Meadow.Foundation.Displays.Lcd.CharacterDisplay

CharacterDisplay
Status
Source code	GitHub
NuGet package

The CharacterDisplay class represents a multiline liquid crystal character display.

These displays are commonly found in 16x2 and 20x4 character by row configurations. Each character is represented using a grid of 5x7 pixels.

The current driver implementation uses 4 or 8 GPIO pins. It's common to find controller boards with this displays that provide I2C, SPI, or serial control. These will be supported in a future update.

Code Example

CharacterDisplay display;

public override Task Initialize()
{
    //InitGpio();
    //InitGpioWithPWM();
    //InitI2c();
    InitGrove();

    return base.Initialize();
}

void InitGpio()
{
    Resolver.Log.Info("InitGpio...");

    display = new CharacterDisplay
    (
        pinRS: Device.Pins.D10,
        pinE: Device.Pins.D09,
        pinD4: Device.Pins.D08,
        pinD5: Device.Pins.D07,
        pinD6: Device.Pins.D06,
        pinD7: Device.Pins.D05,
        rows: 4, columns: 20
    );
}

void InitGpioWithPWM()
{
    Resolver.Log.Info("InitGpioWithPWM...");

    display = new CharacterDisplay
    (
        pinV0: Device.Pins.D11,
        pinRS: Device.Pins.D10,
        pinE: Device.Pins.D09,
        pinD4: Device.Pins.D08,
        pinD5: Device.Pins.D07,
        pinD6: Device.Pins.D06,
        pinD7: Device.Pins.D05,
        rows: 4, columns: 20
    );
}

void InitI2c()
{
    Resolver.Log.Info("InitI2c...");

    display = new CharacterDisplay
    (
        i2cBus: Device.CreateI2cBus(I2cBusSpeed.Standard),
        address: (byte)I2cCharacterDisplay.Addresses.Default,
        rows: 4, columns: 20
    );
}

void InitGrove()
{
    Resolver.Log.Info("InitGrove...");

    display = new CharacterDisplay
    (
        i2cBus: Device.CreateI2cBus(I2cBusSpeed.Standard),
        address: (byte)I2cCharacterDisplay.Addresses.Grove,
        rows: 2, columns: 16,
        isGroveDisplay: true
    );
}

void TestCharacterDisplay()
{
    Resolver.Log.Info("TestCharacterDisplay...");

    display.WriteLine("Hello", 0);

    display.WriteLine("Display", 1);

    Thread.Sleep(1000);
    display.WriteLine("Will delete in", 0);

    int count = 5;
    while (count > 0)
    {
        display.WriteLine($"{count--}", 1);
        Thread.Sleep(500);
    }

    display.ClearLines();
    Thread.Sleep(2000);

    display.WriteLine("Cursor test", 0);

    for (int i = 0; i < display.DisplayConfig.Width; i++)
    {
        display.SetCursorPosition((byte)i, 1);
        display.Write("*");
        Thread.Sleep(100);
        display.SetCursorPosition((byte)i, 1);
        display.Write(" ");
    }

    display.ClearLines();
    display.WriteLine("Complete!", 0);
}

public override Task Run()
{
    TestCharacterDisplay();

    Resolver.Log.Info("Test complete");

    return base.Run();
}

Sample project(s) available on GitHub

Wiring Example

Class CharacterDisplay

Represents a single or multirow LCD character display

Assembly: CharacterDisplay.dll

View Source

Declaration

public class CharacterDisplay : ITextDisplay, IDisplay

Implements:
Meadow.Peripherals.Displays.ITextDisplay, Meadow.Peripherals.Displays.IDisplay

Properties

DisplayConfig

The display configuration for text display menu

View Source

Declaration

public TextDisplayConfig DisplayConfig { get; }

Methods

ClearLine(byte)

Clear a line of text

View Source

Declaration

public void ClearLine(byte lineNumber)

Parameters

Type	Name	Description
System.Byte	lineNumber	The line to clear (0 indexed)

ClearLines()

Clear all lines

View Source

Declaration

public void ClearLines()

SaveCustomCharacter(byte[], byte)

Save a custom character to the display

View Source

Declaration

public void SaveCustomCharacter(byte[] characterMap, byte address)

Parameters

Type	Name	Description
System.Byte[]	characterMap	The character data
System.Byte	address	The display character address (0-7)

SetCursorPosition(byte, byte)

Set the cursor position

View Source

Declaration

public void SetCursorPosition(byte column, byte line)

Parameters

Type	Name	Description
System.Byte	column	The cursor column
System.Byte	line	The cursor line

Write(string)

Write a string to the display

View Source

Declaration

public void Write(string text)

Parameters

Type	Name	Description
System.String	text	The text to show as a string

WriteLine(string, byte, bool)

Write text to a line

View Source

Declaration

public void WriteLine(string text, byte lineNumber, bool showCursor = false)

Parameters

Type	Name	Description
System.String	text	The text to display
System.Byte	lineNumber	The target line
System.Boolean	showCursor	If true, show the cursor

Show()

Update the display

View Source

Declaration

public void Show()

Implements

• Meadow.Peripherals.Displays.ITextDisplay
• Meadow.Peripherals.Displays.IDisplay