go-api-bindings: github.com/Tinkerforge/go-api-bindings/nfc_rfid_bricklet Index | Files

package nfc_rfid_bricklet

import "github.com/Tinkerforge/go-api-bindings/nfc_rfid_bricklet"

Reads and writes NFC and RFID tags.

See also the documentation here: https://www.tinkerforge.com/en/doc/Software/Bricklets/NFCRFID_Bricklet_Go.html.

Index

Package Files

nfc_rfid_bricklet.go

Constants

const DeviceDisplayName = "NFC/RFID Bricklet"
const DeviceIdentifier = 246

type Function Uses

type Function = uint8
const (
    FunctionRequestTagID                  Function = 1
    FunctionGetTagID                      Function = 2
    FunctionGetState                      Function = 3
    FunctionAuthenticateMifareClassicPage Function = 4
    FunctionWritePage                     Function = 5
    FunctionRequestPage                   Function = 6
    FunctionGetPage                       Function = 7
    FunctionGetIdentity                   Function = 255
    FunctionCallbackStateChanged          Function = 8
)

type Key Uses

type Key = uint8
const (
    KeyA Key = 0
    KeyB Key = 1
)

type NFCRFIDBricklet Uses

type NFCRFIDBricklet struct {
    // contains filtered or unexported fields
}

func New Uses

func New(uid string, ipcon *ipconnection.IPConnection) (NFCRFIDBricklet, error)

Creates an object with the unique device ID `uid`. This object can then be used after the IP Connection `ipcon` is connected.

func (*NFCRFIDBricklet) AuthenticateMifareClassicPage Uses

func (device *NFCRFIDBricklet) AuthenticateMifareClassicPage(page uint16, keyNumber Key, key [6]uint8) (err error)

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 RegisterStateChangedCallback 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 RegisterStateChangedCallback callback)

6. Call RequestPage or WritePage to read/write page

Associated constants:

* KeyA
* KeyB

func (*NFCRFIDBricklet) DeregisterStateChangedCallback Uses

func (device *NFCRFIDBricklet) DeregisterStateChangedCallback(registrationId uint64)

Remove a registered State Changed callback.

func (*NFCRFIDBricklet) GetAPIVersion Uses

func (device *NFCRFIDBricklet) GetAPIVersion() [3]uint8

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.

func (*NFCRFIDBricklet) GetIdentity Uses

func (device *NFCRFIDBricklet) GetIdentity() (uid string, connectedUid string, position rune, hardwareVersion [3]uint8, firmwareVersion [3]uint8, deviceIdentifier uint16, err error)

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). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an `Isolator Bricklet <isolator_bricklet>` is always as position 'z'.

The device identifier numbers can be found `here <device_identifier>`. |device_identifier_constant|

func (*NFCRFIDBricklet) GetPage Uses

func (device *NFCRFIDBricklet) GetPage() (data [16]uint8, err error)

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

func (*NFCRFIDBricklet) GetResponseExpected Uses

func (device *NFCRFIDBricklet) GetResponseExpected(functionID Function) (bool, error)

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.

See SetResponseExpected for the list of function ID constants available for this function.

func (*NFCRFIDBricklet) GetState Uses

func (device *NFCRFIDBricklet) GetState() (state State, idle bool, err error)

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.

Associated constants:

* StateInitialization
* StateIdle
* StateError
* StateRequestTagID
* StateRequestTagIDReady
* StateRequestTagIDError
* StateAuthenticatingMifareClassicPage
* StateAuthenticatingMifareClassicPageReady
* StateAuthenticatingMifareClassicPageError
* StateWritePage
* StateWritePageReady
* StateWritePageError
* StateRequestPage
* StateRequestPageReady
* StateRequestPageError

func (*NFCRFIDBricklet) GetTagID Uses

func (device *NFCRFIDBricklet) GetTagID() (tagType TagType, tidLength uint8, tid [7]uint8, err error)

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

RegisterStateChangedCallback callback)

3. Call GetTagID

Associated constants:

* TagTypeMifareClassic
* TagTypeType1
* TagTypeType2

func (*NFCRFIDBricklet) RegisterStateChangedCallback Uses

func (device *NFCRFIDBricklet) RegisterStateChangedCallback(fn func(State, bool)) uint64

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

func (*NFCRFIDBricklet) RequestPage Uses

func (device *NFCRFIDBricklet) RequestPage(page uint16) (err error)

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 RegisterStateChangedCallback 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 RegisterStateChangedCallback 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.

func (*NFCRFIDBricklet) RequestTagID Uses

func (device *NFCRFIDBricklet) RequestTagID(tagType TagType) (err error)

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 RegisterStateChangedCallback 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.

Associated constants:

* TagTypeMifareClassic
* TagTypeType1
* TagTypeType2

func (*NFCRFIDBricklet) SetResponseExpected Uses

func (device *NFCRFIDBricklet) SetResponseExpected(functionID Function, responseExpected bool) error

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.

func (*NFCRFIDBricklet) SetResponseExpectedAll Uses

func (device *NFCRFIDBricklet) SetResponseExpectedAll(responseExpected bool)

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

func (*NFCRFIDBricklet) WritePage Uses

func (device *NFCRFIDBricklet) WritePage(page uint16, data [16]uint8) (err error)

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

RegisterStateChangedCallback 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

RegisterStateChangedCallback callback)

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

type State Uses

type State = uint8
const (
    StateInitialization                       State = 0
    StateIdle                                 State = 128
    StateError                                State = 192
    StateRequestTagID                         State = 2
    StateRequestTagIDReady                    State = 130
    StateRequestTagIDError                    State = 194
    StateAuthenticatingMifareClassicPage      State = 3
    StateAuthenticatingMifareClassicPageReady State = 131
    StateAuthenticatingMifareClassicPageError State = 195
    StateWritePage                            State = 4
    StateWritePageReady                       State = 132
    StateWritePageError                       State = 196
    StateRequestPage                          State = 5
    StateRequestPageReady                     State = 133
    StateRequestPageError                     State = 197
)

type TagType Uses

type TagType = uint8
const (
    TagTypeMifareClassic TagType = 0
    TagTypeType1         TagType = 1
    TagTypeType2         TagType = 2
)

Package nfc_rfid_bricklet imports 5 packages (graph). Updated 2020-05-29. Refresh now. Tools for package owners.