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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-matlab">Software</a> / MATLAB/Octave - Dual Button Bricklet

.. |device_identifier_constant| replace:: There is also a :ref:`constant <dual_button_bricklet_matlab_constants>` for the device identifier of this Bricklet.

.. _dual_button_bricklet_matlab:

MATLAB/Octave - Dual Button Bricklet
====================================

This is the description of the :ref:`MATLAB/Octave API bindings <api_bindings_matlab>` for the :ref:`Dual Button Bricklet <dual_button_bricklet>`. General information and technical
specifications for the Dual Button Bricklet are summarized in its :ref:`hardware description
<dual_button_bricklet_description>`.

An :ref:`installation guide <api_bindings_matlab_install>` for the MATLAB/Octave API
bindings is part of their general description.

.. _dual_button_bricklet_matlab_examples:


Examples
--------

The example code below is `Public Domain (CC0 1.0)
<http://creativecommons.org/publicdomain/zero/1.0/>`__.

Callback (MATLAB)
^^^^^^^^^^^^^^^^^

`Download (matlab_example_callback.m) <https://github.com/Tinkerforge/dual-button-bricklet/raw/master/software/examples/matlab/matlab_example_callback.m>`__

.. literalinclude:: DualButton_Bricklet_MATLAB_matlab_example_callback.m
 :language: matlab
 :linenos:
 :tab-width: 4

Callback (Octave)
^^^^^^^^^^^^^^^^^

`Download (octave_example_callback.m) <https://github.com/Tinkerforge/dual-button-bricklet/raw/master/software/examples/matlab/octave_example_callback.m>`__

.. literalinclude:: DualButton_Bricklet_MATLAB_octave_example_callback.m
 :language: octave_fixed
 :linenos:
 :tab-width: 4

.. _dual_button_bricklet_matlab_api:

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
^^^^^^^^^^^^^^^


.. matlab:function:: class BrickletDualButton(String uid, IPConnection ipcon)

 Creates an object with the unique device ID ``uid``.

 In MATLAB:

 .. code-block:: matlab

  import com.tinkerforge.BrickletDualButton;

  dualButton = BrickletDualButton('YOUR_DEVICE_UID', ipcon);

 In Octave:

 .. code-block:: octave_fixed

  dualButton = java_new("com.tinkerforge.BrickletDualButton", "YOUR_DEVICE_UID", ipcon);

 This object can then be used after the IP Connection is connected
 (see examples :ref:`above <dual_button_bricklet_matlab_examples>`).


.. matlab:function:: public void BrickletDualButton::setLEDState(short ledL, short ledR)

 Sets the state of the LEDs. Possible states are:
 
 * 0 = AutoToggleOn: Enables auto toggle with initially enabled LED.
 * 1 = AutoToggleOff: Activates auto toggle with initially disabled LED.
 * 2 = On: Enables LED (auto toggle is disabled).
 * 3 = Off: Disables LED (auto toggle is disabled).
 
 In auto toggle mode the LED is toggled automatically at each press of a button.
 
 If you just want to set one of the LEDs and don't know the current state
 of the other LED, you can get the state with :matlab:func:`getLEDState() <BrickletDualButton::getLEDState>` or you
 can use :matlab:func:`setSelectedLEDState() <BrickletDualButton::setSelectedLEDState>`.
 
 The default value is (1, 1).
 
 The following constants are available for this function:
 
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_ON = 0
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_OFF = 1
 * BrickletDualButton.LED_STATE_ON = 2
 * BrickletDualButton.LED_STATE_OFF = 3
 
.. matlab:function:: public BrickletDualButton.LEDState BrickletDualButton::getLEDState()

 Returns the current state of the LEDs, as set by :matlab:func:`setLEDState() <BrickletDualButton::setLEDState>`.
 
 The following constants are available for this function:
 
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_ON = 0
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_OFF = 1
 * BrickletDualButton.LED_STATE_ON = 2
 * BrickletDualButton.LED_STATE_OFF = 3
 
 The returned object has the public member variables ``short ledL`` and ``short ledR``.

.. matlab:function:: public BrickletDualButton.ButtonState BrickletDualButton::getButtonState()

 Returns the current state for both buttons. Possible states are:
 
 * 0 = pressed
 * 1 = released
 
 The following constants are available for this function:
 
 * BrickletDualButton.BUTTON_STATE_PRESSED = 0
 * BrickletDualButton.BUTTON_STATE_RELEASED = 1
 
 The returned object has the public member variables ``short buttonL`` and ``short buttonR``.



Advanced Functions
^^^^^^^^^^^^^^^^^^

.. matlab:function:: public void BrickletDualButton::setSelectedLEDState(short led, short state)

 Sets the state of the selected LED (0 or 1). 
 
 The other LED remains untouched.
 
 The following constants are available for this function:
 
 * BrickletDualButton.LED_LEFT = 0
 * BrickletDualButton.LED_RIGHT = 1
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_ON = 0
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_OFF = 1
 * BrickletDualButton.LED_STATE_ON = 2
 * BrickletDualButton.LED_STATE_OFF = 3
 
.. matlab:function:: public short[] BrickletDualButton::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.
 
.. matlab:function:: public boolean BrickletDualButton::getResponseExpected(short 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
 :matlab:func:`setResponseExpected() <BrickletDualButton::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 :matlab:func:`setResponseExpected() <BrickletDualButton::setResponseExpected>`
 for the list of function ID constants available for this function.
 
.. matlab:function:: public void BrickletDualButton::setResponseExpected(short 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 and callbacks it is always disabled.
 
 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:
 
 * BrickletDualButton.FUNCTION_SET_LED_STATE = 1
 * BrickletDualButton.FUNCTION_SET_SELECTED_LED_STATE = 5
 
.. matlab:function:: public void BrickletDualButton::setResponseExpectedAll(boolean responseExpected)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. matlab:function:: public BrickletDualButton.Identity BrickletDualButton::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 :ref:`here <device_identifier>`.
 |device_identifier_constant|
 
 The returned object has the public member variables ``String uid``, ``String connectedUid``, ``char position``, ``short[] hardwareVersion``, ``short[] firmwareVersion`` and ``int deviceIdentifier``.



.. _dual_button_bricklet_matlab_callbacks:

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:

.. code-block:: matlab

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

    set(device, 'ExampleCallback', @(h, e) cb_example(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:

.. code-block:: octave_fixed

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

    device.addExampleCallback(@cb_example);

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.



.. matlab:member:: public callback BrickletDualButton.StateChangedCallback

 :param buttonL: short
 :param buttonR: short
 :param ledL: short
 :param ledR: short


 This callback is called whenever a button is pressed. 
 
 Possible states for buttons are:
 
 * 0 = pressed
 * 1 = released
 
 Possible states for LEDs are:
 
 * 0 = AutoToggleOn: Auto toggle enabled and LED on.
 * 1 = AutoToggleOff: Auto toggle enabled and LED off.
 * 2 = On: LED on (auto toggle is disabled).
 * 3 = Off: LED off (auto toggle is disabled).
 
 The following constants are available for this function:
 
 * BrickletDualButton.BUTTON_STATE_PRESSED = 0
 * BrickletDualButton.BUTTON_STATE_RELEASED = 1
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_ON = 0
 * BrickletDualButton.LED_STATE_AUTO_TOGGLE_OFF = 1
 * BrickletDualButton.LED_STATE_ON = 2
 * BrickletDualButton.LED_STATE_OFF = 3
 

 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
 ``addStateChangedCallback()`` function. An added callback function can be removed with
 the ``removeStateChangedCallback()`` function.



.. _dual_button_bricklet_matlab_constants:

Constants
^^^^^^^^^

.. matlab:member:: public static final int BrickletDualButton.DEVICE_IDENTIFIER

 This constant is used to identify a Dual Button Bricklet.

 The :matlab:func:`getIdentity() <BrickletDualButton::getIdentity>` function and the
 :matlab:member:`EnumerateCallback <IPConnection.EnumerateCallback>`
 callback of the IP Connection have a ``deviceIdentifier`` parameter to specify
 the Brick's or Bricklet's type.

