 
+
+
 inline MCP23017_REGISTER operator+(MCP23017_REGISTER a, MCP23017_PORT b) {
+
 	return static_cast<MCP23017_REGISTER>(static_cast<uint8_t>(a) + static_cast<uint8_t>(b));
+
 };
 
+
+
 class MCP23017
+
 {
+
 private:
+
 	TwoWire* _bus;
+
 	uint8_t _deviceAddr;
+
 public:
+
 	/**
+
 	 * Instantiates a new instance to interact with a MCP23017 at the specified address.
+
 	 */
+
 	MCP23017(uint8_t address, TwoWire& bus = Wire);
+
 	~MCP23017();
+
 #ifdef _DEBUG
+
 	void debug();
+
 #endif
+
 	/**
+
 	 * Initializes the chip with the default configuration.
+
 	 * Enables Byte mode (IOCON.BANK = 0 and IOCON.SEQOP = 1).
+
 	 * Enables pull-up resistors for all pins. This will only be effective for input pins.
+
 	 * 
+
 	 * See "3.2.1 Byte mode and Sequential mode".
+
 	 */
+
 	void init();
+
 	/**
+
 	 * Controls the pins direction on a whole port at once.
+
 	 * 
+
 	 * 1 = Pin is configured as an input.
+
 	 * 0 = Pin is configured as an output.
+
 	 * 
+
 	 * See "3.5.1 I/O Direction register".
+
 	 */
-	void portMode(MCP23017_PORT port, uint8_t value);
+
+	void portMode(MCP23017_PORT port, uint8_t value, bool inverted=false);
+
 	/**
+
 	 * Controls a single pin direction. 
+
 	 * Pin 0-7 for port A, 8-15 fo port B.
+
 	 * 
+
 	 * 1 = Pin is configured as an input.
+
 	 * 0 = Pin is configured as an output.
+
 	 *
+
 	 * See "3.5.1 I/O Direction register".
+
 	 */
-	void pinMode(uint8_t pin, uint8_t mode);
+
+	void pinMode(uint8_t pin, uint8_t mode, bool inverted=false);
+
+
 
 	/**
+
 	 * Writes a single pin state.
+
 	 * Pin 0-7 for port A, 8-15 for port B.
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */
+
 	void digitalWrite(uint8_t pin, uint8_t state);
+
 	/**
+
 	 * Reads a single pin state.
+
 	 * Pin 0-7 for port A, 8-15 for port B.
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */ 
+
 	uint8_t digitalRead(uint8_t pin);
 
+
+
 	/**
+
 	 * Writes pins state to a whole port.
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */
+
 	void writePort(MCP23017_PORT port, uint8_t value);
+
 	/**
+
 	 * Writes pins state to both ports.
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */
+
 	void write(uint16_t value);
 
+
+
 	/**
+
 	 * Reads pins state for a whole port.
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */
+
 	uint8_t readPort(MCP23017_PORT port);
+
 	/**
+
 	 * Reads pins state for both ports. 
+
 	 * 
+
 	 * 1 = Logic-high
+
 	 * 0 = Logic-low
+
 	 * 
+
 	 * See "3.5.10 Port register".
+
 	 */
+
 	uint16_t read();
 
+
+
 	/**
+
 	 * Writes a single register value.
+
 	 */
+
 	void writeRegister(MCP23017_REGISTER reg, uint8_t value);
+
 	/**
+
 	 * Writes values to a register pair.
+
 	 * 
+
 	 * For portA and portB variable to effectively match the desired port,
+
 	 * you have to supply a portA register address to reg. Otherwise, values
+
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
+
 	 */
+
 	void writeRegister(MCP23017_REGISTER reg, uint8_t portA, uint8_t portB);
+
 	/**
+
 	 * Reads a single register value.
+
 	 */
+
 	uint8_t readRegister(MCP23017_REGISTER reg);
+
 	/**
+
 	 * Reads the values from a register pair.
+
 	 * 
+
 	 * For portA and portB variable to effectively match the desired port,
+
 	 * you have to supply a portA register address to reg. Otherwise, values
+
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
+
 	 */
+
 	void readRegister(MCP23017_REGISTER reg, uint8_t& portA, uint8_t& portB);
 
+
+
 #ifdef _MCP23017_INTERRUPT_SUPPORT_
 
+
+
 	/**
+
 	 * Controls how the interrupt pins act with each other.
+
 	 * If intMode is SEPARATED, interrupt conditions on a port will cause its respective INT pin to active.
+
 	 * If intMode is OR, interrupt pins are OR'ed so an interrupt on one of the port will cause both pints to active.
+
 	 * 
+
 	 * Controls the IOCON.MIRROR bit. 
+
 	 * See "3.5.6 Configuration register".
+
 	 */
+
 	void interruptMode(MCP23017_INTMODE intMode);
+
 	/**
+
 	 * Configures interrupt registers using an Arduino-like API.
+
 	 * mode can be one of CHANGE, FALLING or RISING.
+
 	 */
+
 	void interrupt(MCP23017_PORT port, uint8_t mode);
+
 	/**
+
 	 * Disable interrupts for the specified port.
+
 	 */
+
 	void disableInterrupt(MCP23017_PORT port);
+
 	/**
+
 	 * Reads which pin caused the interrupt.
+
 	 */
+
 	void interruptedBy(uint8_t& portA, uint8_t& portB);
+
 	/**
+
 	 * Clears interrupts on both ports.
+
 	 */
+
 	void clearInterrupts();
+
 	/**
+
 	 * Clear interrupts on both ports. Returns port values at the time the interrupt occured.
+
 	 */
+
 	void clearInterrupts(uint8_t& portA, uint8_t& portB);
 
+
+
 #endif
+
 };
\ No newline at end of file

From 1b75617af74a931c95a6e02017be9a7dc99eb96e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Tue, 25 Feb 2020 01:40:38 +0100
Subject: [PATCH 02/15] removed blank lines

---
 src/MCP23017.cpp | 227 +----------------------------------------------
 src/MCP23017.h   | 217 --------------------------------------------
 2 files changed, 4 insertions(+), 440 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 5175b36..cf0b825 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -1,440 +1,221 @@
 #include "MCP23017.h"
 
-
-
 MCP23017::MCP23017(uint8_t address, TwoWire& bus) {
-
 	_deviceAddr = address;
-
 	_bus = &bus;
-
 }
 
-
-
 MCP23017::~MCP23017() {}
 
-
-
 void MCP23017::init()
-
 {
-
 	//BANK = 	0 : sequential register addresses
-
 	//MIRROR = 	0 : use configureInterrupt 
-
 	//SEQOP = 	1 : sequential operation disabled, address pointer does not increment
-
 	//DISSLW = 	0 : slew rate enabled
-
 	//HAEN = 	0 : hardware address pin is always enabled on 23017
-
 	//ODR = 	0 : open drain output
-
 	//INTPOL = 	0 : interrupt active low
-
 	writeRegister(MCP23017_REGISTER::IOCON, 0b00100000);
 
-
-
 	//enable all pull up resistors (will be effective for input pins only)
-
 	writeRegister(MCP23017_REGISTER::GPPUA, 0xFF, 0xFF);
-
 }
 
-
-
 void MCP23017::portMode(MCP23017_PORT port, uint8_t value, bool inverted)
-
 {
-
 	writeRegister(MCP23017_REGISTER::IODIRA + port, value);
 
 	if( inverted ){
-
 		writeRegister(MCP23017_REGISTER::IPOLA + port, value);
-
 	}
-
 }
 
-
-
-void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
-
+void MCP23017::pinMode(uint8_t pin, uint8_t mode)
 {
-
 	MCP23017_REGISTER iodirreg = MCP23017_REGISTER::IODIRA;
-
 	uint8_t iodir;
-
-	if( pin > 7 )
-
+	if(pin > 7)
 	{
-
 		iodirreg = MCP23017_REGISTER::IODIRB;
-
 		pin -= 8;
-
 	}
-
-
-
 	if( inverted && mode == INPUT ){
 
-
-
 	MCP23017_REGISTER reg;
-
 	uint8_t pol;
 
-	
-
 	if( pin < 8 ) {
-
 		pol = readRegister(MCP23017_REGISTER::IPOLA);
-
 	} else {
-
 		pol = readRegister(MCP23017_REGISTER::IPOLB);
-
 	}
-
-
-
 	pol = readRegister(reg);
-
 	pol |= _BV(pin);
-
+	
 	writeRegister( reg, pol );
-
-	} 
+} 
 
 
 
 	iodir = readRegister(iodirreg);
-
 	if(mode == OUTPUT) {
-
 		iodir &= ~_BV(pin);
-
 	} else{
-
 		 iodir |= _BV(pin);
-
 	}
 
-	
-
 	writeRegister( iodirreg, iodir );
-
-	
-
 }
 
-
-
 void MCP23017::digitalWrite(uint8_t pin, uint8_t state)
-
 {
-
 	MCP23017_REGISTER gpioreg = MCP23017_REGISTER::GPIOA;
-
 	uint8_t gpio;
-
 	if(pin > 7)
-
 	{
-
 		gpioreg = MCP23017_REGISTER::GPIOB;
-
 		pin -= 8;
-
 	}
 
-
-
 	gpio = readRegister(gpioreg);
-
 	if(state == HIGH) gpio |= _BV(pin);
-
 	else gpio &= ~_BV(pin);
 
-
-
 	writeRegister(gpioreg, gpio);
-
 }
 
-
-
 uint8_t MCP23017::digitalRead(uint8_t pin)
-
 {
-
 	MCP23017_REGISTER gpioreg = MCP23017_REGISTER::GPIOA;
-
 	uint8_t gpio;
-
 	if(pin > 7)
-
 	{
-
 		gpioreg = MCP23017_REGISTER::GPIOB;
-
 		pin -=8;
-
 	}
 
-
-
 	gpio = readRegister(gpioreg);
-
 	if((gpio & _BV(pin)) == _BV(pin)) return HIGH;
-
 	return LOW;
-
 }
 
-
-
 void MCP23017::writePort(MCP23017_PORT port, uint8_t value)
-
 {
-
 	writeRegister(MCP23017_REGISTER::GPIOA + port, value);
-
 }
 
-
-
 void MCP23017::write(uint16_t value)
-
 {
-
 	writeRegister(MCP23017_REGISTER::GPIOA, lowByte(value), highByte(value));
-
 }
 
-
-
 uint8_t MCP23017::readPort(MCP23017_PORT port)
-
 {
-
 	return readRegister(MCP23017_REGISTER::GPIOA + port);
-
 }
 
-
-
 uint16_t MCP23017::read()
-
 {
-
 	uint8_t a = readPort(MCP23017_PORT::A);
-
 	uint8_t b = readPort(MCP23017_PORT::B);
 
-
-
 	return a | b << 8;
-
 }
 
-
-
 void MCP23017::writeRegister(MCP23017_REGISTER reg, uint8_t value)
-
 {
-
 	_bus->beginTransmission(_deviceAddr);
-
 	_bus->write(static_cast<uint8_t>(reg));
-
 	_bus->write(value);
-
 	_bus->endTransmission();
-
 }
 
-
-
 void MCP23017::writeRegister(MCP23017_REGISTER reg, uint8_t portA, uint8_t portB)
-
 {
-
 	_bus->beginTransmission(_deviceAddr);
-
 	_bus->write(static_cast<uint8_t>(reg));
-
 	_bus->write(portA);
-
 	_bus->write(portB);
-
 	_bus->endTransmission();
-
 }
 
 
-
-
-
 uint8_t MCP23017::readRegister(MCP23017_REGISTER reg)
-
 {
-
 	_bus->beginTransmission(_deviceAddr);
-
 	_bus->write(static_cast<uint8_t>(reg));
-
 	_bus->endTransmission();
-
 	_bus->requestFrom(_deviceAddr, (uint8_t)1);
-
 	return _bus->read();
-
 }
 
-
-
 void MCP23017::readRegister(MCP23017_REGISTER reg, uint8_t& portA, uint8_t& portB)
-
 {
-
 	_bus->beginTransmission(_deviceAddr);
-
 	_bus->write(static_cast<uint8_t>(reg));
-
 	_bus->endTransmission();
-
 	_bus->requestFrom(_deviceAddr, (uint8_t)2);
-
 	portA = _bus->read();
-
 	portB = _bus->read();
-
 }
 
-
-
 #ifdef _MCP23017_INTERRUPT_SUPPORT_
 
-
-
 void MCP23017::interruptMode(MCP23017_INTMODE intMode)
-
 {
-
 	uint8_t iocon = readRegister(MCP23017_REGISTER::IOCON);
-
 	if(intMode == MCP23017_INTMODE::OR) iocon |= static_cast<uint8_t>(MCP23017_INTMODE::OR);
-
 	else iocon &= ~(static_cast<uint8_t>(MCP23017_INTMODE::OR));
 
-
-
 	writeRegister(MCP23017_REGISTER::IOCON, iocon);
-
 }
 
-
-
 void MCP23017::interrupt(MCP23017_PORT port, uint8_t mode)
-
 {
-
 	MCP23017_REGISTER defvalreg = MCP23017_REGISTER::DEFVALA + port;
-
 	MCP23017_REGISTER intconreg = MCP23017_REGISTER::INTCONA + port;
 
-
-
 	//enable interrupt for port
-
 	writeRegister(MCP23017_REGISTER::GPINTENA + port, 0xFF);
-
 	switch(mode)
-
 	{
-
 	case CHANGE:
-
 		//interrupt on change
-
 		writeRegister(intconreg, 0);
-
 		break;
-
 	case FALLING:
-
 		//interrupt falling : compared against defval, 0xff
-
 		writeRegister(intconreg, 0xFF);
-
 		writeRegister(defvalreg, 0xFF);
-
 		break;
-
 	case RISING:
-
 		//interrupt falling : compared against defval, 0x00
-
 		writeRegister(intconreg, 0xFF);
-
 		writeRegister(defvalreg, 0x00);
-
 		break;
-
 	}
-
 }
 
-
-
 void MCP23017::interruptedBy(uint8_t& portA, uint8_t& portB)
-
 {
-
 	readRegister(MCP23017_REGISTER::INTFA, portA, portB);
-
 }
 
-
-
 void MCP23017::disableInterrupt(MCP23017_PORT port)
-
 {
-
 	writeRegister(MCP23017_REGISTER::GPINTENA + port, 0x00);
-
 }
 
-
-
 void MCP23017::clearInterrupts()
-
 {
-
 	uint8_t a, b;
-
 	clearInterrupts(a, b);
-
 }
 
-
-
 void MCP23017::clearInterrupts(uint8_t& portA, uint8_t& portB)
-
 {
-
 	readRegister(MCP23017_REGISTER::INTCAPA, portA, portB);
-
 }
 
-
-
 #endif
-
diff --git a/src/MCP23017.h b/src/MCP23017.h
index 4d23052..4cd5a43 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -1,435 +1,218 @@
 #pragma once
 
-
-
 #include <Arduino.h>
-
 #include <Wire.h>
 
-
-
 #define _MCP23017_INTERRUPT_SUPPORT_ ///< Enables support for MCP23017 interrupts.
 
-
-
 enum class MCP23017_PORT : uint8_t
-
 {
-
 	A = 0,
-
 	B = 1
-
 };
 
-
-
 /**
-
  * Controls if the two interrupt pins mirror each other.
-
  * See "3.6 Interrupt Logic".
-
  */
-
 enum class MCP23017_INTMODE : uint8_t
-
 {
-
 	SEPARATED = 0,	///< Interrupt pins are kept independent
-
 	OR = 0b01000000	///< Interrupt pins are mirrored
-
 };
 
-
-
 /**
-
  * Registers addresses.
-
  * The library use addresses for IOCON.BANK = 0.
-
  * See "3.2.1 Byte mode and Sequential mode".
-
  */
-
 enum class MCP23017_REGISTER : uint8_t
-
 {
-
 	IODIRA		= 0x00, 		///< Controls the direction of the data I/O for port A.
-
 	IODIRB		= 0x01,			///< Controls the direction of the data I/O for port B.
-
 	IPOLA		= 0x02,			///< Configures the polarity on the corresponding GPIO port bits for port A.
-
 	IPOLB		= 0x03,			///< Configures the polarity on the corresponding GPIO port bits for port B.
-
 	GPINTENA	= 0x04,			///< Controls the interrupt-on-change for each pin of port A.
-
 	GPINTENB	= 0x05,			///< Controls the interrupt-on-change for each pin of port B.
-
 	DEFVALA		= 0x06,			///< Controls the default comparaison value for interrupt-on-change for port A.
-
 	DEFVALB		= 0x07,			///< Controls the default comparaison value for interrupt-on-change for port B.
-
 	INTCONA		= 0x08,			///< Controls how the associated pin value is compared for the interrupt-on-change for port A.
-
 	INTCONB		= 0x09,			///< Controls how the associated pin value is compared for the interrupt-on-change for port B.
-
 	IOCON		= 0x0A,			///< Controls the device.
-
 	GPPUA		= 0x0C,			///< Controls the pull-up resistors for the port A pins.
-
 	GPPUB		= 0x0D,			///< Controls the pull-up resistors for the port B pins.
-
 	INTFA		= 0x0E,			///< Reflects the interrupt condition on the port A pins.
-
 	INTFB		= 0x0F,			///< Reflects the interrupt condition on the port B pins.
-
 	INTCAPA		= 0x10,			///< Captures the port A value at the time the interrupt occured.
-
 	INTCAPB		= 0x11,			///< Captures the port B value at the time the interrupt occured.
-
 	GPIOA		= 0x12,			///< Reflects the value on the port A.
-
 	GPIOB		= 0x13,			///< Reflects the value on the port B.
-
 	OLATA		= 0x14,			///< Provides access to the port A output latches.
-
 	OLATB		= 0x15,			///< Provides access to the port B output latches.
-
 };
 
-
-
 inline MCP23017_REGISTER operator+(MCP23017_REGISTER a, MCP23017_PORT b) {
-
 	return static_cast<MCP23017_REGISTER>(static_cast<uint8_t>(a) + static_cast<uint8_t>(b));
-
 };
 
-
-
 class MCP23017
-
 {
-
 private:
-
 	TwoWire* _bus;
-
 	uint8_t _deviceAddr;
-
 public:
-
 	/**
-
 	 * Instantiates a new instance to interact with a MCP23017 at the specified address.
-
 	 */
-
 	MCP23017(uint8_t address, TwoWire& bus = Wire);
-
 	~MCP23017();
-
 #ifdef _DEBUG
-
 	void debug();
-
 #endif
-
 	/**
-
 	 * Initializes the chip with the default configuration.
-
 	 * Enables Byte mode (IOCON.BANK = 0 and IOCON.SEQOP = 1).
-
 	 * Enables pull-up resistors for all pins. This will only be effective for input pins.
-
 	 * 
-
 	 * See "3.2.1 Byte mode and Sequential mode".
-
 	 */
-
 	void init();
-
 	/**
-
 	 * Controls the pins direction on a whole port at once.
-
 	 * 
-
 	 * 1 = Pin is configured as an input.
-
 	 * 0 = Pin is configured as an output.
-
 	 * 
-
 	 * See "3.5.1 I/O Direction register".
-
 	 */
-
 	void portMode(MCP23017_PORT port, uint8_t value, bool inverted=false);
-
 	/**
-
 	 * Controls a single pin direction. 
-
 	 * Pin 0-7 for port A, 8-15 fo port B.
-
 	 * 
-
 	 * 1 = Pin is configured as an input.
-
 	 * 0 = Pin is configured as an output.
-
 	 *
-
 	 * See "3.5.1 I/O Direction register".
-
 	 */
-
 	void pinMode(uint8_t pin, uint8_t mode, bool inverted=false);
 
-
-
 	/**
-
 	 * Writes a single pin state.
-
 	 * Pin 0-7 for port A, 8-15 for port B.
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */
-
 	void digitalWrite(uint8_t pin, uint8_t state);
-
 	/**
-
 	 * Reads a single pin state.
-
 	 * Pin 0-7 for port A, 8-15 for port B.
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */ 
-
 	uint8_t digitalRead(uint8_t pin);
 
-
-
 	/**
-
 	 * Writes pins state to a whole port.
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */
-
 	void writePort(MCP23017_PORT port, uint8_t value);
-
 	/**
-
 	 * Writes pins state to both ports.
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */
-
 	void write(uint16_t value);
 
-
-
 	/**
-
 	 * Reads pins state for a whole port.
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */
-
 	uint8_t readPort(MCP23017_PORT port);
-
 	/**
-
 	 * Reads pins state for both ports. 
-
 	 * 
-
 	 * 1 = Logic-high
-
 	 * 0 = Logic-low
-
 	 * 
-
 	 * See "3.5.10 Port register".
-
 	 */
-
 	uint16_t read();
 
-
-
 	/**
-
 	 * Writes a single register value.
-
 	 */
-
 	void writeRegister(MCP23017_REGISTER reg, uint8_t value);
-
 	/**
-
 	 * Writes values to a register pair.
-
 	 * 
-
 	 * For portA and portB variable to effectively match the desired port,
-
 	 * you have to supply a portA register address to reg. Otherwise, values
-
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
-
 	 */
-
 	void writeRegister(MCP23017_REGISTER reg, uint8_t portA, uint8_t portB);
-
 	/**
-
 	 * Reads a single register value.
-
 	 */
-
 	uint8_t readRegister(MCP23017_REGISTER reg);
-
 	/**
-
 	 * Reads the values from a register pair.
-
 	 * 
-
 	 * For portA and portB variable to effectively match the desired port,
-
 	 * you have to supply a portA register address to reg. Otherwise, values
-
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
-
 	 */
-
 	void readRegister(MCP23017_REGISTER reg, uint8_t& portA, uint8_t& portB);
 
-
-
 #ifdef _MCP23017_INTERRUPT_SUPPORT_
 
-
-
 	/**
-
 	 * Controls how the interrupt pins act with each other.
-
 	 * If intMode is SEPARATED, interrupt conditions on a port will cause its respective INT pin to active.
-
 	 * If intMode is OR, interrupt pins are OR'ed so an interrupt on one of the port will cause both pints to active.
-
 	 * 
-
 	 * Controls the IOCON.MIRROR bit. 
-
 	 * See "3.5.6 Configuration register".
-
 	 */
-
 	void interruptMode(MCP23017_INTMODE intMode);
-
 	/**
-
 	 * Configures interrupt registers using an Arduino-like API.
-
 	 * mode can be one of CHANGE, FALLING or RISING.
-
 	 */
-
 	void interrupt(MCP23017_PORT port, uint8_t mode);
-
 	/**
-
 	 * Disable interrupts for the specified port.
-
 	 */
-
 	void disableInterrupt(MCP23017_PORT port);
-
 	/**
-
 	 * Reads which pin caused the interrupt.
-
 	 */
-
 	void interruptedBy(uint8_t& portA, uint8_t& portB);
-
 	/**
-
 	 * Clears interrupts on both ports.
-
 	 */
-
 	void clearInterrupts();
-
 	/**
-
 	 * Clear interrupts on both ports. Returns port values at the time the interrupt occured.
-
 	 */
-
 	void clearInterrupts(uint8_t& portA, uint8_t& portB);
 
-
-
 #endif
-
 };
\ No newline at end of file

From da9eed46cbeba544925a1a9bdc7293cb91cff619 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Tue, 25 Feb 2020 01:43:02 +0100
Subject: [PATCH 03/15] .

---
 src/MCP23017.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index cf0b825..aace7e5 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -31,7 +31,7 @@ void MCP23017::portMode(MCP23017_PORT port, uint8_t value, bool inverted)
 	}
 }
 
-void MCP23017::pinMode(uint8_t pin, uint8_t mode)
+void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 {
 	MCP23017_REGISTER iodirreg = MCP23017_REGISTER::IODIRA;
 	uint8_t iodir;
@@ -52,7 +52,7 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode)
 	}
 	pol = readRegister(reg);
 	pol |= _BV(pin);
-	
+
 	writeRegister( reg, pol );
 } 
 

From dba31dcc29d538d08eec2ec613ce3d9eedc6b525 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 17:44:51 +0100
Subject: [PATCH 04/15] Update src/MCP23017.cpp

That is quite more efficient!

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.cpp | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index aace7e5..578f625 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -22,13 +22,10 @@ void MCP23017::init()
 	writeRegister(MCP23017_REGISTER::GPPUA, 0xFF, 0xFF);
 }
 
-void MCP23017::portMode(MCP23017_PORT port, uint8_t value, bool inverted)
+void MCP23017::portMode(MCP23017_PORT port, uint8_t dir, uint8_t inverted)
 {
-	writeRegister(MCP23017_REGISTER::IODIRA + port, value);
-
-	if( inverted ){
-		writeRegister(MCP23017_REGISTER::IPOLA + port, value);
-	}
+   writeRegister(MCP23017_REGISTER::IODIRA + port, dir);
+   writeRegister(MCP23017_REGISTER::IPOLA + port, inverted);
 }
 
 void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)

From 1d75401f0de9be5d58a866f4825529a10e5ce303 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 17:54:03 +0100
Subject: [PATCH 05/15] Update src/MCP23017.h

See above.

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/MCP23017.h b/src/MCP23017.h
index 4cd5a43..cb47cff 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -85,7 +85,7 @@ class MCP23017
 	 * 
 	 * See "3.5.1 I/O Direction register".
 	 */
-	void portMode(MCP23017_PORT port, uint8_t value, bool inverted=false);
+	void portMode(MCP23017_PORT port, uint8_t dir, uint8_t inverted=0x00);
 	/**
 	 * Controls a single pin direction. 
 	 * Pin 0-7 for port A, 8-15 fo port B.
@@ -215,4 +215,4 @@ class MCP23017
 	void clearInterrupts(uint8_t& portA, uint8_t& portB);
 
 #endif
-};
\ No newline at end of file
+};

From 7b369a90ed1ed5582304294f3b059ae9b81ce79e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 18:22:13 +0100
Subject: [PATCH 06/15] Update src/MCP23017.cpp

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 578f625..e9bc8f7 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -62,7 +62,8 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 		 iodir |= _BV(pin);
 	}
 
-	writeRegister( iodirreg, iodir );
+	writeRegister(iodirreg, iodir);
+	writeRegister(polreg, pol);
 }
 
 void MCP23017::digitalWrite(uint8_t pin, uint8_t state)

From b048c19f172b433c23c4d48c780790fb290ca955 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 18:22:24 +0100
Subject: [PATCH 07/15] Update src/MCP23017.cpp

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index e9bc8f7..25d7307 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -59,7 +59,10 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 	if(mode == OUTPUT) {
 		iodir &= ~_BV(pin);
 	} else{
-		 iodir |= _BV(pin);
+	iodir |= _BV(pin);
+	
+	if(inverted) pol |= _BV(pin);
+	else pol &= ~_BV(pin);
 	}
 
 	writeRegister(iodirreg, iodir);

From 8bd158e955ff70e6172606b05c3f2c98e29efcfb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 18:22:34 +0100
Subject: [PATCH 08/15] Update src/MCP23017.cpp

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 25d7307..70ff192 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -56,6 +56,7 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 
 
 	iodir = readRegister(iodirreg);
+	pol = readRegister(polreg);
 	if(mode == OUTPUT) {
 		iodir &= ~_BV(pin);
 	} else{

From 76a6ede191474ee366c708171f59bf94c77cbf65 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Fri, 28 Feb 2020 18:23:00 +0100
Subject: [PATCH 09/15] Update src/MCP23017.cpp

You are right.

Co-Authored-By: Bertrand Lemasle <blemasle@gmail.com>
---
 src/MCP23017.cpp | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 70ff192..07a2ab0 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -37,23 +37,6 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 		iodirreg = MCP23017_REGISTER::IODIRB;
 		pin -= 8;
 	}
-	if( inverted && mode == INPUT ){
-
-	MCP23017_REGISTER reg;
-	uint8_t pol;
-
-	if( pin < 8 ) {
-		pol = readRegister(MCP23017_REGISTER::IPOLA);
-	} else {
-		pol = readRegister(MCP23017_REGISTER::IPOLB);
-	}
-	pol = readRegister(reg);
-	pol |= _BV(pin);
-
-	writeRegister( reg, pol );
-} 
-
-
 
 	iodir = readRegister(iodirreg);
 	pol = readRegister(polreg);

From 5892189de48d58f968e06610743309dc9b9d4eab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Fri, 28 Feb 2020 22:17:17 +0100
Subject: [PATCH 10/15] Added examples/InvertedInput/InvertedInputs.ino

---
 examples/InvertedInput/InvertedInputs.ino | 53 +++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 examples/InvertedInput/InvertedInputs.ino

diff --git a/examples/InvertedInput/InvertedInputs.ino b/examples/InvertedInput/InvertedInputs.ino
new file mode 100644
index 0000000..8ba2459
--- /dev/null
+++ b/examples/InvertedInput/InvertedInputs.ino
@@ -0,0 +1,53 @@
+#include <Arduino.h>
+#include <MCP23017.h>
+
+/**
+ * Please connect:
+ * 
+ *    A0  =>  B0
+ *    A1  =>  B1
+ *    A2  =>  B2
+ *    A3  =>  B3
+ *    A4  =>  B4
+ *    A5  =>  B5
+ *    A6  =>  B6
+ *    A7  =>  B7
+ */
+  
+MCP23017 mcp = MCP23017();
+
+void setup() {
+    Wire.begin();
+    mcp.init();
+
+    Serial.begin(115200);
+
+	// All pins on Port A are inverted inputs
+	mp.portMode( MCP23017_PORT::A, INPUT, 0b11111111 );
+	mp.portMode( MCP23017_PORT::B, OUTPUT );
+
+	for ( int i=8; i<16 ;i++ ){
+		mp.digitalWrite( i, HIGH );
+		if ( mp.digitalRead(i) == mp.digitalRead(i-8) ){
+			Serial.writeln( "Your connections are wrong, please check for it." );
+		}
+	}
+
+	for ( int i=0; i<16; i++ ){
+
+		if ( i< 8 )
+			mp.pinMode( i, INPUT, true );
+		else
+			mp.pinMode( i, OUTPUT );
+	}
+
+	for ( int i=0; i<8 ;i++ ){
+		mp.digitalWrite( i, HIGH );
+		if ( mp.digitalRead(i) == mp.digitalRead(i+8) ){
+			Serial.writeln( "Your connections are wrong, please check for it." );
+		}
+	}
+
+}
+
+void loop() {}
\ No newline at end of file

From 4c9b31db893c46510edfa6ea2eb0b545f86e20c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Sun, 1 Mar 2020 17:23:59 +0100
Subject: [PATCH 11/15] - Added examples/InvertedInput/InvertedInputs.ino -
 modified documentation

---
 examples/InvertedInput/InvertedInputs.ino  |  53 -------
 examples/InvertedInputs/InvertedInputs.ino | 105 +++++++++++++
 src/MCP23017.cpp                           |  63 +++++---
 src/MCP23017.h                             | 162 +++++++++++++--------
 4 files changed, 247 insertions(+), 136 deletions(-)
 delete mode 100644 examples/InvertedInput/InvertedInputs.ino
 create mode 100644 examples/InvertedInputs/InvertedInputs.ino

diff --git a/examples/InvertedInput/InvertedInputs.ino b/examples/InvertedInput/InvertedInputs.ino
deleted file mode 100644
index 8ba2459..0000000
--- a/examples/InvertedInput/InvertedInputs.ino
+++ /dev/null
@@ -1,53 +0,0 @@
-#include <Arduino.h>
-#include <MCP23017.h>
-
-/**
- * Please connect:
- * 
- *    A0  =>  B0
- *    A1  =>  B1
- *    A2  =>  B2
- *    A3  =>  B3
- *    A4  =>  B4
- *    A5  =>  B5
- *    A6  =>  B6
- *    A7  =>  B7
- */
-  
-MCP23017 mcp = MCP23017();
-
-void setup() {
-    Wire.begin();
-    mcp.init();
-
-    Serial.begin(115200);
-
-	// All pins on Port A are inverted inputs
-	mp.portMode( MCP23017_PORT::A, INPUT, 0b11111111 );
-	mp.portMode( MCP23017_PORT::B, OUTPUT );
-
-	for ( int i=8; i<16 ;i++ ){
-		mp.digitalWrite( i, HIGH );
-		if ( mp.digitalRead(i) == mp.digitalRead(i-8) ){
-			Serial.writeln( "Your connections are wrong, please check for it." );
-		}
-	}
-
-	for ( int i=0; i<16; i++ ){
-
-		if ( i< 8 )
-			mp.pinMode( i, INPUT, true );
-		else
-			mp.pinMode( i, OUTPUT );
-	}
-
-	for ( int i=0; i<8 ;i++ ){
-		mp.digitalWrite( i, HIGH );
-		if ( mp.digitalRead(i) == mp.digitalRead(i+8) ){
-			Serial.writeln( "Your connections are wrong, please check for it." );
-		}
-	}
-
-}
-
-void loop() {}
\ No newline at end of file
diff --git a/examples/InvertedInputs/InvertedInputs.ino b/examples/InvertedInputs/InvertedInputs.ino
new file mode 100644
index 0000000..1eb0e37
--- /dev/null
+++ b/examples/InvertedInputs/InvertedInputs.ino
@@ -0,0 +1,105 @@
+#include <Arduino.h>
+#include <MCP23017.h>
+
+/**
+ * Please connect:
+ *    A5  => SCL   (ON UNO R3)
+ *    A4  => SDA   (ON UNO R3)
+ *    A3  => RST   (ON UNO R3)
+ *    A0  =>  B0
+ *    A1  =>  B1
+ *    A2  =>  B2
+ *    A3  =>  B3
+ *    A4  =>  B4
+ *    A5  =>  B5
+ *    A6  =>  B6
+ *    A7  =>  B7
+ */
+
+#define MCP23017_ADDR 0x20
+  
+MCP23017 mcp = MCP23017(MCP23017_ADDR);
+
+void setup() {
+  
+    Serial.begin(115200);
+    delay(200);
+    //Serial.write(27); Serial.print("[2J"); // CLRSCR
+    //Serial.write(27); Serial.print("[H");  // HOME
+
+    pinMode( A3, OUTPUT );
+    
+    digitalWrite( A3, LOW );
+    delay(50);
+    digitalWrite( A3, HIGH );
+    delay(50);
+    
+    Wire.begin();
+    mcp.init();
+
+    bool error = false;
+  
+	  mcp.portMode( MCP23017_PORT::A, INPUT, 0xFF ); // PORT A is input inverted
+	  mcp.portMode( MCP23017_PORT::B, OUTPUT );      // PORT B is output
+    mcp.writePort (MCP23017_PORT::B, 0xFF);
+  
+    Serial.println("##### Checking setting port mode #####\n" );
+	  for ( uint8_t i=0; i<8 ; i++ ){
+      
+    error |= ( mcp.digitalRead(i) != mcp.digitalRead(i+8) );
+		if ( mcp.digitalRead(i) != HIGH ){
+			Serial.print( "Your connection ");
+      Serial.print( i );
+			Serial.print(" was wrong, please check it: " );
+      Serial.print("IN: " );
+      Serial.print( mcp.digitalRead(i) ? "HIGH" : "LOW" );
+      Serial.print(", OUT: " );
+      Serial.println( mcp.digitalRead(i+8) ? "HIGH" : "LOW" );
+		}
+	}
+	
+  if ( error )
+  Serial.println("--------- FAILED (see above) ----------");
+  else
+  Serial.println("------------- SUCCEEDED --------------");
+  
+  error = false;
+    digitalWrite( A3, LOW );
+    delay(50);
+    digitalWrite( A3, HIGH );
+ delay(50);
+ 
+  Serial.println("\n##### Checking setting pin mode #####\n" );
+  
+	for ( uint8_t i=0; i<16; i++ ){
+		if ( i< 8 )
+      mcp.pinMode( i, OUTPUT ); // PORT A is output
+		else
+      mcp.pinMode( i, INPUT, true );  // PORT B is input inverted
+	}
+
+   mcp.writePort (MCP23017_PORT::A, 0xFF);
+      Serial.print( mcp.readPort(MCP23017_PORT::B) );
+  
+	for ( uint8_t i=0; i<8 ; i++ ){
+    error |= ( mcp.digitalRead(i+8) != mcp.digitalRead(i) );
+//    if ( mcp.digitalRead(i+8) == HIGH ){
+    if ( true ){
+      Serial.print( "Your connection " );
+      Serial.print( i );
+      Serial.print(" was wrong, please check it: " );
+      Serial.print("IN: " );
+      Serial.print( mcp.digitalRead(i+8) ? "HIGH" : "LOW" );
+      Serial.print(", OUT: " );
+      Serial.println( mcp.digitalRead(i) ? "HIGH" : "LOW" );
+		}
+	}
+
+  if ( error )
+  Serial.println("--------- FAILED (see above) ----------");
+  else
+  Serial.println("------------- SUCCEEDED --------------");
+
+}
+
+void loop() {}
diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 07a2ab0..984c001 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -7,50 +7,69 @@ MCP23017::MCP23017(uint8_t address, TwoWire& bus) {
 
 MCP23017::~MCP23017() {}
 
-void MCP23017::init()
-{
-	//BANK = 	0 : sequential register addresses
-	//MIRROR = 	0 : use configureInterrupt 
-	//SEQOP = 	1 : sequential operation disabled, address pointer does not increment
-	//DISSLW = 	0 : slew rate enabled
-	//HAEN = 	0 : hardware address pin is always enabled on 23017
-	//ODR = 	0 : open drain output
-	//INTPOL = 	0 : interrupt active low
+void MCP23017::begin(uint8_t pullup_a, uint8_t pullup_b)
+{
+	//IOCON.BANK   = 	0 : sequential register addresses
+	//IOCON.MIRROR = 	0 : use configureInterrupt 
+	//IOCON.SEQOP  = 	1 : sequential operation disabled, address pointer does not increment
+	//IOCON.DISSLW = 	0 : slew rate enabled
+	//IOCON.HAEN   = 	0 : hardware address pin is always enabled on 23017
+	//IOCON.ODR    = 	0 : open drain output
+	//IOCON.INTPOL = 	0 : interrupt active low
+	//IOCON bit 0 is spare
 	writeRegister(MCP23017_REGISTER::IOCON, 0b00100000);
 
 	//enable all pull up resistors (will be effective for input pins only)
-	writeRegister(MCP23017_REGISTER::GPPUA, 0xFF, 0xFF);
+	writeRegister(MCP23017_REGISTER::GPPUA, pullup_a, pullup_b);
 }
 
-void MCP23017::portMode(MCP23017_PORT port, uint8_t dir, uint8_t inverted)
+void MCP23017::portMode(MCP23017_PORT port, uint8_t modes, uint8_t pullups, uint8_t inverteds)
 {
-   writeRegister(MCP23017_REGISTER::IODIRA + port, dir);
-   writeRegister(MCP23017_REGISTER::IPOLA + port, inverted);
+   writeRegister(MCP23017_REGISTER::IODIRA + port, modes);
+   writeRegister(MCP23017_REGISTER::IPOLA  + port, inverteds);
+   writeRegister(MCP23017_REGISTER::GPPUA  + port, pullups);
 }
 
 void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 {
 	MCP23017_REGISTER iodirreg = MCP23017_REGISTER::IODIRA;
+	MCP23017_REGISTER polreg   = MCP23017_REGISTER::IPOLA;
+	MCP23017_REGISTER pullreg  = MCP23017_REGISTER::GPPUA;
 	uint8_t iodir;
+	uint8_t pol;
+	uint8_t pull;
+
 	if(pin > 7)
 	{
 		iodirreg = MCP23017_REGISTER::IODIRB;
+		polreg = MCP23017_REGISTER::IPOLB;
+		pullreg = MCP23017_REGISTER::GPPUB;
 		pin -= 8;
 	}
 
 	iodir = readRegister(iodirreg);
 	pol = readRegister(polreg);
+	pull = readRegister(pullreg);
+
 	if(mode == OUTPUT) {
 		iodir &= ~_BV(pin);
+		pol &= ~_BV(pin);
 	} else{
-	iodir |= _BV(pin);
-	
-	if(inverted) pol |= _BV(pin);
-	else pol &= ~_BV(pin);
+		iodir |= _BV(pin);
+		
+		if(mode==INPUT_PULLUP) pull |= _BV(pin);
+		else pull &= ~_BV(pin);
+		
+		if(inverted) pol |= _BV(pin);
+		else pol &= ~_BV(pin);
 	}
 
 	writeRegister(iodirreg, iodir);
 	writeRegister(polreg, pol);
+
+	if(mode==INPUT_PULLUP){
+		writeRegister(pullreg, pull);
+	}
 }
 
 void MCP23017::digitalWrite(uint8_t pin, uint8_t state)
@@ -85,14 +104,14 @@ uint8_t MCP23017::digitalRead(uint8_t pin)
 	return LOW;
 }
 
-void MCP23017::writePort(MCP23017_PORT port, uint8_t value)
+void MCP23017::writePort(MCP23017_PORT port, uint8_t values)
 {
-	writeRegister(MCP23017_REGISTER::GPIOA + port, value);
+	writeRegister(MCP23017_REGISTER::GPIOA + port, values);
 }
 
-void MCP23017::write(uint16_t value)
+void MCP23017::write(uint16_t values)
 {
-	writeRegister(MCP23017_REGISTER::GPIOA, lowByte(value), highByte(value));
+	writeRegister(MCP23017_REGISTER::GPIOA, lowByte(values), highByte(values));
 }
 
 uint8_t MCP23017::readPort(MCP23017_PORT port)
@@ -194,7 +213,7 @@ void MCP23017::disableInterrupt(MCP23017_PORT port)
 
 void MCP23017::clearInterrupts()
 {
-	uint8_t a, b;
+	uint8_t a=0, b=0;
 	clearInterrupts(a, b);
 }
 
diff --git a/src/MCP23017.h b/src/MCP23017.h
index cb47cff..ce45ced 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -51,6 +51,7 @@ enum class MCP23017_REGISTER : uint8_t
 	OLATB		= 0x15,			///< Provides access to the port B output latches.
 };
 
+/// @brief operator for adding a B-offset to the A-register
 inline MCP23017_REGISTER operator+(MCP23017_REGISTER a, MCP23017_PORT b) {
 	return static_cast<MCP23017_REGISTER>(static_cast<uint8_t>(a) + static_cast<uint8_t>(b));
 };
@@ -63,119 +64,138 @@ class MCP23017
 public:
 	/**
 	 * Instantiates a new instance to interact with a MCP23017 at the specified address.
+	 * @param address: bus address of MCP23017 (0x20 ~ 0x27)
+	 * @param bus: refence to i2c bus object
 	 */
 	MCP23017(uint8_t address, TwoWire& bus = Wire);
 	~MCP23017();
 #ifdef _DEBUG
 	void debug();
 #endif
+
 	/**
 	 * Initializes the chip with the default configuration.
 	 * Enables Byte mode (IOCON.BANK = 0 and IOCON.SEQOP = 1).
-	 * Enables pull-up resistors for all pins. This will only be effective for input pins.
+	 * Enables pull-up resistors for all pins by default. 
+	 * This will only be effective for input pins.
+	 * <See "3.2.1 Byte mode and Sequential mode".>
 	 * 
+	 * @param pullup_a: bitmask for port A
+	 * @param pullup_b: bitmask for port B
 	 * See "3.2.1 Byte mode and Sequential mode".
 	 */
-	void init();
+	void begin(uint8_t pullup_a=0xFF, uint8_t pullup_b=0xFF);
+
 	/**
 	 * Controls the pins direction on a whole port at once.
+	 * <See "3.5.1 I/O IODIR I/O DIRECTION REGISTER <0x00>", 
+	 *      "3.5.2 I NPUT POLARITY REGISTER <0x01>",
+	 *      "3.5.7 PULL-UP RESISTOR CONFIGURATION REGISTER <0x06>">
+	 * @param port:      MCP23017 port A or B
+	 * @param modes:     direction of whole port
+	 * 		       INPUT or 0x0
+	 *             OUTPUT or0x01
+	 * @param pullup:    bitmask for internal 100k pullup resistors
+	 * @param inverteds: bitmask for inverted mode
 	 * 
-	 * 1 = Pin is configured as an input.
-	 * 0 = Pin is configured as an output.
-	 * 
-	 * See "3.5.1 I/O Direction register".
 	 */
-	void portMode(MCP23017_PORT port, uint8_t dir, uint8_t inverted=0x00);
+	void portMode(MCP23017_PORT port, uint8_t modes, uint8_t pullups=0xFF, uint8_t inverteds=0x00);
+
 	/**
-	 * Controls a single pin direction. 
-	 * Pin 0-7 for port A, 8-15 fo port B.
-	 * 
-	 * 1 = Pin is configured as an input.
-	 * 0 = Pin is configured as an output.
-	 *
-	 * See "3.5.1 I/O Direction register".
+	 * Sets a single pins' direction. When the pin is an input pin
+	 * a pullup and/or an inverted option can be specified
+	 * <See "3.5.1 I/O IODIR I/O DIRECTION REGISTER <0x00>", 
+	 *      "3.5.2 I NPUT POLARITY REGISTER <0x01>",
+	 *      "3.5.7 PULL-UP RESISTOR CONFIGURATION REGISTER <0x06>">
+	 * @param pin: Controls a single pin direction. 
+	 *       Pin 0-7 for port A, 8-15 fo port B.
+	 * @param mode: 
+	 *             INPUT or 0x00
+	 *             INPUT_PULLUP or 0x02
+	 *             OUTPUT or 0x01
 	 */
 	void pinMode(uint8_t pin, uint8_t mode, bool inverted=false);
 
 	/**
 	 * Writes a single pin state.
-	 * Pin 0-7 for port A, 8-15 for port B.
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param pin:   Pin 0-7 for port A, 8-15 for port B.
+	 * @param state: HIGH or 0x01
+	 *         LOW  or 0x00
 	 */
 	void digitalWrite(uint8_t pin, uint8_t state);
+
 	/**
 	 * Reads a single pin state.
-	 * Pin 0-7 for port A, 8-15 for port B.
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param pin:   Pin 0-7 for port A, 8-15 for port B.
+	 * @param return HIGH or 0x01, LOW or 0x00 
+	 *         depending the hardwarestate of the pin
 	 */ 
 	uint8_t digitalRead(uint8_t pin);
 
 	/**
 	 * Writes pins state to a whole port.
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param port:      MCP23017 port A or B
+	 * @param values:    bitmask to manipulate the given port as OUTPUT
 	 */
-	void writePort(MCP23017_PORT port, uint8_t value);
+	void writePort(MCP23017_PORT port, uint8_t values);
+
 	/**
 	 * Writes pins state to both ports.
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param values:    bitmask to manipulate all OUTPUT of the chip
 	 */
-	void write(uint16_t value);
+	void write(uint16_t values);
 
 	/**
 	 * Reads pins state for a whole port.
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param port:  MCP23017 port A or B
+	 * @param return HIGH or 0x01, LOW or 0x00 
+	 *         depending the hardwarestate of the pin
 	 */
 	uint8_t readPort(MCP23017_PORT port);
+
 	/**
 	 * Reads pins state for both ports. 
-	 * 
-	 * 1 = Logic-high
-	 * 0 = Logic-low
-	 * 
-	 * See "3.5.10 Port register".
+	 * <See "3.5.10 Port register <0x09>".>
+	 * @param return HIGH or 0x01, LOW or 0x00 
+	 *         depending the hardwarestate of the pin
 	 */
 	uint16_t read();
 
 	/**
-	 * Writes a single register value.
+	 * Writes a single register @reg with the specified value @val.
 	 */
 	void writeRegister(MCP23017_REGISTER reg, uint8_t value);
+
 	/**
 	 * Writes values to a register pair.
 	 * 
-	 * For portA and portB variable to effectively match the desired port,
+	 * @note For portA and portB variable to effectively match the desired port,
 	 * you have to supply a portA register address to reg. Otherwise, values
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
 	 */
 	void writeRegister(MCP23017_REGISTER reg, uint8_t portA, uint8_t portB);
+
 	/**
-	 * Reads a single register value.
+	 * Reads a single registers value.
+	 * @param reg: register to read
+	 *       port A: 0x00 ~ 0A0
+	 *       port B: 0x10 ~ 1A0
 	 */
 	uint8_t readRegister(MCP23017_REGISTER reg);
+
 	/**
 	 * Reads the values from a register pair.
+	 * @param reg:   register to read
+	 *               port A: 0x00 ~ 0A0
+	 * @param portA: reference to port A value; returns the value by reference
+	 * @param portB: reference to port B value; returns the value by reference
 	 * 
-	 * For portA and portB variable to effectively match the desired port,
+	 * @note For portA and portB variable to effectively match the desired port,
 	 * you have to supply a portA register address to reg. Otherwise, values
 	 * will be reversed due to the way the MCP23017 works in Byte mode.
 	 */
@@ -184,33 +204,53 @@ class MCP23017
 #ifdef _MCP23017_INTERRUPT_SUPPORT_
 
 	/**
-	 * Controls how the interrupt pins act with each other.
+	 * @brief Controls how the interrupt pins act with each other.
 	 * If intMode is SEPARATED, interrupt conditions on a port will cause its respective INT pin to active.
 	 * If intMode is OR, interrupt pins are OR'ed so an interrupt on one of the port will cause both pints to active.
+	 * <See "3.5.6 I/O EXPANDER CONFIGURATION REGISTER <0x05>".>
 	 * 
-	 * Controls the IOCON.MIRROR bit. 
-	 * See "3.5.6 Configuration register".
+	 * @param intMode  Controls the IOCON.MIRROR bit
 	 */
 	void interruptMode(MCP23017_INTMODE intMode);
+
 	/**
-	 * Configures interrupt registers using an Arduino-like API.
-	 * mode can be one of CHANGE, FALLING or RISING.
+	 * @brief Configures interrupt registers using an Arduino-like API-mode .
+	 * <See "3.5.3 INTERRUPT-ON-CHANGE CONTROL REGISTER".>
+	 * 
+	 * @param port   MCP23017 port A or B
+	 * @param mode   Can be one of CHANGE, FALLING or RISING
 	 */
 	void interrupt(MCP23017_PORT port, uint8_t mode);
+
 	/**
-	 * Disable interrupts for the specified port.
+	 * @brief Disables interrupts for the specified port.
+	 * <See "3.5.3 INTERRUPT-ON-CHANGE CONTROL REGISTER".>
+	 * 
+	 * @param port MCP23017 port A or B
 	 */
 	void disableInterrupt(MCP23017_PORT port);
+
 	/**
-	 * Reads which pin caused the interrupt.
+	 * @brief Reads which pin caused the interrupt.
+	 * <See "3.5.9 GPINTEN: INTERRUPT CAPTURED REGISTER".>
+	 * 
+	 * @param portA reference to port A value; returns the value by reference
+	 * @param portB reference to port B value; returns the value by reference
 	 */
 	void interruptedBy(uint8_t& portA, uint8_t& portB);
+
 	/**
-	 * Clears interrupts on both ports.
+	 * @brief Clears interrupts on both ports.
+	 * <See "3.5.9 INTERRUPT CAPTURED REGISTER".>
 	 */
 	void clearInterrupts();
+
 	/**
-	 * Clear interrupts on both ports. Returns port values at the time the interrupt occured.
+	 * @brief Clear interrupts on both ports. Returns port values at the time the interrupt occured.
+	 * <See "3.5.9 INTERRUPT CAPTURED REGISTER".>
+	 * 
+	 * @param portA reference to port A value; returns the value by reference
+	 * @param portB reference to port B value; returns the value by reference
 	 */
 	void clearInterrupts(uint8_t& portA, uint8_t& portB);
 

From 7ab6cdf5439c00b70806d5a62a5f10c25d166132 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Sun, 1 Mar 2020 19:06:24 +0100
Subject: [PATCH 12/15] Fixed pinMode()

---
 src/MCP23017.cpp | 52 +++++++++++++++++++++++++++++-------------------
 src/MCP23017.h   | 21 +++++++++++++------
 2 files changed, 46 insertions(+), 27 deletions(-)

diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 984c001..3e168b1 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -35,9 +35,6 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 	MCP23017_REGISTER iodirreg = MCP23017_REGISTER::IODIRA;
 	MCP23017_REGISTER polreg   = MCP23017_REGISTER::IPOLA;
 	MCP23017_REGISTER pullreg  = MCP23017_REGISTER::GPPUA;
-	uint8_t iodir;
-	uint8_t pol;
-	uint8_t pull;
 
 	if(pin > 7)
 	{
@@ -47,29 +44,42 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 		pin -= 8;
 	}
 
-	iodir = readRegister(iodirreg);
-	pol = readRegister(polreg);
-	pull = readRegister(pullreg);
+	uint8_t iodir = readRegister(iodirreg);
+	uint8_t pol   = readRegister(polreg);
+	uint8_t pull  = readRegister(pullreg);
 
-	if(mode == OUTPUT) {
-		iodir &= ~_BV(pin);
-		pol &= ~_BV(pin);
-	} else{
+	if(mode == OUTPUT) 
+	{
 		iodir |= _BV(pin);
+		pol   &= ~_BV(pin);
+		pull  &= ~_BV(pin);
+	} 
+	else
+	{
+		iodir &= ~_BV(pin);
 		
-		if(mode==INPUT_PULLUP) pull |= _BV(pin);
-		else pull &= ~_BV(pin);
-		
-		if(inverted) pol |= _BV(pin);
-		else pol &= ~_BV(pin);
-	}
-
-	writeRegister(iodirreg, iodir);
-	writeRegister(polreg, pol);
+		if(mode==INPUT_PULLUP)
+		{
+			pull |= _BV(pin); 
+		}  
+		else 
+		{
+			pull &= ~_BV(pin);
+		}
 
-	if(mode==INPUT_PULLUP){
 		writeRegister(pullreg, pull);
+		
+		if(inverted) 
+		{
+			pol |= _BV(pin); 
+		}
+		else
+		{
+			pol &= ~_BV(pin);
+		}
+		writeRegister(polreg, pol);
 	}
+	writeRegister(iodirreg, iodir);
 }
 
 void MCP23017::digitalWrite(uint8_t pin, uint8_t state)
@@ -222,4 +232,4 @@ void MCP23017::clearInterrupts(uint8_t& portA, uint8_t& portB)
 	readRegister(MCP23017_REGISTER::INTCAPA, portA, portB);
 }
 
-#endif
+#endif //  _MCP23017_INTERRUPT_SUPPORT_
diff --git a/src/MCP23017.h b/src/MCP23017.h
index ce45ced..7a866a6 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -3,7 +3,7 @@
 #include <Arduino.h>
 #include <Wire.h>
 
-#define _MCP23017_INTERRUPT_SUPPORT_ ///< Enables support for MCP23017 interrupts.
+#define _MCP23017_INTERRUPT_SUPPORT_  ///< Enables support for MCP23017 interrupts.
 
 enum class MCP23017_PORT : uint8_t
 {
@@ -13,7 +13,7 @@ enum class MCP23017_PORT : uint8_t
 
 /**
  * Controls if the two interrupt pins mirror each other.
- * See "3.6 Interrupt Logic".
+ * <See "3.6 Interrupt Logic".>
  */
 enum class MCP23017_INTMODE : uint8_t
 {
@@ -24,7 +24,7 @@ enum class MCP23017_INTMODE : uint8_t
 /**
  * Registers addresses.
  * The library use addresses for IOCON.BANK = 0.
- * See "3.2.1 Byte mode and Sequential mode".
+ * <See "3.2.1 Byte mode and Sequential mode".>
  */
 enum class MCP23017_REGISTER : uint8_t
 {
@@ -73,6 +73,14 @@ class MCP23017
 	void debug();
 #endif
 
+	/**
+	 * @brief deprecated, for backward compability only
+	 * 
+	 */
+	inline void init(){
+		begin();
+	}
+
 	/**
 	 * Initializes the chip with the default configuration.
 	 * Enables Byte mode (IOCON.BANK = 0 and IOCON.SEQOP = 1).
@@ -84,7 +92,7 @@ class MCP23017
 	 * @param pullup_b: bitmask for port B
 	 * See "3.2.1 Byte mode and Sequential mode".
 	 */
-	void begin(uint8_t pullup_a=0xFF, uint8_t pullup_b=0xFF);
+	void begin(uint8_t pullup_a=0x00, uint8_t pullup_b=0x00);
 
 	/**
 	 * Controls the pins direction on a whole port at once.
@@ -99,7 +107,7 @@ class MCP23017
 	 * @param inverteds: bitmask for inverted mode
 	 * 
 	 */
-	void portMode(MCP23017_PORT port, uint8_t modes, uint8_t pullups=0xFF, uint8_t inverteds=0x00);
+	void portMode(MCP23017_PORT port, uint8_t modes, uint8_t pullups=0xff, uint8_t inverteds=0x00);
 
 	/**
 	 * Sets a single pins' direction. When the pin is an input pin
@@ -222,6 +230,7 @@ class MCP23017
 	 */
 	void interrupt(MCP23017_PORT port, uint8_t mode);
 
+
 	/**
 	 * @brief Disables interrupts for the specified port.
 	 * <See "3.5.3 INTERRUPT-ON-CHANGE CONTROL REGISTER".>
@@ -254,5 +263,5 @@ class MCP23017
 	 */
 	void clearInterrupts(uint8_t& portA, uint8_t& portB);
 
-#endif
+#endif //  _MCP23017_INTERRUPT_SUPPORT_
 };

From 1baf2a04deef6b2e3e2b36a77030c83fa2c9c4cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Sun, 1 Mar 2020 19:30:55 +0100
Subject: [PATCH 13/15] added interrupt capability in InvertedInputs.ino

---
 examples/InvertedInputs/InvertedInputs.ino | 188 ++++++++++++---------
 src/MCP23017.cpp                           |   5 +-
 src/MCP23017.h                             |   2 +-
 3 files changed, 114 insertions(+), 81 deletions(-)

diff --git a/examples/InvertedInputs/InvertedInputs.ino b/examples/InvertedInputs/InvertedInputs.ino
index 1eb0e37..550d93a 100644
--- a/examples/InvertedInputs/InvertedInputs.ino
+++ b/examples/InvertedInputs/InvertedInputs.ino
@@ -1,4 +1,6 @@
 #include <Arduino.h>
+
+#define MCP23017_INTERRUPT_SUPPORT 1
 #include <MCP23017.h>
 
 /**
@@ -17,89 +19,119 @@
  */
 
 #define MCP23017_ADDR 0x20
-  
+
 MCP23017 mcp = MCP23017(MCP23017_ADDR);
 
-void setup() {
-  
-    Serial.begin(115200);
-    delay(200);
-    //Serial.write(27); Serial.print("[2J"); // CLRSCR
-    //Serial.write(27); Serial.print("[H");  // HOME
-
-    pinMode( A3, OUTPUT );
-    
-    digitalWrite( A3, LOW );
-    delay(50);
-    digitalWrite( A3, HIGH );
-    delay(50);
-    
-    Wire.begin();
-    mcp.init();
-
-    bool error = false;
-  
-	  mcp.portMode( MCP23017_PORT::A, INPUT, 0xFF ); // PORT A is input inverted
-	  mcp.portMode( MCP23017_PORT::B, OUTPUT );      // PORT B is output
-    mcp.writePort (MCP23017_PORT::B, 0xFF);
-  
-    Serial.println("##### Checking setting port mode #####\n" );
-	  for ( uint8_t i=0; i<8 ; i++ ){
-      
-    error |= ( mcp.digitalRead(i) != mcp.digitalRead(i+8) );
-		if ( mcp.digitalRead(i) != HIGH ){
-			Serial.print( "Your connection ");
-      Serial.print( i );
-			Serial.print(" was wrong, please check it: " );
-      Serial.print("IN: " );
-      Serial.print( mcp.digitalRead(i) ? "HIGH" : "LOW" );
-      Serial.print(", OUT: " );
-      Serial.println( mcp.digitalRead(i+8) ? "HIGH" : "LOW" );
-		}
-	}
-	
-  if ( error )
-  Serial.println("--------- FAILED (see above) ----------");
+void int_pinA(){
+  Serial.println("\n#####   INTERRUPT PORT A FIRED   #####\n");
+}
+
+void int_pinB(){
+  Serial.println("\n#####   INTERRUPT PORT B FIRED   #####\n");
+}
+
+void setup()
+{
+  Serial.begin(115200);
+  delay(200);
+  // Serial.write(27); Serial.print("[2J"); // CLRSCR
+  // Serial.write(27); Serial.print("[H");  // HOME
+
+  // reset pin
+  pinMode(A3, OUTPUT);
+  digitalWrite(A3, LOW);
+  delay(50);
+  digitalWrite(A3, HIGH);
+  delay(50);
+
+  // interrupt pins
+  pinMode(2, INPUT_PULLUP);
+  pinMode(3, INPUT_PULLUP);
+
+  attachInterrupt(digitalPinToInterrupt(2), int_pinA, RISING);
+  attachInterrupt(digitalPinToInterrupt(3), int_pinB, RISING);
+
+  Wire.begin();
+  mcp.begin(0x00, 0x00);
+  mcp.interruptMode(MCP23017_INTMODE::SEPARATED);
+  mcp.interrupt(MCP23017_PORT::A, CHANGE);
+  mcp.interrupt(MCP23017_PORT::B, CHANGE);
+
+  bool error = false;
+
+  // PORT A is input inverted with pullups
+  mcp.portMode( MCP23017_PORT::A, INPUT, 0xFF, 0xFF); 
+  mcp.clearInterrupts();
+
+  // PORT B is output
+  mcp.portMode(MCP23017_PORT::B, OUTPUT);
+
+  // Set all output pins to HIGH
+  mcp.writePort(MCP23017_PORT::B, 0xFF);
+
+  Serial.println("##### Checking setting port mode #####\n");
+  for (uint8_t i = 0; i < 8; i++)
+  {
+
+    error |= (mcp.digitalRead(i) != mcp.digitalRead(i + 8));
+    if (error)
+    {
+      Serial.print("Your connection ");
+      Serial.print(i);
+      Serial.print(" was wrong, please check it: ");
+      Serial.print("IN: ");
+      Serial.print(mcp.digitalRead(i) ? "HIGH" : "LOW");
+      Serial.print(", OUT: ");
+      Serial.println(mcp.digitalRead(i + 8) ? "HIGH" : "LOW");
+    }
+  }
+
+  if (error)
+    Serial.println("--------- FAILED (see above) ----------");
   else
-  Serial.println("------------- SUCCEEDED --------------");
-  
+    Serial.println("------------- SUCCEEDED --------------");
+
   error = false;
-    digitalWrite( A3, LOW );
-    delay(50);
-    digitalWrite( A3, HIGH );
- delay(50);
- 
-  Serial.println("\n##### Checking setting pin mode #####\n" );
-  
-	for ( uint8_t i=0; i<16; i++ ){
-		if ( i< 8 )
-      mcp.pinMode( i, OUTPUT ); // PORT A is output
-		else
-      mcp.pinMode( i, INPUT, true );  // PORT B is input inverted
-	}
-
-   mcp.writePort (MCP23017_PORT::A, 0xFF);
-      Serial.print( mcp.readPort(MCP23017_PORT::B) );
-  
-	for ( uint8_t i=0; i<8 ; i++ ){
-    error |= ( mcp.digitalRead(i+8) != mcp.digitalRead(i) );
-//    if ( mcp.digitalRead(i+8) == HIGH ){
-    if ( true ){
-      Serial.print( "Your connection " );
-      Serial.print( i );
-      Serial.print(" was wrong, please check it: " );
-      Serial.print("IN: " );
-      Serial.print( mcp.digitalRead(i+8) ? "HIGH" : "LOW" );
-      Serial.print(", OUT: " );
-      Serial.println( mcp.digitalRead(i) ? "HIGH" : "LOW" );
-		}
-	}
-
-  if ( error )
-  Serial.println("--------- FAILED (see above) ----------");
-  else
-  Serial.println("------------- SUCCEEDED --------------");
+  mcp.clearInterrupts();
+
+  Serial.println("\n##### Checking setting pin mode #####\n");
+
+  for (uint8_t i = 0; i < 16; i++)
+  {
+    if (i < 8)
+    {
+      // PORT A is output for now
+      mcp.pinMode(i, OUTPUT); 
+    }
+    else
+    {
+      // PORT B is input for now, inverted inputs with pullups
+      mcp.pinMode(i, INPUT_PULLUP, true);
+    }
+  }
 
+  // Set all output pins to HIGH
+  mcp.writePort(MCP23017_PORT::A, 0xFF);  
+
+  for (uint8_t i = 0; i < 8; i++)
+  {
+    error |= (mcp.digitalRead(i) != mcp.digitalRead(i + 8));
+    if (error)
+    {
+      Serial.print("Your connection ");
+      Serial.print(i);
+      Serial.print(" was wrong, please check it: ");
+      Serial.print("IN: ");
+      Serial.print(mcp.digitalRead(i + 8) ? "HIGH" : "LOW");
+      Serial.print(", OUT: ");
+      Serial.println(mcp.digitalRead(i) ? "HIGH" : "LOW");
+    }
+  }
+
+  if (error)
+    Serial.println("--------- FAILED (see above) ----------");
+  else
+    Serial.println("------------- SUCCEEDED --------------");
 }
 
 void loop() {}
diff --git a/src/MCP23017.cpp b/src/MCP23017.cpp
index 3e168b1..da02b49 100644
--- a/src/MCP23017.cpp
+++ b/src/MCP23017.cpp
@@ -67,7 +67,6 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 			pull &= ~_BV(pin);
 		}
 
-		writeRegister(pullreg, pull);
 		
 		if(inverted) 
 		{
@@ -77,8 +76,10 @@ void MCP23017::pinMode(uint8_t pin, uint8_t mode, bool inverted)
 		{
 			pol &= ~_BV(pin);
 		}
-		writeRegister(polreg, pol);
 	}
+
+	writeRegister(polreg, pol);
+	writeRegister(pullreg, pull);
 	writeRegister(iodirreg, iodir);
 }
 
diff --git a/src/MCP23017.h b/src/MCP23017.h
index 7a866a6..a23524f 100644
--- a/src/MCP23017.h
+++ b/src/MCP23017.h
@@ -217,7 +217,7 @@ class MCP23017
 	 * If intMode is OR, interrupt pins are OR'ed so an interrupt on one of the port will cause both pints to active.
 	 * <See "3.5.6 I/O EXPANDER CONFIGURATION REGISTER <0x05>".>
 	 * 
-	 * @param intMode  Controls the IOCON.MIRROR bit
+	 * @param intMode  When OR, the INTn pins are functionally OR’ed so that an interrupt on either port will cause both pins to activate. Otherwise use SEPARATED as parameter.
 	 */
 	void interruptMode(MCP23017_INTMODE intMode);
 

From 0fa87a0549e379ec77c5ca3a4e9eb2f5abb58033 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <joerg@bernau.family>
Date: Sun, 1 Mar 2020 20:12:44 +0100
Subject: [PATCH 14/15] Added comment to InvertedInputs.ino

---
 examples/InvertedInputs/InvertedInputs.ino | 30 ++++++++++++++--------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/examples/InvertedInputs/InvertedInputs.ino b/examples/InvertedInputs/InvertedInputs.ino
index 550d93a..cd57b90 100644
--- a/examples/InvertedInputs/InvertedInputs.ino
+++ b/examples/InvertedInputs/InvertedInputs.ino
@@ -4,18 +4,26 @@
 #include <MCP23017.h>
 
 /**
+ * This sketch demonstrates the pin capabilities in pin- and portmode. 
+ * Each of the 16 bits can eigher  be an input which is inverted or not 
+ * or having a 100k pullup resistor in same mode or just beeing an output.
+ * 
+ * Some Interrupt capabilites are also shown
+ * 
  * Please connect:
- *    A5  => SCL   (ON UNO R3)
- *    A4  => SDA   (ON UNO R3)
- *    A3  => RST   (ON UNO R3)
- *    A0  =>  B0
- *    A1  =>  B1
- *    A2  =>  B2
- *    A3  =>  B3
- *    A4  =>  B4
- *    A5  =>  B5
- *    A6  =>  B6
- *    A7  =>  B7
+ *    A5   => SCL   (ON UNO R3)
+ *    A4   => SDA   (ON UNO R3)
+ *    A3   => RST   (ON UNO R3)
+ *    INTA =>  D2   (ON UNO R3)
+ *    INTB =>  D3   (ON UNO R3)
+ *    A0   =>  B0
+ *    A1   =>  B1
+ *    A2   =>  B2
+ *    A3   =>  B3
+ *    A4   =>  B4
+ *    A5   =>  B5
+ *    A6   =>  B6
+ *    A7   =>  B7
  */
 
 #define MCP23017_ADDR 0x20

From ccf1ad454e5e13aa801e095f7195b1eb739f1436 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Bernau?= <Joerg.Bernau@web.de>
Date: Wed, 4 Mar 2020 13:29:25 +0100
Subject: [PATCH 15/15] Add files via upload

---
 DOCUMENTATION.MD | 721 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 721 insertions(+)
 create mode 100644 DOCUMENTATION.MD

diff --git a/DOCUMENTATION.MD b/DOCUMENTATION.MD
new file mode 100644
index 0000000..219c471
--- /dev/null
+++ b/DOCUMENTATION.MD
@@ -0,0 +1,721 @@
+<div id="top">
+
+<div id="titlearea">
+
+<table>
+<colgroup>
+<col style="width: 100%" />
+</colgroup>
+<tbody>
+<tr class="odd">
+<td><div id="projectname">
+
+</div>
+<div id="projectbrief">
+MCP23017 16-Bit I/O Expander with Serial Interface
+</div></td>
+</tr>
+</tbody>
+</table>
+
+</div>
+
+<div id="main-nav">
+
+</div>
+
+<div id="MSearchSelectWindow" onmouseover="return searchBox.OnSearchSelectShow()" onmouseout="return searchBox.OnSearchSelectHide()" onkeydown="return searchBox.OnSearchSelectKey(event)">
+
+</div>
+
+<div id="MSearchResultsWindow">
+
+</div>
+
+</div>
+
+<div class="header">
+
+</div>
+
+</div>
+
+<div class="contents">
+
+## <span id="pub-methods"></span> Public Member Functions
+
+</div>
+
+#### [MCP23017](#mcp23017) (uint8\_t address, TwoWire \&bus=Wire)
+#### void [init](#init)()
+#### void [begin](#BEGIN)(uint8\_t pullup\_a=0x00, uint8\_t pullup\_b=0x00)
+#### void [portMode](#400)(MCP23017\_PORT port, uint8\_t modes, uint8\_t pullups=0xff, uint8\_t inverteds=0x00)
+#### void [pinMode](#500)(uint8\_t pin, uint8\_t mode, bool inverted=false)
+#### void [digitalWrite](#600)(uint8\_t pin, uint8\_t state)
+#### uint8\_t [digitalRead](#700)(uint8\_t pin)
+#### void [writePort](#800)(MCP23017\_PORT port, uint8\_t values)
+#### void [write](#900)(uint16\_t values)
+#### uint8\_t [readPort](#1000)(MCP23017\_PORT port)
+#### uint16\_t [read](#1100)()
+#### void [writeRegister](#1200)(MCP23017\_REGISTER reg, uint8\_t value)
+#### void [writeRegister](#1300)(MCP23017\_REGISTER reg, uint8\_t portA, uint8\_t portB)
+#### uint8\_t [readRegister](#1400)(MCP23017\_REGISTER reg)
+#### void [readRegister](#1500)(MCP23017\_REGISTER reg, uint8\_t \&portA, uint8\_t \&portB)
+#### void [interruptMode](#1600)(MCP23017\_INTMODE intMode)
+#### void [interrupt](#1700)(MCP23017\_PORT port, uint8\_t mode)
+#### void [disableInterrupt](#1800)(MCP23017\_PORT port)
+#### void [interruptedBy](#1900)(uint8\_t \&portA, uint8\_t \&portB)
+#### void [clearInterrupts](#2000)()
+#### void [clearInterrupts](#2100)(uint8\_t \&portA, uint8\_t \&portB)
+
+## Constructor & Destructor Documentation
+
+## <span class="permalink">[◆ ](#TOC)</span>MCP23017()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                    |   |           |                |
+| ------------------ | - | --------- | -------------- |
+| MCP23017::MCP23017 | ( | uint8\_t  | *address*,     |
+|                    |   | TwoWire & | *bus* = `Wire` |
+|                    | ) |           |                |
+
+</div>
+
+<div class="memdoc">
+
+Instantiates a new instance to interact with a MCP23017 at the specified
+address.
+
+  - Parameters
+    
+    |         |                                        |
+    | ------- | -------------------------------------- |
+    | address | bus address of MCP23017 (0x20 \~ 0x27) |
+    | bus     | refence to i2c bus object              |
+    
+
+</div>
+
+</div>
+
+## Member Function Documentation
+
+## <span class="permalink">[◆ ](#TOC)</span>begin()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                      |   |          |                       |
+| -------------------- | - | -------- | --------------------- |
+| void MCP23017::begin | ( | uint8\_t | *pullup\_a* = `0x00`, |
+|                      |   | uint8\_t | *pullup\_b* = `0x00`  |
+|                      | ) |          |                       |
+
+</div>
+
+<div class="memdoc">
+
+Initializes the chip with the default configuration. Enables Byte mode
+(IOCON.BANK = 0 and IOCON.SEQOP = 1). Enables pull-up resistors for all
+pins by default. This will only be effective for input pins.
+
+  - Note  
+    See: "3.2.1 Byte mode and Sequential mode"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |           |                                                               |
+    | --------- | ------------------------------------------------------------- |
+    | pullup\_a | bitmask for port A                                            |
+    | pullup\_b | bitmask for port B See "3.2.1 Byte mode and Sequential mode". |
+    
+
+</div>
+
+</div>
+
+<span id="a47e31859ed3fdd709d60dee11239042f"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>clearInterrupts() <span class="overload">\[1/2\]</span>
+
+<div class="memitem">
+
+<div class="memdoc">
+
+Clears interrupts on both ports.
+
+  - Note  
+    See: "3.5.9 INTERRUPT CAPTURED REGISTER"
+
+</div>
+
+</div>
+
+<span id="aed02c9fef408d86f1369254e17cd6c2b"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>clearInterrupts() <span class="overload">\[2/2\]</span>
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                                |   |            |          |
+| ------------------------------ | - | ---------- | -------- |
+| void MCP23017::clearInterrupts | ( | uint8\_t & | *portA*, |
+|                                |   | uint8\_t & | *portB*  |
+|                                | ) |            |          |
+
+</div>
+
+<div class="memdoc">
+
+Clear interrupts on both ports. Returns port values at the time the
+interrupt occured.
+
+  - Note  
+    See: "3.5.9 INTERRUPT CAPTURED REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |       |                                                           |
+    | ----- | --------------------------------------------------------- |
+    | portA | reference to port A value; returns the value by reference |
+    | portB | reference to port B value; returns the value by reference |
+    
+
+</div>
+
+</div>
+
+<span id="a47eb64469c2dc6d1b9e0ba7637f0bebd"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>digitalRead()
+
+<div class="memitem">
+
+<div class="memdoc">
+
+Reads a single pin state.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |        |                                                                  |
+    | ------ | ---------------------------------------------------------------- |
+    | pin    | Pin 0-7 for port A, 8-15 for port B.                             |
+    | return | HIGH or 0x01, LOW or 0x00 depending the hardwarestate of the pin |
+    
+
+</div>
+
+</div>
+
+<span id="a148aa7b0464c6bee4d50ab591636605b"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>digitalWrite()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                             |   |          |         |
+| --------------------------- | - | -------- | ------- |
+| void MCP23017::digitalWrite | ( | uint8\_t | *pin*,  |
+|                             |   | uint8\_t | *state* |
+|                             | ) |          |         |
+
+</div>
+
+<div class="memdoc">
+
+Writes a single pin state.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |       |                                      |
+    | ----- | ------------------------------------ |
+    | pin   | Pin 0-7 for port A, 8-15 for port B. |
+    | state | HIGH or 0x01 LOW or 0x00             |
+    
+
+</div>
+
+</div>
+
+<span id="af8b8a5ee7578effe78be5cfc4c31319b"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>disableInterrupt()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                                 |   |                |        |   |
+| ------------------------------- | - | -------------- | ------ | - |
+| void MCP23017::disableInterrupt | ( | MCP23017\_PORT | *port* | ) |
+
+</div>
+
+<div class="memdoc">
+
+Disables interrupts for the specified port.
+
+  - Note  
+    See: "3.5.3 INTERRUPT-ON-CHANGE CONTROL REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |      |                      |
+    | ---- | -------------------- |
+    | port | MCP23017 port A or B |
+    
+
+</div>
+
+</div>
+
+<span id="adb0e51e254e2af89455a155f313e8ce8"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>interrupt()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                          |   |                |         |
+| ------------------------ | - | -------------- | ------- |
+| void MCP23017::interrupt | ( | MCP23017\_PORT | *port*, |
+|                          |   | uint8\_t       | *mode*  |
+|                          | ) |                |         |
+
+</div>
+
+<div class="memdoc">
+
+Configures interrupt registers using an Arduino-like API-mode .
+
+  - Note  
+    See: "3.5.3 INTERRUPT-ON-CHANGE CONTROL REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |      |                                         |
+    | ---- | --------------------------------------- |
+    | port | MCP23017 port A or B                    |
+    | mode | Can be one of CHANGE, FALLING or RISING |
+    
+
+</div>
+
+</div>
+
+<span id="a821758bb3e5197e817ad43b61c898a92"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>interruptedBy()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                              |   |            |          |
+| ---------------------------- | - | ---------- | -------- |
+| void MCP23017::interruptedBy | ( | uint8\_t & | *portA*, |
+|                              |   | uint8\_t & | *portB*  |
+|                              | ) |            |          |
+
+</div>
+
+<div class="memdoc">
+
+Reads which pin caused the interrupt.
+
+  - Note  
+    See: "3.5.9 GPINTEN: INTERRUPT CAPTURED REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |       |                                                           |
+    | ----- | --------------------------------------------------------- |
+    | portA | reference to port A value; returns the value by reference |
+    | portB | reference to port B value; returns the value by reference |
+    
+
+</div>
+
+</div>
+
+<span id="a70f416b065a40b31f0a132fd8311d482"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>interruptMode()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                              |   |                   |           |   |
+| ---------------------------- | - | ----------------- | --------- | - |
+| void MCP23017::interruptMode | ( | MCP23017\_INTMODE | *intMode* | ) |
+
+</div>
+
+<div class="memdoc">
+
+Controls how the interrupt pins act with each other. If intMode is
+SEPARATED, interrupt conditions on a port will cause its respective INT
+pin to active. If intMode is OR, interrupt pins are OR'ed so an
+interrupt on one of the port will cause both pints to active.
+
+  - Note  
+    See: "3.5.6 I/O EXPANDER CONFIGURATION REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |         |                                                                                                                                                           |
+    | ------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
+    | intMode | When OR, the INTn pins are functionally OR’ed so that an interrupt on either port will cause both pins to activate. Otherwise use SEPARATED as parameter. |
+    
+
+</div>
+
+</div>
+
+<span id="a42e5f4aafc0e7378a74b54d95285fa05"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>pinMode()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                        |   |          |                      |
+| ---------------------- | - | -------- | -------------------- |
+| void MCP23017::pinMode | ( | uint8\_t | *pin*,               |
+|                        |   | uint8\_t | *mode*,              |
+|                        |   | bool     | *inverted* = `false` |
+|                        | ) |          |                      |
+
+</div>
+
+<div class="memdoc">
+
+Sets a single pins' direction. When the pin is an input pin a pullup
+and/or an inverted option can be specified.
+
+  - Note  
+    See: "3.5.1 I/O IODIR I/O DIRECTION REGISTER", "3.5.2 INPUT POLARITY REGISTER", "3.5.7 PULL-UP RESISTOR CONFIGURATION REGISTER"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |      |                                                                      |
+    | ---- | -------------------------------------------------------------------- |
+    | pin  | Controls a single pin direction. Pin 0-7 for port A, 8-15 fo port B. |
+    | mode | INPUT or 0x00 INPUT\_PULLUP or 0x02 OUTPUT or 0x01                   |
+    
+
+</div>
+
+</div>
+
+<span id="a3da348d5702bb69c3e79f8fc67331f58"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>portMode()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                         |   |                |                      |
+| ----------------------- | - | -------------- | -------------------- |
+| void MCP23017::portMode | ( | MCP23017\_PORT | *port*,              |
+|                         |   | uint8\_t       | *modes*,             |
+|                         |   | uint8\_t       | *pullups* = `0xff`,  |
+|                         |   | uint8\_t       | *inverteds* = `0x00` |
+|                         | ) |                |                      |
+
+</div>
+
+<div class="memdoc">
+
+Controls the pins direction on a whole port at once.
+
+  - Note  
+    See: "3.5.1 I/O IODIR I/O DIRECTION REGISTER", "3.5.2 INPUT POLARITY REGISTER", "3.5.7 PULL-UP RESISTOR CONFIGURATION REGISTER
+
+<!-- end list -->
+
+  - Parameters
+    
+    |           |                                                    |
+    | --------- | -------------------------------------------------- |
+    | port      | MCP23017 port A or B                               |
+    | modes     | direction of whole port INPUT or 0x0 OUTPUT or0x01 |
+    | pullup    | bitmask for internal 100k pullup resistors         |
+    | inverteds | bitmask for inverted mode                          |
+    
+
+</div>
+
+</div>
+
+<span id="ad9b2aa218f2eaf8e6499433bb3d6434b"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>read()
+
+<div class="memitem">
+
+<div class="memdoc">
+
+Reads pins state for both ports.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |        |                                                                  |
+    | ------ | ---------------------------------------------------------------- |
+    | return | HIGH or 0x01, LOW or 0x00 depending the hardwarestate of the pin |
+    
+
+</div>
+
+</div>
+
+<span id="a9defbd5c7ae971480f2a8b78b4f74586"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>readPort()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                             |   |                |        |   |
+| --------------------------- | - | -------------- | ------ | - |
+| uint8\_t MCP23017::readPort | ( | MCP23017\_PORT | *port* | ) |
+
+</div>
+
+<div class="memdoc">
+
+Reads pins state for a whole port.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |        |                                                                  |
+    | ------ | ---------------------------------------------------------------- |
+    | port   | MCP23017 port A or B                                             |
+    | return | HIGH or 0x01, LOW or 0x00 depending the hardwarestate of the pin |
+    
+
+</div>
+
+</div>
+
+<span id="a6df25b3bd2488aeacd972f5afc5bf2b5"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>readRegister() <span class="overload">\[1/2\]</span>
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                                 |   |                    |       |   |
+| ------------------------------- | - | ------------------ | ----- | - |
+| uint8\_t MCP23017::readRegister | ( | MCP23017\_REGISTER | *reg* | ) |
+
+</div>
+
+<div class="memdoc">
+
+Reads a single registers value.
+
+  - Parameters
+    
+    |     |                                                          |
+    | --- | -------------------------------------------------------- |
+    | reg | register to read port A: 0x00 \~ 0A0 port B: 0x10 \~ 1A0 |
+    
+
+</div>
+
+</div>
+
+<span id="ab6a8df6d72dd496d857ebce4ec2fe541"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>readRegister() <span class="overload">\[2/2\]</span>
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                             |   |                    |          |
+| --------------------------- | - | ------------------ | -------- |
+| void MCP23017::readRegister | ( | MCP23017\_REGISTER | *reg*,   |
+|                             |   | uint8\_t &         | *portA*, |
+|                             |   | uint8\_t &         | *portB*  |
+|                             | ) |                    |          |
+
+</div>
+
+<div class="memdoc">
+
+Reads the values from a register pair.
+
+  - Parameters
+    
+    |       |                                                           |
+    | ----- | --------------------------------------------------------- |
+    | reg   | register to read port A: 0x00 \~ 0A0                      |
+    | portA | reference to port A value; returns the value by reference |
+    | portB | reference to port B value; returns the value by reference |
+    
+
+<!-- end list -->
+
+  - Note  
+    For portA and portB variable to effectively match the desired port,
+    you have to supply a portA register address to reg. Otherwise,
+    values will be reversed due to the way the MCP23017 works in Byte
+    mode.
+
+</div>
+
+</div>
+
+<span id="a8f1b4232f8295f980f8326a5aa77b65b"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>write()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                      |   |           |          |   |
+| -------------------- | - | --------- | -------- | - |
+| void MCP23017::write | ( | uint16\_t | *values* | ) |
+
+</div>
+
+<div class="memdoc">
+
+Writes pins state to both ports.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |        |                                              |
+    | ------ | -------------------------------------------- |
+    | values | bitmask to manipulate all OUTPUT of the chip |
+    
+
+</div>
+
+</div>
+
+<span id="ac6a375edfb48825d717fc578673125a4"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>writePort()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                          |   |                |          |
+| ------------------------ | - | -------------- | -------- |
+| void MCP23017::writePort | ( | MCP23017\_PORT | *port*,  |
+|                          |   | uint8\_t       | *values* |
+|                          | ) |                |          |
+
+</div>
+
+<div class="memdoc">
+
+Writes pins state to a whole port.
+
+  - Note  
+    See: "3.5.10 Port register"
+
+<!-- end list -->
+
+  - Parameters
+    
+    |        |                                                |
+    | ------ | ---------------------------------------------- |
+    | port   | MCP23017 port A or B                           |
+    | values | bitmask to manipulate the given port as OUTPUT |
+    
+
+</div>
+
+</div>
+
+<span id="a8b4d40141dd9646f80f35f302283a354"></span>
+
+## <span class="permalink">[◆ ](#TOC)</span>writeRegister()
+
+<div class="memitem">
+
+<div class="memproto">
+
+|                              |   |                    |          |
+| ---------------------------- | - | ------------------ | -------- |
+| void MCP23017::writeRegister | ( | MCP23017\_REGISTER | *reg*,   |
+|                              |   | uint8\_t           | *portA*, |
+|                              |   | uint8\_t           | *portB*  |
+|                              | ) |                    |          |
+
+</div>
+
+<div class="memdoc">
+
+Writes values to a register pair.
+
+  - Note  
+    For portA and portB variable to effectively match the desired port,
+    you have to supply a portA register address to reg. Otherwise,
+    values will be reversed due to the way the MCP23017 works in Byte
+    mode.
+
+</div>
+
+</div>
+
+-----
\ No newline at end of file