Abstract base class for GPIO expander devices. More...

#include <IoExpanderBase.hpp>

Inheritance diagram for IoExpanderBase:

Public Member Functions
	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.

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

virtual uint16_t	digitalReadPort ()
	Read the values of all input pins.

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.

Protected Member Functions
virtual bool	initImpl (uint8_t param)=0
	Chip‑specific initialization.

virtual void	configPinsImpl (uint16_t pinMask, uint8_t mode)=0
	Hardware‑specific implementation of batch pin mode configuration.

virtual void	pinModeImpl (uint8_t pin, uint8_t mode)=0
	Hardware‑specific implementation of pinMode().

virtual void	digitalWriteImpl (uint8_t pin, bool value)=0
	Hardware‑specific implementation of digitalWrite().

virtual bool	digitalReadImpl (uint8_t pin)=0
	Hardware‑specific implementation of digitalRead().

Protected Attributes
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)

Detailed Description

Abstract base class for GPIO expander devices.

This class provides a common interface for controlling GPIO expanders with any number of pins. It manages pin mode caching, output state caching, and delegates hardware‑specific operations to pure virtual functions implemented by derived classes.

Definition at line 42 of file IoExpanderBase.hpp.

Constructor & Destructor Documentation

◆ IoExpanderBase()

IoExpanderBase::IoExpanderBase ( uint8_t pinCount )

inline

Construct a new IoExpanderBase object.

Allocates internal arrays for pin modes and output states. If allocation fails, _pinCount is set to 0 and subsequent operations will be safely rejected.

Parameters

pinCount Number of GPIO pins provided by the expander.

Definition at line 54 of file IoExpanderBase.hpp.

References _outputStates, _pinCount, _pinModes, and pinCount().

◆ ~IoExpanderBase()

virtual IoExpanderBase::~IoExpanderBase ( )

virtualdefault

Virtual destructor.

Ensures proper cleanup of derived classes. The std::unique_ptr members automatically release their memory.

Member Function Documentation

◆ configPins()

void IoExpanderBase::configPins	(	uint16_t	pinMask,
		uint8_t	mode
	)

inline

Configure multiple pins as input or output simultaneously.

This function sets the direction of all pins specified in the mask to the given mode. It validates the arguments and updates the internal pin mode cache before delegating the hardware configuration to the pure virtual function configPinsImpl(), which must be implemented by derived classes.

Parameters

pinMask	Bitmask where a 1 indicates the pin should be configured. Bit 0 corresponds to pin 0, bit 15 to pin 15 (if applicable). Only the lowest _pinCount bits are considered.
mode	Desired mode: INPUT or OUTPUT (as defined in the Arduino framework).

Note

This function logs errors and returns early if:

The expander is not initialized (comm is null).
The internal pin mode cache is uninitialized.
An invalid mode is provided.

Definition at line 99 of file IoExpanderBase.hpp.

References _pinModes, configPinsImpl(), and SENSORLIB_LOG_E.

Referenced by setup().

◆ configPinsImpl()

virtual void IoExpanderBase::configPinsImpl	(	uint16_t	pinMask,
		uint8_t	mode
	)

protectedpure virtual

Hardware‑specific implementation of batch pin mode configuration.

Parameters

pinMask	Bitmask of pins to configure.
mode	Desired mode (INPUT or OUTPUT).

Implemented in IoExpanderPCA9570, and IoExpanderXL9555.

Referenced by configPins().

◆ deinit()

virtual void IoExpanderBase::deinit ( )

inlinevirtual

Deinitialize the expander.

Can be overridden by derived classes to perform chip‑specific cleanup (e.g., power‑down, reset). The base implementation does nothing.

Definition at line 77 of file IoExpanderBase.hpp.

◆ digitalRead()

bool IoExpanderBase::digitalRead ( uint8_t pin )

inline

Read the digital value from an input pin.

Reads the current state from hardware via digitalReadImpl().

Parameters

pin	Pin number (0 .. pinCount()-1). Must be configured as INPUT.

Returns: true Pin is HIGH.; false Pin is LOW (or error, logged).

Definition at line 182 of file IoExpanderBase.hpp.

References _pinCount, _pinModes, digitalReadImpl(), and SENSORLIB_LOG_E.

Referenced by digitalReadPort(), loop(), TouchDrvDigitalRead(), and IoExpanderSPI::transferDataBits().

◆ digitalReadImpl()

virtual bool IoExpanderBase::digitalReadImpl ( uint8_t pin )

protectedpure virtual

Hardware‑specific implementation of digitalRead().

Called by digitalRead() after validating arguments.

Parameters

pin	Pin number.

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

Implemented in IoExpanderPCA9570, and IoExpanderXL9555.

Referenced by digitalRead().

◆ digitalReadPort()

virtual uint16_t IoExpanderBase::digitalReadPort ( )

inlinevirtual

Read the values of all input pins.

The default implementation reads each input pin individually. Derived classes may override this to perform a faster register read.

Returns: uint16_t Bitmask where bit i is 1 if input pin i is HIGH.

Reimplemented in IoExpanderPCA9570, and IoExpanderXL9555.

Definition at line 248 of file IoExpanderBase.hpp.

References _outputStates, _pinCount, _pinModes, digitalRead(), i, and SENSORLIB_LOG_E.

◆ digitalToggle()

void IoExpanderBase::digitalToggle ( uint8_t pin )

inline

Toggle the state of an output pin.

Inverts the current cached output state and writes it to the pin.

Parameters

pin	Pin number (0 .. pinCount()-1). Must be configured as OUTPUT.

Definition at line 207 of file IoExpanderBase.hpp.

References _outputStates, _pinModes, digitalWrite(), and SENSORLIB_LOG_E.

Referenced by loop().

◆ digitalWrite()

void IoExpanderBase::digitalWrite	(	uint8_t	pin,
		bool	value
	)

inline

Write a digital value to an output pin.

The value is cached in _outputStates and the hardware is updated via digitalWriteImpl().

Parameters

pin	Pin number (0 .. pinCount()-1). Must be configured as OUTPUT.
value	true for HIGH, false for LOW.

Definition at line 150 of file IoExpanderBase.hpp.

References _outputStates, _pinCount, _pinModes, digitalWriteImpl(), and SENSORLIB_LOG_E.

Referenced by AW9364LedDriver::_digitalWrite(), IoExpanderSPI::beginSPI(), digitalToggle(), digitalWritePort(), loop(), testInit(), TouchDrvDigitalWrite(), and IoExpanderSPI::transferDataBits().

◆ digitalWriteImpl()

virtual void IoExpanderBase::digitalWriteImpl	(	uint8_t	pin,
		bool	value
	)

protectedpure virtual

Hardware‑specific implementation of digitalWrite().

Called by digitalWrite() after validating arguments and updating the cache.

Parameters

pin	Pin number.
value	true for HIGH, false for LOW.

Implemented in IoExpanderPCA9570, and IoExpanderXL9555.

Referenced by digitalWrite().

◆ digitalWritePort()

virtual void IoExpanderBase::digitalWritePort	(	uint16_t	mask,
		uint16_t	values
	)

inlinevirtual

Write to multiple pins simultaneously using a mask.

The default implementation writes each selected pin individually. Derived classes may override this with a more efficient register‑based write when the hardware supports it.

Parameters

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

Reimplemented in IoExpanderPCA9570, and IoExpanderXL9555.

Definition at line 231 of file IoExpanderBase.hpp.

References _pinCount, digitalWrite(), and i.

◆ initImpl()

virtual bool IoExpanderBase::initImpl ( uint8_t param )

protectedpure virtual

Chip‑specific initialization.

Called by all begin() overloads after the communication object is set up. Derived classes should perform any necessary hardware configuration (e.g., reset, verify device ID, set default registers).

Parameters

param Opaque parameter passed from begin() (typically I2C address).

Returns: true Initialization successful.; false Initialization failed.

Implemented in IoExpanderPCA9570, and IoExpanderXL9555.

◆ pinCount()

uint8_t IoExpanderBase::pinCount ( ) const

inline

Get the total number of pins provided by this expander.

Returns: uint8_t Pin count.

Definition at line 268 of file IoExpanderBase.hpp.

References _pinCount.

Referenced by IoExpanderBase().

◆ pinMode()

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

inline

Set the direction of a GPIO pin.

The mode is cached in _pinModes and the hardware is updated via the pure virtual function pinModeImpl().

Parameters

pin	Pin number (0 .. pinCount()-1).
mode	Pin mode: INPUT or OUTPUT (as defined in Arduino framework).

Definition at line 122 of file IoExpanderBase.hpp.

References _pinCount, _pinModes, pinModeImpl(), and SENSORLIB_LOG_E.

Referenced by AW9364LedDriver::_pinMode(), IoExpanderSPI::beginSPI(), testInit(), and TouchDrvPinMode().

◆ pinModeImpl()

virtual void IoExpanderBase::pinModeImpl	(	uint8_t	pin,
		uint8_t	mode
	)

protectedpure virtual

Hardware‑specific implementation of pinMode().

Called by pinMode() after validating arguments and updating the cache.

Parameters

pin	Pin number.
mode	Desired mode (INPUT or OUTPUT).

Implemented in IoExpanderPCA9570, and IoExpanderXL9555.

Referenced by pinMode().

◆ pinToMask()

uint16_t IoExpanderBase::pinToMask ( uint8_t pin ) const

inline

Convert a pin number to its corresponding bitmask.

This utility function returns a 16-bit mask with a single bit set at the position corresponding to the given pin number. The mask can be used with batch functions such as digitalWritePort() or configPins().

Parameters

pin	Pin number (0 to pinCount()-1).

Returns: uint16_t Bitmask with bit (pin) set to 1. Returns 0 and logs an error if the pin number is out of range.

Definition at line 285 of file IoExpanderBase.hpp.

References _pinCount, and SENSORLIB_LOG_E.

Member Data Documentation

◆ _outputStates

std::unique_ptr<bool[]> IoExpanderBase::_outputStates

protected

Cached output states (true = HIGH)

Definition at line 349 of file IoExpanderBase.hpp.

Referenced by digitalReadPort(), digitalToggle(), digitalWrite(), IoExpanderPCA9570::digitalWritePort(), IoExpanderXL9555::digitalWritePort(), and IoExpanderBase().

◆ _pinCount

uint8_t IoExpanderBase::_pinCount

protected

Number of GPIO pins.

Definition at line 347 of file IoExpanderBase.hpp.

Referenced by digitalRead(), digitalReadPort(), digitalWrite(), digitalWritePort(), IoExpanderBase(), pinCount(), pinMode(), and pinToMask().

◆ _pinModes

std::unique_ptr<uint8_t[]> IoExpanderBase::_pinModes

protected

Cached pin modes (INPUT/OUTPUT)

Definition at line 348 of file IoExpanderBase.hpp.

Referenced by configPins(), IoExpanderPCA9570::configPinsImpl(), IoExpanderXL9555::configPinsImpl(), digitalRead(), digitalReadPort(), digitalToggle(), digitalWrite(), IoExpanderBase(), and pinMode().

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

IoExpanderBase.hpp

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ IoExpanderBase()

◆ ~IoExpanderBase()

Member Function Documentation

◆ configPins()

◆ configPinsImpl()

◆ deinit()

◆ digitalRead()

◆ digitalReadImpl()

◆ digitalReadPort()

◆ digitalToggle()

◆ digitalWrite()

◆ digitalWriteImpl()

◆ digitalWritePort()

◆ initImpl()

◆ pinCount()

◆ pinMode()

◆ pinModeImpl()

◆ pinToMask()

Member Data Documentation

◆ _outputStates

◆ _pinCount

◆ _pinModes