Delphi/Lazarus - NFC/RFID Bricklet¶

Scan For Tags¶

Download (ExampleScanForTags.pas)

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program ExampleScanForTags;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletNFCRFID;

type
  TExample = class
  private
    ipcon: TIPConnection;
    nr: TBrickletNFCRFID;
    currentTagType: byte;
  public
    procedure StateChangedCB(sender: TBrickletNFCRFID; const state: byte;
                             const idle: boolean);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your NFC/RFID Bricklet }

var
  e: TExample;

{ Callback procedure for state changed callback }
procedure TExample.StateChangedCB(sender: TBrickletNFCRFID; const state: byte;
                                  const idle: boolean);
  var tagType: byte;
  var tidLength: byte;
  var tid: {$ifdef FPC}array [0..6] of byte{$else}TArray0To6OfUInt8{$endif};
  var s: string;
  var i: byte;
begin
  if state = BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_READY then begin
    sender.GetTagID(tagType, tidLength, tid);
    s := 'Found tag of type ' + IntToStr(tagType);
    s := s + ' with ID [' + IntToHex(tid[0], 2);
    for i := 1 to (tidLength - 1) do begin
      s := s + ' ' + IntToHex(tid[i], 2);
    end;
    s := s + ']';
    WriteLn(s);
  end;

  { Cycle through all types }
  if idle then begin
    currentTagType := (currentTagType + 1) mod 3;
    sender.RequestTagID(currentTagType);
  end;
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  nr := TBrickletNFCRFID.Create(UID, ipcon);

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

  { Register state changed callback to procedure StateChangedCB }
  nr.OnStateChanged := {$ifdef FPC}@{$endif}StateChangedCB;

  { Start scan loop }
  currentTagType := BRICKLET_NFC_RFID_TAG_TYPE_MIFARE_CLASSIC;
  nr.RequestTagID(currentTagType);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Write Read Type 2¶

Download (ExampleWriteReadType2.pas)

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program ExampleWriteReadType2;

{$ifdef MSWINDOWS}{$apptype CONSOLE}{$endif}
{$ifdef FPC}{$mode OBJFPC}{$H+}{$endif}

uses
  SysUtils, IPConnection, BrickletNFCRFID;

type
  TExample = class
  private
    ipcon: TIPConnection;
    nr: TBrickletNFCRFID;
  public
    procedure StateChangedCB(sender: TBrickletNFCRFID; const state: byte;
                             const idle: boolean);
    procedure Execute;
  end;

const
  HOST = 'localhost';
  PORT = 4223;
  UID = 'XYZ'; { Change XYZ to the UID of your NFC/RFID Bricklet }

var
  e: TExample;

{ Callback procedure for state changed callback }
procedure TExample.StateChangedCB(sender: TBrickletNFCRFID; const state: byte;
                                  const idle: boolean);
  const dataWrite: {$ifdef FPC}array [0..15] of byte{$else}TArray0To15OfUInt8{$endif} =
    (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
  var s: String;
  var dataRead: {$ifdef FPC}array [0..15] of byte{$else}TArray0To15OfUInt8{$endif};
  var i: byte;
begin
  if state = BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_READY then begin
    { Write 16 byte to pages 5-8 }
    WriteLn('Tag found');
    sender.WritePage(5, dataWrite);
    WriteLn('Writing data...');
  end
  else if state = BRICKLET_NFC_RFID_STATE_WRITE_PAGE_READY then begin
    { Request pages 5-8 }
    sender.RequestPage(5);
    WriteLn('Requesting data...');
  end
  else if state = BRICKLET_NFC_RFID_STATE_REQUEST_PAGE_READY then begin
    { Get and print pages }
    dataRead := sender.GetPage();
    s := 'Read data: [' + IntToStr(dataRead[0]);
    for i:= 1 to 15 do begin
      s := s + ' ' + IntToStr(dataRead[i]);
    end;
    s := s + ']';
    WriteLn(s);
  end
  else if (state And (1 Shl 6)) = (1 Shl 6) then begin
    WriteLn('Error: ' + IntToStr(state));
  end;
end;

procedure TExample.Execute;
begin
  { Create IP connection }
  ipcon := TIPConnection.Create;

  { Create device object }
  nr := TBrickletNFCRFID.Create(UID, ipcon);

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

  { Register state changed callback to procedure StateChangedCB }
  nr.OnStateChanged := {$ifdef FPC}@{$endif}StateChangedCB;

  { Select NFC Forum Type 2 tag }
  nr.RequestTagID(BRICKLET_NFC_RFID_TAG_TYPE_TYPE2);

  WriteLn('Press key to exit');
  ReadLn;
  ipcon.Destroy; { Calls ipcon.Disconnect internally }
end;

begin
  e := TExample.Create;
  e.Execute;
  e.Destroy;
end.

Basic Functions¶

constructor TBrickletNFCRFID.Create(const uid: string; ipcon: TIPConnection)¶

Parameters:	uid – Type: string ipcon – Type: TIPConnection
Returns:	nfcRFID – Type: TBrickletNFCRFID

Creates an object with the unique device ID uid:

nfcRFID := TBrickletNFCRFID.Create('YOUR_DEVICE_UID', ipcon);

This object can then be used after the IP Connection is connected.

procedure TBrickletNFCRFID.RequestTagID(const tagType: byte)¶

Parameters:	tagType – Type: byte, Range: See constants

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 RequestTagID 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 OnStateChanged callback or you can poll GetState 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 GetTagID.

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 RequestTagID 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 RequestTagID.

The following constants are available for this function:

For tagType:

• BRICKLET_NFC_RFID_TAG_TYPE_MIFARE_CLASSIC = 0
• BRICKLET_NFC_RFID_TAG_TYPE_TYPE1 = 1
• BRICKLET_NFC_RFID_TAG_TYPE_TYPE2 = 2

procedure TBrickletNFCRFID.GetTagID(out tagType: byte; out tidLength: byte; out tid: array [0..6] of byte)¶

Output Parameters:	tagType – Type: byte, Range: See constants tidLength – Type: byte, Range: [4, 7] tid – Type: array [0..6] of byte, Range: [0 to 255]

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 RequestTagID.

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

1. Call RequestTagID
2. Wait for state to change to RequestTagIDReady (see GetState or OnStateChanged callback)
3. Call GetTagID

The following constants are available for this function:

For tagType:

• BRICKLET_NFC_RFID_TAG_TYPE_MIFARE_CLASSIC = 0
• BRICKLET_NFC_RFID_TAG_TYPE_TYPE1 = 1
• BRICKLET_NFC_RFID_TAG_TYPE_TYPE2 = 2

procedure TBrickletNFCRFID.GetState(out state: byte; out idle: boolean)¶

Output Parameters:	state – Type: byte, Range: See constants idle – Type: boolean

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 RequestPage, 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 GetPage.

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

The following constants are available for this function:

For state:

• BRICKLET_NFC_RFID_STATE_INITIALIZATION = 0
• BRICKLET_NFC_RFID_STATE_IDLE = 128
• BRICKLET_NFC_RFID_STATE_ERROR = 192
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID = 2
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_READY = 130
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_ERROR = 194
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE = 4
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE_READY = 132
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE_ERROR = 196
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE = 5
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE_READY = 133
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE_ERROR = 197

procedure TBrickletNFCRFID.AuthenticateMifareClassicPage(const page: word; const keyNumber: byte; const key: array [0..5] of byte)¶

Parameters:	page – Type: word, Range: [0 to 216 - 1] keyNumber – Type: byte, Range: See constants key – Type: array [0..5] of byte, Range: [0 to 255]

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 RequestTagID
2. Wait for state to change to RequestTagIDReady (see GetState or OnStateChanged callback)
3. If looking for a specific tag then call GetTagID and check if the expected tag was found, if it was not found go back to step 1
4. Call AuthenticateMifareClassicPage with page and key for the page
5. Wait for state to change to AuthenticatingMifareClassicPageReady (see GetState or OnStateChanged callback)
6. Call RequestPage or WritePage to read/write page

The following constants are available for this function:

For keyNumber:

• BRICKLET_NFC_RFID_KEY_A = 0
• BRICKLET_NFC_RFID_KEY_B = 1

procedure TBrickletNFCRFID.WritePage(const page: word; const data: array [0..15] of byte)¶

Parameters:	page – Type: word, Range: [0 to 216 - 1] data – Type: array [0..15] of byte, Range: [0 to 255]

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 RequestTagID
2. Wait for state to change to RequestTagIDReady (see GetState or OnStateChanged callback)
3. If looking for a specific tag then call GetTagID and check if the expected tag was found, if it was not found got back to step 1
4. Call WritePage with page number and data
5. Wait for state to change to WritePageReady (see GetState or OnStateChanged callback)

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

procedure TBrickletNFCRFID.RequestPage(const page: word)¶

Parameters:	page – Type: word, Range: [0 to 216 - 1]

Reads 16 bytes starting from the given page and stores them into a buffer. The buffer can then be read out with GetPage. 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 RequestTagID
2. Wait for state to change to RequestTagIDReady (see GetState or OnStateChanged callback)
3. If looking for a specific tag then call GetTagID and check if the expected tag was found, if it was not found got back to step 1
4. Call RequestPage with page number
5. Wait for state to change to RequestPageReady (see GetState or OnStateChanged callback)
6. Call GetPage 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 AuthenticateMifareClassicPage.

function TBrickletNFCRFID.GetPage: array [0..15] of byte¶

Returns:	data – Type: array [0..15] of byte, Range: [0 to 255]

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

Advanced Functions¶

procedure TBrickletNFCRFID.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)¶

Output Parameters:

uid – Type: string, Length: up to 8 connectedUid – Type: string, Length: up to 8 position – Type: char, Range: ['a' to 'h', 'z'] hardwareVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] firmwareVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255] deviceIdentifier – Type: word, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

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 by assigning a procedure to an callback property of the device object:

procedure TExample.MyCallback(sender: TBrickletNFCRFID; const value: longint);
begin
  WriteLn(Format('Value: %d', [value]));
end;

nfcRFID.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback properties and their parameter types are described below.

property TBrickletNFCRFID.OnStateChanged¶

procedure(sender: TBrickletNFCRFID; const state: byte; const idle: boolean) of object;

Callback Parameters:	sender – Type: TBrickletNFCRFID state – Type: byte, Range: See constants idle – Type: boolean

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

The following constants are available for this function:

For state:

• BRICKLET_NFC_RFID_STATE_INITIALIZATION = 0
• BRICKLET_NFC_RFID_STATE_IDLE = 128
• BRICKLET_NFC_RFID_STATE_ERROR = 192
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID = 2
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_READY = 130
• BRICKLET_NFC_RFID_STATE_REQUEST_TAG_ID_ERROR = 194
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE = 3
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_READY = 131
• BRICKLET_NFC_RFID_STATE_AUTHENTICATING_MIFARE_CLASSIC_PAGE_ERROR = 195
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE = 4
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE_READY = 132
• BRICKLET_NFC_RFID_STATE_WRITE_PAGE_ERROR = 196
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE = 5
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE_READY = 133
• BRICKLET_NFC_RFID_STATE_REQUEST_PAGE_ERROR = 197

Virtual Functions¶

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

function TBrickletNFCRFID.GetAPIVersion: array [0..2] of byte¶

Output Parameters:	apiVersion – Type: array [0..2] of byte 0: major – Type: byte, Range: [0 to 255] 1: minor – Type: byte, Range: [0 to 255] 2: revision – Type: byte, Range: [0 to 255]

Returns the version of the API definition 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.

function TBrickletNFCRFID.GetResponseExpected(const functionId: byte): boolean¶

Parameters:	functionId – Type: byte, Range: See constants
Returns:	responseExpected – Type: boolean

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 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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

• BRICKLET_NFC_RFID_FUNCTION_REQUEST_TAG_ID = 1
• BRICKLET_NFC_RFID_FUNCTION_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 4
• BRICKLET_NFC_RFID_FUNCTION_WRITE_PAGE = 5
• BRICKLET_NFC_RFID_FUNCTION_REQUEST_PAGE = 6

procedure TBrickletNFCRFID.SetResponseExpected(const functionId: byte; const responseExpected: boolean)¶

Parameters:	functionId – Type: byte, Range: See constants responseExpected – Type: boolean

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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

• BRICKLET_NFC_RFID_FUNCTION_REQUEST_TAG_ID = 1
• BRICKLET_NFC_RFID_FUNCTION_AUTHENTICATE_MIFARE_CLASSIC_PAGE = 4
• BRICKLET_NFC_RFID_FUNCTION_WRITE_PAGE = 5
• BRICKLET_NFC_RFID_FUNCTION_REQUEST_PAGE = 6

procedure TBrickletNFCRFID.SetResponseExpectedAll(const responseExpected: boolean)¶

Parameters:	responseExpected – Type: boolean

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

Constants¶

const BRICKLET_NFC_RFID_DEVICE_IDENTIFIER¶

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

The GetIdentity function and the TIPConnection.OnEnumerate callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

const BRICKLET_NFC_RFID_DEVICE_DISPLAY_NAME¶

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