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

.. |device_identifier_constant| unicode:: 0xA0
   :trim:

.. _dual_button_bricklet_shell:

Shell - Dual Button Bricklet
============================

This is the description of the :ref:`Shell API bindings <api_bindings_shell>` 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_shell_install>` for the Shell API
bindings is part of their general description.

.. _dual_button_bricklet_shell_examples:


Examples
--------

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

Callback
^^^^^^^^

`Download (example-callback.sh) <https://github.com/Tinkerforge/dual-button-bricklet/raw/master/software/examples/shell/example-callback.sh>`__

.. literalinclude:: DualButton_Bricklet_Shell_example-callback.sh
 :language: bash
 :linenos:
 :tab-width: 4

.. _dual_button_bricklet_shell_api:

API
---

Possible exit codes for all ``tinkerforge`` commands are:

* 1: interrupted (ctrl+c)
* 2: syntax error
* 21: Python 2.5 or newer is required
* 22: Python ``argparse`` module is missing
* 23: socket error
* 24: other exception
* 25: invalid placeholder in format string
* 26: authentication error
* 201: timeout occurred
* 209: invalid argument value
* 210: function is not supported
* 211: unknown error



Command Structure
^^^^^^^^^^^^^^^^^

The common options of the ``call`` and ``dispatch`` commands are documented
:ref:`here <ipcon_shell_api>`. The specific command structure is shown below.

.. sh:function:: X Stinkerforge Pcall Ndual-button-bricklet A[<option>..] L<uid> L<function> L[<argument>..]

 :param <uid>: string
 :param <function>: string

 The ``call`` command is used to call a function of the Dual Button Bricklet. It can take several
 options:

 * ``--help`` shows help for the specific ``call`` command and exits
 * ``--list-functions`` shows a list of known functions of the Dual Button Bricklet and exits


.. sh:function:: X Stinkerforge Pdispatch Ndual-button-bricklet A[<option>..] L<uid> L<callback>

 :param <uid>: string
 :param <callback>: string

 The ``dispatch`` command is used to dispatch a callback of the Dual Button Bricklet. It can
 take several options:

 * ``--help`` shows help for the specific ``dispatch`` command and exits
 * ``--list-callbacks`` shows a list of known callbacks of the Dual Button Bricklet and exits


.. sh:function:: X Stinkerforge Scall Pdual-button-bricklet L<uid> N<function> A[<option>..] L[<argument>..]

 :param <uid>: string
 :param <function>: string

 The ``<function>`` to be called can take different options depending of its
 kind. All functions can take the following options:

 * ``--help`` shows help for the specific function and exits

 Getter functions can take the following options:

 * ``--execute <command>`` shell command line to execute for each incoming
   response (see section about :ref:`output formatting <ipcon_shell_output>`
   for details)

 Setter functions can take the following options:

 * ``--expect-response`` requests response and waits for it

 The ``--expect-response`` option for setter functions allows to detect
 timeouts and other error conditions calls of setters as well. The device will
 then send a response for this purpose. If this option is not given for a
 setter function then no response is send and errors are silently ignored,
 because they cannot be detected.


.. sh:function:: X Stinkerforge Sdispatch Pdual-button-bricklet L<uid> N<callback> A[<option>..]

 :param <uid>: string
 :param <callback>: string

 The ``<callback>`` to be dispatched can take several options:

 * ``--help`` shows help for the specific callback and exits
 * ``--execute <command>`` shell command line to execute for each incoming
   response (see section about :ref:`output formatting <ipcon_shell_output>`
   for details)



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



.. sh:function:: tinkerforge call dual-button-bricklet <uid> set-led-state <led-l> <led-r> 

 :param <led-l>: int (has symbols)
 :param <led-r>: int (has symbols)

 :noreturn: no output

 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 :sh:func:`get-led-state <dual-button-bricklet get-led-state>` or you
 can use :sh:func:`set-selected-led-state <dual-button-bricklet set-selected-led-state>`.
 
 The default value is (1, 1).
 
 The following symbols are available for this function:
 
 * ``auto-toggle-on`` = 0, for <led-l> and <led-r>
 * ``auto-toggle-off`` = 1, for <led-l> and <led-r>
 * ``on`` = 2, for <led-l> and <led-r>
 * ``off`` = 3, for <led-l> and <led-r>
 
.. sh:function:: tinkerforge call dual-button-bricklet <uid> get-led-state  


 :returns led-l: int (has symbols)
 :returns led-r: int (has symbols)

 Returns the current state of the LEDs, as set by :sh:func:`set-led-state <dual-button-bricklet set-led-state>`.
 
 The following symbols are available for this function:
 
 * ``auto-toggle-on`` = 0, for led-l and led-r
 * ``auto-toggle-off`` = 1, for led-l and led-r
 * ``on`` = 2, for led-l and led-r
 * ``off`` = 3, for led-l and led-r
 
.. sh:function:: tinkerforge call dual-button-bricklet <uid> get-button-state  


 :returns button-l: int (has symbols)
 :returns button-r: int (has symbols)

 Returns the current state for both buttons. Possible states are:
 
 * 0 = pressed
 * 1 = released
 
 The following symbols are available for this function:
 
 * ``pressed`` = 0, for button-l and button-r
 * ``released`` = 1, for button-l and button-r
 


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

.. sh:function:: tinkerforge call dual-button-bricklet <uid> set-selected-led-state <led> <state> 

 :param <led>: int (has symbols)
 :param <state>: int (has symbols)

 :noreturn: no output

 Sets the state of the selected LED (0 or 1). 
 
 The other LED remains untouched.
 
 The following symbols are available for this function:
 
 * ``left`` = 0, for <led>
 * ``right`` = 1, for <led>
 * ``auto-toggle-on`` = 0, for <state>
 * ``auto-toggle-off`` = 1, for <state>
 * ``on`` = 2, for <state>
 * ``off`` = 3, for <state>
 
.. sh:function:: tinkerforge call dual-button-bricklet <uid> get-identity  


 :returns uid: string
 :returns connected-uid: string
 :returns position: char
 :returns hardware-version: int,int,int
 :returns firmware-version: int,int,int
 :returns device-identifier: int (has symbols)

 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|
 


.. _dual_button_bricklet_shell_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be used to receive time critical or recurring data from the
device:

.. code-block:: bash

    tinkerforge dispatch dual-button-bricklet <uid> example

The available callbacks 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.

.. sh:function::  tinkerforge dispatch dual-button-bricklet <uid> state-changed

 :returns button-l: int (has symbols)
 :returns button-r: int (has symbols)
 :returns led-l: int (has symbols)
 :returns led-r: int (has symbols)


 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 symbols are available for this function:
 
 * ``pressed`` = 0, for button-l and button-r
 * ``released`` = 1, for button-l and button-r
 * ``auto-toggle-on`` = 0, for led-l and led-r
 * ``auto-toggle-off`` = 1, for led-l and led-r
 * ``on`` = 2, for led-l and led-r
 * ``off`` = 3, for led-l and led-r
 


