Standard 16x2 character LCD screen (LCD1602) driven over I2C. More...

#include <LCD1602.h>

Inheritance diagram for RumPi::LCD1602:

Collaboration diagram for RumPi::LCD1602:

Public Member Functions
	LCD1602 (const LCD1602 &)=delete

LCD1602 &	operator= (const LCD1602 &)=delete

	LCD1602 (const int LCDAddr)
	Builds an LCD1602 at the given I2C address, opening the i2c device and enabling the backlight. More...

	LCD1602 (const int LCDAddr, const int fileDescriptor)
	Builds an LCD1602 at the given I2C address using an already-open file descriptor. More...

	LCD1602 (const int LCDAddr, const int fileDescriptor, const int blen)
	Builds an LCD1602 at the given I2C address using an already-open file descriptor and explicit backlight setting. More...

virtual	~LCD1602 ()
	Destroys the screen, turning it off first. More...

virtual void	TurnOn () override
	Initializes the LCD (8-bit then 4-bit mode, 2 lines, display on without cursor blink) and clears the screen. More...

virtual void	TurnOff () override
	Turns the display off. More...

virtual void	ProcessRawValues () override
	No-op: the LCD is an output device with no raw values to process. More...

virtual std::string	ToString () const override
	Serializes the LCD's I2C address, file descriptor, and backlight flag to a string. More...

void	ClearScreen ()
	Clears the screen. More...

void	WriteToScreen (int &x, int &y, const char data[])
	Writes a string starting at the given cursor position, clamping x to 0-15 and y to 0-1. More...

Public Member Functions inherited from RumPi::BaseComponent
	BaseComponent ()
	Builds a base component with an unknown type and an empty name. More...

virtual	~BaseComponent ()
	Virtual destructor so deleting a component through a BaseComponent* also cleans up the concrete subclass. More...

virtual void	TurnOn ()=0
	Turns the component on (e.g. More...

virtual void	TurnOff ()=0
	Turns the component off. More...

virtual std::string	ToString () const =0
	Serializes the component's current readings to a string (usually JSON). More...

virtual void	ProcessRawValues ()=0
	Reads and processes the component's latest raw values (called once per poll). More...

virtual EComponentType	GetComponentType () const
	Gets the component's type. More...

const std::string &	GetName () const
	Gets the component's unique per-instance name. More...

void	SetName (const std::string &name)
	Sets the component's unique per-instance name. More...

Private Member Functions
void	WriteWord (const int word)
	Writes a raw word to the LCD over I2C, setting or clearing the backlight bit according to the backlight flag. More...

void	SendCommand (const int command)
	Sends a command byte to the LCD in two 4-bit nibbles, toggling the enable line for each. More...

void	SendData (const int data)
	Sends a data byte to the LCD in two 4-bit nibbles, toggling the enable line for each. More...

Private Attributes
int	myLCDAddress
	The LCD's I2C address. More...

int	myFileDescriptor
	The open i2c device file descriptor. More...

bool	myOwnsFileDescriptor
	True if this component opened (and must close) the fd; false if borrowed. More...

int	myBLEN
	Backlight enable flag (1 = on). More...

Additional Inherited Members
Static Public Member Functions inherited from RumPi::BaseComponent
static std::string	ComponentTypeToString (const EComponentType theComponentTypeToConvert)
	Maps an EComponentType to its string name. More...

static EComponentType	StringToComponentType (const std::string &theComponentTypeName)
	Maps a type name back to its EComponentType (the inverse of ComponentTypeToString), so the client can turn the type carried on the wire back into a value it can look an icon up with. More...

Protected Attributes inherited from RumPi::BaseComponent
EComponentType	myComponentType
	The kind of component this is (set by each concrete subclass). More...

std::string	myName
	A unique per-instance name, assigned when the component is added to the manager. More...

Detailed Description

Standard 16x2 character LCD screen (LCD1602) driven over I2C.

Author: Eddie O'Hagan

Date: 8/13/2026

Constructor & Destructor Documentation

◆ LCD1602() [1/4]

RumPi::LCD1602::LCD1602 ( const LCD1602 & )

delete

◆ LCD1602() [2/4]

RumPi::LCD1602::LCD1602 ( const int LCDAddr )

Builds an LCD1602 at the given I2C address, opening the i2c device and enabling the backlight.

Author: Eddie O'Hagan

Date: 8/13/2026

LCD1602 screen(0x27);

RumPi::LCD1602::LCD1602

LCD1602(const LCD1602 &)=delete

Parameters

[in] LCDAddr The LCD's I2C address.

◆ LCD1602() [3/4]

RumPi::LCD1602::LCD1602	(	const int	LCDAddr,
		const int	fileDescriptor
	)

Builds an LCD1602 at the given I2C address using an already-open file descriptor.

Author: Eddie O'Hagan

Date: 8/13/2026

LCD1602 screen(0x27, existingFd);

Parameters

[in]	LCDAddr	The LCD's I2C address.
[in]	fileDescriptor	An already-open i2c device file descriptor.

◆ LCD1602() [4/4]

RumPi::LCD1602::LCD1602	(	const int	LCDAddr,
		const int	fileDescriptor,
		const int	blen
	)

Builds an LCD1602 at the given I2C address using an already-open file descriptor and explicit backlight setting.

Author: Eddie O'Hagan

Date: 8/13/2026

LCD1602 screen(0x27, existingFd, 1);

Parameters

[in]	LCDAddr	The LCD's I2C address.
[in]	fileDescriptor	An already-open i2c device file descriptor.
[in]	blen	The backlight enable flag (1 = on).

◆ ~LCD1602()

RumPi::LCD1602::~LCD1602 ( )

virtual

Destroys the screen, turning it off first.

Author: Eddie O'Hagan

Date: 8/13/2026

LCD1602* screen = new LCD1602(0x27);

delete screen;

Member Function Documentation

◆ ClearScreen()

void RumPi::LCD1602::ClearScreen ( )

Clears the screen.

Author: Eddie O'Hagan

Date: 8/13/2026

screen.ClearScreen();

◆ operator=()

LCD1602 & RumPi::LCD1602::operator= ( const LCD1602 & )

delete

◆ ProcessRawValues()

void RumPi::LCD1602::ProcessRawValues ( )

overridevirtual

No-op: the LCD is an output device with no raw values to process.

Author: Eddie O'Hagan

Date: 8/13/2026

screen.ProcessRawValues();

Implements RumPi::BaseComponent.

◆ SendCommand()

void RumPi::LCD1602::SendCommand ( const int command )

private

Sends a command byte to the LCD in two 4-bit nibbles, toggling the enable line for each.

Author: Eddie O'Hagan

Date: 8/13/2026

SendCommand(0x01);

RumPi::LCD1602::SendCommand

void SendCommand(const int command)

Sends a command byte to the LCD in two 4-bit nibbles, toggling the enable line for each.

Definition: LCD1602.cpp:148

Parameters

[in] command The command byte to send.

◆ SendData()

void RumPi::LCD1602::SendData ( const int data )

private

Sends a data byte to the LCD in two 4-bit nibbles, toggling the enable line for each.

Author: Eddie O'Hagan

Date: 8/13/2026

SendData('A');

RumPi::LCD1602::SendData

void SendData(const int data)

Sends a data byte to the LCD in two 4-bit nibbles, toggling the enable line for each.

Definition: LCD1602.cpp:183

Parameters

[in] data The data byte to send.

◆ ToString()

std::string RumPi::LCD1602::ToString ( ) const

overridevirtual

Serializes the LCD's I2C address, file descriptor, and backlight flag to a string.

Author: Eddie O'Hagan

Date: 8/13/2026

std::string data = screen.ToString();

Returns: A string describing the LCD.

Implements RumPi::BaseComponent.

◆ TurnOff()

void RumPi::LCD1602::TurnOff ( )

overridevirtual

Turns the display off.

Author: Eddie O'Hagan

Date: 8/13/2026

screen.TurnOff();

Implements RumPi::BaseComponent.

◆ TurnOn()

void RumPi::LCD1602::TurnOn ( )

overridevirtual

Initializes the LCD (8-bit then 4-bit mode, 2 lines, display on without cursor blink) and clears the screen.

Author: Eddie O'Hagan

Date: 8/13/2026

screen.TurnOn();

Implements RumPi::BaseComponent.

◆ WriteToScreen()

void RumPi::LCD1602::WriteToScreen	(	int &	x,
		int &	y,
		const char	data[]
	)

Writes a string starting at the given cursor position, clamping x to 0-15 and y to 0-1.

Author: Eddie O'Hagan

Date: 8/13/2026

int x = 0;
int y = 0;
screen.WriteToScreen(x, y, "Hello");

Parameters

[in,out]	x	The column (clamped to 0-15).
[in,out]	y	The row (clamped to 0-1).
[in]	data	The null-terminated string to write.

◆ WriteWord()

void RumPi::LCD1602::WriteWord ( const int word )

private

Writes a raw word to the LCD over I2C, setting or clearing the backlight bit according to the backlight flag.

Author: Eddie O'Hagan

Date: 8/13/2026

WriteWord(0x08);

RumPi::LCD1602::WriteWord

void WriteWord(const int word)

Writes a raw word to the LCD over I2C, setting or clearing the backlight bit according to the backlig...

Definition: LCD1602.cpp:120

Parameters

[in] word The word to write.

Member Data Documentation

◆ myBLEN

int RumPi::LCD1602::myBLEN

private

Backlight enable flag (1 = on).

◆ myFileDescriptor

int RumPi::LCD1602::myFileDescriptor

private

The open i2c device file descriptor.

◆ myLCDAddress

int RumPi::LCD1602::myLCDAddress

private

The LCD's I2C address.

◆ myOwnsFileDescriptor

bool RumPi::LCD1602::myOwnsFileDescriptor

private

True if this component opened (and must close) the fd; false if borrowed.

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

Source/Headers/RumPi/Components/LCD1602.h
Source/Implementations/RumPi/Components/LCD1602.cpp

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ LCD1602() [1/4]

◆ LCD1602() [2/4]

◆ LCD1602() [3/4]

◆ LCD1602() [4/4]

◆ ~LCD1602()

Member Function Documentation

◆ ClearScreen()

◆ operator=()

◆ ProcessRawValues()

◆ SendCommand()

◆ SendData()

◆ ToString()

◆ TurnOff()

◆ TurnOn()

◆ WriteToScreen()

◆ WriteWord()

Member Data Documentation

◆ myBLEN

◆ myFileDescriptor

◆ myLCDAddress

◆ myOwnsFileDescriptor