..
 #############################################################
 # This file was automatically generated on 2015-05-08.      #
 #                                                           #
 # If you have a bugfix for this file and want to commit it, #
 # please fix the bug in the generator. You can find a link  #
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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-perl">Software</a> / Perl - NFC/RFID Bricklet

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

.. _nfc_rfid_bricklet_perl:

Perl - NFC/RFID Bricklet
========================

This is the description of the :ref:`Perl API bindings <api_bindings_perl>` for the :ref:`NFC/RFID Bricklet <nfc_rfid_bricklet>`. General information and technical
specifications for the NFC/RFID Bricklet are summarized in its :ref:`hardware description
<nfc_rfid_bricklet_description>`.

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

.. _nfc_rfid_bricklet_perl_examples:


Examples
--------

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

Scan For Tags
^^^^^^^^^^^^^

`Download (example_scan_for_tags.pl) <https://github.com/Tinkerforge/nfc-rfid-bricklet/raw/master/software/examples/perl/example_scan_for_tags.pl>`__

.. literalinclude:: NFCRFID_Bricklet_Perl_example_scan_for_tags.pl
 :language: perl
 :linenos:
 :tab-width: 4

Write Read Type2
^^^^^^^^^^^^^^^^

`Download (example_write_read_type2.pl) <https://github.com/Tinkerforge/nfc-rfid-bricklet/raw/master/software/examples/perl/example_write_read_type2.pl>`__

.. literalinclude:: NFCRFID_Bricklet_Perl_example_write_read_type2.pl
 :language: perl
 :linenos:
 :tab-width: 4

.. _nfc_rfid_bricklet_perl_api:

API
---

Generally, every subroutine of the Perl bindings can report an error as
``Tinkerforge::Error`` object via ``croak()``. The object has a
``get_code()`` and a ``get_message()`` subroutine. There are different
error code:

* Error->ALREADY_CONNECTED = 11
* Error->NOT_CONNECTED = 12
* Error->CONNECT_FAILED = 13
* Error->INVALID_FUNCTION_ID = 21
* Error->TIMEOUT = 31
* Error->INVALID_PARAMETER = 41
* Error->FUNCTION_NOT_SUPPORTED = 42
* Error->UNKNOWN_ERROR = 43

All methods listed below are thread-safe.




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


.. perl:function:: BrickletNFCRFID->new($uid, $ipcon)

 :param $uid: string
 :param $ipcon: IPConnection
 :rtype: BrickletNFCRFID

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

 .. code-block:: perl

    $nfc_rfid = BrickletNFCRFID->new("YOUR_DEVICE_UID", $ipcon);

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


.. perl:function:: BrickletNFCRFID->request_tag_id($tag_type)

 :param $tag_type: int
 :rtype: undef

 To read or write a tag that is in proximity of the NFC/RFID Bricklet you 
 first have to call this function with the expected tag type as parameter.
 It is no problem if you don't know the tag type. You can cycle through 
 the available tag types until the tag gives an answer to the request.
 
 Current the following tag types are supported:
 
 * Mifare Classic (``tag_type`` = 0)
 * NFC Forum Type 1 (``tag_type`` = 1)
 * NFC Forum Type 2 (``tag_type`` = 2)
 
 After you call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>` the NFC/RFID Bricklet will try to read 
 the tag ID from the tag. After this process is done the state will change.
 You can either register the :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>` callback or you can poll
 :perl:func:`get_state() <BrickletNFCRFID->get_state>` to find out about the state change.
 
 If the state changes to *RequestTagIDError* it means that either there was 
 no tag present or that the tag is of an incompatible type. If the state 
 changes to *RequestTagIDReady* it means that a compatible tag was found 
 and that the tag ID could be read out. You can now get the tag ID by
 calling :perl:func:`get_tag_id() <BrickletNFCRFID->get_tag_id>`.
 
 If two tags are in the proximity of the NFC/RFID Bricklet, this
 function will cycle through the tags. To select a specific tag you have
 to call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>` until the correct tag id is found.
 
 In case of any *Error* state the selection is lost and you have to
 start again by calling :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`.
 
 The following constants are available for this function:
 
 * BrickletNFCRFID->TAG_TYPE_MIFARE_CLASSIC = 0
 * BrickletNFCRFID->TAG_TYPE_TYPE1 = 1
 * BrickletNFCRFID->TAG_TYPE_TYPE2 = 2
 
.. perl:function:: BrickletNFCRFID->get_tag_id()

 :rtype: [int, int, [int, int, int, int, int, int, int]]

 Returns the tag type, tag ID and the length of the tag ID 
 (4 or 7 bytes are possible length). This function can only be called if the
 NFC/RFID is currently in one of the *Ready* states. The returned ID
 is the ID that was saved through the last call of :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`.
 
 To get the tag ID of a tag the approach is as follows:
 
 1. Call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`
 2. Wait for state to change to *RequestTagIDReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>` or
    :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 3. Call :perl:func:`get_tag_id() <BrickletNFCRFID->get_tag_id>`
 
 The following constants are available for this function:
 
 * BrickletNFCRFID->TAG_TYPE_MIFARE_CLASSIC = 0
 * BrickletNFCRFID->TAG_TYPE_TYPE1 = 1
 * BrickletNFCRFID->TAG_TYPE_TYPE2 = 2
 
 The returned array contains the elements ``tag_type``, ``tid_length`` and ``tid``.

.. perl:function:: BrickletNFCRFID->get_state()

 :rtype: [int, bool]

 Returns the current state of the NFC/RFID Bricklet.
 
 On startup the Bricklet will be in the *Initialization* state. The
 initialization will only take about 20ms. After that it changes to *Idle*.
 
 The functions of this Bricklet can be called in the *Idle* state and all of
 the *Ready* and *Error* states.
 
 Example: If you call :perl:func:`request_page() <BrickletNFCRFID->request_page>`, the state will change to 
 *RequestPage* until the reading of the page is finished. Then it will change
 to either *RequestPageReady* if it worked or to *RequestPageError* if it
 didn't. If the request worked you can get the page by calling :perl:func:`get_page() <BrickletNFCRFID->get_page>`.
 
 The same approach is used analogously for the other API functions.
 
 Possible states are:
 
 * Initialization = 0
 * Idle = 128
 * Error = 192
 * RequestTagID = 2
 * RequestTagIDReady = 130
 * RequestTagIDError = 194
 * AuthenticatingMifareClassicPage = 3
 * AuthenticatingMifareClassicPageReady = 131
 * AuthenticatingMifareClassicPageError = 195
 * WritePage = 4
 * WritePageReady = 132
 * WritePageError = 196
 * RequestPage = 5
 * RequestPageReady = 133
 * RequestPageError = 197
 
 The following constants are available for this function:
 
 * BrickletNFCRFID->STATE_INITIALIZATION = 0
 * BrickletNFCRFID->STATE_IDLE = 128
 * BrickletNFCRFID->STATE_ERROR = 192
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID = 2
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID_READY = 130
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID_ERROR = 194
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
 * BrickletNFCRFID->STATE_WRITE_PAGE = 4
 * BrickletNFCRFID->STATE_WRITE_PAGE_READY = 132
 * BrickletNFCRFID->STATE_WRITE_PAGE_ERROR = 196
 * BrickletNFCRFID->STATE_REQUEST_PAGE = 5
 * BrickletNFCRFID->STATE_REQUEST_PAGE_READY = 133
 * BrickletNFCRFID->STATE_REQUEST_PAGE_ERROR = 197
 
 The returned array contains the elements ``state`` and ``idle``.

.. perl:function:: BrickletNFCRFID->authenticate_mifare_classic_page($page, $key_number, @key)

 :param $page: int
 :param $key_number: int
 :param @key: [int, int, int, int, int, int]
 :rtype: undef

 Mifare Classic tags use authentication. If you want to read from or write to
 a Mifare Classic page you have to authenticate it beforehand.
 Each page can be authenticated with two keys: A (``key_number`` = 0) and B
 (``key_number`` = 1). A new Mifare Classic
 tag that has not yet been written to can can be accessed with key A
 and the default key ``[0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]``.
 
 The approach to read or write a Mifare Classic page is as follows:
 
 1. Call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`
 2. Wait for state to change to *RequestTagIDReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>`
    or :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 3. If looking for a specific tag then call :perl:func:`get_tag_id() <BrickletNFCRFID->get_tag_id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :perl:func:`authenticate_mifare_classic_page() <BrickletNFCRFID->authenticate_mifare_classic_page>` with page and key for the page
 5. Wait for state to change to *AuthenticatingMifareClassicPageReady* (see
    :perl:func:`get_state() <BrickletNFCRFID->get_state>` or :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 6. Call :perl:func:`request_page() <BrickletNFCRFID->request_page>` or :perl:func:`write_page() <BrickletNFCRFID->write_page>` to read/write page
 
 The following constants are available for this function:
 
 * BrickletNFCRFID->KEY_A = 0
 * BrickletNFCRFID->KEY_B = 1
 
.. perl:function:: BrickletNFCRFID->write_page($page, @data)

 :param $page: int
 :param @data: [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]
 :rtype: undef

 Writes 16 bytes starting from the given page. How many pages are written
 depends on the tag type. The page sizes are as follows:
 
 * Mifare Classic page size: 16 byte (one page is written)
 * NFC Forum Type 1 page size: 8 byte (two pages are written)
 * NFC Forum Type 2 page size: 4 byte (four pages are written)
 
 The general approach for writing to a tag is as follows:
 
 1. Call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`
 2. Wait for state to change to *RequestTagIDReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>` or
    :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 3. If looking for a specific tag then call :perl:func:`get_tag_id() <BrickletNFCRFID->get_tag_id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :perl:func:`write_page() <BrickletNFCRFID->write_page>` with page number and data
 5. Wait for state to change to *WritePageReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>` or
    :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 
 If you use a Mifare Classic tag you have to authenticate a page before you
 can write to it. See :perl:func:`authenticate_mifare_classic_page() <BrickletNFCRFID->authenticate_mifare_classic_page>`.
 
.. perl:function:: BrickletNFCRFID->request_page($page)

 :param $page: int
 :rtype: undef

 Reads 16 bytes starting from the given page and stores them into a buffer. 
 The buffer can then be read out with :perl:func:`get_page() <BrickletNFCRFID->get_page>`.
 How many pages are read depends on the tag type. The page sizes are 
 as follows:
 
 * Mifare Classic page size: 16 byte (one page is read)
 * NFC Forum Type 1 page size: 8 byte (two pages are read)
 * NFC Forum Type 2 page size: 4 byte (four pages are read)
 
 The general approach for reading a tag is as follows:
 
 1. Call :perl:func:`request_tag_id() <BrickletNFCRFID->request_tag_id>`
 2. Wait for state to change to *RequestTagIDReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>`
    or :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 3. If looking for a specific tag then call :perl:func:`get_tag_id() <BrickletNFCRFID->get_tag_id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :perl:func:`request_page() <BrickletNFCRFID->request_page>` with page number
 5. Wait for state to change to *RequestPageReady* (see :perl:func:`get_state() <BrickletNFCRFID->get_state>`
    or :perl:attr:`CALLBACK_STATE_CHANGED <BrickletNFCRFID->CALLBACK_STATE_CHANGED>`)
 6. Call :perl:func:`get_page() <BrickletNFCRFID->get_page>` to retrieve the page from the buffer
 
 If you use a Mifare Classic tag you have to authenticate a page before you
 can read it. See :perl:func:`authenticate_mifare_classic_page() <BrickletNFCRFID->authenticate_mifare_classic_page>`.
 
.. perl:function:: BrickletNFCRFID->get_page()

 :rtype: [int, int, int, int, int, int, int, int, int, int, int, int, int, int, int, int]

 Returns 16 bytes of data from an internal buffer. To fill the buffer
 with specific pages you have to call :perl:func:`request_page() <BrickletNFCRFID->request_page>` beforehand.
 


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

.. perl:function:: BrickletNFCRFID->get_api_version()

 :rtype: [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.
 
.. perl:function:: BrickletNFCRFID->get_response_expected($function_id)

 :param $function_id: int
 :rtype: bool

 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
 :perl:func:`set_response_expected() <BrickletNFCRFID->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 :perl:func:`set_response_expected() <BrickletNFCRFID->set_response_expected>`
 for the list of function ID constants available for this function.
 
.. perl:function:: BrickletNFCRFID->set_response_expected($function_id, $response_expected)

 :param $function_id: int
 :param $response_expected: bool
 :rtype: undef

 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:
 
 * BrickletNFCRFID->FUNCTION_REQUEST_TAG_ID = 1
 * BrickletNFCRFID->FUNCTION_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 4
 * BrickletNFCRFID->FUNCTION_WRITE_PAGE = 5
 * BrickletNFCRFID->FUNCTION_REQUEST_PAGE = 6
 
.. perl:function:: BrickletNFCRFID->set_response_expected_all($response_expected)

 :param $response_expected: bool
 :rtype: undef

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. perl:function:: BrickletNFCRFID->get_identity()

 :rtype: [string, string, char, [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 contains the elements ``uid``, ``connected_uid``, ``position``, ``hardware_version``, ``firmware_version`` and ``device_identifier``.



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


.. perl:function:: BrickletNFCRFID->register_callback($id, $callback)

 :param $id: int
 :param $callback: string
 :rtype: undef

 Registers a callback with ID ``$id`` to the function named ``$callback``. The
 available IDs with corresponding function signatures are listed
 :ref:`below <nfc_rfid_bricklet_perl_callbacks>`.




.. _nfc_rfid_bricklet_perl_callbacks:

Callbacks
^^^^^^^^^

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

.. code-block:: perl

    sub my_callback
    {
        print "@_[0]";
    }

    $nfc_rfid->register_callback(BrickletNFCRFID->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the
IP Connection. In contrast to many other programming languages, variables are
not automatically shared between threads in Perl. If you want to share a global
variable between a callback function and the rest for your program it has to be
marked as ``:shared``. See the documentation of the `threads::shared
<http://perldoc.perl.org/threads/shared.html>`__ Perl module for more details.

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.

.. perl:attribute:: BrickletNFCRFID->CALLBACK_STATE_CHANGED

 :param $state: int
 :param $idle: bool


 This callback is called if the state of the NFC/RFID Bricklet changes.
 See :perl:func:`get_state() <BrickletNFCRFID->get_state>` for more information about the possible states.
 
 The following constants are available for this function:
 
 * BrickletNFCRFID->STATE_INITIALIZATION = 0
 * BrickletNFCRFID->STATE_IDLE = 128
 * BrickletNFCRFID->STATE_ERROR = 192
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID = 2
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID_READY = 130
 * BrickletNFCRFID->STATE_REQUEST_TAG_ID_ERROR = 194
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
 * BrickletNFCRFID->STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
 * BrickletNFCRFID->STATE_WRITE_PAGE = 4
 * BrickletNFCRFID->STATE_WRITE_PAGE_READY = 132
 * BrickletNFCRFID->STATE_WRITE_PAGE_ERROR = 196
 * BrickletNFCRFID->STATE_REQUEST_PAGE = 5
 * BrickletNFCRFID->STATE_REQUEST_PAGE_READY = 133
 * BrickletNFCRFID->STATE_REQUEST_PAGE_ERROR = 197
 


.. _nfc_rfid_bricklet_perl_constants:

Constants
^^^^^^^^^

.. perl:attribute:: BrickletNFCRFID->DEVICE_IDENTIFIER

 This constant is used to identify a NFC/RFID Bricklet.

 The :perl:func:`get_identity() <BrickletNFCRFID->get_identity>` function and the
 :perl: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.

