This is an old version of the documentation. View the latest version here.
Control Surface  1.0.0
MIDI Control Surface library for Arduino
Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | Private Attributes | Static Private Attributes | List of all members
ExtendedIOElement Class Referenceabstract

An abstract base class for Extended Input/Output elements. More...

#include <ExtendedIOElement.hpp>

Inheritance diagram for ExtendedIOElement:
Collaboration diagram for ExtendedIOElement:

Public Member Functions

virtual ~ExtendedIOElement ()
 
virtual void pinMode (pin_t pin, uint8_t mode)=0
 Set the mode of a given pin. More...
 
virtual void digitalWrite (pin_t pin, uint8_t state)=0
 Set the output of the given pin to the given state. More...
 
virtual int digitalRead (pin_t pin)=0
 Read the state of the given pin. More...
 
virtual void analogWrite (pin_t pin, analog_t val)=0
 Write an analog (or PWM) value to the given pin. More...
 
virtual analog_t analogRead (pin_t pin)=0
 Read the analog value of the given pin. More...
 
virtual void begin ()=0
 Initialize the extended IO element. More...
 
virtual void update ()=0
 Update the extended IO element: write the internal state to the physical outputs, or read the physical state into the input buffers. More...
 
pin_t pin (pin_t pin) const
 Get the extended IO pin number of a given physical pin of this extended IO element. More...
 
pin_t operator[] (pin_t pin) const
 Get the extended IO pin number of a given physical pin of this extended IO element. More...
 
pin_t getLength () const
 Get the number of pins this IO element has. More...
 
pin_t getEnd () const
 Get the largest global extended IO pin number that belongs to this extended IO element. More...
 
pin_t getStart () const
 Get the smallest global extended IO pin number that belongs to this extended IO element. More...
 

Static Public Member Functions

static void beginAll ()
 Initialize all extended IO elements. More...
 
static DoublyLinkedList< ExtendedIOElement > & getAll ()
 Get the list of all Extended IO elements. More...
 

Protected Member Functions

 ExtendedIOElement (pin_t length)
 Create an ExtendedIOElement with the given number of pins. More...
 

Protected Attributes

ExtendedIOElementnext
 
ExtendedIOElementprevious
 

Private Attributes

const pin_t length
 
const pin_t start
 
const pin_t end
 

Static Private Attributes

static pin_t offset = NUM_DIGITAL_PINS + NUM_ANALOG_INPUTS
 
static DoublyLinkedList< ExtendedIOElementelements
 

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.
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 is not an 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 noticable 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 much 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 noticable to human users.

Definition at line 59 of file ExtendedIOElement.hpp.

Constructor & Destructor Documentation

◆ ExtendedIOElement()

ExtendedIOElement::ExtendedIOElement ( pin_t  length)
protected

Create an ExtendedIOElement with the given number of pins.

Parameters
lengthThe number of pins this element has.

Definition at line 8 of file ExtendedIOElement.cpp.

◆ ~ExtendedIOElement()

ExtendedIOElement::~ExtendedIOElement ( )
virtual

Definition at line 19 of file ExtendedIOElement.cpp.

Member Function Documentation

◆ pinMode()

virtual void ExtendedIOElement::pinMode ( pin_t  pin,
uint8_t  mode 
)
pure virtual

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

◆ digitalWrite()

virtual void ExtendedIOElement::digitalWrite ( pin_t  pin,
uint8_t  state 
)
pure virtual

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

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

Implemented in ShiftRegisterOutBase< N >, and MAX7219.

◆ digitalRead()

virtual int ExtendedIOElement::digitalRead ( pin_t  pin)
pure virtual

Read the state of the given pin.

Parameters
pinThe (zero-based) pin of this IO element.
Returns
The state of the given pin.

Implemented in AnalogMultiplex< N >, ShiftRegisterOutBase< N >, and MAX7219.

◆ analogWrite()

virtual void ExtendedIOElement::analogWrite ( pin_t  pin,
analog_t  val 
)
pure virtual

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

Parameters
pinThe (zero-based) pin of this IO element.
valThe new analog value to set the pin to.

Implemented in MAX7219, and ShiftRegisterOutBase< N >.

◆ analogRead()

virtual analog_t ExtendedIOElement::analogRead ( pin_t  pin)
pure virtual

Read the analog value of the given pin.

Parameters
pinThe (zero-based) pin of this IO element.
Returns
The new analog value of pin.

Implemented in ShiftRegisterOutBase< N >, MAX7219, and AnalogMultiplex< N >.

◆ begin()

virtual void ExtendedIOElement::begin ( )
pure virtual

Initialize the extended IO element.

Implemented in AnalogMultiplex< N >, ShiftRegisterOut< N >, SPIShiftRegisterOut< N >, and MAX7219.

◆ beginAll()

void ExtendedIOElement::beginAll ( )
static

Initialize all extended IO elements.

Definition at line 21 of file ExtendedIOElement.cpp.

◆ update()

virtual void ExtendedIOElement::update ( )
pure virtual

Update the extended IO element: write the internal state to the physical outputs, or read the physical state into the input buffers.

Implemented in AnalogMultiplex< N >, MAX7219, ShiftRegisterOut< N >, and SPIShiftRegisterOut< N >.

◆ pin()

pin_t ExtendedIOElement::pin ( pin_t  pin) const

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

Parameters
pinThe zero-based physical pin number of this IO element.
Returns
The global, unique extended IO pin number for the given pin.
Examples
1.First-Output.ino, and Toggle-LEDs.ino.

Definition at line 26 of file ExtendedIOElement.cpp.

◆ operator[]()

pin_t ExtendedIOElement::operator[] ( pin_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
pinThe zero-based physical pin number of this IO element.
Returns
The global, unique extended IO pin number for the given pin.

Definition at line 41 of file ExtendedIOElement.cpp.

◆ getLength()

pin_t ExtendedIOElement::getLength ( ) const

Get the number of pins this IO element has.

Returns
The number of pins this IO element has.
Examples
1.AnalogReadSerial.ino, and 2.DigitalReadSerial.ino.

Definition at line 43 of file ExtendedIOElement.cpp.

◆ getEnd()

pin_t ExtendedIOElement::getEnd ( ) const

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

Definition at line 45 of file ExtendedIOElement.cpp.

◆ getStart()

pin_t ExtendedIOElement::getStart ( ) const

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

Definition at line 47 of file ExtendedIOElement.cpp.

◆ getAll()

DoublyLinkedList< ExtendedIOElement > & ExtendedIOElement::getAll ( )
static

Get the list of all Extended IO elements.

Definition at line 49 of file ExtendedIOElement.cpp.

Member Data Documentation

◆ length

const pin_t ExtendedIOElement::length
private

Definition at line 189 of file ExtendedIOElement.hpp.

◆ start

const pin_t ExtendedIOElement::start
private

Definition at line 190 of file ExtendedIOElement.hpp.

◆ end

const pin_t ExtendedIOElement::end
private

Definition at line 191 of file ExtendedIOElement.hpp.

◆ offset

pin_t ExtendedIOElement::offset = NUM_DIGITAL_PINS + NUM_ANALOG_INPUTS
staticprivate

Definition at line 192 of file ExtendedIOElement.hpp.

◆ elements

DoublyLinkedList< ExtendedIOElement > ExtendedIOElement::elements
staticprivate

Definition at line 194 of file ExtendedIOElement.hpp.

◆ next

ExtendedIOElement * DoublyLinkable< ExtendedIOElement >::next
protectedinherited

Definition at line 301 of file LinkedList.hpp.

◆ previous

ExtendedIOElement * DoublyLinkable< ExtendedIOElement >::previous
protectedinherited

Definition at line 302 of file LinkedList.hpp.


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