Concrete driver for the PCA9570 4‑bit output‑only I2C GPIO expander. More...

#include <IoExpanderPCA9570.hpp>

Inheritance diagram for IoExpanderPCA9570:

Public Types
enum	Port { PORT_ALL = 0x0F }

Public Member Functions
	IoExpanderPCA9570 ()
	Construct a new IoExpanderPCA9570 object.

	~IoExpanderPCA9570 ()=default
	Destroy the IoExpanderPCA9570 object.

void	digitalWritePort (uint16_t mask, uint16_t values) override
	Write to multiple pins simultaneously using a mask.

uint16_t	digitalReadPort () override
	Read the current output register value.

Public Member Functions inherited from IoExpanderBase
	IoExpanderBase (uint8_t pinCount)
	Construct a new IoExpanderBase object.

virtual	~IoExpanderBase ()=default
	Virtual destructor.

virtual void	deinit ()
	Deinitialize the expander.

void	configPins (uint16_t pinMask, uint8_t mode)
	Configure multiple pins as input or output simultaneously.

void	pinMode (uint8_t pin, uint8_t mode)
	Set the direction of a GPIO pin.

void	digitalWrite (uint8_t pin, bool value)
	Write a digital value to an output pin.

bool	digitalRead (uint8_t pin)
	Read the digital value from an input pin.

void	digitalToggle (uint8_t pin)
	Toggle the state of an output pin.

uint8_t	pinCount () const
	Get the total number of pins provided by this expander.

uint16_t	pinToMask (uint8_t pin) const
	Convert a pin number to its corresponding bitmask.

Public Member Functions inherited from I2CDeviceNoHal
bool	begin (SensorCommCustom::CustomCallback callback, uint8_t addr)
	Initialize the sensor using custom callback interface.

Public Member Functions inherited from DeviceBeginCommon
virtual	~DeviceBeginCommon ()

uint8_t	getAddress () const

uint8_t	getInterface () const

Public Member Functions inherited from SensorCommWrapper
	SensorCommWrapper ()=default

int	readReg (uint8_t reg) const

int	readRegBuff (uint8_t reg, uint8_t *buf, size_t len) const

int	readBuff (uint8_t *buf, size_t len) const

int	writeReg (uint8_t reg, uint8_t val)

int	writeRegBuff (uint8_t reg, uint8_t *buf, size_t len)

int	writeBuff (uint8_t *buf, size_t len)

int	writeThenRead (const uint8_t write_buffer, size_t write_len, uint8_t read_buffer, size_t read_len)

bool	setRegBit (uint8_t reg, uint8_t bit)

bool	clrRegBit (uint8_t reg, uint8_t bit)

bool	getRegBit (uint8_t reg, uint8_t bit)

int	updateBits (uint8_t reg, uint8_t mask, uint8_t value_shifted)

void	setAddress (uint8_t address)

void	setAck (bool enable)

Public Member Functions inherited from SensorCommInterface
virtual	~SensorCommInterface ()=default

Protected Member Functions
void	pinModeImpl (uint8_t pin, uint8_t mode) override
	Set the direction of a single pin.

void	configPinsImpl (uint16_t pinMask, uint8_t mode) override
	Hardware‑specific implementation for configuring multiple pins simultaneously.

void	digitalWriteImpl (uint8_t pin, bool value) override
	Write a digital value to an output pin.

bool	digitalReadImpl (uint8_t pin) override
	Read the current output value of a pin.

bool	initImpl (uint8_t param) override
	Perform chip‑specific initialization.

Protected Member Functions inherited from DeviceBeginCommon
	DeviceBeginCommon ()=default

virtual bool	ensureValid () const override

virtual SensorCommBase *	getComm () const override

virtual void	beforeBegin ()

virtual void	afterCommReady ()

virtual void	afterInitSuccess (uint8_t param)

virtual void	onBeginFail ()

bool	fail ()

void	clearCommState ()

template<typename CreateComm >
bool	beginLifecycle (uint8_t addr, uint8_t iface, uint8_t initParam, CreateComm createComm)

Additional Inherited Members
Protected Attributes inherited from IoExpanderBase
uint8_t	_pinCount
	Number of GPIO pins.

std::unique_ptr< uint8_t[]>	_pinModes
	Cached pin modes (INPUT/OUTPUT)

std::unique_ptr< bool[]>	_outputStates
	Cached output states (true = HIGH)

Protected Attributes inherited from DeviceBeginCommon
std::unique_ptr< SensorCommBase >	comm

std::unique_ptr< SensorHal >	hal

std::unique_ptr< SensorCommStatic >	staticComm

uint8_t	_addr = 0

uint8_t	_iface = COMM_CUSTOM

Detailed Description

Concrete driver for the PCA9570 4‑bit output‑only I2C GPIO expander.

The PCA9570 provides 4 output‑only pins. All pins are configured as outputs by default; pinMode() will accept only OUTPUT. Reading a pin returns the last written value (output register).

Definition at line 49 of file IoExpanderPCA9570.hpp.

Member Enumeration Documentation

◆ Port

enum IoExpanderPCA9570::Port

Enumerator
PORT_ALL

Definition at line 53 of file IoExpanderPCA9570.hpp.

Constructor & Destructor Documentation

◆ IoExpanderPCA9570()

IoExpanderPCA9570::IoExpanderPCA9570 ( )

inline

Construct a new IoExpanderPCA9570 object.

Initializes the base class with the fixed pin count of 4.

Definition at line 62 of file IoExpanderPCA9570.hpp.

◆ ~IoExpanderPCA9570()

IoExpanderPCA9570::~IoExpanderPCA9570 ( )

default

Destroy the IoExpanderPCA9570 object.

Member Function Documentation

◆ configPinsImpl()

void IoExpanderPCA9570::configPinsImpl	(	uint16_t	pinMask,
		uint8_t	mode
	)

inlineoverrideprotectedvirtual

Hardware‑specific implementation for configuring multiple pins simultaneously.

The PCA9570 has fixed output‑only pins; therefore, this function does not perform any hardware configuration. It validates that the requested mode is OUTPUT (as INPUT is not supported) and updates the internal pin mode cache accordingly.

Parameters

pinMask	Bitmask of pins to configure (ignored, as all pins behave identically).
mode	Desired mode. Only OUTPUT is accepted; INPUT will log an error.

Note: This function assumes that comm and _pinModes are valid (checked in the base class configPins() before calling here).

Implements IoExpanderBase.

Definition at line 164 of file IoExpanderPCA9570.hpp.

References IoExpanderBase::_pinModes, i, and SENSORLIB_LOG_E.

◆ digitalReadImpl()

bool IoExpanderPCA9570::digitalReadImpl ( uint8_t pin )

inlineoverrideprotectedvirtual

Read the current output value of a pin.

Since PCA9570 has no input capability, this returns the last written value (output register state).

Parameters

pin	Pin number (0‑3).

Returns: true Pin is currently set HIGH.; false Pin is currently set LOW.

Implements IoExpanderBase.

Definition at line 210 of file IoExpanderPCA9570.hpp.

References digitalReadPort().

◆ digitalReadPort()

uint16_t IoExpanderPCA9570::digitalReadPort ( )

inlineoverridevirtual

Read the current output register value.

Returns: uint16_t Low 4 bits contain the output state of pins 0‑3.

Reimplemented from IoExpanderBase.

Definition at line 119 of file IoExpanderPCA9570.hpp.

References SensorCommWrapper::readBuff(), and SENSORLIB_LOG_E.

Referenced by digitalReadImpl(), and digitalWriteImpl().

◆ digitalWriteImpl()

void IoExpanderPCA9570::digitalWriteImpl	(	uint8_t	pin,
		bool	value
	)

inlineoverrideprotectedvirtual

Write a digital value to an output pin.

Reads the current output register, updates the specified bit, and writes the new value back.

Parameters

pin	Pin number (0‑3).
value	true for HIGH, false for LOW.

Implements IoExpanderBase.

Definition at line 189 of file IoExpanderPCA9570.hpp.

References digitalReadPort(), and SensorCommWrapper::writeRegBuff().

◆ digitalWritePort()

void IoExpanderPCA9570::digitalWritePort	(	uint16_t	mask,
		uint16_t	values
	)

inlineoverridevirtual

Write to multiple pins simultaneously using a mask.

Reads the current output register, modifies only the bits specified by the mask, and writes the result back. The internal output state cache is also updated.

Parameters

mask	Bitmask where a 1 indicates the pin should be updated.
values	Bitmask of the new values for the selected pins.

Reimplemented from IoExpanderBase.

Definition at line 79 of file IoExpanderPCA9570.hpp.

References IoExpanderBase::_outputStates, i, SensorCommWrapper::readBuff(), SENSORLIB_LOG_E, and SensorCommWrapper::writeRegBuff().

Referenced by loop().

◆ initImpl()

bool IoExpanderPCA9570::initImpl ( uint8_t param )

inlineoverrideprotectedvirtual

Perform chip‑specific initialization.

Reads the device ID registers to verify communication and logs the manufacturer ID, part ID, and revision.

Parameters

param No use

Returns: true Initialization successful (device ID read succeeded).; false Initialization failed.

Implements IoExpanderBase.

Definition at line 226 of file IoExpanderPCA9570.hpp.

References SensorCommWrapper::readRegBuff(), SENSORLIB_LOG_D, and SENSORLIB_LOG_E.

◆ pinModeImpl()

void IoExpanderPCA9570::pinModeImpl	(	uint8_t	pin,
		uint8_t	mode
	)

inlineoverrideprotectedvirtual

Set the direction of a single pin.

The PCA9570 only supports output mode; therefore, any request for INPUT mode is rejected with an error. No hardware configuration is performed because all pins are fixed as outputs.

Parameters

pin	Pin number (0‑3). (Not used, as all pins behave identically.)
mode	Desired mode. Only OUTPUT is accepted.

Implements IoExpanderBase.

Definition at line 141 of file IoExpanderPCA9570.hpp.

References SENSORLIB_LOG_E.

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

IoExpanderPCA9570.hpp

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ Port

Constructor & Destructor Documentation

◆ IoExpanderPCA9570()

◆ ~IoExpanderPCA9570()

Member Function Documentation

◆ configPinsImpl()

◆ digitalReadImpl()

◆ digitalReadPort()

◆ digitalWriteImpl()

◆ digitalWritePort()

◆ initImpl()

◆ pinModeImpl()