LCD

I2C

output

Medium RAM

0.1.0

#Description

An LCD is a simple display that can display up to 32 characters and change its background colour. Perfect for showing simple states or messages.

#Links

Open Wiki for Grove ComponentGet the Grove Component

#Aliases

• LCD Display

#Functions

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#JavaScript / Node.js

@blokdots/components on npm ↗

ClassLCDextends I2cComponentBase

LCD component for controlling a 16x2 I2C character display with RGB backlight (Grove LCD RGB Backlight). Extends ComponentBase as a complex output component with custom serial commands.

#Value type

TypeScript

interface LCDValue {
  string: string;
  backgroundColor: string;
}

#Constructor options

Option	Type	Required	Description	Inherited from
pin	I2CPinID	required	—	I2cComponentBase

#Events

Event	Parameters	Description
change	value: LCDValue	—

#Methods

drawString(text: string)

Draw text on the display using the shadow-diff streaming protocol. Only changed character cells are rewritten, avoiding flicker. Long text is automatically chunked by the serial protocol layer.

print(text: string)

@deprecated Use drawString() instead. Kept for backwards compatibility.

clear()

Clear the display.

setCursor(col: number, row: number)

Set the cursor position.

setRGB(r: number, g: number, b: number)

Set backlight color using RGB values.

bgColor(hex: string)

Set backlight color using a hex string.

backlightOff()

Turn off the backlight.

get i2cId→ I2CPinIDfrom I2cComponentBase

The resolved I2C pin ID (e.g. "i2c-0"). Useful for logging or passing back to the Arduino sketch.

#Example

JavaScript

import { Board, LCD } from "@blokdots/components";

const board = new Board("/dev/ttyACM0");
await board.open();

const lCD = new LCD({ board, pin: "example" });

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#C++ (Arduino)

ClassLCDDisplayextends ComponentBase

16x2 I2C LCD with RGB backlight using Seeed's Grove_LCD_RGB_Backlight library. - Uses ComponentBase begin()/tick() registration. - Optional EventBus "changed" event emission (rate-limited).

#Required libraries

• #include <Wire.h> — Wire
• #include <rgb_lcd.h> — Grove - LCD RGB Backlight v1.0.2

#Setup

C++

#include "blokdots.h"

LCDDisplay myComponent();

#Constructor

LCDDisplay(cols, rows, charSize, wire, startR, startG, startB, startBacklightOn)

Parameter	Type	Default
cols	uint8_t	16
rows	uint8_t	2
charSize	uint8_t	LCD_5x8DOTS
wire	TwoWire	Wire
startR	uint8_t	255
startG	uint8_t	255
startB	uint8_t	255
startBacklightOn	bool	true

LCDDisplay(bus, evtChanged, cols, rows, charSize, wire, startR, startG, startB, startBacklightOn, minEmitIntervalMs)

Parameter	Type	Default
bus	EventBus	required
evtChanged	uint8_t	required
cols	uint8_t	16
rows	uint8_t	2
charSize	uint8_t	LCD_5x8DOTS
wire	TwoWire	Wire
startR	uint8_t	255
startG	uint8_t	255
startB	uint8_t	255
startBacklightOn	bool	true
minEmitIntervalMs	uint16_t	0

#Methods

clear()

home()

setCursor(col, row)

Parameter	Type	Default
col	uint8_t	required
row	uint8_t	required

print(s)

Print helpers — all route through drawString() for shadow-diff / no-flicker.

Parameter	Type	Default
s	const char	required

print(v)

Parameter	Type	Default
v	int	required

print(v)

Parameter	Type	Default
v	unsigned int	required

print(v)

Parameter	Type	Default
v	long	required

print(v)

Parameter	Type	Default
v	unsigned long	required

print(v, digits)

Parameter	Type	Default
v	float	required
digits	uint8_t	2

setRGB(r, g, b)

Parameter	Type	Default
r	uint8_t	required
g	uint8_t	required
b	uint8_t	required

setRGB(c)

NEW: blokdots::Color overload

Parameter	Type	Default
c	blokdots::Color	required

bgColor(r, g, b)

alias (kept for compatibility)

Parameter	Type	Default
r	uint8_t	required
g	uint8_t	required
b	uint8_t	required

bgColor(c)

NEW: blokdots::Color alias

Parameter	Type	Default
c	blokdots::Color	required

bgColor(hex)

Optional: hex input, uses your color utils

Parameter	Type	Default
hex	const char	required

backlightOff()

isBacklightOn()→ bool

setLine(row, text)

Parameter	Type	Default
row	uint8_t	required
text	const char	required

setText2(line0, line1)

Parameter	Type	Default
line0	const char	required
line1	const char	required

drawString(text)

Uses the same shadow-diff logic: only changed cells are written.

Parameter	Type	Default
text	const char	required

beginDrawString()

drawStringChunk(text)

Parameter	Type	Default
text	const char	required

endDrawString()

displayOn()

displayOff()

cursorOn()

cursorOff()

blinkOn()

blinkOff()

blinkLEDOn()

blinkLEDOff()

autoscrollOn()

autoscrollOff()

leftToRight()

rightToLeft()

scrollDisplayLeft()

scrollDisplayRight()

createChar(location, charmap[])

Parameter	Type	Default
location	uint8_t	required
charmap[]	uint8_t	required

columns()→ uint8_t

rowsCount()→ uint8_t