Delphi/Lazarus - LED Strip Bricklet

This is the description of the Delphi/Lazarus API bindings for the LED Strip Bricklet. General information and technical specifications for the LED Strip Bricklet are summarized in its hardware description.

An installation guide for the Delphi/Lazarus API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (ExampleSimple.pas)

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program ExampleSimple;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletLEDStrip;

type
  TExample = class
  private
    ipcon: TIPConnection;
    ls: TBrickletLEDStrip;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your LED Strip Bricklet }

var
  e: TExample;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  ls := TBrickletLEDStrip.Create(UID, ipcon);

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

  { Set first 10 LEDs to green }
  ls.SetRGBValues(0, 10, [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                  [255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Callback

Download (ExampleCallback.pas)

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program ExampleCallback;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletLEDStrip;

type
  TExample = class
  private
    ipcon: TIPConnection;
    ls: TBrickletLEDStrip;
    r: {$ifdef FPC}array [0..15] of byte{$else}TArray0To15OfUInt8{$endif};
    g: {$ifdef FPC}array [0..15] of byte{$else}TArray0To15OfUInt8{$endif};
    b: {$ifdef FPC}array [0..15] of byte{$else}TArray0To15OfUInt8{$endif};
    rIndex: integer;
  public
    procedure FrameRenderedCB(sender: TBrickletLEDStrip; const length: word);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your LED Strip Bricklet }
  NUM_LEDS = 16;

var
  e: TExample;

{ Use frame rendered callback to move the active LED every frame }
procedure TExample.FrameRenderedCB(sender: TBrickletLEDStrip; const length: word);
begin
  b[rIndex] := 0;
  if rIndex = NUM_LEDS-1 then begin
    rIndex := 0
  end
  else begin
    rIndex := rIndex + 1
  end;
  b[rIndex] := 255;

  { Set new data for next render cycle }
  sender.SetRGBValues(0, NUM_LEDS, r, g, b);
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  ls := TBrickletLEDStrip.Create(UID, ipcon);

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

  { Set frame duration to 50ms (20 frames per second) }
  ls.SetFrameDuration(50);

  { Register frame rendered callback to procedure FrameRenderedCB }
  ls.OnFrameRendered := {$ifdef FPC}@{$endif}FrameRenderedCB;

  { Set initial rgb values to get started }
  ls.SetRGBValues(0, NUM_LEDS, r, g, b);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

API

Since Delphi does not support multiple return values directly, we use the out keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.

Basic Functions

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

Creates an object with the unique device ID uid:

ledStrip := TBrickletLEDStrip.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected (see examples above).

procedure TBrickletLEDStrip.SetRGBValues(const index: word; const length: byte; const r: array [0..15] of byte; const g: array [0..15] of byte; const b: array [0..15] of byte)

Sets the RGB values for the LEDs with the given length starting from index.

To make the colors show correctly you need to configure the chip type (SetChipType) and a 3-channel channel mapping (SetChannelMapping) according to the connected LEDs.

The maximum length is 16, the index goes from 0 to 319 and the rgb values have 8 bits each.

Example: If you set

  • index to 5,
  • length to 3,
  • r to [255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
  • g to [0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] and
  • b to [0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

the LED with index 5 will be red, 6 will be green and 7 will be blue.

Note

Depending on the LED circuitry colors can be permuted.

The colors will be transfered to actual LEDs when the next frame duration ends, see SetFrameDuration.

Generic approach:

  • Set the frame duration to a value that represents the number of frames per second you want to achieve.
  • Set all of the LED colors for one frame.
  • Wait for the OnFrameRendered callback.
  • Set all of the LED colors for next frame.
  • Wait for the OnFrameRendered callback.
  • and so on.

This approach ensures that you can change the LED colors with a fixed frame rate.

The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of SetRGBValues with index + length above the bounds is ignored completely.

procedure TBrickletLEDStrip.GetRGBValues(const index: word; const length: byte; out r: array [0..15] of byte; out g: array [0..15] of byte; out b: array [0..15] of byte)

Returns RGB value with the given length starting from the given index.

The values are the last values that were set by SetRGBValues.

procedure TBrickletLEDStrip.SetFrameDuration(const duration: word)

Sets the frame duration in ms.

Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).

For an explanation of the general approach see SetRGBValues.

Default value: 100ms (10 frames per second).

function TBrickletLEDStrip.GetFrameDuration: word

Returns the frame duration in ms as set by SetFrameDuration.

function TBrickletLEDStrip.GetSupplyVoltage: word

Returns the current supply voltage of the LEDs. The voltage is given in mV.

procedure TBrickletLEDStrip.SetClockFrequency(const frequency: longword)

Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).

The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling GetClockFrequency.

If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.

With a decreasing frequency your maximum frames per second will decrease too.

The default value is 1.66MHz.

Note

The frequency in firmware version 2.0.0 is fixed at 2MHz.

New in version 2.0.1 (Plugin).

function TBrickletLEDStrip.GetClockFrequency: longword

Returns the currently used clock frequency as set by SetClockFrequency.

New in version 2.0.1 (Plugin).

procedure TBrickletLEDStrip.SetChipType(const chip: word)

Sets the type of the LED driver chip. We currently support the chips

  • WS2801,
  • WS2811,
  • WS2812 / SK6812 / NeoPixel RGB,
  • SK6812RGBW / NeoPixel RGBW (Chip Type = WS2812),
  • LPD8806 and
  • APA102 / DotStar.

The default value is WS2801 (2801).

The following constants are available for this function:

  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2801 = 2801
  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2811 = 2811
  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2812 = 2812
  • BRICKLET_LED_STRIP_CHIP_TYPE_LPD8806 = 8806
  • BRICKLET_LED_STRIP_CHIP_TYPE_APA102 = 102

New in version 2.0.2 (Plugin).

function TBrickletLEDStrip.GetChipType: word

Returns the currently used chip type as set by SetChipType.

The following constants are available for this function:

  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2801 = 2801
  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2811 = 2811
  • BRICKLET_LED_STRIP_CHIP_TYPE_WS2812 = 2812
  • BRICKLET_LED_STRIP_CHIP_TYPE_LPD8806 = 8806
  • BRICKLET_LED_STRIP_CHIP_TYPE_APA102 = 102

New in version 2.0.2 (Plugin).

procedure TBrickletLEDStrip.SetRGBWValues(const index: word; const length: byte; const r: array [0..11] of byte; const g: array [0..11] of byte; const b: array [0..11] of byte; const w: array [0..11] of byte)

Sets the RGBW values for the LEDs with the given length starting from index.

To make the colors show correctly you need to configure the chip type (SetChipType) and a 4-channel channel mapping (SetChannelMapping) according to the connected LEDs.

The maximum length is 12, the index goes from 0 to 239 and the rgbw values have 8 bits each.

Example: If you set

  • index to 5,
  • length to 4,
  • r to [255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
  • g to [0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
  • b to [0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0] and
  • w to [0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0]

the LED with index 5 will be red, 6 will be green, 7 will be blue and 8 will be white.

Note

Depending on the LED circuitry colors can be permuted.

The colors will be transfered to actual LEDs when the next frame duration ends, see SetFrameDuration.

Generic approach:

  • Set the frame duration to a value that represents the number of frames per second you want to achieve.
  • Set all of the LED colors for one frame.
  • Wait for the OnFrameRendered callback.
  • Set all of the LED colors for next frame.
  • Wait for the OnFrameRendered callback.
  • and so on.

This approach ensures that you can change the LED colors with a fixed frame rate.

The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of SetRGBWValues with index + length above the bounds is ignored completely.

The LPD8806 LED driver chips have 7-bit channels for RGB. Internally the LED Strip Bricklets divides the 8-bit values set using this function by 2 to make them 7-bit. Therefore, you can just use the normal value range (0-255) for LPD8806 LEDs.

The brightness channel of the APA102 LED driver chips has 5-bit. Internally the LED Strip Bricklets divides the 8-bit values set using this function by 8 to make them 5-bit. Therefore, you can just use the normal value range (0-255) for the brightness channel of APA102 LEDs.

New in version 2.0.6 (Plugin).

procedure TBrickletLEDStrip.GetRGBWValues(const index: word; const length: byte; out r: array [0..11] of byte; out g: array [0..11] of byte; out b: array [0..11] of byte; out w: array [0..11] of byte)

Returns RGBW values with the given length starting from the given index.

The values are the last values that were set by SetRGBWValues.

New in version 2.0.6 (Plugin).

procedure TBrickletLEDStrip.SetChannelMapping(const mapping: byte)

Sets the channel mapping for the connected LEDs.

SetRGBValues and SetRGBWValues take the data in RGB(W) order. But the connected LED driver chips might have their 3 or 4 channels in a different order. For example, the WS2801 chips typically use BGR order, the WS2812 chips typically use GRB order and the APA102 chips typically use WBGR order.

The APA102 chips are special. They have three 8-bit channels for RGB and an additional 5-bit channel for the overall brightness of the RGB LED making them 4-channel chips. Internally the brightness channel is the first channel, therefore one of the Wxyz channel mappings should be used. Then the W channel controls the brightness.

If a 3-channel mapping is selected then SetRGBValues has to be used. Calling SetRGBWValues with a 3-channel mapping will produce incorrect results. Vice-versa if a 4-channel mapping is selected then SetRGBWValues has to be used. Calling SetRGBValues with a 4-channel mapping will produce incorrect results.

The default value is BGR (36).

The following constants are available for this function:

  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGB = 6
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBG = 9
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRG = 33
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGR = 36
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRB = 18
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBR = 24
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGBW = 27
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGWB = 30
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBGW = 39
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBWG = 45
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RWGB = 54
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RWBG = 57
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRWB = 78
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRBW = 75
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBWR = 108
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBRW = 99
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GWBR = 120
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GWRB = 114
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRGW = 135
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRWG = 141
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGRW = 147
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGWR = 156
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BWRG = 177
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BWGR = 180
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WRBG = 201
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WRGB = 198
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WGBR = 216
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WGRB = 210
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WBGR = 228
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WBRG = 225

New in version 2.0.6 (Plugin).

function TBrickletLEDStrip.GetChannelMapping: byte

Returns the currently used channel mapping as set by SetChannelMapping.

The following constants are available for this function:

  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGB = 6
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBG = 9
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRG = 33
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGR = 36
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRB = 18
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBR = 24
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGBW = 27
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RGWB = 30
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBGW = 39
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RBWG = 45
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RWGB = 54
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_RWBG = 57
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRWB = 78
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GRBW = 75
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBWR = 108
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GBRW = 99
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GWBR = 120
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_GWRB = 114
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRGW = 135
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BRWG = 141
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGRW = 147
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BGWR = 156
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BWRG = 177
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_BWGR = 180
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WRBG = 201
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WRGB = 198
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WGBR = 216
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WGRB = 210
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WBGR = 228
  • BRICKLET_LED_STRIP_CHANNEL_MAPPING_WBRG = 225

New in version 2.0.6 (Plugin).

Advanced Functions

function TBrickletLEDStrip.GetAPIVersion: array [0..2] of byte

Returns the version of the API definition (major, minor, revision) 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 TBrickletLEDStrip.GetResponseExpected(const functionId: byte): 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 send and errors are silently ignored, because they cannot be detected.

See SetResponseExpected for the list of function ID constants available for this function.

procedure TBrickletLEDStrip.SetResponseExpected(const functionId: byte; const responseExpected: 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 send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • BRICKLET_LED_STRIP_FUNCTION_SET_RGB_VALUES = 1
  • BRICKLET_LED_STRIP_FUNCTION_SET_FRAME_DURATION = 3
  • BRICKLET_LED_STRIP_FUNCTION_SET_CLOCK_FREQUENCY = 7
  • BRICKLET_LED_STRIP_FUNCTION_SET_CHIP_TYPE = 9
  • BRICKLET_LED_STRIP_FUNCTION_SET_RGBW_VALUES = 11
  • BRICKLET_LED_STRIP_FUNCTION_SET_CHANNEL_MAPPING = 13
  • BRICKLET_LED_STRIP_FUNCTION_ENABLE_FRAME_RENDERED_CALLBACK = 15
  • BRICKLET_LED_STRIP_FUNCTION_DISABLE_FRAME_RENDERED_CALLBACK = 16
procedure TBrickletLEDStrip.SetResponseExpectedAll(const responseExpected: boolean)

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

procedure TBrickletLEDStrip.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)

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' or 'd'.

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

Callback Configuration Functions

procedure TBrickletLEDStrip.EnableFrameRenderedCallback

Enables the OnFrameRendered callback.

By default the callback is enabled.

New in version 2.0.6 (Plugin).

procedure TBrickletLEDStrip.DisableFrameRenderedCallback

Disables the OnFrameRendered callback.

By default the callback is enabled.

New in version 2.0.6 (Plugin).

function TBrickletLEDStrip.IsFrameRenderedCallbackEnabled: boolean

Returns true if the OnFrameRendered callback is enabled, false otherwise.

New in version 2.0.6 (Plugin).

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: TBrickletLEDStrip; const param: word);
begin
  WriteLn(param);
end;

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

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

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

property TBrickletLEDStrip.OnFrameRendered
procedure(sender: TBrickletLEDStrip; const length: word) of object;

This callback is triggered directly after a new frame is rendered. The parameter is the number of LEDs in that frame.

You should send the data for the next frame directly after this callback was triggered.

For an explanation of the general approach see SetRGBValues.

Constants

const BRICKLET_LED_STRIP_DEVICE_IDENTIFIER

This constant is used to identify a LED Strip 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_LED_STRIP_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a LED Strip Bricklet.