Java - NFC Bricklet

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

An installation guide for the Java API bindings is part of their general description.

Examples

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

Scan For Tags

Download (ExampleScanForTags.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletNFC;

public class ExampleScanForTags {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your NFC Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletNFC nfc = new BrickletNFC(UID, ipcon); // Create device object

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

        // Add reader state changed listener
        nfc.addReaderStateChangedListener(new BrickletNFC.ReaderStateChangedListener() {
            public void readerStateChanged(int state, boolean idle) {
                if (state == BrickletNFC.READER_STATE_IDLE) {
                    try {
                        nfc.readerRequestTagID();
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if(state == BrickletNFC.READER_STATE_REQUEST_TAG_ID_READY) {
                    try{
                        int i = 0;
                        StringBuilder tag = new StringBuilder();
                        BrickletNFC.ReaderGetTagID ret = nfc.readerGetTagID();

                        for (int v : ret.tagID) {
                            if (i < ret.tagID.length - 1) {
                                tag.append(String.format("0x%X ", v));
                            }
                            else {
                                tag.append(String.format("0x%X", v));
                            }

                            i++;
                        }

                        System.out.format("Found tag of type %d with ID [%s]\n", ret.tagType, tag);
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if (state == BrickletNFC.READER_STATE_REQUEST_TAG_ID_ERROR) {
                    System.out.println("Request tag ID error");
                }
            }
        });

        // Enable reader mode
        nfc.setMode(BrickletNFC.MODE_READER);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Emulate NDEF

Download (ExampleEmulateNDEF.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletNFC;

public class ExampleEmulateNDEF {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your NFC Bricklet
    private static final String UID = "XYZ";
    private static final String NDEF_URI = "www.tinkerforge.com";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletNFC nfc = new BrickletNFC(UID, ipcon); // Create device object

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

        // Add cardemu state changed listener
        nfc.addCardemuStateChangedListener(new BrickletNFC.CardemuStateChangedListener() {
            public void cardemuStateChanged(int state, boolean idle) {
                if (state == BrickletNFC.CARDEMU_STATE_IDLE) {
                    try {
                        int[] ndefRecordURI = new int[NDEF_URI.toCharArray().length + 5];

                        // Only short records are supported
                        ndefRecordURI[0] = 0xD1;                              // MB/ME/CF/SR=1/IL/TNF
                        ndefRecordURI[1] = 0x01;                              // TYPE LENGTH
                        ndefRecordURI[2] = NDEF_URI.toCharArray().length + 1; // Length
                        ndefRecordURI[3] = (int)'U';                          // Type
                        ndefRecordURI[4] = 0x04;                              // Status

                        for (int i = 0; i < NDEF_URI.toCharArray().length; i++) {
                            ndefRecordURI[5 + i] = (int)NDEF_URI.toCharArray()[i];
                        }

                        nfc.cardemuWriteNDEF(ndefRecordURI);
                        nfc.cardemuStartDiscovery();
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if(state == BrickletNFC.CARDEMU_STATE_DISCOVER_READY) {
                    try {
                        nfc.cardemuStartTransfer(BrickletNFC.CARDEMU_TRANSFER_WRITE);
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if (state == BrickletNFC.CARDEMU_STATE_DISCOVER_ERROR) {
                    System.out.println("Discover error");
                }
                else if (state == BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF_ERROR) {
                    System.out.println("Transfer NDEF error");
                }
                else if (state == BrickletNFC.READER_STATE_REQUEST_TAG_ID_ERROR) {
                    System.out.println("Request tag ID error");
                }
            }
        });

        // Enable cardemu mode
        nfc.setMode(BrickletNFC.MODE_CARDEMU);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Write Read Type 2

Download (ExampleWriteReadType2.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletNFC;

public class ExampleWriteReadType2 {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your NFC Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletNFC nfc = new BrickletNFC(UID, ipcon); // Create device object

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

        // Add reader state changed listener
        nfc.addReaderStateChangedListener(new BrickletNFC.ReaderStateChangedListener() {
            public void readerStateChanged(int state, boolean idle) {
                if (state == BrickletNFC.READER_STATE_IDLE) {
                    try {
                        nfc.readerRequestTagID();
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if(state == BrickletNFC.READER_STATE_REQUEST_TAG_ID_READY) {
                    try{
                        int i = 0;
                        StringBuilder tag = new StringBuilder();
                        BrickletNFC.ReaderGetTagID ret = nfc.readerGetTagID();

                        if (ret.tagType != BrickletNFC.TAG_TYPE_TYPE2) {
                            System.out.println("Tag is not type-2");

                            return;
                        }

                        for (int v : ret.tagID) {
                            if (i < ret.tagID.length - 1) {
                                tag.append(String.format("0x%X ", v));
                            }
                            else {
                                tag.append(String.format("0x%X", v));
                            }

                            i++;
                        }

                        System.out.format("Found tag of type %d with ID [%s]\n", ret.tagType, tag);

                        nfc.readerRequestPage(1, 4);
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if (state == BrickletNFC.READER_STATE_REQUEST_TAG_ID_ERROR) {
                    System.out.println("Request tag ID error");
                }
                else if (state == BrickletNFC.READER_STATE_REQUEST_PAGE_READY) {
                    try {
                        int[] page = nfc.readerReadPage();

                        System.out.format("Page read: 0x%X 0x%X 0x%X 0x%X\n", page[0], page[1], page[2], page[3]);
                        nfc.readerWritePage(1, page);
                    }
                    catch (Exception e) {
                        return;
                    }
                }
                else if (state == BrickletNFC.READER_STATE_WRITE_PAGE_READY) {
                    System.out.println("Write page ready");
                }
                else if (state == BrickletNFC.READER_STATE_REQUEST_PAGE_ERROR) {
                    System.out.println("Request page error");
                }
                else if (state == BrickletNFC.READER_STATE_WRITE_PAGE_ERROR) {
                    System.out.println("Write page error");
                }
            }
        });

        nfc.setMode(BrickletNFC.MODE_READER);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

API

Generally, every method of the Java bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.

Since Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.

The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*

All methods listed below are thread-safe.

Basic Functions

public class BrickletNFC(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletNFC nfc = new BrickletNFC("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected (see examples above).

public void setMode(int mode)

Sets the mode. The NFC Bricklet supports four modes:

  • Off
  • Card Emulation (Cardemu): Emulates a tag for other readers
  • Peer to Peer (P2P): Exchange data with other readers
  • Reader: Reads and writes tags

If you change a mode, the Bricklet will reconfigure the hardware for this mode. Therefore, you can only use functions corresponding to the current mode. For example, in Reader mode you can only use Reader functions.

The default mode is "off".

The following constants are available for this function:

  • BrickletNFC.MODE_OFF = 0
  • BrickletNFC.MODE_CARDEMU = 1
  • BrickletNFC.MODE_P2P = 2
  • BrickletNFC.MODE_READER = 3
public int getMode()

Returns the mode as set by setMode().

The following constants are available for this function:

  • BrickletNFC.MODE_OFF = 0
  • BrickletNFC.MODE_CARDEMU = 1
  • BrickletNFC.MODE_P2P = 2
  • BrickletNFC.MODE_READER = 3
public void readerRequestTagID()

To read or write a tag that is in proximity of the NFC 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 answers the request.

Currently the following tag types are supported:

  • Mifare Classic
  • NFC Forum Type 1
  • NFC Forum Type 2
  • NFC Forum Type 3
  • NFC Forum Type 4

After you call readerRequestTagID() the NFC 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 ReaderStateChangedListener listener or you can poll readerGetState() to find out about the state change.

If the state changes to ReaderRequestTagIDError it means that either there was no tag present or that the tag has an incompatible type. If the state changes to ReaderRequestTagIDReady it means that a compatible tag was found and that the tag ID has been saved. You can now read out the tag ID by calling readerGetTagID().

If two tags are in the proximity of the NFC Bricklet, this function will cycle through the tags. To select a specific tag you have to call readerRequestTagID() until the correct tag ID is found.

In case of any ReaderError state the selection is lost and you have to start again by calling readerRequestTagID().

public BrickletNFC.ReaderGetTagIDLowLevel readerGetTagID()

Returns the tag type and the tag ID. This function can only be called if the NFC Bricklet is currently in one of the ReaderReady states. The returned tag ID is the tag ID that was saved through the last call of readerRequestTagID().

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

  1. Call readerRequestTagID()
  2. Wait for state to change to ReaderRequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. Call readerGetTagID()

The following constants are available for this function:

  • BrickletNFC.TAG_TYPE_MIFARE_CLASSIC = 0
  • BrickletNFC.TAG_TYPE_TYPE1 = 1
  • BrickletNFC.TAG_TYPE_TYPE2 = 2
  • BrickletNFC.TAG_TYPE_TYPE3 = 3
  • BrickletNFC.TAG_TYPE_TYPE4 = 4

The returned object has the public member variables int tagType and int[] tagID.

public BrickletNFC.ReaderGetState readerGetState()

Returns the current reader state of the NFC Bricklet.

On startup the Bricklet will be in the ReaderInitialization state. The initialization will only take about 20ms. After that it changes to ReaderIdle.

The Bricklet is also reinitialized if the mode is changed, see setMode().

The functions of this Bricklet can be called in the ReaderIdle state and all of the ReaderReady and ReaderError states.

Example: If you call readerRequestPage(), the state will change to ReaderRequestPage until the reading of the page is finished. Then it will change to either ReaderRequestPageReady if it worked or to ReaderRequestPageError if it didn't. If the request worked you can get the page by calling readerReadPage().

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

The following constants are available for this function:

  • BrickletNFC.READER_STATE_INITIALIZATION = 0
  • BrickletNFC.READER_STATE_IDLE = 128
  • BrickletNFC.READER_STATE_ERROR = 192
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID = 2
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID_READY = 130
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID_ERROR = 194
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 3
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE_READY = 131
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE_ERROR = 195
  • BrickletNFC.READER_STATE_WRITE_PAGE = 4
  • BrickletNFC.READER_STATE_WRITE_PAGE_READY = 132
  • BrickletNFC.READER_STATE_WRITE_PAGE_ERROR = 196
  • BrickletNFC.READER_STATE_REQUEST_PAGE = 5
  • BrickletNFC.READER_STATE_REQUEST_PAGE_READY = 133
  • BrickletNFC.READER_STATE_REQUEST_PAGE_ERROR = 197
  • BrickletNFC.READER_STATE_WRITE_NDEF = 6
  • BrickletNFC.READER_STATE_WRITE_NDEF_READY = 134
  • BrickletNFC.READER_STATE_WRITE_NDEF_ERROR = 198
  • BrickletNFC.READER_STATE_REQUEST_NDEF = 7
  • BrickletNFC.READER_STATE_REQUEST_NDEF_READY = 135
  • BrickletNFC.READER_STATE_REQUEST_NDEF_ERROR = 199

The returned object has the public member variables int state and boolean idle.

public void readerWriteNDEF(int[] ndef)

Writes NDEF formated data with a maximum of 255 bytes.

This function currently supports NFC Forum Type 2 and 4.

The general approach for writing a NDEF message is as follows:

  1. Call readerRequestTagID()
  2. Wait for state to change to ReaderRequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. If looking for a specific tag then call readerGetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call readerWriteNDEF() with the NDEF message that you want to write
  5. Wait for state to change to ReaderWriteNDEFReady (see readerGetState() or ReaderStateChangedListener listener)
public void readerRequestNDEF()

Reads NDEF formated data from a tag.

This function currently supports NFC Forum Type 1, 2, 3 and 4.

The general approach for reading a NDEF message is as follows:

  1. Call readerRequestTagID()
  2. Wait for state to change to RequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. If looking for a specific tag then call readerGetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call readerRequestNDEF()
  5. Wait for state to change to ReaderRequestNDEFReady (see readerGetState() or ReaderStateChangedListener listener)
  6. Call readerReadNDEF() to retrieve the NDEF message from the buffer
public int[] readerReadNDEF()

Returns the NDEF data from an internal buffer. To fill the buffer with a NDEF message you have to call readerRequestNDEF() beforehand.

The buffer can have a size of up to 8192 bytes.

public void readerAuthenticateMifareClassicPage(int page, int keyNumber, int[] key)

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 readerRequestTagID()
  2. Wait for state to change to ReaderRequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. If looking for a specific tag then call readerGetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call readerAuthenticateMifareClassicPage() with page and key for the page
  5. Wait for state to change to ReaderAuthenticatingMifareClassicPageReady (see readerGetState() or ReaderStateChangedListener listener)
  6. Call readerRequestPage() or readerWritePage() to read/write page

The authentication will always work for one whole sector (4 pages).

The following constants are available for this function:

  • BrickletNFC.KEY_A = 0
  • BrickletNFC.KEY_B = 1
public void readerWritePage(int page, int[] data)

Writes a maximum of 8192 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
  • NFC Forum Type 1 page size: 8 byte
  • NFC Forum Type 2 page size: 4 byte
  • NFC Forum Type 3 page size: 16 byte
  • NFC Forum Type 4: No pages, page = file selection (CC or NDEF, see below)

The general approach for writing to a tag is as follows:

  1. Call readerRequestTagID()
  2. Wait for state to change to ReaderRequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. If looking for a specific tag then call readerGetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call readerWritePage() with page number and data
  5. Wait for state to change to ReaderWritePageReady (see readerGetState() or ReaderStateChangedListener listener)

If you use a Mifare Classic tag you have to authenticate a page before you can write to it. See readerAuthenticateMifareClassicPage().

NFC Forum Type 4 tags are not organized into pages but different files. We currently support two files: Capability Container file (CC) and NDEF file.

Choose CC by setting page to 3 or NDEF by setting page to 4.

The following constants are available for this function:

  • BrickletNFC.READER_WRITE_TYPE4_CAPABILITY_CONTAINER = 3
  • BrickletNFC.READER_WRITE_TYPE4_NDEF = 4
public void readerRequestPage(int page, int length)

Reads a maximum of 8192 bytes starting from the given page and stores them into a buffer. The buffer can then be read out with readerReadPage(). How many pages are read depends on the tag type. The page sizes are as follows:

  • Mifare Classic page size: 16 byte
  • NFC Forum Type 1 page size: 8 byte
  • NFC Forum Type 2 page size: 4 byte
  • NFC Forum Type 3 page size: 16 byte
  • NFC Forum Type 4: No pages, page = file selection (CC or NDEF, see below)

The general approach for reading a tag is as follows:

  1. Call readerRequestTagID()
  2. Wait for state to change to RequestTagIDReady (see readerGetState() or ReaderStateChangedListener listener)
  3. If looking for a specific tag then call readerGetTagID() and check if the expected tag was found, if it was not found got back to step 1
  4. Call readerRequestPage() with page number
  5. Wait for state to change to ReaderRequestPageReady (see readerGetState() or ReaderStateChangedListener listener)
  6. Call readerReadPage() 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 readerAuthenticateMifareClassicPage().

NFC Forum Type 4 tags are not organized into pages but different files. We currently support two files: Capability Container file (CC) and NDEF file.

Choose CC by setting page to 3 or NDEF by setting page to 4.

The following constants are available for this function:

  • BrickletNFC.READER_REQUEST_TYPE4_CAPABILITY_CONTAINER = 3
  • BrickletNFC.READER_REQUEST_TYPE4_NDEF = 4
public int[] readerReadPage()

Returns the page data from an internal buffer. To fill the buffer with specific pages you have to call readerRequestPage() beforehand.

The buffer can have a size of up to 8192 bytes.

public BrickletNFC.CardemuGetState cardemuGetState()

Returns the current cardemu state of the NFC Bricklet.

On startup the Bricklet will be in the CardemuInitialization state. The initialization will only take about 20ms. After that it changes to CardemuIdle.

The Bricklet is also reinitialized if the mode is changed, see setMode().

The functions of this Bricklet can be called in the CardemuIdle state and all of the CardemuReady and CardemuError states.

Example: If you call cardemuStartDiscovery(), the state will change to CardemuDiscover until the discovery is finished. Then it will change to either CardemuDiscoverReady if it worked or to CardemuDiscoverError if it didn't.

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

The following constants are available for this function:

  • BrickletNFC.CARDEMU_STATE_INITIALIZATION = 0
  • BrickletNFC.CARDEMU_STATE_IDLE = 128
  • BrickletNFC.CARDEMU_STATE_ERROR = 192
  • BrickletNFC.CARDEMU_STATE_DISCOVER = 2
  • BrickletNFC.CARDEMU_STATE_DISCOVER_READY = 130
  • BrickletNFC.CARDEMU_STATE_DISCOVER_ERROR = 194
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF = 3
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF_READY = 131
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF_ERROR = 195

The returned object has the public member variables int state and boolean idle.

public void cardemuStartDiscovery()

Starts the discovery process. If you call this function while a NFC reader device is near to the NFC Bricklet the state will change from CardemuDiscovery to CardemuDiscoveryReady.

If no NFC reader device can be found or if there is an error during discovery the cardemu state will change to CardemuDiscoveryError. In this case you have to restart the discovery process.

If the cardemu state changes to CardemuDiscoveryReady you can start the NDEF message transfer with cardemuWriteNDEF() and cardemuStartTransfer().

public void cardemuWriteNDEF(int[] ndef)

Writes the NDEF messages that is to be transferred to the NFC peer.

The maximum supported NDEF message size in Cardemu mode is 255 byte.

You can call this function at any time in Cardemu mode. The internal buffer will not be overwritten until you call this function again or change the mode.

public void cardemuStartTransfer(int transfer)

You can start the transfer of a NDEF message if the cardemu state is CardemuDiscoveryReady.

Before you call this function to start a write transfer, the NDEF message that is to be transferred has to be written via cardemuWriteNDEF() first.

After you call this function the state will change to CardemuTransferNDEF. It will change to CardemuTransferNDEFReady if the transfer was successful or CardemuTransferNDEFError if it wasn't.

The following constants are available for this function:

  • BrickletNFC.CARDEMU_TRANSFER_ABORT = 0
  • BrickletNFC.CARDEMU_TRANSFER_WRITE = 1
public BrickletNFC.P2PGetState p2pGetState()

Returns the current P2P state of the NFC Bricklet.

On startup the Bricklet will be in the P2PInitialization state. The initialization will only take about 20ms. After that it changes to P2PIdle.

The Bricklet is also reinitialized if the mode is changed, see setMode().

The functions of this Bricklet can be called in the P2PIdle state and all of the P2PReady and P2PError states.

Example: If you call p2pStartDiscovery(), the state will change to P2PDiscover until the discovery is finished. Then it will change to either P2PDiscoverReady* if it worked or to P2PDiscoverError if it didn't.

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

The following constants are available for this function:

  • BrickletNFC.P2P_STATE_INITIALIZATION = 0
  • BrickletNFC.P2P_STATE_IDLE = 128
  • BrickletNFC.P2P_STATE_ERROR = 192
  • BrickletNFC.P2P_STATE_DISCOVER = 2
  • BrickletNFC.P2P_STATE_DISCOVER_READY = 130
  • BrickletNFC.P2P_STATE_DISCOVER_ERROR = 194
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF = 3
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF_READY = 131
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF_ERROR = 195

The returned object has the public member variables int state and boolean idle.

public void p2pStartDiscovery()

Starts the discovery process. If you call this function while another NFC P2P enabled device is near to the NFC Bricklet the state will change from P2PDiscovery to P2PDiscoveryReady.

If no NFC P2P enabled device can be found or if there is an error during discovery the P2P state will change to P2PDiscoveryError. In this case you have to restart the discovery process.

If the P2P state changes to P2PDiscoveryReady you can start the NDEF message transfer with p2pStartTransfer().

public void p2pWriteNDEF(int[] ndef)

Writes the NDEF messages that is to be transferred to the NFC peer.

The maximum supported NDEF message size for P2P transfer is 255 byte.

You can call this function at any time in P2P mode. The internal buffer will not be overwritten until you call this function again, change the mode or use P2P to read an NDEF messages.

public void p2pStartTransfer(int transfer)

You can start the transfer of a NDEF message if the P2P state is P2PDiscoveryReady.

Before you call this function to start a write transfer, the NDEF message that is to be transferred has to be written via p2pWriteNDEF() first.

After you call this function the P2P state will change to P2PTransferNDEF. It will change to P2PTransferNDEFReady if the transfer was successfull or P2PTransferNDEFError if it wasn't.

If you started a write transfer you are now done. If you started a read transfer you can now use p2pReadNDEF() to read the NDEF message that was written by the NFC peer.

The following constants are available for this function:

  • BrickletNFC.P2P_TRANSFER_ABORT = 0
  • BrickletNFC.P2P_TRANSFER_WRITE = 1
  • BrickletNFC.P2P_TRANSFER_READ = 2
public int[] p2pReadNDEF()

Returns the NDEF message that was written by a NFC peer in NFC P2P mode. The maximum NDEF length is 8192 byte.

The NDEF message is ready if you called p2pStartTransfer() with a read transfer and the P2P state changed to P2PTransferNDEFReady.

Advanced Functions

public void setDetectionLEDConfig(int config)

Sets the detection LED configuration. By default the LED shows if a card/reader is detected.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

  • BrickletNFC.DETECTION_LED_CONFIG_OFF = 0
  • BrickletNFC.DETECTION_LED_CONFIG_ON = 1
  • BrickletNFC.DETECTION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletNFC.DETECTION_LED_CONFIG_SHOW_DETECTION = 3
public int getDetectionLEDConfig()

Returns the configuration as set by setDetectionLEDConfig()

The following constants are available for this function:

  • BrickletNFC.DETECTION_LED_CONFIG_OFF = 0
  • BrickletNFC.DETECTION_LED_CONFIG_ON = 1
  • BrickletNFC.DETECTION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletNFC.DETECTION_LED_CONFIG_SHOW_DETECTION = 3
public void setMaximumTimeout(int timeout)

Sets the maximum timeout in ms.

This is a global maximum used for all internal state timeouts. The timeouts depend heavily on the used tags etc. For example: If you use a Type 2 tag and you want to detect if it is present, you have to use readerRequestTagID() and wait for the state to change to either the error state or the ready state.

With the default configuration this takes 2-3 seconds. By setting the maximum timeout to 100ms you can reduce this time to ~150-200ms. For Type 2 this would also still work with a 20ms timeout (a Type 2 tag answers usually within 10ms). A type 4 tag can take up to 500ms in our tests.

If you need a fast response time to discover if a tag is present or not you can find a good timeout value by trial and error for your specific tag.

By default we use a very conservative timeout, to be sure that any Tag can always answer in time.

Default timeout: 2000ms.

New in version 2.0.1 (Plugin).

public int getMaximumTimeout()

Returns the timeout as set by setMaximumTimeout()

New in version 2.0.1 (Plugin).

public int[] 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.

public boolean getResponseExpected(int functionId)

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 listener configuration functions it is enabled by default too, but can be disabled by 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 setResponseExpected() for the list of function ID constants available for this function.

public void setResponseExpected(int functionId, boolean responseExpected)

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 listener 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:

  • BrickletNFC.FUNCTION_SET_MODE = 1
  • BrickletNFC.FUNCTION_READER_REQUEST_TAG_ID = 3
  • BrickletNFC.FUNCTION_READER_WRITE_NDEF = 6
  • BrickletNFC.FUNCTION_READER_REQUEST_NDEF = 7
  • BrickletNFC.FUNCTION_READER_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 9
  • BrickletNFC.FUNCTION_READER_WRITE_PAGE = 10
  • BrickletNFC.FUNCTION_READER_REQUEST_PAGE = 11
  • BrickletNFC.FUNCTION_CARDEMU_START_DISCOVERY = 15
  • BrickletNFC.FUNCTION_CARDEMU_WRITE_NDEF = 16
  • BrickletNFC.FUNCTION_CARDEMU_START_TRANSFER = 17
  • BrickletNFC.FUNCTION_P2P_START_DISCOVERY = 20
  • BrickletNFC.FUNCTION_P2P_WRITE_NDEF = 21
  • BrickletNFC.FUNCTION_P2P_START_TRANSFER = 22
  • BrickletNFC.FUNCTION_SET_DETECTION_LED_CONFIG = 25
  • BrickletNFC.FUNCTION_SET_MAXIMUM_TIMEOUT = 27
  • BrickletNFC.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletNFC.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletNFC.FUNCTION_RESET = 243
  • BrickletNFC.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletNFC.SPITFPErrorCount getSPITFPErrorCount()

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned object has the public member variables long errorCountAckChecksum, long errorCountMessageChecksum, long errorCountFrame and long errorCountOverflow.

public int setBootloaderMode(int mode)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletNFC.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletNFC.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletNFC.BOOTLOADER_STATUS_OK = 0
  • BrickletNFC.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletNFC.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletNFC.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletNFC.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletNFC.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletNFC.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletNFC.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletNFC.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
public void setWriteFirmwarePointer(long pointer)

Sets the firmware pointer for writeFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public int writeFirmware(int[] data)

Writes 64 Bytes of firmware at the position as written by setWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public void setStatusLEDConfig(int config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletNFC.STATUS_LED_CONFIG_OFF = 0
  • BrickletNFC.STATUS_LED_CONFIG_ON = 1
  • BrickletNFC.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletNFC.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletNFC.STATUS_LED_CONFIG_OFF = 0
  • BrickletNFC.STATUS_LED_CONFIG_ON = 1
  • BrickletNFC.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletNFC.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getChipTemperature()

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

public void reset()

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

public void writeUID(long uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

public long readUID()

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

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

The returned object has the public member variables String uid, String connectedUid, char position, int[] hardwareVersion, int[] firmwareVersion and int deviceIdentifier.

Listeners

Listeners can be registered to receive time critical or recurring data from the device. The registration is done with "add*Listener" functions of the device object.

The parameter is a listener class object, for example:

device.addExampleListener(new BrickletNFC.ExampleListener() {
    public void property(int value) {
        System.out.println("Value: " + value);
    }
});

The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding "remove*Listener" function.

Note

Using listeners 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.

public class BrickletNFC.ReaderStateChangedListener()

This listener can be added with the addReaderStateChangedListener() function. An added listener can be removed with the removeReaderStateChangedListener() function.

public void readerStateChanged(int state, boolean idle)

This listener is called if the reader state of the NFC Bricklet changes. See readerGetState() for more information about the possible states.

The following constants are available for this function:

  • BrickletNFC.READER_STATE_INITIALIZATION = 0
  • BrickletNFC.READER_STATE_IDLE = 128
  • BrickletNFC.READER_STATE_ERROR = 192
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID = 2
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID_READY = 130
  • BrickletNFC.READER_STATE_REQUEST_TAG_ID_ERROR = 194
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 3
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE_READY = 131
  • BrickletNFC.READER_STATE_AUTHENTICATE_MIFARE_CLASSIC_PAGE_ERROR = 195
  • BrickletNFC.READER_STATE_WRITE_PAGE = 4
  • BrickletNFC.READER_STATE_WRITE_PAGE_READY = 132
  • BrickletNFC.READER_STATE_WRITE_PAGE_ERROR = 196
  • BrickletNFC.READER_STATE_REQUEST_PAGE = 5
  • BrickletNFC.READER_STATE_REQUEST_PAGE_READY = 133
  • BrickletNFC.READER_STATE_REQUEST_PAGE_ERROR = 197
  • BrickletNFC.READER_STATE_WRITE_NDEF = 6
  • BrickletNFC.READER_STATE_WRITE_NDEF_READY = 134
  • BrickletNFC.READER_STATE_WRITE_NDEF_ERROR = 198
  • BrickletNFC.READER_STATE_REQUEST_NDEF = 7
  • BrickletNFC.READER_STATE_REQUEST_NDEF_READY = 135
  • BrickletNFC.READER_STATE_REQUEST_NDEF_ERROR = 199
public class BrickletNFC.CardemuStateChangedListener()

This listener can be added with the addCardemuStateChangedListener() function. An added listener can be removed with the removeCardemuStateChangedListener() function.

public void cardemuStateChanged(int state, boolean idle)

This listener is called if the cardemu state of the NFC Bricklet changes. See cardemuGetState() for more information about the possible states.

The following constants are available for this function:

  • BrickletNFC.CARDEMU_STATE_INITIALIZATION = 0
  • BrickletNFC.CARDEMU_STATE_IDLE = 128
  • BrickletNFC.CARDEMU_STATE_ERROR = 192
  • BrickletNFC.CARDEMU_STATE_DISCOVER = 2
  • BrickletNFC.CARDEMU_STATE_DISCOVER_READY = 130
  • BrickletNFC.CARDEMU_STATE_DISCOVER_ERROR = 194
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF = 3
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF_READY = 131
  • BrickletNFC.CARDEMU_STATE_TRANSFER_NDEF_ERROR = 195
public class BrickletNFC.P2PStateChangedListener()

This listener can be added with the addP2PStateChangedListener() function. An added listener can be removed with the removeP2PStateChangedListener() function.

public void p2pStateChanged(int state, boolean idle)

This listener is called if the P2P state of the NFC Bricklet changes. See p2pGetState() for more information about the possible states.

The following constants are available for this function:

  • BrickletNFC.P2P_STATE_INITIALIZATION = 0
  • BrickletNFC.P2P_STATE_IDLE = 128
  • BrickletNFC.P2P_STATE_ERROR = 192
  • BrickletNFC.P2P_STATE_DISCOVER = 2
  • BrickletNFC.P2P_STATE_DISCOVER_READY = 130
  • BrickletNFC.P2P_STATE_DISCOVER_ERROR = 194
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF = 3
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF_READY = 131
  • BrickletNFC.P2P_STATE_TRANSFER_NDEF_ERROR = 195

Constants

public static final int BrickletNFC.DEVICE_IDENTIFIER

This constant is used to identify a NFC Bricklet.

The getIdentity() function and the EnumerateListener listener of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

public static final String BrickletNFC.DEVICE_DISPLAY_NAME

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