Delphi/Lazarus - Joystick Bricklet 2.0

This is the description of the Delphi/Lazarus API bindings for the Joystick Bricklet 2.0. General information and technical specifications for the Joystick Bricklet 2.0 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, BrickletJoystickV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    j: TBrickletJoystickV2;
  public
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Joystick Bricklet 2.0 }

var
  e: TExample;

procedure TExample.Execute;
var x, y: smallint;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  j := TBrickletJoystickV2.Create(UID, ipcon);

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

  { Get current position }
  j.GetPosition(x, y);

  WriteLn(Format('Position [X]: %d', [x]));
  WriteLn(Format('Position [Y]: %d', [y]));

  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, BrickletJoystickV2;

type
  TExample = class
  private
    ipcon: TIPConnection;
    j: TBrickletJoystickV2;
  public
    procedure PressedCB(sender: TBrickletJoystickV2; const pressed: boolean);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your Joystick Bricklet 2.0 }

var
  e: TExample;

{ Callback procedure for pressed callback }
procedure TExample.PressedCB(sender: TBrickletJoystickV2; const pressed: boolean);
begin
  WriteLn(Format('Pressed: %d', [pressed]));
end;

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

  { Create device object }
  j := TBrickletJoystickV2.Create(UID, ipcon);

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

  { Register pressed callback to procedure PressedCB }
  j.OnPressed := {$ifdef FPC}@{$endif}PressedCB;

  { Set period for pressed callback to 0.01s (10ms) }
  j.SetPressedCallbackConfiguration(10, true);

  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 TBrickletJoystickV2.Create(const uid: string; ipcon: TIPConnection)
Parameters:
  • uid – Type: string
  • ipcon – Type: TIPConnection
Returns:
  • joystickV2 – Type: TBrickletJoystickV2

Creates an object with the unique device ID uid:

joystickV2 := TBrickletJoystickV2.Create('YOUR_DEVICE_UID', ipcon);

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

procedure TBrickletJoystickV2.GetPosition(out x: smallint; out y: smallint)
Output Parameters:
  • x – Type: smallint, Range: [-100 to 100]
  • y – Type: smallint, Range: [-100 to 100]

Returns the position of the joystick. The middle position of the joystick is x=0, y=0. The returned values are averaged and calibrated (see Calibrate).

If you want to get the position periodically, it is recommended to use the OnPosition callback and set the period with SetPositionCallbackConfiguration.

function TBrickletJoystickV2.IsPressed: boolean
Returns:
  • pressed – Type: boolean

Returns true if the button is pressed and false otherwise.

If you want to get the press-state periodically, it is recommended to use the OnPressed callback and set the period with SetPressedCallbackConfiguration.

Advanced Functions

procedure TBrickletJoystickV2.Calibrate

Calibrates the middle position of the joystick. If your Joystick Bricklet 2.0 does not return x=0 and y=0 in the middle position, call this function while the joystick is standing still in the middle position.

The resulting calibration will be saved in non-volatile memory, thus you only have to calibrate it once.

procedure TBrickletJoystickV2.GetSPITFPErrorCount(out errorCountAckChecksum: longword; out errorCountMessageChecksum: longword; out errorCountFrame: longword; out errorCountOverflow: longword)
Output Parameters:
  • errorCountAckChecksum – Type: longword, Range: [0 to 232 - 1]
  • errorCountMessageChecksum – Type: longword, Range: [0 to 232 - 1]
  • errorCountFrame – Type: longword, Range: [0 to 232 - 1]
  • errorCountOverflow – Type: longword, Range: [0 to 232 - 1]

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

procedure TBrickletJoystickV2.SetStatusLEDConfig(const config: byte)
Parameters:
  • config – Type: byte, Range: See constants, Default: 3

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

For config:

  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletJoystickV2.GetStatusLEDConfig: byte
Returns:
  • config – Type: byte, Range: See constants, Default: 3

Returns the configuration as set by SetStatusLEDConfig

The following constants are available for this function:

For config:

  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_OFF = 0
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_ON = 1
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BRICKLET_JOYSTICK_V2_STATUS_LED_CONFIG_SHOW_STATUS = 3
function TBrickletJoystickV2.GetChipTemperature: smallint
Returns:
  • temperature – Type: smallint, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

procedure TBrickletJoystickV2.Reset

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

procedure TBrickletJoystickV2.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.

Callback Configuration Functions

procedure TBrickletJoystickV2.SetPositionCallbackConfiguration(const period: longword; const valueHasToChange: boolean)
Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • valueHasToChange – Type: boolean, Default: false

The period is the period with which the OnPosition callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after at least one of the values has changed. If the values didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

procedure TBrickletJoystickV2.GetPositionCallbackConfiguration(out period: longword; out valueHasToChange: boolean)
Output Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • valueHasToChange – Type: boolean, Default: false

Returns the callback configuration as set by SetPositionCallbackConfiguration.

procedure TBrickletJoystickV2.SetPressedCallbackConfiguration(const period: longword; const valueHasToChange: boolean)
Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • valueHasToChange – Type: boolean, Default: false

The period is the period with which the OnPressed callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after at least one of the values has changed. If the values didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

procedure TBrickletJoystickV2.GetPressedCallbackConfiguration(out period: longword; out valueHasToChange: boolean)
Output Parameters:
  • period – Type: longword, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0
  • valueHasToChange – Type: boolean, Default: false

Returns the callback configuration as set by SetPressedCallbackConfiguration.

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: TBrickletJoystickV2; const value: longint);
begin
  WriteLn(Format('Value: %d', [value]));
end;

joystickV2.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback properties and their parameter types 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 TBrickletJoystickV2.OnPosition
procedure(sender: TBrickletJoystickV2; const x: smallint; const y: smallint) of object;
Callback Parameters:
  • sender – Type: TBrickletJoystickV2
  • x – Type: smallint, Range: [-100 to 100]
  • y – Type: smallint, Range: [-100 to 100]

This callback is triggered periodically according to the configuration set by SetPositionCallbackConfiguration.

The parameters are the same as with GetPosition.

property TBrickletJoystickV2.OnPressed
procedure(sender: TBrickletJoystickV2; const pressed: boolean) of object;
Callback Parameters:
  • sender – Type: TBrickletJoystickV2
  • pressed – Type: boolean

This callback is triggered periodically according to the configuration set by SetPressedCallbackConfiguration.

The parameters are the same as with IsPressed.

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 TBrickletJoystickV2.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 TBrickletJoystickV2.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_JOYSTICK_V2_FUNCTION_CALIBRATE = 3
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_POSITION_CALLBACK_CONFIGURATION = 4
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_PRESSED_CALLBACK_CONFIGURATION = 7
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BRICKLET_JOYSTICK_V2_FUNCTION_RESET = 243
  • BRICKLET_JOYSTICK_V2_FUNCTION_WRITE_UID = 248
procedure TBrickletJoystickV2.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_JOYSTICK_V2_FUNCTION_CALIBRATE = 3
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_POSITION_CALLBACK_CONFIGURATION = 4
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_PRESSED_CALLBACK_CONFIGURATION = 7
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BRICKLET_JOYSTICK_V2_FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BRICKLET_JOYSTICK_V2_FUNCTION_RESET = 243
  • BRICKLET_JOYSTICK_V2_FUNCTION_WRITE_UID = 248
procedure TBrickletJoystickV2.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.

Internal Functions

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

function TBrickletJoystickV2.SetBootloaderMode(const mode: byte): byte
Parameters:
  • mode – Type: byte, Range: See constants
Returns:
  • status – Type: byte, Range: See constants

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

For mode:

  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For status:

  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_OK = 0
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_INVALID_MODE = 1
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_NO_CHANGE = 2
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_STATUS_CRC_MISMATCH = 5
function TBrickletJoystickV2.GetBootloaderMode: byte
Returns:
  • mode – Type: byte, Range: See constants

Returns the current bootloader mode, see SetBootloaderMode.

The following constants are available for this function:

For mode:

  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_BOOTLOADER = 0
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE = 1
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BRICKLET_JOYSTICK_V2_BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
procedure TBrickletJoystickV2.SetWriteFirmwarePointer(const pointer: longword)
Parameters:
  • pointer – Type: longword, Unit: 1 B, Range: [0 to 232 - 1]

Sets the firmware pointer for WriteFirmware. The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

function TBrickletJoystickV2.WriteFirmware(const data: array [0..63] of byte): byte
Parameters:
  • data – Type: array [0..63] of byte, Range: [0 to 255]
Returns:
  • status – Type: byte, Range: [0 to 255]

Writes 64 Bytes of firmware at the position as written by SetWriteFirmwarePointer before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

procedure TBrickletJoystickV2.WriteUID(const uid: longword)
Parameters:
  • uid – Type: longword, Range: [0 to 232 - 1]

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

function TBrickletJoystickV2.ReadUID: longword
Returns:
  • uid – Type: longword, Range: [0 to 232 - 1]

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

Constants

const BRICKLET_JOYSTICK_V2_DEVICE_IDENTIFIER

This constant is used to identify a Joystick Bricklet 2.0.

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_JOYSTICK_V2_DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Joystick Bricklet 2.0.