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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-php">Software</a> / PHP - Hall Effect Bricklet

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

.. _hall_effect_bricklet_php:

PHP - Hall Effect Bricklet
==========================

This is the description of the :ref:`PHP API bindings <api_bindings_php>` for the :ref:`Hall Effect Bricklet <hall_effect_bricklet>`. General information and technical
specifications for the Hall Effect Bricklet are summarized in its :ref:`hardware description
<hall_effect_bricklet_description>`.

An :ref:`installation guide <api_bindings_php_install>` for the PHP API
bindings is part of their general description.

.. _hall_effect_bricklet_php_examples:


Examples
--------

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

Simple
^^^^^^

`Download (ExampleSimple.php) <https://github.com/Tinkerforge/hall-effect-bricklet/raw/master/software/examples/php/ExampleSimple.php>`__

.. literalinclude:: HallEffect_Bricklet_PHP_ExampleSimple.php
 :language: php
 :linenos:
 :tab-width: 4

Callback
^^^^^^^^

`Download (ExampleCallback.php) <https://github.com/Tinkerforge/hall-effect-bricklet/raw/master/software/examples/php/ExampleCallback.php>`__

.. literalinclude:: HallEffect_Bricklet_PHP_ExampleCallback.php
 :language: php
 :linenos:
 :tab-width: 4

.. _hall_effect_bricklet_php_api:

API
---

Functions that return multiple values return them in an associative array.




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


.. php:function:: class BrickletHallEffect(string $uid, IPConnection $ipcon)

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

 .. code-block:: php

    <?php   $hall_effect = new BrickletHallEffect('YOUR_DEVICE_UID', $ipcon);   ?>

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


.. php:function:: bool BrickletHallEffect::getValue()

 Returns *true* if a magnetic field of 35 Gauss (3.5mT) or greater is detected.
 
.. php:function:: int BrickletHallEffect::getEdgeCount(bool $reset_counter)

 Returns the current value of the edge counter. You can configure
 edge type (rising, falling, both) that is counted with
 :php:func:`setEdgeCountConfig() <BrickletHallEffect::setEdgeCountConfig>`.
 
 If you set the reset counter to *true*, the count is set back to 0
 directly after it is read.
 


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

.. php:function:: void BrickletHallEffect::setEdgeCountConfig(int $edge_type, int $debounce)

 The edge type parameter configures if rising edges, falling edges or 
 both are counted. Possible edge types are:
 
 * 0 = rising (default)
 * 1 = falling
 * 2 = both
 
 A magnetic field of 35 Gauss (3.5mT) or greater causes a falling edge and a
 magnetic field of 25 Gauss (2.5mT) or smaller causes a rising edge.
 
 If a magnet comes near the Bricklet the signal goes low (falling edge), if
 a magnet is removed from the vicinity the signal goes high (rising edge).
 
 The debounce time is given in ms.
 
 Configuring an edge counter resets its value to 0.
 
 If you don't know what any of this means, just leave it at default. The
 default configuration is very likely OK for you.
 
 Default values: 0 (edge type) and 100ms (debounce time)
 
 The following constants are available for this function:
 
 * BrickletHallEffect::EDGE_TYPE_RISING = 0
 * BrickletHallEffect::EDGE_TYPE_FALLING = 1
 * BrickletHallEffect::EDGE_TYPE_BOTH = 2
 
.. php:function:: array BrickletHallEffect::getEdgeCountConfig()

 Returns the edge type and debounce time as set by :php:func:`setEdgeCountConfig() <BrickletHallEffect::setEdgeCountConfig>`.
 
 The following constants are available for this function:
 
 * BrickletHallEffect::EDGE_TYPE_RISING = 0
 * BrickletHallEffect::EDGE_TYPE_FALLING = 1
 * BrickletHallEffect::EDGE_TYPE_BOTH = 2
 
 The returned array has the keys ``edge_type`` and ``debounce``.

.. php:function:: array BrickletHallEffect::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.
 
.. php:function:: bool BrickletHallEffect::getResponseExpected(int $function_id)

 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
 :php:func:`setResponseExpected() <BrickletHallEffect::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 :php:func:`setResponseExpected() <BrickletHallEffect::setResponseExpected>`
 for the list of function ID constants available for this function.
 
.. php:function:: void BrickletHallEffect::setResponseExpected(int $function_id, bool $response_expected)

 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:
 
 * BrickletHallEffect::FUNCTION_SET_EDGE_COUNT_CONFIG = 3
 * BrickletHallEffect::FUNCTION_SET_EDGE_INTERRUPT = 5
 * BrickletHallEffect::FUNCTION_SET_EDGE_COUNT_CALLBACK_PERIOD = 7
 
.. php:function:: void BrickletHallEffect::setResponseExpectedAll(bool $response_expected)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. php:function:: array BrickletHallEffect::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 array has the keys ``uid``, ``connected_uid``, ``position``, ``hardware_version``, ``firmware_version`` and ``device_identifier``.



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


.. php:function:: void BrickletHallEffect::registerCallback(int $id, callable $callback, mixed $userData = NULL)

 Registers a callback with ID *$id* to the callable *$callback*.
 The *$userData*  will be given as a parameter of the callback.

 The available  IDs with corresponding function signatures are listed
 :ref:`below <hall_effect_bricklet_php_callbacks>`.


.. php:function:: void BrickletHallEffect::setEdgeInterrupt(int $edges)

 Sets the number of edges until an interrupt is invoked.
 
 If *edges* is set to n, an interrupt is invoked for every n-th detected edge.
 
 If *edges* is set to 0, the interrupt is disabled.
 
 Default value is 0.
 
.. php:function:: int BrickletHallEffect::getEdgeInterrupt()

 Returns the edges as set by :php:func:`setEdgeInterrupt() <BrickletHallEffect::setEdgeInterrupt>`.
 
.. php:function:: void BrickletHallEffect::setEdgeCountCallbackPeriod(int $period)

 Sets the period in ms with which the :php:member:`CALLBACK_EDGE_COUNT <BrickletHallEffect::CALLBACK_EDGE_COUNT>` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :php:member:`CALLBACK_EDGE_COUNT <BrickletHallEffect::CALLBACK_EDGE_COUNT>` is only triggered if the edge count has changed since the
 last triggering.
 
 The default value is 0.
 
.. php:function:: int BrickletHallEffect::getEdgeCountCallbackPeriod()

 Returns the period as set by :php:func:`setEdgeCountCallbackPeriod() <BrickletHallEffect::setEdgeCountCallbackPeriod>`.
 


.. _hall_effect_bricklet_php_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the :php:func:`registerCallback() <BrickletHallEffect::registerCallback>` function of
the device object. The first parameter is the callback ID and the second
parameter the callback function:

.. code-block:: php

    <?php

    function myCallback($param)
    {
        echo $param . "\n";
    }

    $hall_effect->registerCallback(BrickletHallEffect::CALLBACK_EXAMPLE, 'myCallback');

    ?>

The available constants with corresponding function signatures 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.

.. php:member:: int BrickletHallEffect::CALLBACK_EDGE_COUNT

 .. code-block:: php

  <?php   void callback(int $count, bool $value [, mixed $userData])   ?>

 This callback is triggered periodically with the period that is set by
 :php:func:`setEdgeCountCallbackPeriod() <BrickletHallEffect::setEdgeCountCallbackPeriod>`. The parameters are the
 current count and the current value (see :php:func:`getValue() <BrickletHallEffect::getValue>` and :php:func:`getEdgeCount() <BrickletHallEffect::getEdgeCount>`).
 
 :php:member:`CALLBACK_EDGE_COUNT <BrickletHallEffect::CALLBACK_EDGE_COUNT>` is only triggered if the count or value changed since the
 last triggering.
 


.. _hall_effect_bricklet_php_constants:

Constants
^^^^^^^^^

.. php:member:: int BrickletHallEffect::DEVICE_IDENTIFIER

 This constant is used to identify a Hall Effect Bricklet.

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

