Adafruit_MCP23XXX Class Reference

Base class for all MCP23XXX variants. More...

#include <Adafruit_MCP23XXX.h>

Inheritance diagram for Adafruit_MCP23XXX:

Public Member Functions
bool	begin_I2C (uint8_t i2c_addr=MCP23XXX_ADDR, TwoWire *wire=&Wire)
	Initialize MCP using I2C. More...
bool	begin_SPI (uint8_t cs_pin, SPIClass *theSPI=&SPI, uint8_t _hw_addr=0x00)
	Initialize MCP using hardware SPI. More...
bool	begin_SPI (int8_t cs_pin, int8_t sck_pin, int8_t miso_pin, int8_t mosi_pin, uint8_t _hw_addr=0x00)
	Initialize MCP using software SPI. More...
void	pinMode (uint8_t pin, uint8_t mode)
	Configures the specified pin to behave either as an input or an output. More...
uint8_t	digitalRead (uint8_t pin)
	Reads the value from a specified digital pin, either HIGH or LOW. More...
void	digitalWrite (uint8_t pin, uint8_t value)
	Write a HIGH or a LOW value to a digital pin. More...
uint8_t	readGPIO (uint8_t port=0)
	Bulk read all pins on a port. More...
void	writeGPIO (uint8_t value, uint8_t port=0)
	Bulk write all pins on a port. More...
void	setupInterrupts (bool mirroring, bool openDrain, uint8_t polarity)
	Configure the interrupt system. More...
void	setupInterruptPin (uint8_t pin, uint8_t mode=CHANGE)
	Enable interrupt and set mode for given pin. More...
void	disableInterruptPin (uint8_t pin)
	Disable interrupt for given pin. More...
void	clearInterrupts ()
	Clear interrupts. NOTE:If using DEFVAL, INT clears only if interrupt condition does not exist. See Fig 1-7 in datasheet.
uint8_t	getLastInterruptPin ()
	Gets the pin that caused the latest interrupt, from INTF, without clearing any interrupt flags. More...
uint16_t	getCapturedInterrupt ()
	Get pin states captured at time of interrupt. More...

Protected Member Functions
uint16_t	getRegister (uint8_t baseAddress, uint8_t port=0)
	helper to get register address More...

Protected Attributes
Adafruit_I2CDevice *	i2c_dev = nullptr
	Pointer to I2C bus interface.
Adafruit_SPIDevice *	spi_dev = nullptr
	Pointer to SPI bus interface.
uint8_t	pinCount
	Total number of GPIO pins.
uint8_t	hw_addr
	HW address matching A2/A1/A0 pins.

Detailed Description

Base class for all MCP23XXX variants.

Member Function Documentation

begin_I2C()

bool Adafruit_MCP23XXX::begin_I2C	(	uint8_t	i2c_addr = MCP23XXX_ADDR,
		TwoWire *	wire = &Wire
	)

Initialize MCP using I2C.

Parameters

i2c_addr	I2C address
wire	Pointer to Wire instance

Returns

true if initialization successful, otherwise false.

begin_SPI() [1/2]

bool Adafruit_MCP23XXX::begin_SPI	(	uint8_t	cs_pin,
		SPIClass *	theSPI = &SPI,
		uint8_t	_hw_addr = 0x00
	)

Initialize MCP using hardware SPI.

Parameters

cs_pin	Pin to use for SPI chip select
theSPI	Pointer to SPI instance
_hw_addr	Hardware address (pins A2, A1, A0)

Returns

true if initialization successful, otherwise false.

begin_SPI() [2/2]

bool Adafruit_MCP23XXX::begin_SPI	(	int8_t	cs_pin,
		int8_t	sck_pin,
		int8_t	miso_pin,
		int8_t	mosi_pin,
		uint8_t	_hw_addr = 0x00
	)

Initialize MCP using software SPI.

Parameters

cs_pin	Pin to use for SPI chip select
sck_pin	Pin to use for SPI clock
miso_pin	Pin to use for SPI MISO
mosi_pin	Pin to use for SPI MOSI
_hw_addr	Hardware address (pins A2, A1, A0)

Returns

true if initialization successful, otherwise false.

pinMode()

void Adafruit_MCP23XXX::pinMode	(	uint8_t	pin,
		uint8_t	mode
	)

Configures the specified pin to behave either as an input or an output.

Parameters

pin	the Arduino pin number to set the mode of
mode	INPUT, OUTPUT, or INPUT_PULLUP

digitalRead()

uint8_t Adafruit_MCP23XXX::digitalRead

(

uint8_t

pin

)

Reads the value from a specified digital pin, either HIGH or LOW.

Parameters

pin	the Arduino pin number you want to read

Returns

HIGH or LOW

digitalWrite()

void Adafruit_MCP23XXX::digitalWrite	(	uint8_t	pin,
		uint8_t	value
	)

Write a HIGH or a LOW value to a digital pin.

Parameters

pin	the Arduino pin number
value	HIGH or LOW

readGPIO()

uint8_t Adafruit_MCP23XXX::readGPIO

(

uint8_t

port = 0

)

Bulk read all pins on a port.

Parameters

port	0 for Port A, 1 for Port B (MCP23X17 only).

Returns

current pin states of port as a uint8_t.

writeGPIO()

void Adafruit_MCP23XXX::writeGPIO	(	uint8_t	value,
		uint8_t	port = 0
	)

Bulk write all pins on a port.

Parameters

value	pin states to write as a uint8_t.
port	0 for Port A, 1 for Port B (MCP23X17 only).

setupInterrupts()

void Adafruit_MCP23XXX::setupInterrupts	(	bool	mirroring,
		bool	openDrain,
		uint8_t	polarity
	)

Configure the interrupt system.

Parameters

mirroring	true to OR both INTA and INTB pins.
openDrain	true for open drain output, false for active drive output.
polarity	HIGH or LOW

setupInterruptPin()

void Adafruit_MCP23XXX::setupInterruptPin	(	uint8_t	pin,
		uint8_t	mode = CHANGE
	)

Enable interrupt and set mode for given pin.

Parameters

pin	Pin to enable.
mode	CHANGE, LOW, HIGH

disableInterruptPin()

void Adafruit_MCP23XXX::disableInterruptPin

(

uint8_t

pin

)

Disable interrupt for given pin.

Parameters

pin	Pin to disable.

getLastInterruptPin()

uint8_t Adafruit_MCP23XXX::getLastInterruptPin

(

)

Gets the pin that caused the latest interrupt, from INTF, without clearing any interrupt flags.

Returns

Pin that caused lastest interrupt.

getCapturedInterrupt()

uint16_t Adafruit_MCP23XXX::getCapturedInterrupt

(

)

Get pin states captured at time of interrupt.

Returns

Mutli-bit value representing pin states.

getRegister()

uint16_t Adafruit_MCP23XXX::getRegister ( uint8_t  baseAddress, uint8_t  port = 0  )

protected

helper to get register address

Parameters

baseAddress	base register address
port	0 for A, 1 for B (MCP23X17 only)

Returns

calculated register address

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The documentation for this class was generated from the following files:

• Adafruit_MCP23XXX.h
• Adafruit_MCP23XXX.cpp