Remarks

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 MeadowApp()
{
    //InitGpio();
    //InitGpioWithPWM();
    InitI2c();

    TestCharacterDisplay();

    Console.WriteLine("Test complete");
}

void InitGpio() 
{
    Console.WriteLine("InitGpio...");

    display = new CharacterDisplay
    (
        device: Device,
        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()
{
    Console.WriteLine("InitGpioWithPWM...");

    display = new CharacterDisplay
    (
        device: Device,
        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()
{
    Console.WriteLine("InitI2c...");

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

void TestCharacterDisplay() 
{
    Console.WriteLine("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);
}

Sample project(s) available on GitHub

Wiring Example

Characteristic	Locus
Inheritance	System.Object > CharacterDisplay
Namespace	Meadow.Foundation.Displays.Lcd
Assembly	CharacterDisplay.dll

Syntax

public class CharacterDisplay : ITextDisplay

Constructors

CharacterDisplay(IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, Byte, Byte)

Declaration

public CharacterDisplay(IDigitalOutputPort portRS, IDigitalOutputPort portE, IDigitalOutputPort portD4, IDigitalOutputPort portD5, IDigitalOutputPort portD6, IDigitalOutputPort portD7, byte rows = null, byte columns = null)

Parameters

Type	Name	Description
IDigitalOutputPort	portRS
IDigitalOutputPort	portE
IDigitalOutputPort	portD4
IDigitalOutputPort	portD5
IDigitalOutputPort	portD6
IDigitalOutputPort	portD7
System.Byte	rows
System.Byte	columns

CharacterDisplay(II2cBus, Byte, Byte, Byte)

Declaration

public CharacterDisplay(II2cBus i2cBus, byte address = null, byte rows = null, byte columns = null)

Parameters

Type	Name	Description
II2cBus	i2cBus
System.Byte	address
System.Byte	rows
System.Byte	columns

CharacterDisplay(IMeadowDevice, IPin, IPin, IPin, IPin, IPin, IPin, IPin, Byte, Byte)

Declaration

public CharacterDisplay(IMeadowDevice device, IPin pinV0, IPin pinRS, IPin pinE, IPin pinD4, IPin pinD5, IPin pinD6, IPin pinD7, byte rows = null, byte columns = null)

Parameters

Type	Name	Description
IMeadowDevice	device
IPin	pinV0
IPin	pinRS
IPin	pinE
IPin	pinD4
IPin	pinD5
IPin	pinD6
IPin	pinD7
System.Byte	rows
System.Byte	columns

CharacterDisplay(IMeadowDevice, IPin, IPin, IPin, IPin, IPin, IPin, Byte, Byte)

Declaration

public CharacterDisplay(IMeadowDevice device, IPin pinRS, IPin pinE, IPin pinD4, IPin pinD5, IPin pinD6, IPin pinD7, byte rows = null, byte columns = null)

Parameters

Type	Name	Description
IMeadowDevice	device
IPin	pinRS
IPin	pinE
IPin	pinD4
IPin	pinD5
IPin	pinD6
IPin	pinD7
System.Byte	rows
System.Byte	columns

CharacterDisplay(IPwmPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, IDigitalOutputPort, Byte, Byte)

Declaration

public CharacterDisplay(IPwmPort portV0, IDigitalOutputPort portRS, IDigitalOutputPort portE, IDigitalOutputPort portD4, IDigitalOutputPort portD5, IDigitalOutputPort portD6, IDigitalOutputPort portD7, byte rows = null, byte columns = null)

Parameters

Type	Name	Description
IPwmPort	portV0
IDigitalOutputPort	portRS
IDigitalOutputPort	portE
IDigitalOutputPort	portD4
IDigitalOutputPort	portD5
IDigitalOutputPort	portD6
IDigitalOutputPort	portD7
System.Byte	rows
System.Byte	columns

Fields

characterDisplay

Declaration

protected ICharacterDisplay characterDisplay

Field Value

Type	Description
ICharacterDisplay

Properties

DisplayConfig

Declaration

public TextDisplayConfig DisplayConfig { get; }

Property Value

Type	Description
TextDisplayConfig

Methods

ClearLine(Byte)

Declaration

public void ClearLine(byte lineNumber)

Parameters

Type	Name	Description
System.Byte	lineNumber

ClearLines()

Declaration

public void ClearLines()

SaveCustomCharacter(Byte[], Byte)

Declaration

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

Parameters

Type	Name	Description
System.Byte[]	characterMap
System.Byte	address

SetCursorPosition(Byte, Byte)

Declaration

public void SetCursorPosition(byte column, byte line)

Parameters

Type	Name	Description
System.Byte	column
System.Byte	line

Show()

Declaration

public void Show()

Write(String)

Declaration

public void Write(string text)

Parameters

Type	Name	Description
System.String	text

WriteLine(String, Byte, Boolean)

Declaration

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

Parameters

Type	Name	Description
System.String	text
System.Byte	lineNumber
System.Boolean	showCursor