GpioExpanderAdapter Class Reference

Description

The base class/interface specification for GPIO expanders.

#include <GpioExpanderAdapter.h>

Inheritance diagram for GpioExpanderAdapter:

Public Member Functions
virtual void	begin ()=0
	Initialize the expander. (Idempotent) More...
virtual void	update ()=0
	Read the state of all pins on the expander. More...
virtual bool	read (byte pin)=0
	Returns the state of a pin on the expander. More...
virtual void	attachPin (byte pin, int mode=INPUT_PULLUP)=0
	Use it to configure individual pin mode, if expander allows it. Not all of them do. More...
void	write (byte pin, bool state)
	Optionally implemented by concrete GpioExpanderAdapters if they support writing to pins. More...
bool	canWrite ()
	Returns true if the concrete GpioExpanderAdapter has implemented the write() method. More...

Member Function Documentation

attachPin()

virtual void GpioExpanderAdapter::attachPin ( byte  pin, int  mode = INPUT_PULLUP  )

pure virtual

Use it to configure individual pin mode, if expander allows it. Not all of them do.

Implemented in AdafruitMCP23017ExpanderAdapter, AdafruitPCF8574ExpanderAdapter, AdafruitPCF8575ExpanderAdapter, HC165ExpanderAdapter, and RobTillaartPCF8575ExpanderAdapter.

begin()

virtual void GpioExpanderAdapter::begin ( )

pure virtual

Initialize the expander. (Idempotent)

Implemented in AdafruitMCP23017ExpanderAdapter, AdafruitPCF8574ExpanderAdapter, AdafruitPCF8575ExpanderAdapter, HC165ExpanderAdapter, and RobTillaartPCF8575ExpanderAdapter.

canWrite()

bool GpioExpanderAdapter::canWrite ( )

inline

Returns true if the concrete GpioExpanderAdapter has implemented the write() method.

Returns

true The impemented GpioExpanderAdapter can write to pins.

false The default, ie unimplemented

read()

virtual bool GpioExpanderAdapter::read ( byte  pin )

pure virtual

Returns the state of a pin on the expander.

Returns

true aka HIGH

false aka LOW

Implemented in AdafruitMCP23017ExpanderAdapter, AdafruitPCF8574ExpanderAdapter, AdafruitPCF8575ExpanderAdapter, HC165ExpanderAdapter, and RobTillaartPCF8575ExpanderAdapter.

update()

virtual void GpioExpanderAdapter::update ( )

pure virtual

Read the state of all pins on the expander.

Expander pins generally cannot be read like regular GPIO pins, they have to be 'scanned' for their current state before reading individual pins.

Implemented in AdafruitMCP23017ExpanderAdapter, AdafruitPCF8574ExpanderAdapter, AdafruitPCF8575ExpanderAdapter, HC165ExpanderAdapter, and RobTillaartPCF8575ExpanderAdapter.

write()

void GpioExpanderAdapter::write ( byte  pin, bool  state  )

inline

Optionally implemented by concrete GpioExpanderAdapters if they support writing to pins.

Not used by InputEvents but provided so 'app' code can write to the GPIO expander.

Parameters

pin	The pin number on the expander
state	HIGH or LOW (true/false)

---

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

• src/GpioExpanderAdapter/GpioExpanderAdapter.h