Visual Basic .NET - LCD 20x4 Bricklet¶

Hello World¶

Download (ExampleHelloWorld.vb)

 1Imports System
 2Imports Tinkerforge
 3
 4Module ExampleHelloWorld
 5    Const HOST As String = "localhost"
 6    Const PORT As Integer = 4223
 7    Const UID As String = "XYZ" ' Change XYZ to the UID of your LCD 20x4 Bricklet
 8
 9    Sub Main()
10        Dim ipcon As New IPConnection() ' Create IP connection
11        Dim lcd As New BrickletLCD20x4(UID, ipcon) ' Create device object
12
13        ipcon.Connect(HOST, PORT) ' Connect to brickd
14        ' Don't use device before ipcon is connected
15
16        ' Turn backlight on
17        lcd.BacklightOn()
18
19        ' Write "Hello World"
20        lcd.WriteLine(0, 0, "Hello World")
21
22        Console.WriteLine("Press key to exit")
23        Console.ReadLine()
24        ipcon.Disconnect()
25    End Sub
26End Module

Button Callback¶

Download (ExampleButtonCallback.vb)

 1Imports System
 2Imports Tinkerforge
 3
 4Module ExampleButtonCallback
 5    Const HOST As String = "localhost"
 6    Const PORT As Integer = 4223
 7    Const UID As String = "XYZ" ' Change XYZ to the UID of your LCD 20x4 Bricklet
 8
 9    ' Callback subroutine for button pressed callback
10    Sub ButtonPressedCB(ByVal sender As BrickletLCD20x4, ByVal button As Byte)
11        Console.WriteLine("Button Pressed: " + button.ToString())
12    End Sub
13
14    ' Callback subroutine for button released callback
15    Sub ButtonReleasedCB(ByVal sender As BrickletLCD20x4, ByVal button As Byte)
16        Console.WriteLine("Button Released: " + button.ToString())
17    End Sub
18
19    Sub Main()
20        Dim ipcon As New IPConnection() ' Create IP connection
21        Dim lcd As New BrickletLCD20x4(UID, ipcon) ' Create device object
22
23        ipcon.Connect(HOST, PORT) ' Connect to brickd
24        ' Don't use device before ipcon is connected
25
26        ' Register button pressed callback to subroutine ButtonPressedCB
27        AddHandler lcd.ButtonPressedCallback, AddressOf ButtonPressedCB
28
29        ' Register button released callback to subroutine ButtonReleasedCB
30        AddHandler lcd.ButtonReleasedCallback, AddressOf ButtonReleasedCB
31
32        Console.WriteLine("Press key to exit")
33        Console.ReadLine()
34        ipcon.Disconnect()
35    End Sub
36End Module

Unicode¶

Download (ExampleUnicode.vb)

  1Imports System
  2Imports Tinkerforge
  3
  4Module ExampleUnicode
  5    Const HOST As String = "localhost"
  6    Const PORT As Integer = 4223
  7    Const UID As String = "XYZ" ' Change XYZ to the UID of your LCD 20x4 Bricklet
  8
  9    ' Maps a normal UTF-16 encoded string to the LCD charset
 10    Function UTF16ToKS0066U(ByVal utf16 As String) As String
 11        Dim ks0066u As String = ""
 12        Dim c As Char
 13        Dim i As Integer = 0
 14
 15        While i < utf16.Length
 16            Dim codePoint As Integer = Char.ConvertToUtf32(utf16, i)
 17
 18            if Char.IsSurrogate(utf16, i) Then
 19                ' Skip low surrogate
 20                i += 1
 21            End If
 22
 23            ' ASCII subset from JIS X 0201
 24            if (codePoint >= &H0020) And (codePoint <= &H007e) Then
 25                ' The LCD charset doesn't include '\' and '~', use similar characters instead
 26                Select Case codePoint
 27                    Case &H005c
 28                        c = Chr(&H00a4) ' REVERSE SOLIDUS maps to IDEOGRAPHIC COMMA
 29                    Case &H007e
 30                        c = Chr(&H002d) ' TILDE maps to HYPHEN-MINUS
 31                    Case Else
 32                        c = Chr(codePoint)
 33                End Select
 34            ' Katakana subset from JIS X 0201
 35            Else If (codePoint >= &Hff61) And (codePoint <= &Hff9f) Then
 36                c = Chr(codePoint - &Hfec0)
 37            ' Special characters
 38            Else
 39                Select Case codePoint
 40                    Case &H00a5
 41                        c = Chr(&H5c) ' YEN SIGN
 42                    Case &H2192
 43                        c = Chr(&H7e) ' RIGHTWARDS ARROW
 44                    Case &H2190
 45                        c = Chr(&H7f) ' LEFTWARDS ARROW
 46                    Case &H00b0
 47                        c = Chr(&Hdf) ' DEGREE SIGN maps to KATAKANA SEMI-VOICED SOUND MARK
 48                    Case &H03b1
 49                        c = Chr(&He0) ' GREEK SMALL LETTER ALPHA
 50                    Case &H00c4
 51                        c = Chr(&He1) ' LATIN CAPITAL LETTER A WITH DIAERESIS
 52                    Case &H00e4
 53                        c = Chr(&He1) ' LATIN SMALL LETTER A WITH DIAERESIS
 54                    Case &H00df
 55                        c = Chr(&He2) ' LATIN SMALL LETTER SHARP S
 56                    Case &H03b5
 57                        c = Chr(&He3) ' GREEK SMALL LETTER EPSILON
 58                    Case &H00b5
 59                        c = Chr(&He4) ' MICRO SIGN
 60                    Case &H03bc
 61                        c = Chr(&He4) ' GREEK SMALL LETTER MU
 62                    Case &H03c2
 63                        c = Chr(&He5) ' GREEK SMALL LETTER FINAL SIGMA
 64                    Case &H03c1
 65                        c = Chr(&He6) ' GREEK SMALL LETTER RHO
 66                    Case &H221a
 67                        c = Chr(&He8) ' SQUARE ROOT
 68                    Case &H00b9
 69                        c = Chr(&He9) ' SUPERSCRIPT ONE maps to SUPERSCRIPT (minus) ONE
 70                    Case &H00a4
 71                        c = Chr(&Heb) ' CURRENCY SIGN
 72                    Case &H00a2
 73                        c = Chr(&Hec) ' CENT SIGN
 74                    Case &H2c60
 75                        c = Chr(&Hed) ' LATIN CAPITAL LETTER L WITH DOUBLE BAR
 76                    Case &H00f1
 77                        c = Chr(&Hee) ' LATIN SMALL LETTER N WITH TILDE
 78                    Case &H00d6
 79                        c = Chr(&Hef) ' LATIN CAPITAL LETTER O WITH DIAERESIS
 80                    Case &H00f6
 81                        c = Chr(&Hef) ' LATIN SMALL LETTER O WITH DIAERESIS
 82                    Case &H03f4
 83                        c = Chr(&Hf2) ' GREEK CAPITAL THETA SYMBOL
 84                    Case &H221e
 85                        c = Chr(&Hf3) ' INFINITY
 86                    Case &H03a9
 87                        c = Chr(&Hf4) ' GREEK CAPITAL LETTER OMEGA
 88                    Case &H00dc
 89                        c = Chr(&Hf5) ' LATIN CAPITAL LETTER U WITH DIAERESIS
 90                    Case &H00fc
 91                        c = Chr(&Hf5) ' LATIN SMALL LETTER U WITH DIAERESIS
 92                    Case &H03a3
 93                        c = Chr(&Hf6) ' GREEK CAPITAL LETTER SIGMA
 94                    Case &H03c0
 95                        c = Chr(&Hf7) ' GREEK SMALL LETTER PI
 96                    Case &H0304
 97                        c = Chr(&Hf8) ' COMBINING MACRON
 98                    Case &H00f7
 99                        c = Chr(&Hfd) ' DIVISION SIGN
100                    Case &H25a0
101                        c = Chr(&Hff) ' BLACK SQUARE
102                    Case Else
103                        c = Chr(&Hff) ' BLACK SQUARE
104                End Select
105            End If
106
107            ' Special handling for 'x' followed by COMBINING MACRON
108            If c = Chr(&Hf8) Then
109                If Not ks0066u.EndsWith("x") Then
110                    c = Chr(&Hff) ' BLACK SQUARE
111                End If
112
113                If ks0066u.Length > 0 Then
114                    ks0066u = ks0066u.Remove(ks0066u.Length - 1, 1)
115                End If
116            End If
117
118            ks0066u += c
119            i += 1
120        End While
121
122        Return ks0066u
123    End Function
124
125    Sub Main()
126        Dim ipcon As New IPConnection() ' Create IP connection
127        Dim lcd As New BrickletLCD20x4(UID, ipcon) ' Create device object
128
129        ipcon.Connect(HOST, PORT) ' Connect to brickd
130        ' Don't use device before ipcon is connected
131
132        ' Turn backlight on
133        lcd.BacklightOn()
134
135        ' Write some strings using the UTF16ToKS0066U function to map to the LCD charset
136        lcd.WriteLine(0, 0, UTF16ToKS0066U("Stromstärke: 17µA"))
137        lcd.WriteLine(1, 0, UTF16ToKS0066U("Temperatur:  23°C"))
138
139        ' Write a string directly including characters from the LCD charset
140        lcd.WriteLine(2, 0, "Drehzahl:   750min" + Chr(&He9))
141
142        Console.WriteLine("Press key to exit")
143        Console.ReadLine()
144        ipcon.Disconnect()
145    End Sub
146End Module

Basic Functions¶

Class BrickletLCD20x4(ByVal uid As String, ByVal ipcon As IPConnection)¶

Creates an object with the unique device ID uid:

Dim lcd20x4 As New BrickletLCD20x4("YOUR_DEVICE_UID", ipcon)

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

Sub BrickletLCD20x4.WriteLine(ByVal line As Byte, ByVal position As Byte, ByVal text As String)¶

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.

Sub BrickletLCD20x4.ClearDisplay()¶

Deletes all characters from the display.

Sub BrickletLCD20x4.BacklightOn()¶

Turns the backlight on.

Sub BrickletLCD20x4.BacklightOff()¶

Turns the backlight off.

Function BrickletLCD20x4.IsBacklightOn() As Boolean¶

Returns:	backlight – Type: Boolean

Returns true if the backlight is on and false otherwise.

Advanced Functions¶

Sub BrickletLCD20x4.SetConfig(ByVal cursor As Boolean, ByVal blinking As Boolean)¶

Parameters:	cursor – Type: Boolean, Default: false blinking – Type: Boolean, 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().

Sub BrickletLCD20x4.GetConfig(ByRef cursor As Boolean, ByRef blinking As Boolean)¶

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

Returns the configuration as set by SetConfig().

Function BrickletLCD20x4.IsButtonPressed(ByVal button As Byte) As Boolean¶

Parameters:	button – Type: Byte, Range: [0 to 3]
Returns:	pressed – Type: Boolean

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.

Sub BrickletLCD20x4.SetCustomCharacter(ByVal index As Byte, ByVal character() As Byte)¶

Parameters:	index – Type: Byte, Range: [0 to 7] character – Type: Byte Array, 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.

Added in version 2.0.1$nbsp;(Plugin).

Function BrickletLCD20x4.GetCustomCharacter(ByVal index As Byte) As Byte()¶

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

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

Added in version 2.0.1$nbsp;(Plugin).

Sub BrickletLCD20x4.SetDefaultText(ByVal line As Byte, ByVal text As String)¶

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().

Added in version 2.0.2$nbsp;(Plugin).

Function BrickletLCD20x4.GetDefaultText(ByVal line As Byte) As String¶

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().

Added in version 2.0.2$nbsp;(Plugin).

Sub BrickletLCD20x4.SetDefaultTextCounter(ByVal counter As Integer)¶

Parameters:	counter – Type: Integer, 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.

Added in version 2.0.2$nbsp;(Plugin).

Function BrickletLCD20x4.GetDefaultTextCounter() As Integer¶

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

Returns the current value of the default text counter.

Added in version 2.0.2$nbsp;(Plugin).

Sub BrickletLCD20x4.GetIdentity(ByRef uid As String, ByRef connectedUid As String, ByRef position As Char, ByRef hardwareVersion() As Byte, ByRef firmwareVersion() As Byte, ByRef deviceIdentifier As Integer)¶

Output Parameters:

uid – Type: String, Length: up to 8 connectedUid – Type: String, Length: up to 8 position – Type: Char, Range: ["a"C to "h"C, "z"C] hardwareVersion – Type: Byte Array, 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 Array, 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: Integer, 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 assigning a procedure to an callback property of the device object:

Sub MyCallback(ByVal sender As BrickletLCD20x4, ByVal value As Short)
    Console.WriteLine("Value: {0}", value)
End Sub

AddHandler lcd20x4.ExampleCallback, AddressOf MyCallback

The available callback property and their type of parameters are described below.

Event BrickletLCD20x4.ButtonPressedCallback(ByVal sender As BrickletLCD20x4, ByVal button As Byte)¶

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(ByVal sender As BrickletLCD20x4, ByVal button As Byte)¶

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.

Function BrickletLCD20x4.GetAPIVersion() As Byte()¶

Output Parameters:	apiVersion – Type: Byte Array, 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.

Function BrickletLCD20x4.GetResponseExpected(ByVal functionId As Byte) As Boolean¶

Parameters:	functionId – Type: Byte, Range: See constants
Returns:	responseExpected – Type: Boolean

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

Sub BrickletLCD20x4.SetResponseExpected(ByVal functionId As Byte, ByVal responseExpected As Boolean)¶

Parameters:	functionId – Type: Byte, Range: See constants responseExpected – Type: Boolean

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

Sub BrickletLCD20x4.SetResponseExpectedAll(ByVal responseExpected As Boolean)¶

Parameters:	responseExpected – Type: Boolean

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

Constants¶

Const 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.

Const BrickletLCD20x4.DEVICE_DISPLAY_NAME¶

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