#include <AH/Hardware/ExtendedInputOutput/ExtendedIOElement.hpp>

Detailed Description

An abstract base class for Extended Input/Output elements.

The limited number of IO pins of the Arduino can be extended by adding multiplexers, shift registers, IO expanders, etc.
ExtendedIOElement serves as a base class for all these expanders.

The pins of each extended IO element are mapped to a pin number greater than the greatest Arduino pin number, represented by the ExtIO::pin_t type.
You can supply this pin number to the IO functions in the ExtIO namespace.
If the pin number corresponds to an actual Arduino pin, the default Arduino IO function (digitalRead, digitalWrite, ...) will be called.
If the pin number does not correspond to a valid Arduino pin, it is an extended IO pin number, so the extended IO element that this pin belongs to is looked up, and the IO function for this element is executed with the correct pin number.

For example: Imagine an Arduino with 20 pins (e.g. the Arduino UNO). Pins 0 - 19 will correspond to the Arduino pins, and ExtIO::digitalRead(pin) will have the exact same effect as the standard digitalRead(pin) function (albeit a little slower).
Now, we'll add two 8-channel analog multiplexers, let's call them mux1 and mux2.
The first pin (pin 0) of mux1 will be extended IO pin number 20, the last pin (pin 7) of mux1 will be extended IO pin number 27, etc. The first pin of mux2 will be extended IO pin number 28, you get the idea. If you now call ExtIO::digitalRead(mux1.pin(7)) or ExtIO::digitalRead(27), both will be translated to mux1.digitalRead(7).

The number of extended IO elements is limited only by the size of pin_t. However, looking up the extended IO element for a given extended IO pin number uses linear search, so that might add some noticeable overhead for large pin numbers.

The design here is a compromise: saving a pointer to each extended IO element to find it directly would be faster than having to search all elements each time. On the other hand, it would require each pin_t variable to be at least one byte larger. Since almost all other classes in this library store pin variables, the memory penalty would be too large, especially on AVR microcontrollers.
Another reason to do it this way, is that this approach is still fast enough to make sure it is not noticeable to human users.
If you need faster extended GPIO access, you can use the ExtIO::CachedExtIOPin class.

Definition at line 58 of file ExtendedIOElement.hpp.

Inheritance diagram for ExtendedIOElement:

Collaboration diagram for ExtendedIOElement:

Public Member Functions
virtual void	pinMode (pin_int_t pin, PinMode_t mode)
	Set the mode of a given pin.
virtual void	pinModeBuffered (pin_int_t pin, PinMode_t mode)=0
	Set the mode of a given pin in the software buffer.
virtual void	digitalWrite (pin_int_t pin, PinStatus_t state)
	Set the output of the given pin to the given state.
virtual void	digitalWriteBuffered (pin_int_t pin, PinStatus_t state)=0
	Set the output of a given pin in the software buffer.
virtual PinStatus_t	digitalRead (pin_int_t pin)
	Read the state of the given pin.
virtual PinStatus_t	digitalReadBuffered (pin_int_t pin)=0
	Read the state of the given pin from the software buffer.
virtual void	analogWrite (pin_int_t pin, analog_t val)
	Write an analog (or PWM) value to the given pin.
virtual void	analogWriteBuffered (pin_int_t pin, analog_t val)=0
	Write an analog (or PWM) value to the software buffer given pin.
virtual analog_t	analogRead (pin_int_t pin)
	Read the analog value of the given pin.
virtual analog_t	analogReadBuffered (pin_int_t pin)=0
	Read the analog value of the given pin from the software buffer.
virtual void	begin ()=0
	Initialize the extended IO element.
virtual void	updateBufferedOutputs ()=0
	Write the internal state to the physical outputs.
virtual void	updateBufferedInputs ()=0
	Read the physical state into the input buffers.
pin_t	pin (pin_int_t pin) const
	Get the extended IO pin number of a given physical pin of this extended IO element.
pin_t	operator[] (pin_int_t pin) const
	Get the extended IO pin number of a given physical pin of this extended IO element.
pin_int_t	getLength () const
	Get the number of pins this IO element has.
pin_t	getEnd () const
	Get the largest global extended IO pin number that belongs to this extended IO element.
pin_t	getStart () const
	Get the smallest global extended IO pin number that belongs to this extended IO element.

Static Public Member Functions
static void	beginAll ()
	Initialize all extended IO elements.
static void	updateAllBufferedOutputs ()
	Write the internal states to the physical outputs for all extended IO elements.
static void	updateAllBufferedInputs ()
	Read the physical state into the input buffers for all extended IO elements.
static DoublyLinkedList< ExtendedIOElement > &	getAll ()
	Get the list of all Extended IO elements.

Protected Member Functions
	ExtendedIOElement (pin_int_t length)
	Create an ExtendedIOElement with the given number of pins.
	ExtendedIOElement (const ExtendedIOElement &)=delete
	Copying not allowed.
	ExtendedIOElement (ExtendedIOElement &&)=default
	Move constructor.
ExtendedIOElement &	operator= (const ExtendedIOElement &)=delete
	Copying not allowed.
ExtendedIOElement &	operator= (ExtendedIOElement &&)=delete
	Move assignment.

Private Attributes
const pin_int_t	length
const pin_t	start
const pin_t	end

Static Private Attributes
static pin_t	offset = NUM_DIGITAL_PINS + NUM_ANALOG_INPUTS

Constructor & Destructor Documentation

◆ ExtendedIOElement() [1/3]

ExtendedIOElement ( pin_int_t length )

protected

Create an ExtendedIOElement with the given number of pins.

Parameters

length The number of pins this element has.

Definition at line 7 of file ExtendedIOElement.cpp.

◆ ExtendedIOElement() [2/3]

ExtendedIOElement ( const ExtendedIOElement & )

protecteddelete

Copying not allowed.

◆ ExtendedIOElement() [3/3]

ExtendedIOElement ( ExtendedIOElement && )

protecteddefault

Move constructor.

Member Function Documentation

◆ operator=() [1/2]

ExtendedIOElement & operator= ( const ExtendedIOElement & )

protecteddelete

Copying not allowed.

◆ operator=() [2/2]

ExtendedIOElement & operator= ( ExtendedIOElement && )

protecteddelete

Move assignment.

◆ pinMode()

virtual void pinMode	(	pin_int_t	pin,
		PinMode_t	mode )

inlinevirtual

Set the mode of a given pin.

Note: This function might not be implemented by all subclasses.
Some extended IO types, such as shift registers, can only be used as outputs.
On others, it might be implemented, but it could impact all pins of the IO element. For example, enabling the internal pull-up resistor on an analog multiplexer affects all pins of the mux.

Parameters

pin	The (zero-based) pin of this IO element.
mode	The mode to set the pin to (e.g. INPUT, OUTPUT or INPUT_PULLUP).

Definition at line 95 of file ExtendedIOElement.hpp.

◆ pinModeBuffered()

virtual void pinModeBuffered	(	pin_int_t	pin,
		PinMode_t	mode )

pure virtual

Set the mode of a given pin in the software buffer.

The buffer is written to the ExtIO device when updateBufferedOutputs is called.

◆ digitalWrite()

virtual void digitalWrite	(	pin_int_t	pin,
		PinStatus_t	state )

inlinevirtual

Set the output of the given pin to the given state.

Parameters

pin	The (zero-based) pin of this IO element.
state	The new state to set the pin to.

Definition at line 116 of file ExtendedIOElement.hpp.

◆ digitalWriteBuffered()

virtual void digitalWriteBuffered	(	pin_int_t	pin,
		PinStatus_t	state )

pure virtual

Set the output of a given pin in the software buffer.

The buffer is written to the ExtIO device when updateBufferedOutputs is called.

◆ digitalRead()

virtual PinStatus_t digitalRead ( pin_int_t pin )

inlinevirtual

Read the state of the given pin.

Parameters

pin	The (zero-based) pin of this IO element.

Returns: The state of the given pin.

Definition at line 136 of file ExtendedIOElement.hpp.

◆ digitalReadBuffered()

virtual PinStatus_t digitalReadBuffered ( pin_int_t pin )

pure virtual

Read the state of the given pin from the software buffer.

To update the buffer, you have to call updateBufferedInputs first.

◆ analogWrite()

virtual void analogWrite	(	pin_int_t	pin,
		analog_t	val )

inlinevirtual

Write an analog (or PWM) value to the given pin.

Parameters

pin	The (zero-based) pin of this IO element.
val	The new analog value to set the pin to.

Definition at line 156 of file ExtendedIOElement.hpp.

◆ analogWriteBuffered()

virtual void analogWriteBuffered	(	pin_int_t	pin,
		analog_t	val )

pure virtual

Write an analog (or PWM) value to the software buffer given pin.

The buffer is written to the ExtIO device when updateBufferedOutputs is called.

◆ analogRead()

virtual analog_t analogRead ( pin_int_t pin )

inlinevirtual

Read the analog value of the given pin.

Parameters

pin	The (zero-based) pin of this IO element.

Returns: The new analog value of pin.

Definition at line 176 of file ExtendedIOElement.hpp.

◆ analogReadBuffered()

virtual analog_t analogReadBuffered ( pin_int_t pin )

pure virtual

Read the analog value of the given pin from the software buffer.

To update the buffer, you have to call updateBufferedInputs first.

◆ begin()

virtual void begin ( )

pure virtual

Initialize the extended IO element.

◆ beginAll()

void beginAll ( )

static

Initialize all extended IO elements.

Definition at line 17 of file ExtendedIOElement.cpp.

◆ updateBufferedOutputs()

virtual void updateBufferedOutputs ( )

pure virtual

Write the internal state to the physical outputs.

◆ updateAllBufferedOutputs()

void updateAllBufferedOutputs ( )

static

Write the internal states to the physical outputs for all extended IO elements.

Definition at line 21 of file ExtendedIOElement.cpp.

◆ updateBufferedInputs()

virtual void updateBufferedInputs ( )

pure virtual

Read the physical state into the input buffers.

◆ updateAllBufferedInputs()

void updateAllBufferedInputs ( )

static

Read the physical state into the input buffers for all extended IO elements.

Definition at line 25 of file ExtendedIOElement.cpp.

◆ pin()

pin_t pin ( pin_int_t pin ) const

Get the extended IO pin number of a given physical pin of this extended IO element.

Parameters

pin	The zero-based physical pin number of this IO element.

Returns: The global, unique extended IO pin number for the given pin.

Definition at line 29 of file ExtendedIOElement.cpp.

◆ operator[]()

pin_t operator[] ( pin_int_t pin ) const

Get the extended IO pin number of a given physical pin of this extended IO element.

It is alias for ExtendedIOElement::pin.

Parameters

pin	The zero-based physical pin number of this IO element.

Returns: The global, unique extended IO pin number for the given pin.

Definition at line 45 of file ExtendedIOElement.cpp.

◆ getLength()

pin_int_t getLength ( ) const

Get the number of pins this IO element has.

Returns: The number of pins this IO element has.

Definition at line 47 of file ExtendedIOElement.cpp.

◆ getEnd()

pin_t getEnd ( ) const

Get the largest global extended IO pin number that belongs to this extended IO element.

Definition at line 49 of file ExtendedIOElement.cpp.

◆ getStart()

pin_t getStart ( ) const

Get the smallest global extended IO pin number that belongs to this extended IO element.

Definition at line 51 of file ExtendedIOElement.cpp.

◆ getAll()

DoublyLinkedList< ExtendedIOElement > & getAll ( )

static

Get the list of all Extended IO elements.

Definition at line 53 of file ExtendedIOElement.cpp.

Member Data Documentation

◆ length

const pin_int_t length

private

Definition at line 264 of file ExtendedIOElement.hpp.

◆ start

const pin_t start

private

Definition at line 265 of file ExtendedIOElement.hpp.

◆ end

const pin_t end

private

Definition at line 266 of file ExtendedIOElement.hpp.

◆ offset

pin_t offset = NUM_DIGITAL_PINS + NUM_ANALOG_INPUTS

staticprivate

Definition at line 267 of file ExtendedIOElement.hpp.

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

Detailed Description

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Attributes

Static Private Attributes

Constructor & Destructor Documentation

◆ ExtendedIOElement() [1/3]

◆ ExtendedIOElement() [2/3]

◆ ExtendedIOElement() [3/3]

Member Function Documentation

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ pinMode()

◆ pinModeBuffered()

◆ digitalWrite()

◆ digitalWriteBuffered()

◆ digitalRead()

◆ digitalReadBuffered()

◆ analogWrite()

◆ analogWriteBuffered()

◆ analogRead()

◆ analogReadBuffered()

◆ begin()

◆ beginAll()

◆ updateBufferedOutputs()

◆ updateAllBufferedOutputs()

◆ updateBufferedInputs()

◆ updateAllBufferedInputs()

◆ pin()

◆ operator[]()

◆ getLength()

◆ getEnd()

◆ getStart()

◆ getAll()

Member Data Documentation

◆ length

◆ start

◆ end

◆ offset