C# - LCD 20x4 Bricklet¶

Hello World¶

Download (ExampleHelloWorld.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your LCD 20x4 Bricklet

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLCD20x4 lcd = new BrickletLCD20x4(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Turn backlight on
        lcd.BacklightOn();

        // Write "Hello World"
        lcd.WriteLine(0, 0, "Hello World");

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Button Callback¶

Download (ExampleButtonCallback.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your LCD 20x4 Bricklet

    // Callback function for button pressed callback
    static void ButtonPressedCB(BrickletLCD20x4 sender, byte button)
    {
        Console.WriteLine("Button Pressed: " + button);
    }

    // Callback function for button released callback
    static void ButtonReleasedCB(BrickletLCD20x4 sender, byte button)
    {
        Console.WriteLine("Button Released: " + button);
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLCD20x4 lcd = new BrickletLCD20x4(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Register button pressed callback to function ButtonPressedCB
        lcd.ButtonPressedCallback += ButtonPressedCB;

        // Register button released callback to function ButtonReleasedCB
        lcd.ButtonReleasedCallback += ButtonReleasedCB;

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Unicode¶

Download (ExampleUnicode.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your LCD 20x4 Bricklet

    // Maps a normal UTF-16 encoded string to the LCD charset
    static string UTF16ToKS0066U(string utf16)
    {
        string ks0066u = "";
        char c;

        for (int i = 0; i < utf16.Length; i++) {
            int codePoint = Char.ConvertToUtf32(utf16, i);

            if (Char.IsSurrogate(utf16, i)) {
                // Skip low surrogate
                i++;
            }

            // ASCII subset from JIS X 0201
            if (codePoint >= 0x0020 && codePoint <= 0x007e) {
                // The LCD charset doesn't include '\' and '~', use similar characters instead
                switch (codePoint) {
                case 0x005c: c = (char)0xa4; break; // REVERSE SOLIDUS maps to IDEOGRAPHIC COMMA
                case 0x007e: c = (char)0x2d; break; // TILDE maps to HYPHEN-MINUS
                default: c = (char)codePoint; break;
                }
            }
            // Katakana subset from JIS X 0201
            else if (codePoint >= 0xff61 && codePoint <= 0xff9f) {
                c = (char)(codePoint - 0xfec0);
            }
            // Special characters
            else {
                switch (codePoint) {
                case 0x00a5: c = (char)0x5c; break; // YEN SIGN
                case 0x2192: c = (char)0x7e; break; // RIGHTWARDS ARROW
                case 0x2190: c = (char)0x7f; break; // LEFTWARDS ARROW
                case 0x00b0: c = (char)0xdf; break; // DEGREE SIGN maps to KATAKANA SEMI-VOICED SOUND MARK
                case 0x03b1: c = (char)0xe0; break; // GREEK SMALL LETTER ALPHA
                case 0x00c4: c = (char)0xe1; break; // LATIN CAPITAL LETTER A WITH DIAERESIS
                case 0x00e4: c = (char)0xe1; break; // LATIN SMALL LETTER A WITH DIAERESIS
                case 0x00df: c = (char)0xe2; break; // LATIN SMALL LETTER SHARP S
                case 0x03b5: c = (char)0xe3; break; // GREEK SMALL LETTER EPSILON
                case 0x00b5: c = (char)0xe4; break; // MICRO SIGN
                case 0x03bc: c = (char)0xe4; break; // GREEK SMALL LETTER MU
                case 0x03c2: c = (char)0xe5; break; // GREEK SMALL LETTER FINAL SIGMA
                case 0x03c1: c = (char)0xe6; break; // GREEK SMALL LETTER RHO
                case 0x221a: c = (char)0xe8; break; // SQUARE ROOT
                case 0x00b9: c = (char)0xe9; break; // SUPERSCRIPT ONE maps to SUPERSCRIPT (minus) ONE
                case 0x00a4: c = (char)0xeb; break; // CURRENCY SIGN
                case 0x00a2: c = (char)0xec; break; // CENT SIGN
                case 0x2c60: c = (char)0xed; break; // LATIN CAPITAL LETTER L WITH DOUBLE BAR
                case 0x00f1: c = (char)0xee; break; // LATIN SMALL LETTER N WITH TILDE
                case 0x00d6: c = (char)0xef; break; // LATIN CAPITAL LETTER O WITH DIAERESIS
                case 0x00f6: c = (char)0xef; break; // LATIN SMALL LETTER O WITH DIAERESIS
                case 0x03f4: c = (char)0xf2; break; // GREEK CAPITAL THETA SYMBOL
                case 0x221e: c = (char)0xf3; break; // INFINITY
                case 0x03a9: c = (char)0xf4; break; // GREEK CAPITAL LETTER OMEGA
                case 0x00dc: c = (char)0xf5; break; // LATIN CAPITAL LETTER U WITH DIAERESIS
                case 0x00fc: c = (char)0xf5; break; // LATIN SMALL LETTER U WITH DIAERESIS
                case 0x03a3: c = (char)0xf6; break; // GREEK CAPITAL LETTER SIGMA
                case 0x03c0: c = (char)0xf7; break; // GREEK SMALL LETTER PI
                case 0x0304: c = (char)0xf8; break; // COMBINING MACRON
                case 0x00f7: c = (char)0xfd; break; // DIVISION SIGN

                default:
                case 0x25a0: c = (char)0xff; break; // BLACK SQUARE
                }
            }

            // Special handling for 'x' followed by COMBINING MACRON
            if (c == (char)0xf8) {
                if (!ks0066u.EndsWith("x")) {
                    c = (char)0xff; // BLACK SQUARE
                }

                if (ks0066u.Length > 0) {
                    ks0066u = ks0066u.Remove(ks0066u.Length - 1, 1);
                }
            }

            ks0066u += c;
        }

        return ks0066u;
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLCD20x4 lcd = new BrickletLCD20x4(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Turn backlight on
        lcd.BacklightOn();

        // Write some strings using the UTF16ToKS0066U function to map to the LCD charset
        lcd.WriteLine(0, 0, UTF16ToKS0066U("Stromstärke: 17µA"));
        lcd.WriteLine(1, 0, UTF16ToKS0066U("Temperatur:  23°C"));

        // Write a string directly including characters from the LCD charset
        lcd.WriteLine(2, 0, "Drehzahl:   750min\xe9");

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Basic Functions¶

class BrickletLCD20x4(string uid, IPConnection ipcon)¶

Parameters:	uid – Type: string ipcon – Type: IPConnection
Returns:	lcd20x4 – Type: BrickletLCD20x4

Creates an object with the unique device ID uid:

BrickletLCD20x4 lcd20x4 = new BrickletLCD20x4("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected.

void BrickletLCD20x4.WriteLine(byte line, byte position, string text)¶

Parameters:	line – Type: byte, Range: [0 to 3] position – Type: byte, Range: [0 to 19] text – Type: string, Length: up to 20

Writes text to a specific line with a specific position. The text can have a maximum of 20 characters.

For example: (0, 7, "Hello") will write Hello in the middle of the first line of the display.

The display uses a special charset that includes all ASCII characters except backslash and tilde. The LCD charset also includes several other non-ASCII characters, see the charset specification for details. The Unicode example above shows how to specify non-ASCII characters and how to translate from Unicode to the LCD charset.

void BrickletLCD20x4.ClearDisplay()¶

Deletes all characters from the display.

void BrickletLCD20x4.BacklightOn()¶

Turns the backlight on.

void BrickletLCD20x4.BacklightOff()¶

Turns the backlight off.

bool BrickletLCD20x4.IsBacklightOn()¶

Returns:	backlight – Type: bool

Returns true if the backlight is on and false otherwise.

Advanced Functions¶

void BrickletLCD20x4.SetConfig(bool cursor, bool blinking)¶

Parameters:	cursor – Type: bool, Default: false blinking – Type: bool, Default: false

Configures if the cursor (shown as "_") should be visible and if it should be blinking (shown as a blinking block). The cursor position is one character behind the the last text written with WriteLine().

void BrickletLCD20x4.GetConfig(out bool cursor, out bool blinking)¶

Output Parameters:	cursor – Type: bool, Default: false blinking – Type: bool, Default: false

Returns the configuration as set by SetConfig().

bool BrickletLCD20x4.IsButtonPressed(byte button)¶

Parameters:	button – Type: byte, Range: [0 to 3]
Returns:	pressed – Type: bool

Returns true if the button (0 to 2 or 0 to 3 since hardware version 1.2) is pressed.

If you want to react on button presses and releases it is recommended to use the ButtonPressedCallback and ButtonReleasedCallback callbacks.

void BrickletLCD20x4.SetCustomCharacter(byte index, byte[] character)¶

Parameters:	index – Type: byte, Range: [0 to 7] character – Type: byte[], Length: 8, Range: [0 to 31]

The LCD 20x4 Bricklet can store up to 8 custom characters. The characters consist of 5x8 pixels and can be addressed with the index 0-7. To describe the pixels, the first 5 bits of 8 bytes are used. For example, to make a custom character "H", you should transfer the following:

• character[0] = 0b00010001 (decimal value 17)
• character[1] = 0b00010001 (decimal value 17)
• character[2] = 0b00010001 (decimal value 17)
• character[3] = 0b00011111 (decimal value 31)
• character[4] = 0b00010001 (decimal value 17)
• character[5] = 0b00010001 (decimal value 17)
• character[6] = 0b00010001 (decimal value 17)
• character[7] = 0b00000000 (decimal value 0)

The characters can later be written with WriteLine() by using the characters with the byte representation 8 ("\x08" or "\u0008") to 15 ("\x0F" or "\u000F").

You can play around with the custom characters in Brick Viewer version since 2.0.1.

Custom characters are stored by the LCD in RAM, so they have to be set after each startup.

New in version 2.0.1 (Plugin).

byte[] BrickletLCD20x4.GetCustomCharacter(byte index)¶

Parameters:	index – Type: byte, Range: [0 to 7]
Returns:	character – Type: byte[], Length: 8, Range: [0 to 31]

Returns the custom character for a given index, as set with SetCustomCharacter().

New in version 2.0.1 (Plugin).

void BrickletLCD20x4.SetDefaultText(byte line, string text)¶

Parameters:	line – Type: byte, Range: [0 to 3] text – Type: string, Length: up to 20

Sets the default text for lines 0-3. The max number of characters per line is 20.

The default text is shown on the LCD, if the default text counter expires, see SetDefaultTextCounter().

New in version 2.0.2 (Plugin).

string BrickletLCD20x4.GetDefaultText(byte line)¶

Parameters:	line – Type: byte, Range: [0 to 3]
Returns:	text – Type: string, Length: up to 20

Returns the default text for a given line (0-3) as set by SetDefaultText().

New in version 2.0.2 (Plugin).

void BrickletLCD20x4.SetDefaultTextCounter(int counter)¶

Parameters:	counter – Type: int, Unit: 1 ms, Range: [-231 to 231 - 1], Default: -1

Sets the default text counter. This counter is decremented each ms by the LCD firmware. If the counter reaches 0, the default text (see SetDefaultText()) is shown on the LCD.

This functionality can be used to show a default text if the controlling program crashes or the connection is interrupted.

A possible approach is to call SetDefaultTextCounter() every minute with the parameter 1000*60*2 (2 minutes). In this case the default text will be shown no later than 2 minutes after the controlling program crashes.

A negative counter turns the default text functionality off.

New in version 2.0.2 (Plugin).

int BrickletLCD20x4.GetDefaultTextCounter()¶

Returns:	counter – Type: int, Unit: 1 ms, Range: [-231 to 231 - 1], Default: -1

Returns the current value of the default text counter.

New in version 2.0.2 (Plugin).

void BrickletLCD20x4.GetIdentity(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)¶

Output Parameters:

uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: char, Range: ['a' to 'h', 'z'] hardwareVersion – Type: byte[], Length: 3 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] firmwareVersion – Type: byte[], Length: 3 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] deviceIdentifier – Type: int, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callbacks¶

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by appending your callback handler to the corresponding event:

void MyCallback(BrickletLCD20x4 sender, int value)
{
    System.Console.WriteLine("Value: " + value);
}

lcd20x4.ExampleCallback += MyCallback;

The available events are described below.

event BrickletLCD20x4.ButtonPressedCallback(BrickletLCD20x4 sender, byte button)¶

Callback Parameters:	sender – Type: BrickletLCD20x4 button – Type: byte, Range: [0 to 3]

This callback is triggered when a button is pressed. The parameter is the number of the button (0 to 2 or 0 to 3 since hardware version 1.2).

event BrickletLCD20x4.ButtonReleasedCallback(BrickletLCD20x4 sender, byte button)¶

Callback Parameters:	sender – Type: BrickletLCD20x4 button – Type: byte, Range: [0 to 3]

This callback is triggered when a button is released. The parameter is the number of the button (0 to 2 or 0 to 3 since hardware version 1.2).

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

byte[] BrickletLCD20x4.GetAPIVersion()¶

Output Parameters:	apiVersion – Type: byte[], Length: 3 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

bool BrickletLCD20x4.GetResponseExpected(byte functionId)¶

Parameters:	functionId – Type: byte, Range: See constants
Returns:	responseExpected – Type: bool

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

• BrickletLCD20x4.FUNCTION_WRITE_LINE = 1
• BrickletLCD20x4.FUNCTION_CLEAR_DISPLAY = 2
• BrickletLCD20x4.FUNCTION_BACKLIGHT_ON = 3
• BrickletLCD20x4.FUNCTION_BACKLIGHT_OFF = 4
• BrickletLCD20x4.FUNCTION_SET_CONFIG = 6
• BrickletLCD20x4.FUNCTION_SET_CUSTOM_CHARACTER = 11
• BrickletLCD20x4.FUNCTION_SET_DEFAULT_TEXT = 13
• BrickletLCD20x4.FUNCTION_SET_DEFAULT_TEXT_COUNTER = 15

void BrickletLCD20x4.SetResponseExpected(byte functionId, bool responseExpected)¶

Parameters:	functionId – Type: byte, Range: See constants responseExpected – Type: bool

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

• BrickletLCD20x4.FUNCTION_WRITE_LINE = 1
• BrickletLCD20x4.FUNCTION_CLEAR_DISPLAY = 2
• BrickletLCD20x4.FUNCTION_BACKLIGHT_ON = 3
• BrickletLCD20x4.FUNCTION_BACKLIGHT_OFF = 4
• BrickletLCD20x4.FUNCTION_SET_CONFIG = 6
• BrickletLCD20x4.FUNCTION_SET_CUSTOM_CHARACTER = 11
• BrickletLCD20x4.FUNCTION_SET_DEFAULT_TEXT = 13
• BrickletLCD20x4.FUNCTION_SET_DEFAULT_TEXT_COUNTER = 15

void BrickletLCD20x4.SetResponseExpectedAll(bool responseExpected)¶

Parameters:	responseExpected – Type: bool

Changes the response expected flag for all setter and callback configuration functions of this device at once.

Constants¶

int BrickletLCD20x4.DEVICE_IDENTIFIER¶

This constant is used to identify a LCD 20x4 Bricklet.

The GetIdentity() function and the IPConnection.EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

string BrickletLCD20x4.DEVICE_DISPLAY_NAME¶

This constant represents the human readable name of a LCD 20x4 Bricklet.