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

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

.. _nfc_rfid_bricklet_shell:

Shell - NFC/RFID Bricklet
=========================

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

.. _nfc_rfid_bricklet_shell_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.sh) <https://github.com/Tinkerforge/nfc-rfid-bricklet/raw/master/software/examples/shell/example-scan-for-tags.sh>`__

.. literalinclude:: NFCRFID_Bricklet_Shell_example-scan-for-tags.sh
 :language: bash
 :linenos:
 :tab-width: 4

.. _nfc_rfid_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 Nnfc-rfid-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 NFC/RFID 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 NFC/RFID Bricklet and exits


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

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

 The ``dispatch`` command is used to dispatch a callback of the NFC/RFID 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 NFC/RFID Bricklet and exits


.. sh:function:: X Stinkerforge Scall Pnfc-rfid-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 Pnfc-rfid-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 nfc-rfid-bricklet <uid> request-tag-id <tag-type> 

 :param <tag-type>: int (has symbols)

 :noreturn: no output

 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 :sh:func:`request-tag-id <nfc-rfid-bricklet 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 :sh:func:`state-changed <nfc-rfid-bricklet state-changed>` callback or you can poll
 :sh:func:`get-state <nfc-rfid-bricklet 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 :sh:func:`get-tag-id <nfc-rfid-bricklet 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 :sh:func:`request-tag-id <nfc-rfid-bricklet 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 :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`.
 
 The following symbols are available for this function:
 
 * ``mifare-classic`` = 0, for <tag-type>
 * ``type1`` = 1, for <tag-type>
 * ``type2`` = 2, for <tag-type>
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> get-tag-id  


 :returns tag-type: int (has symbols)
 :returns tid-length: int
 :returns tid: 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 :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`.
 
 To get the tag ID of a tag the approach is as follows:
 
 1. Call :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`
 2. Wait for state to change to *RequestTagIDReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>` or
    :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 3. Call :sh:func:`get-tag-id <nfc-rfid-bricklet get-tag-id>`
 
 The following symbols are available for this function:
 
 * ``mifare-classic`` = 0, for tag-type
 * ``type1`` = 1, for tag-type
 * ``type2`` = 2, for tag-type
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> get-state  


 :returns state: int (has symbols)
 :returns idle: 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 :sh:func:`request-page <nfc-rfid-bricklet 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 :sh:func:`get-page <nfc-rfid-bricklet 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 symbols are available for this function:
 
 * ``initialization`` = 0, for state
 * ``idle`` = 128, for state
 * ``error`` = 192, for state
 * ``request-tag-id`` = 2, for state
 * ``request-tag-id-ready`` = 130, for state
 * ``request-tag-id-error`` = 194, for state
 * ``authenticating-mifare-classic-page`` = 3, for state
 * ``authenticating-mifare-classic-page-ready`` = 131, for state
 * ``authenticating-mifare-classic-page-error`` = 195, for state
 * ``write-page`` = 4, for state
 * ``write-page-ready`` = 132, for state
 * ``write-page-error`` = 196, for state
 * ``request-page`` = 5, for state
 * ``request-page-ready`` = 133, for state
 * ``request-page-error`` = 197, for state
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> authenticate-mifare-classic-page <page> <key-number> <key> 

 :param <page>: int
 :param <key-number>: int (has symbols)
 :param <key>: int,int,int,int,int,int

 :noreturn: no output

 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 :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`
 2. Wait for state to change to *RequestTagIDReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>`
    or :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 3. If looking for a specific tag then call :sh:func:`get-tag-id <nfc-rfid-bricklet get-tag-id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :sh:func:`authenticate-mifare-classic-page <nfc-rfid-bricklet authenticate-mifare-classic-page>` with page and key for the page
 5. Wait for state to change to *AuthenticatingMifareClassicPageReady* (see
    :sh:func:`get-state <nfc-rfid-bricklet get-state>` or :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 6. Call :sh:func:`request-page <nfc-rfid-bricklet request-page>` or :sh:func:`write-page <nfc-rfid-bricklet write-page>` to read/write page
 
 The following symbols are available for this function:
 
 * ``a`` = 0, for <key-number>
 * ``b`` = 1, for <key-number>
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> 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

 :noreturn: no output

 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 :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`
 2. Wait for state to change to *RequestTagIDReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>` or
    :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 3. If looking for a specific tag then call :sh:func:`get-tag-id <nfc-rfid-bricklet get-tag-id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :sh:func:`write-page <nfc-rfid-bricklet write-page>` with page number and data
 5. Wait for state to change to *WritePageReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>` or
    :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 
 If you use a Mifare Classic tag you have to authenticate a page before you
 can write to it. See :sh:func:`authenticate-mifare-classic-page <nfc-rfid-bricklet authenticate-mifare-classic-page>`.
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> request-page <page> 

 :param <page>: int

 :noreturn: no output

 Reads 16 bytes starting from the given page and stores them into a buffer. 
 The buffer can then be read out with :sh:func:`get-page <nfc-rfid-bricklet 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 :sh:func:`request-tag-id <nfc-rfid-bricklet request-tag-id>`
 2. Wait for state to change to *RequestTagIDReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>`
    or :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 3. If looking for a specific tag then call :sh:func:`get-tag-id <nfc-rfid-bricklet get-tag-id>` and check if the
    expected tag was found, if it was not found got back to step 1
 4. Call :sh:func:`request-page <nfc-rfid-bricklet request-page>` with page number
 5. Wait for state to change to *RequestPageReady* (see :sh:func:`get-state <nfc-rfid-bricklet get-state>`
    or :sh:func:`state-changed <nfc-rfid-bricklet state-changed>`)
 6. Call :sh:func:`get-page <nfc-rfid-bricklet 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 :sh:func:`authenticate-mifare-classic-page <nfc-rfid-bricklet authenticate-mifare-classic-page>`.
 
.. sh:function:: tinkerforge call nfc-rfid-bricklet <uid> get-page  


 :returns data: 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 :sh:func:`request-page <nfc-rfid-bricklet request-page>` beforehand.
 


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

.. sh:function:: tinkerforge call nfc-rfid-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|
 


.. _nfc_rfid_bricklet_shell_callbacks:

Callbacks
^^^^^^^^^

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

.. code-block:: bash

    tinkerforge dispatch nfc-rfid-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 nfc-rfid-bricklet <uid> state-changed

 :returns state: int (has symbols)
 :returns idle: bool


 This callback is called if the state of the NFC/RFID Bricklet changes.
 See :sh:func:`get-state <nfc-rfid-bricklet get-state>` for more information about the possible states.
 
 The following symbols are available for this function:
 
 * ``initialization`` = 0, for state
 * ``idle`` = 128, for state
 * ``error`` = 192, for state
 * ``request-tag-id`` = 2, for state
 * ``request-tag-id-ready`` = 130, for state
 * ``request-tag-id-error`` = 194, for state
 * ``authenticating-mifare-classic-page`` = 3, for state
 * ``authenticating-mifare-classic-page-ready`` = 131, for state
 * ``authenticating-mifare-classic-page-error`` = 195, for state
 * ``write-page`` = 4, for state
 * ``write-page-ready`` = 132, for state
 * ``write-page-error`` = 196, for state
 * ``request-page`` = 5, for state
 * ``request-page-ready`` = 133, for state
 * ``request-page-error`` = 197, for state
 


