Delphi/Lazarus - LCD 20x4 Bricklet¶

Hello World¶

Download (ExampleHelloWorld.pas)

 1program ExampleHelloWorld;
 2
 3{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
 4{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}
 5
 6uses
 7  SysUtils, IPConnection, BrickletLCD20x4;
 8
 9type
10  TExample = class
11  private
12    ipcon: TIPConnection;
13    lcd: TBrickletLCD20x4;
14  public
15    procedure Execute;
16  end;
17
18const
19  HOST = 'localhost';
20  PORT = 4223;
21  UID = 'XYZ'; { Change XYZ to the UID of your LCD 20x4 Bricklet }
22
23var
24  e: TExample;
25
26procedure TExample.Execute;
27begin
28  { Create IP connection }
29  ipcon := TIPConnection.Create;
30
31  { Create device object }
32  lcd := TBrickletLCD20x4.Create(UID, ipcon);
33
34  { Connect to brickd }
35  ipcon.Connect(HOST, PORT);
36  { Don't use device before ipcon is connected }
37
38  { Turn backlight on }
39  lcd.BacklightOn;
40
41  { Write "Hello World" }
42  lcd.WriteLine(0, 0, 'Hello World');
43
44  WriteLn('Press key to exit');
45  ReadLn;
46  ipcon.Destroy; { Calls ipcon.Disconnect internally }
47end;
48
49begin
50  e := TExample.Create;
51  e.Execute;
52  e.Destroy;
53end.

Button Callback¶

Download (ExampleButtonCallback.pas)

 1program ExampleButtonCallback;
 2
 3{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
 4{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}
 5
 6uses
 7  SysUtils, IPConnection, BrickletLCD20x4;
 8
 9type
10  TExample = class
11  private
12    ipcon: TIPConnection;
13    lcd: TBrickletLCD20x4;
14  public
15    procedure ButtonPressedCB(sender: TBrickletLCD20x4; const button: byte);
16    procedure ButtonReleasedCB(sender: TBrickletLCD20x4; const button: byte);
17    procedure Execute;
18  end;
19
20const
21  HOST = 'localhost';
22  PORT = 4223;
23  UID = 'XYZ'; { Change XYZ to the UID of your LCD 20x4 Bricklet }
24
25var
26  e: TExample;
27
28{ Callback procedure for button pressed callback }
29procedure TExample.ButtonPressedCB(sender: TBrickletLCD20x4; const button: byte);
30begin
31  WriteLn(Format('Button Pressed: %d', [button]));
32end;
33
34{ Callback procedure for button released callback }
35procedure TExample.ButtonReleasedCB(sender: TBrickletLCD20x4; const button: byte);
36begin
37  WriteLn(Format('Button Released: %d', [button]));
38end;
39
40procedure TExample.Execute;
41begin
42  { Create IP connection }
43  ipcon := TIPConnection.Create;
44
45  { Create device object }
46  lcd := TBrickletLCD20x4.Create(UID, ipcon);
47
48  { Connect to brickd }
49  ipcon.Connect(HOST, PORT);
50  { Don't use device before ipcon is connected }
51
52  { Register button pressed callback to procedure ButtonPressedCB }
53  lcd.OnButtonPressed := {$ifdef FPC}@{$endif}ButtonPressedCB;
54
55  { Register button released callback to procedure ButtonReleasedCB }
56  lcd.OnButtonReleased := {$ifdef FPC}@{$endif}ButtonReleasedCB;
57
58  WriteLn('Press key to exit');
59  ReadLn;
60  ipcon.Destroy; { Calls ipcon.Disconnect internally }
61end;
62
63begin
64  e := TExample.Create;
65  e.Execute;
66  e.Destroy;
67end.

Unicode¶

Download (ExampleUnicode.pas)

  1program ExampleUnicode;
  2
  3{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
  4{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}
  5
  6uses
  7  SysUtils, IPConnection, BrickletLCD20x4;
  8
  9type
 10  TExample = class
 11  private
 12    ipcon: TIPConnection;
 13    lcd: TBrickletLCD20x4;
 14  public
 15    function WideStringToKS0066U(const text: WideString): string;
 16    procedure Execute;
 17  end;
 18
 19const
 20  HOST = 'localhost';
 21  PORT = 4223;
 22  UID = 'XYZ'; { Change XYZ to the UID of your LCD 20x4 Bricklet }
 23
 24var
 25  e: TExample;
 26
 27function TExample.WideStringToKS0066U(const text: WideString): string;
 28var i, codePoint: longint; w: word; c: char; ks0066u: string;
 29begin
 30  i := 1;
 31  SetLength(ks0066u, 0);
 32  while (i <= Length(text)) do begin
 33    { WideString is UTF-16, handle surrogates }
 34    w := word(text[i]);
 35    if ((w >= $D800) and (w <= $DBFF)) then begin
 36      codePoint := $10000 + (w - $D800) * $400 + (w - $DC00);
 37      i := i + 2;
 38    end
 39    else begin
 40      codePoint := w;
 41      i := i + 1;
 42    end;
 43    { ASCII subset from JIS X 0201 }
 44    if ((codePoint >= $0020) and (codePoint <= $007E)) then begin
 45      { The LCD charset doesn't include '\' and '~', use similar characters instead }
 46      case codePoint of
 47        $005C: c := char($A4); { REVERSE SOLIDUS maps to IDEOGRAPHIC COMMA }
 48        $007E: c := char($2D); { TILDE maps to HYPHEN-MINUS }
 49        else   c := char(codePoint);
 50      end;
 51    end
 52    { Katakana subset from JIS X 0201 }
 53    else if ((codePoint >= $FF61) and (codePoint <= $FF9F)) then begin
 54      c := char(codePoint - $FEC0);
 55    end
 56    { Special characters }
 57    else begin
 58      case codePoint of
 59        $00A5: c := char($5C); { YEN SIGN }
 60        $2192: c := char($7E); { RIGHTWARDS ARROW }
 61        $2190: c := char($7F); { LEFTWARDS ARROW }
 62        $00B0: c := char($DF); { DEGREE SIGN maps to KATAKANA SEMI-VOICED SOUND MARK }
 63        $03B1: c := char($E0); { GREEK SMALL LETTER ALPHA }
 64        $00C4: c := char($E1); { LATIN CAPITAL LETTER A WITH DIAERESIS }
 65        $00E4: c := char($E1); { LATIN SMALL LETTER A WITH DIAERESIS }
 66        $00DF: c := char($E2); { LATIN SMALL LETTER SHARP S }
 67        $03B5: c := char($E3); { GREEK SMALL LETTER EPSILON }
 68        $00B5: c := char($E4); { MICRO SIGN }
 69        $03BC: c := char($E4); { GREEK SMALL LETTER MU }
 70        $03C2: c := char($E5); { GREEK SMALL LETTER FINAL SIGMA }
 71        $03C1: c := char($E6); { GREEK SMALL LETTER RHO }
 72        $221A: c := char($E8); { SQUARE ROOT }
 73        $00B9: c := char($E9); { SUPERSCRIPT ONE maps to SUPERSCRIPT (minus) ONE }
 74        $00A4: c := char($EB); { CURRENCY SIGN }
 75        $00A2: c := char($EC); { CENT SIGN }
 76        $2C60: c := char($ED); { LATIN CAPITAL LETTER L WITH DOUBLE BAR }
 77        $00F1: c := char($EE); { LATIN SMALL LETTER N WITH TILDE }
 78        $00D6: c := char($EF); { LATIN CAPITAL LETTER O WITH DIAERESIS }
 79        $00F6: c := char($EF); { LATIN SMALL LETTER O WITH DIAERESIS }
 80        $03F4: c := char($F2); { GREEK CAPITAL THETA SYMBOL }
 81        $221E: c := char($F3); { INFINITY }
 82        $03A9: c := char($F4); { GREEK CAPITAL LETTER OMEGA }
 83        $00DC: c := char($F5); { LATIN CAPITAL LETTER U WITH DIAERESIS }
 84        $00FC: c := char($F5); { LATIN SMALL LETTER U WITH DIAERESIS }
 85        $03A3: c := char($F6); { GREEK CAPITAL LETTER SIGMA }
 86        $03C0: c := char($F7); { GREEK SMALL LETTER PI }
 87        $0304: c := char($F8); { COMBINING MACRON }
 88        $00F7: c := char($FD); { DIVISION SIGN }
 89        $25A0: c := char($FF); { BLACK SQUARE }
 90        else   c := char($FF); { BLACK SQUARE }
 91      end
 92    end;
 93    { Special handling for 'x' followed by COMBINING MACRON }
 94    if (c = char($F8)) then begin
 95      if (ks0066u[Length(ks0066u) - 1] <> 'x') then begin
 96        c := char($FF); { BLACK SQUARE }
 97      end;
 98      if (Length(ks0066u) > 0) then begin
 99        SetLength(ks0066u, Length(ks0066u) - 1);
100      end;
101    end;
102    ks0066u := ks0066u + c;
103  end;
104  result := ks0066u;
105end;
106
107procedure TExample.Execute;
108begin
109  { Create IP connection }
110  ipcon := TIPConnection.Create;
111
112  { Create device object }
113  lcd := TBrickletLCD20x4.Create(UID, ipcon);
114
115  { Connect to brickd }
116  ipcon.Connect(HOST, PORT);
117  { Don't use device before ipcon is connected }
118
119  { Turn backlight on }
120  lcd.BacklightOn;
121
122  { Write a string using the WideStringToKS0066U function to map to the LCD charset }
123  { Note: For the Free Pascal Compiler (and Lazarus) UTF8Decode is used to create a
124          WideString. It assumes that your source file is UTF-8 encoded }
125  lcd.WriteLine(0, 0, WideStringToKS0066U({$ifdef FPC}UTF8Decode{$endif}('Stromstärke: 17µA')));
126  lcd.WriteLine(1, 0, WideStringToKS0066U({$ifdef FPC}UTF8Decode{$endif}('Temperatur:  23°C')));
127
128  { Write a string directly including characters from the LCD charset }
129  lcd.WriteLine(2, 0, 'Drehzahl:   750min' + char($E9));
130
131  WriteLn('Press key to exit');
132  ReadLn;
133  ipcon.Destroy; { Calls ipcon.Disconnect internally }
134end;
135
136begin
137  e := TExample.Create;
138  e.Execute;
139  e.Destroy;
140end.

Basic Functions¶

constructor TBrickletLCD20x4.Create(const uid: string; ipcon: TIPConnection)¶

Parameters:	uid – Type: string ipcon – Type: TIPConnection
Returns:	lcd20x4 – Type: TBrickletLCD20x4

Creates an object with the unique device ID uid:

lcd20x4 := TBrickletLCD20x4.Create('YOUR_DEVICE_UID', ipcon);

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

procedure TBrickletLCD20x4.WriteLine(const line: byte; const position: byte; const text: 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.

procedure TBrickletLCD20x4.ClearDisplay¶

Deletes all characters from the display.

procedure TBrickletLCD20x4.BacklightOn¶

Turns the backlight on.

procedure TBrickletLCD20x4.BacklightOff¶

Turns the backlight off.

function TBrickletLCD20x4.IsBacklightOn: boolean¶

Returns:	backlight – Type: boolean

Returns true if the backlight is on and false otherwise.

Advanced Functions¶

procedure TBrickletLCD20x4.SetConfig(const cursor: boolean; const blinking: 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.

procedure TBrickletLCD20x4.GetConfig(out cursor: boolean; out blinking: boolean)¶

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

Returns the configuration as set by SetConfig.

function TBrickletLCD20x4.IsButtonPressed(const button: byte): 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 OnButtonPressed and OnButtonReleased callbacks.

procedure TBrickletLCD20x4.SetCustomCharacter(const index: byte; const character: array [0..7] of byte)¶

Parameters:	index – Type: byte, Range: [0 to 7] character – Type: array [0..7] of byte, 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 TBrickletLCD20x4.GetCustomCharacter(const index: byte): array [0..7] of byte¶

Parameters:	index – Type: byte, Range: [0 to 7]
Returns:	character – Type: array [0..7] of byte, Range: [0 to 31]

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

Added in version 2.0.1$nbsp;(Plugin).

procedure TBrickletLCD20x4.SetDefaultText(const line: byte; const text: 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 TBrickletLCD20x4.GetDefaultText(const line: byte): 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).

procedure TBrickletLCD20x4.SetDefaultTextCounter(const counter: longint)¶

Parameters:	counter – Type: longint, 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 TBrickletLCD20x4.GetDefaultTextCounter: longint¶

Returns:	counter – Type: longint, 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).

procedure TBrickletLCD20x4.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)¶

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: array [0..2] of byte 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: array [0..2] of byte 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: word, 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:

procedure TExample.MyCallback(sender: TBrickletLCD20x4; const value: longint);
begin
  WriteLn(Format('Value: %d', [value]));
end;

lcd20x4.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback properties and their parameter types are described below.

property TBrickletLCD20x4.OnButtonPressed¶

procedure(sender: TBrickletLCD20x4; const button: byte) of object;

Callback Parameters:	sender – Type: TBrickletLCD20x4 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).

property TBrickletLCD20x4.OnButtonReleased¶

procedure(sender: TBrickletLCD20x4; const button: byte) of object;

Callback Parameters:	sender – Type: TBrickletLCD20x4 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 TBrickletLCD20x4.GetAPIVersion: array [0..2] of byte¶

Output Parameters:	apiVersion – Type: array [0..2] of byte 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 TBrickletLCD20x4.GetResponseExpected(const functionId: byte): 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:

• BRICKLET_LCD_20X4_FUNCTION_WRITE_LINE = 1

• BRICKLET_LCD_20X4_FUNCTION_CLEAR_DISPLAY = 2

• BRICKLET_LCD_20X4_FUNCTION_BACKLIGHT_ON = 3

• BRICKLET_LCD_20X4_FUNCTION_BACKLIGHT_OFF = 4

• BRICKLET_LCD_20X4_FUNCTION_SET_CONFIG = 6

• BRICKLET_LCD_20X4_FUNCTION_SET_CUSTOM_CHARACTER = 11

• BRICKLET_LCD_20X4_FUNCTION_SET_DEFAULT_TEXT = 13

• BRICKLET_LCD_20X4_FUNCTION_SET_DEFAULT_TEXT_COUNTER = 15

procedure TBrickletLCD20x4.SetResponseExpected(const functionId: byte; const responseExpected: 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:

• BRICKLET_LCD_20X4_FUNCTION_WRITE_LINE = 1

• BRICKLET_LCD_20X4_FUNCTION_CLEAR_DISPLAY = 2

• BRICKLET_LCD_20X4_FUNCTION_BACKLIGHT_ON = 3

• BRICKLET_LCD_20X4_FUNCTION_BACKLIGHT_OFF = 4

• BRICKLET_LCD_20X4_FUNCTION_SET_CONFIG = 6

• BRICKLET_LCD_20X4_FUNCTION_SET_CUSTOM_CHARACTER = 11

• BRICKLET_LCD_20X4_FUNCTION_SET_DEFAULT_TEXT = 13

• BRICKLET_LCD_20X4_FUNCTION_SET_DEFAULT_TEXT_COUNTER = 15

procedure TBrickletLCD20x4.SetResponseExpectedAll(const responseExpected: boolean)¶

Parameters:	responseExpected – Type: boolean

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

Constants¶

const BRICKLET_LCD_20X4_DEVICE_IDENTIFIER¶

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

The GetIdentity function and the TIPConnection.OnEnumerate callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

const BRICKLET_LCD_20X4_DEVICE_DISPLAY_NAME¶

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