PCF8574IoAbstraction Class Reference

#include <IoAbstractionWire.h>

Inheritance diagram for PCF8574IoAbstraction:

Public Types
enum	{ NEEDS_WRITE_FLAG , PINS_CONFIGURED_READ_FLAG , PCF8575_16BIT_FLAG , INVERTED_LOGIC }

Public Member Functions
	PCF8574IoAbstraction (uint8_t addr, uint8_t interruptPin, WireType wireInstance=nullptr, bool mode16bit=false, bool invertedLogic=false)
void	overrideReadFlag ()
void	pinDirection (pinid_t pin, uint8_t mode) override
void	writeValue (pinid_t pin, uint8_t value) override
uint8_t	readValue (pinid_t pin) override
void	writePort (pinid_t pin, uint8_t port) override
uint8_t	readPort (pinid_t pin) override
void	attachInterrupt (pinid_t pin, RawIntHandler intHandler, uint8_t mode) override
bool	runLoop () override
Public Member Functions inherited from BasicIoAbstraction
uint8_t	digitalRead (pinid_t p)
void	digitalWrite (pinid_t p, uint8_t v)
uint8_t	digitalReadS (pinid_t p)
void	digitalWriteS (pinid_t p, uint8_t v)
void	writePortS (pinid_t p, uint8_t v)
uint8_t	readPortS (pinid_t p)
void	pinMode (pinid_t pin, uint8_t mode)
bool	sync ()

Detailed Description

An implementation of BasicIoAbstraction that supports the PCF8574/PCF8575 i2c IO chip. Providing all possible capabilities of the chip in a similar manner to Arduino pins.

See also

ioFrom8574 for how to create an instance

ioDevicePinMode for setting pin modes

Constructor & Destructor Documentation

PCF8574IoAbstraction()

PCF8574IoAbstraction::PCF8574IoAbstraction	(	uint8_t	addr,
		uint8_t	interruptPin,
		WireType	wireInstance = nullptr,
		bool	mode16bit = false,
		bool	invertedLogic = false
	)

Construct a 8574 expander on i2c address and with interrupts connected to a given pin (0xff no interrupts)

Parameters

addr	the I2C address on the bus
interruptPin	the pin on the Arduino that the interrupt line is connected to
wireInstance	the instance of wire to use for this device, for example &Wire.
mode16bit	transfer 16 bits of data. Used in 8575 expander.
invertedLogic	invert bits sent and received from the expander.

Member Function Documentation

overrideReadFlag()

void PCF8574IoAbstraction::overrideReadFlag ( )

inline

Forces the device to start reading back state during syncs even if no pins are configured as read

pinDirection()

void PCF8574IoAbstraction::pinDirection ( pinid_t  pin, uint8_t  mode  )

overridevirtual

sets the pin direction on the device, notice that on this device input is achieved by setting the port to high so it is always set as INPUT_PULLUP, even if INPUT is chosen

Reimplemented from BasicIoAbstraction.

writeValue()

void PCF8574IoAbstraction::writeValue ( pinid_t  pin, uint8_t  value  )

overridevirtual

writes a new value to the device after a sync.

Reimplemented from BasicIoAbstraction.

readValue()

uint8_t PCF8574IoAbstraction::readValue ( pinid_t  pin )

overridevirtual

reads a value from the last cached state - updated each sync

Reimplemented from BasicIoAbstraction.

writePort()

void PCF8574IoAbstraction::writePort ( pinid_t  pin, uint8_t  port  )

overridevirtual

Writes a complete 8 bit port value, that is updated to the device each sync

Reimplemented from BasicIoAbstraction.

readPort()

uint8_t PCF8574IoAbstraction::readPort ( pinid_t  pin )

overridevirtual

Reads the complete 8 bit byte from the last cached state, that is updated each sync.

Reimplemented from BasicIoAbstraction.

attachInterrupt()

void PCF8574IoAbstraction::attachInterrupt ( pinid_t  pin, RawIntHandler  intHandler, uint8_t  mode  )

overridevirtual

attaches an interrupt handler for this device. Notice for this device, all pin changes will be notified on any pin of the port, it is not configurable at the device level, the type of interrupt will also always be CHANGE.

Reimplemented from BasicIoAbstraction.

runLoop()

bool PCF8574IoAbstraction::runLoop ( )

overridevirtual

updates settings on the board after changes

Reimplemented from BasicIoAbstraction.

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

• src/IoAbstractionWire.h
• src/IoAbstractionWire.cpp