#include <LiquidCrystalIO.h>

Inheritance diagram for LiquidCrystal:

Public Types
enum	BackLightPinMode { BACKLIGHT_NORMAL , BACKLIGHT_INVERTED , BACKLIGHT_PWM }

Public Member Functions
	LiquidCrystal ()
	LiquidCrystal (uint8_t rs, uint8_t rw, uint8_t en, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, LiquidCrystal::BackLightPinMode mode, IoAbstractionRef ioMethod)
	LiquidCrystal (uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7, BasicIoAbstraction *ioMethod=NULL)
	LiquidCrystal (uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7, BasicIoAbstraction *ioMethod=NULL)
	LiquidCrystal (uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, BasicIoAbstraction *ioMethod=NULL)
	LiquidCrystal (uint8_t rs, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, BasicIoAbstraction *ioMethod=NULL)
void	init (uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable, uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3, uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7, BasicIoAbstraction *ioMethod)
void	setIoAbstraction (IoAbstractionRef ioRef)
void	configureBacklightPin (uint8_t backlightPin, BackLightPinMode mode=LiquidCrystal::BACKLIGHT_NORMAL)
void	configureAnalogBacklight (AnalogDevice *analogDevice, uint8_t backlightPin)
void	setDelayTime (uint8_t command, uint8_t settleTime)
void	begin (uint8_t cols, uint8_t rows, uint8_t charsize=LCD_5x8DOTS)
void	clear ()
void	home ()
void	backlight ()
void	noBacklight ()
void	setBacklight (uint8_t state)
void	noDisplay ()
void	display ()
void	noBlink ()
void	blink ()
void	noCursor ()
void	cursor ()
void	scrollDisplayLeft ()
void	scrollDisplayRight ()
void	leftToRight ()
void	rightToLeft ()
void	autoscroll ()
void	noAutoscroll ()
void	setRowOffsets (int row1, int row2, int row3, int row4)
void	createChar (uint8_t charNo, const uint8_t data[])
void	createCharPgm (uint8_t, const uint8_t[])
void	setCursor (uint8_t x, uint8_t y)
size_t	write (uint8_t ch) override
void	command (uint8_t)

Detailed Description

LiquidCrystalIO library works with displays that are compatible with the HD44780 driver. It is derived from the Arduino version, but it supports I2C backpacks and many other configurations. In addition it also uses taskmanager to manage any delays needed for the display hardware, thus reducing the overhead.

Member Enumeration Documentation

◆ BackLightPinMode

enum LiquidCrystal::BackLightPinMode

We support several backlight options, when setting the backlight configuration choose one of the below

Enumerator
BACKLIGHT_NORMAL	the backlight is active HIGH
BACKLIGHT_INVERTED	the backlight is active LOW
BACKLIGHT_PWM	the backlight is connected directly to a PWM pin

Constructor & Destructor Documentation

◆ LiquidCrystal() [1/6]

LiquidCrystal::LiquidCrystal ( )

Sets up the library to work with a DfRobot shield connected on regular pins. For this no configuration is needed.

◆ LiquidCrystal() [2/6]

LiquidCrystal::LiquidCrystal	(	uint8_t	rs,
		uint8_t	rw,
		uint8_t	en,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		LiquidCrystal::BackLightPinMode	mode,
		IoAbstractionRef	ioMethod )

Used by the two helpers that can quickly create an instance of LiquidCrystal for most I2C backpacks. Normally you would use LiquidCrystalI2C_RS_EN or LiquidCrystalI2C_EN_RS instead. An example of using of those helpers is shown below.

At global level (outside of any functions):

LiquidCrystalI2C_RS_EN(variableName, i2cAddr, invertBacklight)

where variableName is the variable name to assign to. For example lcd i2cAddr is the i2c address of the backpack, for example 0x20 invertBacklight true if the backlight function is inverted, otherwise false

Example: variable name lcd, I2C backpack on addr 0x20, with EN-RW-RS arrangement, inverted backlight function:

LiquidCrystalI2C_EN_RS(lcd, 0x20, true)

Parameters

rs	the pin on which RS is connected
rw	the pin on which RW is connected
enable	the pin on which EN is connected
d0	data pin
d1	data pin
d2	data pin
d3	data pin
mode	the backlight mode from the BackLightPinMode enum
ioMethod	the IO device to use

◆ LiquidCrystal() [3/6]

LiquidCrystal::LiquidCrystal	(	uint8_t	rs,
		uint8_t	enable,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		uint8_t	d4,
		uint8_t	d5,
		uint8_t	d6,
		uint8_t	d7,
		BasicIoAbstraction *	ioMethod = NULL )

Sets up liquid crystal in 8 bit mode, optionally providing an IoDevice abstraction

Parameters

rs	the pin on which RS is connected
enable	the pin on which EN is connected
d0	data pin
d1	data pin
d2	data pin
d3	data pin
d4	data pin
d5	data pin
d6	data pin
d7	data pin
ioMethod	optionally an IoAbstractionRef to a different IO device.

◆ LiquidCrystal() [4/6]

LiquidCrystal::LiquidCrystal	(	uint8_t	rs,
		uint8_t	rw,
		uint8_t	enable,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		uint8_t	d4,
		uint8_t	d5,
		uint8_t	d6,
		uint8_t	d7,
		BasicIoAbstraction *	ioMethod = NULL )

Sets up liquid crystal in 8 bit mode, optionally providing an IoDevice abstraction

Parameters

rs	the pin on which RS is connected
rw	the pin on which RW is connected
enable	the pin on which EN is connected
d0	data pin
d1	data pin
d2	data pin
d3	data pin
d4	data pin
d5	data pin
d6	data pin
d7	data pin
ioMethod	optionally an IoAbstractionRef to a different IO device.

◆ LiquidCrystal() [5/6]

LiquidCrystal::LiquidCrystal	(	uint8_t	rs,
		uint8_t	rw,
		uint8_t	enable,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		BasicIoAbstraction *	ioMethod = NULL )

Sets up liquid crystal in 4 bit mode, optionally providing an IoDevice abstraction

Parameters

rs	the pin on which RS is connected
rw	the pin on which RW is connected
enable	the pin on which EN is connected
d0	data pin
d4	data pin
d5	data pin
d6	data pin
d7	data pin
ioMethod	optionally an IoAbstractionRef to a different IO device.

◆ LiquidCrystal() [6/6]

LiquidCrystal::LiquidCrystal	(	uint8_t	rs,
		uint8_t	enable,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		BasicIoAbstraction *	ioMethod = NULL )

Sets up liquid crystal in 4 bit mode, optionally providing an IoDevice abstraction

Parameters

rs	the pin on which RS is connected
enable	the pin on which EN is connected
d4	data pin
d5	data pin
d6	data pin
d7	data pin
ioMethod	optionally an IoAbstractionRef to a different IO device.

Member Function Documentation

◆ init()

void LiquidCrystal::init	(	uint8_t	fourbitmode,
		uint8_t	rs,
		uint8_t	rw,
		uint8_t	enable,
		uint8_t	d0,
		uint8_t	d1,
		uint8_t	d2,
		uint8_t	d3,
		uint8_t	d4,
		uint8_t	d5,
		uint8_t	d6,
		uint8_t	d7,
		BasicIoAbstraction *	ioMethod )

Internal method not normally called by users of the library directly. Called by all the other constructors to actually do the main initialisation of the LCD

Parameters

fourbitmode	if the device is operating in 4 or 8 bit method
rs	the pin on which RS is connected
rw	the pin on which RW is connected
enable	the pin on which EN is connected
d0	data pin
d1	data pin
d2	data pin
d3	data pin
d4	data pin
d5	data pin
d6	data pin
d7	data pin
ioMethod	the IoAbstractionRef or nullptr if not set.

◆ setIoAbstraction()

void LiquidCrystal::setIoAbstraction ( IoAbstractionRef ioRef )

inline

Sets the device that will be used, IE where the LCD pins are connected to.

Parameters

ioRef the reference to an IO device previously created.

◆ configureBacklightPin()

void LiquidCrystal::configureBacklightPin	(	uint8_t	backlightPin,
		BackLightPinMode	mode = LiquidCrystal::BACKLIGHT_NORMAL )

Configure a backlight pin that is used to control the backlight using the setBacklight(level) function. Depending on the type of display you have this may be either:

LiquidCrystal::BACKLIGHT_NORMAL - logic high for backlight on
LiquidCrystal::BACKLIGHT_INVERTED - logic low for backlight on,
LiquidCrystal::BACKLIGHT_PWN backlight pin in connected to a PWM pin and can dim.
Parameters

backlightPin the pin on which the backlight is connected

mode one of the modes specified above

◆ configureAnalogBacklight()

void LiquidCrystal::configureAnalogBacklight	(	AnalogDevice *	analogDevice,
		uint8_t	backlightPin )

This function gives more control over how the PWM/DAC/AnalogOut based backlight is configured, you can provide an analog device, you can specifically tell the analog device if it is PWM or DAC mode. For many cases the regular configureBacklightPin would work.

Parameters

analogDevice	the analog device to use to set the backlight
backlightPin	the pin on which the backlight is set.
isPinPwm	if the pin on the provided device is a PWM or DAC pin

◆ setDelayTime()

void LiquidCrystal::setDelayTime	(	uint8_t	command,
		uint8_t	settleTime )

inline

Sets the delay for a given command, at this moment, this can only set the settle time of a standard command.

Parameters

command	the command to set the delay for, presently only the settle time.
settleTime	the new value of the delay in microseconds.

◆ begin()

void LiquidCrystal::begin	(	uint8_t	cols,
		uint8_t	rows,
		uint8_t	charsize = LCD_5x8DOTS )

Unlike the regular display where this is option, in this variant you absolutely must call this function before use.

Parameters

cols	the number of colums
rows	the number of rows
charsize	the character size, defaulted to 5x8

◆ clear()

void LiquidCrystal::clear ( )

Clears the display completely using the clear command on the device, warning that this is a very slow call taking at least 2000 micros.

◆ home()

void LiquidCrystal::home ( )

Moves the display back to the home position, calling setCursor(0,0) is much faster.

◆ backlight()

void LiquidCrystal::backlight ( )

inline

Turn on the backlight

◆ noBacklight()

void LiquidCrystal::noBacklight ( )

inline

Turn off the backlight

◆ setBacklight()

void LiquidCrystal::setBacklight ( uint8_t state )

set the backlight state depending on how it is configured. If it is set to PWM mode, then this can be a value between 0 and the maximum PWM value.

Parameters

state

◆ noDisplay()

void LiquidCrystal::noDisplay ( )

Turn the display off

◆ display()

void LiquidCrystal::display ( )

Turn the display on

◆ noBlink()

void LiquidCrystal::noBlink ( )

Turn off blinking text

◆ blink()

void LiquidCrystal::blink ( )

Turn on blinking text

◆ noCursor()

void LiquidCrystal::noCursor ( )

Turn off the screen cursor

◆ cursor()

void LiquidCrystal::cursor ( )

Turn on the screen cursor

◆ setRowOffsets()

void LiquidCrystal::setRowOffsets	(	int	row1,
		int	row2,
		int	row3,
		int	row4 )

Internal method that is not really for direct calling by users that initialises the instance with the right memory locations to write rows into.

Parameters

row1	the first display row memory
row2	the second display row memory
row3	the third display row memory
row4	the fourth display row memory

◆ createChar()

void LiquidCrystal::createChar	(	uint8_t	charNo,
		const uint8_t	data[] )

Create a 5x8 character from RAM. You can set any character between 0 and 7

Parameters

charNo	the character number to use
data	the data for the custom character

◆ createCharPgm()

void LiquidCrystal::createCharPgm	(	uint8_t	location,
		const uint8_t	charmap[] )

Create a 5x8 character from PROGMEM. You can set any character between 0 and 7

Parameters

charNo	the character number to use
data	the data for the custom character - from PROGMEM

◆ setCursor()

void LiquidCrystal::setCursor	(	uint8_t	x,
		uint8_t	y )

Sets the cursor position at which the next write will take place

Parameters

x	the x location to move to
y	the y location to move to

◆ write()

size_t LiquidCrystal::write ( uint8_t ch )

inlineoverride

Write a single character to the display and moves the cursor position

Returns: always 1

Parameters

ch	the character to write

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

src/LiquidCrystalIO.h
src/LiquidCrystalIO.cpp

backlightPin	the pin on which the backlight is connected
mode	one of the modes specified above

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ BackLightPinMode

Constructor & Destructor Documentation

◆ LiquidCrystal() [1/6]

◆ LiquidCrystal() [2/6]

◆ LiquidCrystal() [3/6]

◆ LiquidCrystal() [4/6]

◆ LiquidCrystal() [5/6]

◆ LiquidCrystal() [6/6]

Member Function Documentation

◆ init()

◆ setIoAbstraction()

◆ configureBacklightPin()

◆ configureAnalogBacklight()

◆ setDelayTime()

◆ begin()

◆ clear()

◆ home()

◆ backlight()

◆ noBacklight()

◆ setBacklight()

◆ noDisplay()

◆ display()

◆ noBlink()

◆ blink()

◆ noCursor()

◆ cursor()

◆ setRowOffsets()

◆ createChar()

◆ createCharPgm()

◆ setCursor()

◆ write()