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

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

.. _dual_button_bricklet_ruby:

Ruby - Dual Button Bricklet
===========================

This is the description of the :ref:`Ruby API bindings <api_bindings_ruby>` 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_ruby_install>` for the Ruby API
bindings is part of their general description.

.. _dual_button_bricklet_ruby_examples:


Examples
--------

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

Callback
^^^^^^^^

`Download (example_callback.rb) <https://github.com/Tinkerforge/dual-button-bricklet/raw/master/software/examples/ruby/example_callback.rb>`__

.. literalinclude:: DualButton_Bricklet_Ruby_example_callback.rb
 :language: ruby
 :linenos:
 :tab-width: 4

.. _dual_button_bricklet_ruby_api:

API
---

All methods listed below are thread-safe.




Basic Functions
^^^^^^^^^^^^^^^


.. rb:function:: BrickletDualButton::new(uid, ipcon) -> dual_button

 :param uid: str
 :param ipcon: IPConnection

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

 .. code-block:: ruby

    dual_button = BrickletDualButton.new 'YOUR_DEVICE_UID', ipcon

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


.. rb:function:: BrickletDualButton#set_led_state(led_l, led_r) -> nil

 :param led_l: int
 :param led_r: int

 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 :rb:func:`#get_led_state <BrickletDualButton#get_led_state>` or you
 can use :rb:func:`#set_selected_led_state <BrickletDualButton#set_selected_led_state>`.
 
 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
 
.. rb:function:: BrickletDualButton#get_led_state -> [int, int]


 Returns the current state of the LEDs, as set by :rb:func:`#set_led_state <BrickletDualButton#set_led_state>`.
 
 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 array has the values ``led_l`` and ``led_r``.

.. rb:function:: BrickletDualButton#get_button_state -> [int, int]


 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 array has the values ``button_l`` and ``button_r``.



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

.. rb:function:: BrickletDualButton#set_selected_led_state(led, state) -> nil

 :param led: int
 :param state: int

 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
 
.. rb:function:: BrickletDualButton#get_api_version -> [int, int, int]


 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.
 
.. rb:function:: BrickletDualButton#get_response_expected(function_id) -> bool

 :param function_id: int

 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
 :rb:func:`#set_response_expected <BrickletDualButton#set_response_expected>`. 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 :rb:func:`#set_response_expected <BrickletDualButton#set_response_expected>`
 for the list of function ID constants available for this function.
 
.. rb:function:: BrickletDualButton#set_response_expected(function_id, response_expected) -> nil

 :param function_id: int
 :param response_expected: bool

 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
 
.. rb:function:: BrickletDualButton#set_response_expected_all(response_expected) -> nil

 :param response_expected: bool

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. rb:function:: BrickletDualButton#get_identity -> [str, str, str, [int, int, int], [int, int, int], int]


 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 array has the values ``uid``, ``connected_uid``, ``position``, ``hardware_version``, ``firmware_version`` and ``device_identifier``.



Callback Configuration Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


.. rb:function:: BrickletDualButton#register_callback(id) { |param [, ...]| block } -> nil

 :param id: int

 Registers a callback with ID *id* to the given block. The available
 IDs with corresponding function signatures are listed
 :ref:`below <dual_button_bricklet_ruby_callbacks>`.




.. _dual_button_bricklet_ruby_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive time critical or recurring data from
the device. The registration is done with the
:rb:func:`#register_callback <BrickletDualButton#register_callback>` function of
the device object. The first parameter is the callback ID and the second
parameter is a block:

.. code-block:: ruby

    dual_button.register_callback BrickletDualButton::CALLBACK_EXAMPLE, do |param|
      puts "#{param}"
    end

The available constants with inherent number and 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.

.. rb:attribute:: BrickletDualButton::CALLBACK_STATE_CHANGED

 :param button_l: int
 :param button_r: int
 :param led_l: int
 :param led_r: int


 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
 


.. _dual_button_bricklet_ruby_constants:

Constants
^^^^^^^^^

.. rb:attribute:: BrickletDualButton::DEVICE_IDENTIFIER

 This constant is used to identify a Dual Button Bricklet.

 The :rb:func:`#get_identity() <BrickletDualButton#get_identity>` function and the
 :rb:attr:`::CALLBACK_ENUMERATE <IPConnection::CALLBACK_ENUMERATE>`
 callback of the IP Connection have a ``device_identifier`` parameter to specify
 the Brick's or Bricklet's type.

