Rust - NFC/RFID Bricklet

This is the description of the Rust API bindings for the NFC/RFID Bricklet. General information and technical specifications for the NFC/RFID Bricklet are summarized in its hardware description.

An installation guide for the Rust API bindings is part of their general description. Additional documentation can be found on docs.rs.

Examples

The example code below is Public Domain (CC0 1.0).

Scan For Tags

Download (example_scan_for_tags.rs)

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use std::{error::Error, io, thread};
use tinkerforge::{ip_connection::IpConnection, nfc_rfid_bricklet::*};

const HOST: &str = "127.0.0.1";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your NFC/RFID Bricklet

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection
    let nr = NfcRfidBricklet::new(UID, &ipcon); // Create device object

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd
                                          // Don't use device before ipcon is connected

    let state_changed_receiver = nr.get_state_changed_callback_receiver();

    // Spawn thread to handle received events.
    // This thread ends when the `nr` object
    // is dropped, so there is no need for manual cleanup.
    let nr_copy = nr.clone(); //Device objects don't implement Sync, so they can't be shared between threads (by reference). So clone the device and move the copy.
    thread::spawn(move || {
        let mut current_tag_type = NFC_RFID_BRICKLET_TAG_TYPE_MIFARE_CLASSIC;
        for state_change in state_changed_receiver {
            if state_change.idle {
                current_tag_type = (current_tag_type + 1) % 3;
                nr_copy.request_tag_id(current_tag_type);
            }

            if state_change.state == NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_READY {
                let tag_id = nr_copy.get_tag_id().recv().unwrap();
                println!("Found tag of type {} with ID {:x?}", tag_id.tag_type, tag_id.tid[0..tag_id.tid_length as usize].to_vec());
            }
        }
    });

    // Start scan loop
    nr.request_tag_id(NFC_RFID_BRICKLET_TAG_TYPE_MIFARE_CLASSIC);

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

Write Read Type2

Download (example_write_read_type2.rs)

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use std::{error::Error, io, thread};
use tinkerforge::{ip_connection::IpConnection, nfc_rfid_bricklet::*};

const HOST: &str = "127.0.0.1";
const PORT: u16 = 4223;
const UID: &str = "XYZ"; // Change XYZ to the UID of your NFC/RFID Bricklet

fn main() -> Result<(), Box<dyn Error>> {
    let ipcon = IpConnection::new(); // Create IP connection
    let nr = NfcRfidBricklet::new(UID, &ipcon); // Create device object

    ipcon.connect((HOST, PORT)).recv()??; // Connect to brickd
                                          // Don't use device before ipcon is connected

    let state_changed_receiver = nr.get_state_changed_callback_receiver();

    // Spawn thread to handle received events.
    // This thread ends when the `nr` object
    // is dropped, so there is no need for manual cleanup.
    let nr_copy = nr.clone(); //Device objects don't implement Sync, so they can't be shared between threads (by reference). So clone the device and move the copy.
    thread::spawn(move || {
        for state_change in state_changed_receiver {
            if state_change.state == NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_READY {
                println!("Tag found");

                // Write 16 byte to pages 5-8
                let data_write = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];

                nr_copy.write_page(5, data_write);
                println!("Writing data...");
            } else if state_change.state == NFC_RFID_BRICKLET_STATE_WRITE_PAGE_READY {
                // Request pages 5-8
                nr_copy.request_page(5);
                println!("Requesting data...");
            } else if state_change.state == NFC_RFID_BRICKLET_STATE_REQUEST_PAGE_READY {
                // Get and print pages
                let data = nr_copy.get_page().recv().unwrap();

                println!("Read data: {:x?}", data);
            } else if (state_change.state & (1 << 6)) == (1 << 6) {
                // All errors have bit 6 set
                println!("Error: {}", state_change.state);
            }
        }
    });

    // Select NFC Forum Type 2 tag
    nr.request_tag_id(NFC_RFID_BRICKLET_TAG_TYPE_TYPE2);

    println!("Press enter to exit.");
    let mut _input = String::new();
    io::stdin().read_line(&mut _input)?;
    ipcon.disconnect();
    Ok(())
}

API

To allow non-blocking usage, nearly every function of the Rust bindings returns a wrapper around a mpsc::Receiver. To block until the function has finished and get your result, call one of the receiver's recv variants. Those return either the result sent by the device, or any error occured.

Functions returning a result directly will block until the device has finished processing the request.

All functions listed below are thread-safe, those which return a receiver are lock-free.

Basic Functions

pub fn NfcRfidBricklet::new(uid: &str, ip_connection: &IpConnection) → NfcRfidBricklet

Creates a new NfcRfidBricklet object with the unique device ID uid and adds it to the IPConnection ipcon:

This device object can be used after the IP connection has been connected (see examples above).

pub fn NfcRfidBricklet::request_tag_id(&self, tag_type: u8) → ConvertingReceiver<()>

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.

Currently the following tag types are supported:

  • Mifare Classic
  • NFC Forum Type 1
  • NFC Forum Type 2

After you call NfcRfidBricklet::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 NfcRfidBricklet::get_state_changed_callback_receiver callback or you can poll NfcRfidBricklet::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 NfcRfidBricklet::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 NfcRfidBricklet::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 NfcRfidBricklet::request_tag_id.

The following constants are available for this function:

  • NFC_RFID_BRICKLET_TAG_TYPE_MIFARE_CLASSIC = 0
  • NFC_RFID_BRICKLET_TAG_TYPE_TYPE1 = 1
  • NFC_RFID_BRICKLET_TAG_TYPE_TYPE2 = 2
pub fn NfcRfidBricklet::get_tag_id(&self) → ConvertingReceiver<TagId>

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 NfcRfidBricklet::request_tag_id.

To get the tag ID of a tag the approach is as follows:

  1. Call NfcRfidBricklet::request_tag_id
  2. Wait for state to change to RequestTagIDReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  3. Call NfcRfidBricklet::get_tag_id

The following constants are available for this function:

  • NFC_RFID_BRICKLET_TAG_TYPE_MIFARE_CLASSIC = 0
  • NFC_RFID_BRICKLET_TAG_TYPE_TYPE1 = 1
  • NFC_RFID_BRICKLET_TAG_TYPE_TYPE2 = 2
pub fn NfcRfidBricklet::get_state(&self) → ConvertingReceiver<State>

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 NfcRfidBricklet::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 NfcRfidBricklet::get_page.

The same approach is used analogously for the other API functions.

The following constants are available for this function:

  • NFC_RFID_BRICKLET_STATE_INITIALIZATION = 0
  • NFC_RFID_BRICKLET_STATE_IDLE = 128
  • NFC_RFID_BRICKLET_STATE_ERROR = 192
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID = 2
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_READY = 130
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_ERROR = 194
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE = 4
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE_READY = 132
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE_ERROR = 196
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE = 5
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE_READY = 133
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE_ERROR = 197
pub fn NfcRfidBricklet::authenticate_mifare_classic_page(&self, page: u16, key_number: u8, key: [u8; 6]) → ConvertingReceiver<()>

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 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 NfcRfidBricklet::request_tag_id
  2. Wait for state to change to RequestTagIDReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  3. If looking for a specific tag then call NfcRfidBricklet::get_tag_id and check if the expected tag was found, if it was not found go back to step 1
  4. Call NfcRfidBricklet::authenticate_mifare_classic_page with page and key for the page
  5. Wait for state to change to AuthenticatingMifareClassicPageReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  6. Call NfcRfidBricklet::request_page or NfcRfidBricklet::write_page to read/write page

The following constants are available for this function:

  • NFC_RFID_BRICKLET_KEY_A = 0
  • NFC_RFID_BRICKLET_KEY_B = 1
pub fn NfcRfidBricklet::write_page(&self, page: u16, data: [u8; 16]) → ConvertingReceiver<()>

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 NfcRfidBricklet::request_tag_id
  2. Wait for state to change to RequestTagIDReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  3. If looking for a specific tag then call NfcRfidBricklet::get_tag_id and check if the expected tag was found, if it was not found got back to step 1
  4. Call NfcRfidBricklet::write_page with page number and data
  5. Wait for state to change to WritePageReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)

If you use a Mifare Classic tag you have to authenticate a page before you can write to it. See NfcRfidBricklet::authenticate_mifare_classic_page.

pub fn NfcRfidBricklet::request_page(&self, page: u16) → ConvertingReceiver<()>

Reads 16 bytes starting from the given page and stores them into a buffer. The buffer can then be read out with NfcRfidBricklet::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 NfcRfidBricklet::request_tag_id
  2. Wait for state to change to RequestTagIDReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  3. If looking for a specific tag then call NfcRfidBricklet::get_tag_id and check if the expected tag was found, if it was not found got back to step 1
  4. Call NfcRfidBricklet::request_page with page number
  5. Wait for state to change to RequestPageReady (see NfcRfidBricklet::get_state or NfcRfidBricklet::get_state_changed_callback_receiver callback)
  6. Call NfcRfidBricklet::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 NfcRfidBricklet::authenticate_mifare_classic_page.

pub fn NfcRfidBricklet::get_page(&self) → ConvertingReceiver<[u8; 16]>

Returns 16 bytes of data from an internal buffer. To fill the buffer with specific pages you have to call NfcRfidBricklet::request_page beforehand.

Advanced Functions

pub fn NfcRfidBricklet::get_api_version(&self) → [u8; 3]

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.

pub fn NfcRfidBricklet::get_response_expected(&mut self, function_id: u8) → 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 NfcRfidBricklet::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 NfcRfidBricklet::set_response_expected for the list of function ID constants available for this function.

pub fn NfcRfidBricklet::set_response_expected(&mut self, function_id: u8, 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.

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:

  • NFC_RFID_BRICKLET_FUNCTION_REQUEST_TAG_ID = 1
  • NFC_RFID_BRICKLET_FUNCTION_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 4
  • NFC_RFID_BRICKLET_FUNCTION_WRITE_PAGE = 5
  • NFC_RFID_BRICKLET_FUNCTION_REQUEST_PAGE = 6
pub fn NfcRfidBricklet::set_response_expected_all(&mut self, response_expected: bool) → ()

Changes the response expected flag for all setter and callback configuration functions of this device at once.

pub fn NfcRfidBricklet::get_identity(&self) → ConvertingReceiver<Identity>

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 here. There is also a constant for the device identifier of this Bricklet.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the corresponding get_*_callback_receiver function, which returns a receiver for callback events.

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.

pub fn NfcRfidBricklet::get_state_changed_callback_receiver(&self) → ConvertingCallbackReceiver<StateChangedEvent>

Receivers created with this function receive State Changed events.

This callback is called if the state of the NFC/RFID Bricklet changes. See NfcRfidBricklet::get_state for more information about the possible states.

The following constants are available for this function:

  • NFC_RFID_BRICKLET_STATE_INITIALIZATION = 0
  • NFC_RFID_BRICKLET_STATE_IDLE = 128
  • NFC_RFID_BRICKLET_STATE_ERROR = 192
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID = 2
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_READY = 130
  • NFC_RFID_BRICKLET_STATE_REQUEST_TAG_ID_ERROR = 194
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
  • NFC_RFID_BRICKLET_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE = 4
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE_READY = 132
  • NFC_RFID_BRICKLET_STATE_WRITE_PAGE_ERROR = 196
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE = 5
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE_READY = 133
  • NFC_RFID_BRICKLET_STATE_REQUEST_PAGE_ERROR = 197

Constants

NfcRfidBricklet::DEVICE_IDENTIFIER

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

The NfcRfidBricklet::get_identity function and the IpConnection::get_enumerate_callback_receiver callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

NfcRfidBricklet::DEVICE_DISPLAY_NAME

This constant represents the human readable name of a NFC/RFID Bricklet.