MATLAB/Octave - DMX Bricklet

This is the description of the MATLAB/Octave API bindings for the DMX Bricklet. General information and technical specifications for the DMX Bricklet are summarized in its hardware description.

An installation guide for the MATLAB/Octave API bindings is part of their general description.

Examples

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

Simple (MATLAB)

Download (matlab_example_simple.m)

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function matlab_example_simple()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletDMX;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your DMX Bricklet

    ipcon = IPConnection(); % Create IP connection
    dmx = handle(BrickletDMX(UID, ipcon), 'CallbackProperties'); % Create device object

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

    % Configure Bricklet as DMX master
    dmx.setDMXMode(BrickletDMX.DMX_MODE_MASTER);

    % Write DMX frame with 3 channels
    dmx.writeFrame([255 128 0]);

    input('Press key to exit\n', 's');
    ipcon.disconnect();
end

Simple (Octave)

Download (octave_example_simple.m)

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function octave_example_simple()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your DMX Bricklet

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    dmx = javaObject("com.tinkerforge.BrickletDMX", UID, ipcon); % Create device object

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

    % Configure Bricklet as DMX master
    dmx.setDMXMode(dmx.DMX_MODE_MASTER);

    % Write DMX frame with 3 channels
    dmx.writeFrame([255 128 0]);

    input("Press key to exit\n", "s");
    ipcon.disconnect();
end

API

Generally, every method of the MATLAB bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.

Since the MATLAB bindings are based on Java and Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.

The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*

All methods listed below are thread-safe.

Basic Functions

public class BrickletDMX(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletDMX;

dmx = BrickletDMX('YOUR_DEVICE_UID', ipcon);

In Octave:

dmx = java_new("com.tinkerforge.BrickletDMX", "YOUR_DEVICE_UID", ipcon);

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

public void setDMXMode(int dmxMode)

Sets the DMX mode to either master or slave.

Calling this function sets frame number to 0.

The default value is 0 (master).

The following constants are available for this function:

  • BrickletDMX.DMX_MODE_MASTER = 0
  • BrickletDMX.DMX_MODE_SLAVE = 1
public int getDMXMode()

Returns the DMX mode, as set by setDMXMode().

The following constants are available for this function:

  • BrickletDMX.DMX_MODE_MASTER = 0
  • BrickletDMX.DMX_MODE_SLAVE = 1
public void writeFrame(int[] frame)

Writes a DMX frame. The maximum frame size is 512 byte. Each byte represents one channel.

The next frame can be written after the FrameStartedCallback callback was called. The frame is double buffered, so a new frame can be written as soon as the writing of the prior frame starts.

The data will be transfered 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 channels for first frame.
  • Wait for the FrameStartedCallback callback.
  • Set channels for next frame.
  • Wait for the FrameStartedCallback callback.
  • and so on.

This approach ensures that you can set new DMX data with a fixed frame rate.

This function can only be called in master mode.

public BrickletDMX.ReadFrame readFrame()

Returns the last frame that was written by the DMX master. The size of the array is equivalent to the number of channels in the frame. Each byte represents one channel.

The next frame is available after the FrameAvailableCallback callback was called.

Generic approach:

Instead of polling this function you can also use the FrameCallback callback. You can enable it with setFrameCallbackConfig().

The frame number starts at 0 and it is increased by one with each received frame.

This function can only be called in slave mode.

The returned object has the public member variables int[] frame and long frameNumber.

public void setFrameDuration(int frameDuration)

Sets the duration of a frame in ms.

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

If you always want to send a frame as fast as possible you can set this value to 0.

This setting is only used in master mode.

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

public int getFrameDuration()

Returns the frame duration as set by setFrameDuration().

Advanced Functions

public BrickletDMX.FrameErrorCount getFrameErrorCount()

Returns the current number of overrun and framing errors.

The returned object has the public member variables long overrunErrorCount and long framingErrorCount.

public void setCommunicationLEDConfig(int config)

Sets the communication LED configuration. By default the LED shows communication traffic, 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 off.

The following constants are available for this function:

  • BrickletDMX.COMMUNICATION_LED_CONFIG_OFF = 0
  • BrickletDMX.COMMUNICATION_LED_CONFIG_ON = 1
  • BrickletDMX.COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
public int getCommunicationLEDConfig()

Returns the configuration as set by setCommunicationLEDConfig()

The following constants are available for this function:

  • BrickletDMX.COMMUNICATION_LED_CONFIG_OFF = 0
  • BrickletDMX.COMMUNICATION_LED_CONFIG_ON = 1
  • BrickletDMX.COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
public void setErrorLEDConfig(int config)

Sets the error LED configuration.

By default the error LED turns on if there is any error (see FrameErrorCountCallback callback). If you call this function with the Show-Error option again, the LED will turn off until the next error occurs.

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

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

  • BrickletDMX.ERROR_LED_CONFIG_OFF = 0
  • BrickletDMX.ERROR_LED_CONFIG_ON = 1
  • BrickletDMX.ERROR_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.ERROR_LED_CONFIG_SHOW_ERROR = 3
public int getErrorLEDConfig()

Returns the configuration as set by setErrorLEDConfig().

The following constants are available for this function:

  • BrickletDMX.ERROR_LED_CONFIG_OFF = 0
  • BrickletDMX.ERROR_LED_CONFIG_ON = 1
  • BrickletDMX.ERROR_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.ERROR_LED_CONFIG_SHOW_ERROR = 3
public int[] getAPIVersion()

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.

public boolean getResponseExpected(int functionId)

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.

public void setResponseExpected(int functionId, boolean responseExpected)

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:

  • BrickletDMX.FUNCTION_SET_DMX_MODE = 1
  • BrickletDMX.FUNCTION_WRITE_FRAME = 3
  • BrickletDMX.FUNCTION_SET_FRAME_DURATION = 5
  • BrickletDMX.FUNCTION_SET_COMMUNICATION_LED_CONFIG = 8
  • BrickletDMX.FUNCTION_SET_ERROR_LED_CONFIG = 10
  • BrickletDMX.FUNCTION_SET_FRAME_CALLBACK_CONFIG = 12
  • BrickletDMX.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletDMX.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletDMX.FUNCTION_RESET = 243
  • BrickletDMX.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletDMX.SPITFPErrorCount getSPITFPErrorCount()

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.

The returned object has the public member variables long errorCountAckChecksum, long errorCountMessageChecksum, long errorCountFrame and long errorCountOverflow.

public int setBootloaderMode(int mode)

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:

  • BrickletDMX.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletDMX.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletDMX.BOOTLOADER_STATUS_OK = 0
  • BrickletDMX.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletDMX.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletDMX.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletDMX.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletDMX.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletDMX.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletDMX.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletDMX.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
public void setWriteFirmwarePointer(long pointer)

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.

public int writeFirmware(int[] data)

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.

public void setStatusLEDConfig(int config)

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:

  • BrickletDMX.STATUS_LED_CONFIG_OFF = 0
  • BrickletDMX.STATUS_LED_CONFIG_ON = 1
  • BrickletDMX.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletDMX.STATUS_LED_CONFIG_OFF = 0
  • BrickletDMX.STATUS_LED_CONFIG_ON = 1
  • BrickletDMX.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletDMX.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getChipTemperature()

Returns the temperature in °C 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.

public void 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!

public void writeUID(long uid)

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.

public long readUID()

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

public BrickletDMX.Identity getIdentity()

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.

The returned object has the public member variables String uid, String connectedUid, char position, int[] hardwareVersion, int[] firmwareVersion and int deviceIdentifier.

Callback Configuration Functions

public void setFrameCallbackConfig(boolean frameStartedCallbackEnabled, boolean frameAvailableCallbackEnabled, boolean frameCallbackEnabled, boolean frameErrorCountCallbackEnabled)

Enables/Disables the different callbacks. By default the FrameStartedCallback callback and FrameAvailableCallback callback are enabled while the FrameCallback callback and FrameErrorCountCallback callback are disabled.

If you want to use the FrameCallback callback you can enable it and disable the cb:Frame Available callback at the same time. It becomes redundant in this case.

public BrickletDMX.FrameCallbackConfig getFrameCallbackConfig()

Returns the frame callback config as set by setFrameCallbackConfig().

The returned object has the public member variables boolean frameStartedCallbackEnabled, boolean frameAvailableCallbackEnabled, boolean frameCallbackEnabled and boolean frameErrorCountCallbackEnabled.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with "set" function of MATLAB. The parameters consist of the IP Connection object, the callback name and the callback function. For example, it looks like this in MATLAB:

function my_callback(e)
    fprintf('Parameter: %s\n', e.param);
end

set(device, 'ExampleCallback', @(h, e) my_callback(e));

Due to a difference in the Octave Java support the "set" function cannot be used in Octave. The registration is done with "add*Callback" functions of the device object. It looks like this in Octave:

function my_callback(e)
    fprintf("Parameter: %s\n", e.param);
end

device.addExampleCallback(@my_callback);

It is possible to add several callbacks and to remove them with the corresponding "remove*Callback" function.

The parameters of the callback are passed to the callback function as fields of the structure e, which is derived from the java.util.EventObject class. The available callback names with corresponding structure fields 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.

public callback BrickletDMX.FrameStartedCallback

This callback is triggered as soon as a new frame write is started. You should send the data for the next frame directly after this callback was triggered.

For an explanation of the general approach see writeFrame().

This callback can be enabled via setFrameCallbackConfig().

This callback can only be triggered in master mode.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addFrameStartedCallback() function. An added callback function can be removed with the removeFrameStartedCallback() function.

public callback BrickletDMX.FrameAvailableCallback
Parameters:frameNumber -- long

This callback is triggered in slave mode when a new frame was received from the DMX master and it can be read out. You have to read the frame before the master has written the next frame, see readFrame() for more details.

The parameter is the frame number, it is increased by one with each received frame.

This callback can be enabled via setFrameCallbackConfig().

This callback can only be triggered in slave mode.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addFrameAvailableCallback() function. An added callback function can be removed with the removeFrameAvailableCallback() function.

public callback BrickletDMX.FrameCallback
Parameters:
  • frame -- int[]
  • frameNumber -- long

This callback is called as soon as a new frame is available (written by the DMX master).

The size of the array is equivalent to the number of channels in the frame. Each byte represents one channel.

This callback can be enabled via setFrameCallbackConfig().

This callback can only be triggered in slave mode.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addFrameCallback() function. An added callback function can be removed with the removeFrameCallback() function.

public callback BrickletDMX.FrameErrorCountCallback
Parameters:
  • overrunErrorCount -- long
  • framingErrorCount -- long

This callback is called if a new error occurs. It returns the current overrun and framing error count.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addFrameErrorCountCallback() function. An added callback function can be removed with the removeFrameErrorCountCallback() function.

Constants

public static final int BrickletDMX.DEVICE_IDENTIFIER

This constant is used to identify a DMX Bricklet.

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

public static final String BrickletDMX.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a DMX Bricklet.