Python module for near field communication¶

Options¶

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--wait¶

After reading or writing a tag wait until it is removed before returning. This option is implicit when the option --loop is set. Only relevant for reader/writer mode.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

Commands¶

Available commands are listed below. The default if no command is specified is to invoke tagtool.py show.

$ tagtool.py [options] show [-h] [-v]

$ tagtool.py [options] dump [-h] [-o FILE]

$ tagtool.py [options] load [-h] FILE

$ tagtool.py [options] format [-h] {tt1,tt3} ...

$ tagtool.py [options] format tt1 [-h]

$ tagtool.py [options] format tt3 [-h] [--ver STR] [--nbr INT] [--nbw INT]
                                  [--max INT] [--rfu INT] [--wf INT]
                                  [--rw INT] [--len INT] [--crc INT]

$ tagtool.py emulate [-h] [-l] [-k] [-s SIZE] [-p FILE] [FILE] {tt3} ...

$ tagtool.py [options] emulate [options] tt3 [-h] [--idm HEX] [--pmm HEX]
                                             [--sys HEX] [--bitrate {212,424}]

Examples¶

Copy NDEF from one tag to another:

$ tagtool.py dump -o /tmp/tag.ndef && tagtool load /tmp/tag.ndef

Copy NDEF from one tag to many others:

$ tagtool.py dump -o /tmp/tag.ndef && tagtool --loop load /tmp/tag.ndef

Options¶

-v¶

Print informational messages.

-d¶

Print debug information.

Commands¶

$ ndeftool.py print [-h|--help] [message]

$ ndeftool.py make smartposter [-h|--help] [options] reference

$ ndeftool.py make wificfg [-h|--help] [options] network-name

$ ndeftool.py make wificfg [-h|--help] [options] public-key-file

$ ndeftool.py make btcfg [-h|--help] [options] device-address

$ ndeftool.py pack [-h|--help] [options] FILE

$ ndeftool.py split [-h|--help] [options] message-file

$ ndeftool.py cat [-h|--help] record-file [record-file ...]

Examples¶

To build a smartposter that points to the nfcpy documentation page:

$ ndeftool.py make smartposter http://nfcpy.org/docs
d102135370d1010f55036e666370792e6f72672f646f6373

The output can be made readable with the ndeftool print command:

$ ndeftool.py make smartposter http://nfcpy.org/docs | ndeftool.py print
Smartposter Record
  resource = http://nfcpy.org/docs
  action   = default

To get the smartposter as raw bytes specify an output file:

$ ndeftool.py make smartposter http://nfcpy.org/docs -o sp_nfcpy_docs.ndef

Here’s a more complex example setting multi-language smartposter title, icons and a non-default action:

$ ndeftool.py make smartposter http://nfcpy.org/docs -t "nfcpy documentation" -t "de:nfcpy Dokumentation" -i logo.gif -i logo.png -a save -o sp_nfcpy_docs.ndef

It is sometimes helpful to have an NDEF message of specific length where the payload consists of monotonically increasing byte values:

$ python -c "import sys; sys.stdout.write(bytearray([x % 256 for x in xrange(1024-6)]))" | ndeftool.py pack - -o message-1k.ndef

Options¶

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

Commands¶

$ beam.py send [--timeit] {link,text,file,ndef} [-h] [OPTIONS]

$ beam.py send link URI [TITLE]

$ beam.py send text TEXT [OPTIONS]

$ beam.py send file FILE [OPTIONS]

$ beam.py send ndef FILE [OPTIONS]

$ beam.py [OPTIONS] recv {print,save,echo,send} [-h] [OPTIONS]

$ beam.py recv print

$ beam.py recv save FILE

$ beam.py recv echo

$ beam.py [OPTIONS] recv send [-h] TRANSLATIONS

Examples¶

Get a smartphone to open the nfcpy project page (which in fact just points to the code repository and documentation).

$ beam.py send link http://nfcpy.org "nfcpy project home"

Send the source file beam.py. On an Android phone this should pop up the “new tag collected” screen and show that a text/x-python media type has been received.

$ beam.py send file beam.py

The file beam.py is about 11 KB and may take some time to transfer, depending on the phone hardware and software. With a Google Nexus 10 it takes as little as 500 milliseconds while a Nexus 4 won’t do it under 2.5 seconds.

$ beam.py send --timeit file beam.py

Receive a single NDEF message from the peer device and save it to message.ndef (note that if message.ndef exists the received data will be appended):

$ beam.py recv save message.ndef

With the --loop option it gets easy to collect messages into a single file.

$ beam.py --loop recv save collected.ndef

A file that contains a sequence of request/response message pairs can be used to send a specific response message whenever the associated request message was received.

$ echo -n "this is a request message" > request.txt
$ ndeftool.py pack -n '' request.txt -o request.ndef
$ echo -n "this is my reponse message" > response.txt
$ ndeftool.py pack -n '' response.txt -o response.ndef
$ cat request.ndef response.ndef > translation.ndef
$ beam.py recv send translation.ndef

llcp-test-server.py¶

The LLCP test server program implements an NFC device that provides three distinct server applications:

1. A connection-less echo server that accepts connection-less transport mode PDUs. Service data units may have any size between zero and the maximum information unit size announced with the LLCP Link MIU parameter. Inbound service data units enter a linear buffer of service data units. The buffer has a capacity of two service data units. The first service data unit entering the buffer starts a delay timer of 2 seconds (echo delay). Expiration of the delay timer causes service data units in the buffer to be sent back to the original sender, which may be different for each service data unit, until the buffer is completely emptied. The buffer empty condition then re-enables the delay timer start event for the next service data unit.

2. A connection-mode echo server that waits for a connect request and then accepts and processes connection-oriented transport mode PDUs. Further connect requests will be rejected until termination of the data link connection. When accepting the connect request, the receive window parameter is transmitted with a value of 2.

   The connection-oriented mode echo service stores inbound service data units in a linear buffer of service data units. The buffer has a capacity of three service data units. The first service data unit entering the buffer starts a delay timer of 2 seconds (echo delay). Expiration of the delay timer causes service data units in the buffer to be sent back to the orignal sender until the buffer is completely emptied. The buffer empty condition then re-enables the delay timer start event for the next service data unit.

   The echo service determines itself as busy if it is unable to accept further incoming service data units.

3. A connection-mode dump server that accepts connections and then accepts and forgets all data received on a data link connection. This is mostly useful to measure transfer speed under load conditions.

Usage

$ llcp-test-server.py [-h|--help] [OPTION]...

Options

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

llcp-test-client.py¶

Usage

$ llcp-test-client.py [-h|--help] [OPTION]...

Options

-t N, --test N¶

Run test number N. May be set more than once.

-T, --test-all¶

Run all tests.

--cl-echo SAP¶

Service access point address of the connection-less mode echo server.

--co-echo SAP¶

Service access point address of the connection-oriented mode echo server.

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

$ llcp-test-client.py -t 1

$ llcp-test-client.py -t 2

$ llcp-test-client.py -t 3

$ llcp-test-client.py -t 4

$ llcp-test-client.py -t 5

$ llcp-test-client.py -t 6

$ llcp-test-client.py -t 7

$ llcp-test-client.py -t 8

$ llcp-test-client.py -t 9

$ llcp-test-client.py -t 10

$ llcp-test-client.py -t 11

$ llcp-test-client.py -t 12

$ llcp-test-client.py -t 13

$ llcp-test-client.py -t 14

snep-test-server.py¶

The SNEP test server program implements an NFC device that provides two SNEP servers:

1. A Default SNEP Server that is compliant with the NFC Forum Default SNEP Server defined in section 6 of the SNEP specification.

2. A Validation SNEP Server that accepts SNEP Put and Get requests. A Put request causes the server to store the NDEF message transmitted with the request. A Get request causes the server to attempt to return a previously stored NDEF message of the same NDEF message type and identifier as transmitted with the request. The server will keep any number of distinct NDEF messages received with Put request until the client terminates the data link connection.

   The Validation SNEP Server uses the service name urn:nfc:xsn:nfc-forum.org:snep-validation, assigned for the purpose of validating the SNEP candidate specification prior to adoption.

Usage

$ snep-test-server.py [-h|--help] [OPTION]...

Options

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

snep-test-client.py¶

Usage

$ snep-test-client.py [-h|--help] [OPTION]...

Options

-t N, --test N¶

Run test number N. May be set more than once.

-T, --test-all¶

Run all tests.

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

$ snep-test-client.py -t 1

$ snep-test-client.py -t 2

$ snep-test-client.py -t 3

$ snep-test-client.py -t 4

$ snep-test-client.py -t 5

$ snep-test-client.py -t 6

$ snep-test-client.py -t 7

handover-test-server.py¶

Usage:

$ handover-test-server.py [-h|--help] [OPTION]... [CARRIER]...

The handover test server implements the handover selector role. A handover client can connect to the server with the well-known service name urn:nfc:sn:handover and send handover request messages. The server replies with handover select messages populated with carriers provided through CARRIER arguments and matching the a carrier in the received handover request carrier list.

Each CARRIER argument must provide an NDEF message file, which may be a handover select message with one or more alternative carriers (including auxiliary data) or an alternative carrier record optionally followed by one or more auxiliary data records. Note that only the handover select message format allows to specify the carrier power state. All carriers including power state information and auxiliary data records are accumulated into a list of selectable carriers, ordered by argument position and carrier sequence within a handover select message.

Unless the --skip-local option is given, the server attempts to include carriers that are locally available on the host device. Local carriers are always added after all CARRIER arguments.

Options:

--skip-local¶

Skip the local carrier detection. Without this option the handover test server tries to discover locally available carriers and consider them in the selection process. Local carriers are considered after all carriers provided manually.

--select NUM¶

Return at most NUM carriers with the handover select message. The default is to return all matching carriers.

--delay INT¶

Delay the handover response for the number of milliseconds specified as INT. The handover specification says that the server should answer within 1 second and if it doesn’t the client may assume a processing error.

--recv-miu INT¶

Set the maximum information unit size for inbound LLCP packets on the data link connection between the server and the remote client. This value is transmitted with the CC PDU to the remote client.

--recv-buf INT¶

Set the receive window size for inbound LLCP packets on the data link connection between the server and the remote client. This value is transmitted with the CC PDU to the remote client.

--quirks¶

This option causes the handover test server to try support non-compliant implementations if possible and as known. Currently implemented work-arounds are:

• a ‘urn:nfc:sn:snep‘ server is enabled and accepts the GET request with a handover request message that was implemented in Android Jelly Bean
• the version of the handover request message sent by Android Jelly Bean is changed to 1.1 to accomodate the missing collision resolution record that is required for version 1.2.
• the incorrect type-name-format encoding in handover carrier records sent by some Sony Xperia phones is corrected to mime-type.

$ handover-test-server.py --select 0

$ ndeftool.py make btcfg 01:02:03:04:05:06 --activating | handover-test-server --skip-local -

$ examples/handover-test-server.py --delay 10000

handover-test-client.py¶

Usage

$ handover-test-client.py [-h|--help] [OPTION]... [CARRIER]...

The handover test client implements the handover requester role. The handover client connects to the remote server with well-known service name urn:nfc:sn:handover and sends handover request messages populated with carriers provided through one or more CARRIER arguments or implicitly if tests from the test suite are executed. The client expects the server to reply with handover select messages that list carriers matching one or more of the carriers sent with the handover request carrier list.

Each CARRIER argument must provide an NDEF message file which may be a handover message with one or more alternative carriers (including auxiliary data) or an alternative carrier record followed by zero or more auxiliary data records. Note that only the handover message format allows to specify the carrier power state. All carriers, including power state information and auxiliary data records, are accumulated into a list of requestable carriers ordered by argument position and carrier sequence within a handover message.

Options

-t N, --test N¶

Run test number N from the test suite. Multiple tests can be specified.

--relax¶

The --relax option affects how missing optional, but highly recommended, handover data is handled when running test scenarios. Without --relax any missing data is regarded as a test error that terminates test execution. With the --relax option set only a warning message is logged.

--recv-miu INT¶

Set the maximum information unit size for inbound LLCP packets on the data link connection between the client and the remote server. This value is transmitted with the CONNECT PDU to the remote server.

--recv-buf INT¶

Set the receive window size for inbound LLCP packets on the data link connection between the client and the remote server. This value is transmitted with the CONNECT PDU to the remote server.

--quirks¶

This option causes the handover test client to try support non-compliant implementations as much as possible, including and beyond the --relax behavor. The modifications activated with --quirks are:

• After test procedures are completed the client does not terminate the LLCP link but waits until the link is disrupted to prevent the NFC stack segfault and recovery on pre 4.1 Android devices.
• Try sending the handover request message with a SNEP GET request to the remote default SNEP server if the urn:nfc:sn:handover service is not available.

$ handover-test-client.py -t 1

$ handover-test-client.py -t 2

$ handover-test-client.py -t 3

$ handover-test-client.py -t 4

$ handover-test-client.py -t 5

$ handover-test-client.py -t 6

$ handover-test-client.py -t 7

$ handover-test-client.py -t 8

$ handover-test-client.py -t 9

phdc-test-manager.py¶

This program implements an NFC device that provides a PHDC manager with the well-known service name urn:nfc:sn:phdc and a non-standard PHDC manager with the experimental service name urn:nfc:xsn:nfc-forum.org:phdc-validation.

Usage

$ phdc-test-manager.py [-h|--help] [OPTION]...

Options

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

--wait¶

After reading or writing a tag wait until it is removed before returning. This option is implicit when the option --loop is set. Only relevant for reader/writer mode.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

phdc-test-agent.py p2p¶

Usage

$ phdc-test-agent.py p2p [-h|--help] [OPTION]...

Options

-t N, --test N¶

Run test number N. May be set more than once.

-T, --test-all¶

Run all tests.

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

--mode {t,i}¶

Restrict the choice of NFC-DEP connection setup role to either Target (only listen) or Initiator (only poll). If this option is not given the dafault is to alternate between both roles with a randomized listen time.

--miu INT¶

Set a specific value for the LLCP Link MIU. The dafault value is 2175 octets.

--lto INT¶

Set a specific LLCP Link Timeout value. The default link timeout is 500 milliseconds.

--listen-time INT¶

Set the time to listen for initialization command from an NFC-DEP Initiator. The default listen time is 250 milliseconds.

--no-aggregation¶

Disable outbound packet aggregation for LLCP, i.e. do not generate LLCP AGF PDUs if multiple packets are waiting to be send. This is mostly to achieve communication with some older/buggy implementations.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

$ phdc-test-agent.py p2p -t 1

$ phdc-test-agent.py p2p -t 2

$ phdc-test-agent.py p2p -t 3

phdc-test-agent.py tag¶

Usage

$ phdc-test-agent.py tag [-h|--help] [OPTION]...

Options

-t N, --test N¶

Run test number N. May be set more than once.

-T, --test-all¶

Run all tests.

--loop, -l¶

Repeat the command endlessly, use Control-C to abort.

-q¶

Do not print log messages except for errors and warnings.

-d MODULE¶

Output debug messages for MODULE to the log facility. Logs are written to <stderr> unless a log file is set with -f. MODULE is a string that corresponds to an nfcpy module or individual file, with dots between path components. For example, -d nfc enables all nfcpy debug logs, -d nfc.tag enables debug logs for all tag types, and -d nfc.tag.tt3 enables debug logs only for type 3 tags. This option may be given multiple times to enable debug logs for several modules.

-f LOGFILE¶

Write debug log messages to <LOGFILE> instead of <stderr>. Info, warning and error logs will still be printed to <stderr> unless -q is set to supress info messages on <stderr>.

--nolog-symm¶

When operating in peer mode this option prevents logging of LLCP Symmetry PDUs from the nfc.llcp.llc module. Symmetry PDUs are exchanged regularly and quite frequently over an LLCP Link and are logged by default if debug output is enabled for the llcp module.

--device PATH¶

Use a specific reader or search only for a subset of readers. The syntax for PATH is:

• usb[:vendor[:product]] with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.
• usb[:bus[:device]] with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.
• tty:port:driver with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.
• com:port:driver with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.
• udp[:host][:port] with optional host name or address and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

$ phdc-test-agent.py tag -t 1

$ phdc-test-agent.py tag -t 2

$ phdc-test-agent.py tag -t 3

$ phdc-test-agent.py tag -t 4

Type 3 Tags¶

Attribute Block Tests¶

This is a collection of tags to test processing of the the Type 3 Tag attribute information block. These can be used to verify if the NFC device correctly reads or writes tags with different attribute information, both valid and invalid. Below figure (from the NFC Forum Type 3 Tag Operation Specification) shows the Attribute Information Format.

TT3_READ_BV_001¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation hosted on readthedocs" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 80 --max 5 --rw 0

• Settings: Len = Nmaxb * 16, RWFlag = 0x00
• Expected: Fully used tag. Read all data stored (Len)

TT3_READ_BV_002¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --nbr 1

• Settings: Nbr = 1, RWFlag = 0x00
• Expected: Identify as „Read Only“ (normal read-only tag, read only 1 block at a time)

TT3_READ_BV_003¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --max 3

• Nbr > Nbmax, RWFlag = 0x00
• Read Nbmax blocks (NOT read Nbr blocks)

TT3_READ_BV_004¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --wf 15

• WriteFlag = 0x0F, RWFlag = 0x00
• Identify as „corrupted data“ (previous write interrupted)

TT3_READ_BV_005¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --max 3

• Nmaxb * 16 < Len, RWFlag = 0x00
• Identify as „Corrupted data“ (invalid length)

TT3_READ_BV_006¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t `python -c 'print(810*"nfcpy")'` | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 4495 --rw 0

• Nmaxb > 255, Len > 255, RWFlag = 0x00
• Read all data. Identify as „Read Only“. Write prohibited. (normal read-only tag)
• Requires a tag with more than 4 kbyte NDEF capacity

TT3_READ_BI_001¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --nbr 0 --nbw 0

• Nbr = 0, Nbw = 0, RWFlag = 0x00
• Identify as „Corrupted data“ (invalid attribute information block)

TT3_READ_BI_002¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --crc 4660

• Checksum invalid, RWFlag = 0x00
• Identify as „Corrupted data“ (invalid attribute information block)

TT3_READ_BI_003¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --ver 2.0

• Version = 2.0, RWFlag = 0x00
• Identify as unknown version

TT3_READ_BI_004¶

$ ./tagtool.py format
$ ./ndeftool.py make smartposter http://nfcpy.readthedocs.org/ -t "nfcpy documentation" | ./tagtool.py load -
$ ./tagtool.py format tt3 --len 58 --rw 0 --rfu 255

• All unused bytes in attribute block = 0xFF
• Ignore when reading RWFlag = 0x00

TT3_WRITE_BV_001¶

$ ./tagtool.py format tt3 --rw 0

• RWFlag = 0x00, no content
• Identify as „Read Only“. Write prohibited. (normal read-only tag)

TT3_WRITE_BV_002¶

$ ./tagtool.py format tt3 --rw 1

• RWFlag = 0x01, no content
• Identify as „Read/Write“. Write permitted. (normal writtable tag)

TT3_WRITE_BV_003¶

$ ./tagtool.py format tt3 --rw 0 --max 4

• Nbw > Nbmax, RWFlag = 0x01
• Write Nbmax blocks (not write Nbw blocks)

nfc.ContactlessFrontend¶

class nfc.ContactlessFrontend(path=None)¶

The contactless frontend is the main interface class for working with contactless reader devices. A reader device may be opened when an instance is created by providing the path argument, see nfc.ContactlessFrontend.open() for how it must be constructed.

The initializer method raises IOError(errno.ENODEV) if a path is specified but no no reader are found.

open(path)¶

Open a contactless reader device identified by path.

Parameters:	path – search path for contactless reader
Returns True:	if reader was found and activated

Path specification:

usb[:vendor[:product]]

with optional vendor and product as four digit hexadecimal numbers, like usb:054c:06c3 would open the first Sony RC-S380 reader and usb:054c the first Sony reader.

usb[:bus[:device]]

with optional bus and device number as three-digit decimal numbers, like usb:001:023 would specifically mean the usb device with bus number 1 and device id 23 whereas usb:001 would mean to use the first available reader on bus number 1.

tty:port:driver

with mandatory port and driver name should be used on Posix systems to open the serial port at device node /dev/tty<port> and load the driver from module nfc/dev/<driver>.py. A typical example would be tty:USB0:arygon for the Arygon APPx/ADRx at /dev/ttyUSB0.

com:port:driver

with mandatory port and driver name should be used on Windows systems to open the serial port COM<port> and load the nfc/dev/<driver>.py driver module.

udp[:host][:port] with optional host name or address

and port number will use a fake communication channel over UDP/IP. Either value may be omitted in which case host defaults to ‘localhost’ and port defaults to 54321.

close()¶

Close the contacless reader device.

connect(**options)¶

Connect with a contactless target or become connected as a contactless target. The calling thread is blocked until a single activation and deactivation has completed or a callback function supplied as the keyword argument terminate returned True. The result of the terminate function also applies to the loop run after activation, so the example below will make connect() return after 10 seconds from either waiting for a peer device or when connected.

>>> import nfc, time
>>> clf = nfc.ContactlessFrontend('usb')
>>> after5s = lambda: time.time() - started > 5
>>> started = time.time(); clf.connect(llcp={}, terminate=after5s)

Connect options are given as keyword arguments with dictionary values. Possible options are:

• rdwr={key: value, ...} - options for reader/writer operation
• llcp={key: value, ...} - options for peer to peer mode operation
• card={key: value, ...} - options for card emulation operation

Reader/Writer Options

‘targets’: sequence

A list of target specifications with each target of either type TTA, TTB, or TTF. A default set is choosen if ‘targets’ is not provided.

‘on-startup’: function

A function that will be called with the list of targets (from ‘targets’) to search for. Must return a list of targets or None. Only the targets returned are finally considered.

‘on-connect’: function

A function object that will be called with an activated Tag object.

>>> import nfc
>>> def connected(tag):
...     print tag
...     return True
...
>>> clf = nfc.ContactlessFrontend()
>>> clf.connect(rdwr={'on-connect': connected})
Type3Tag IDm=01010501b00ac30b PMm=03014b024f4993ff SYS=12fc
True

Peer To Peer Options

‘on-startup’: function

A function that is called before an attempt is made to establish peer to peer communication. The function receives the initialized LogicalLinkController instance as parameter, which may then be used to allocate and bind communication sockets for service applications. The return value must be either the LogicalLinkController instance or None to effectively remove llcp from the options considered.

‘on-connect’: function

A function that is be called when peer to peer communication was established. The function receives the connected LogicalLinkController instance as parameter, which may then be used to allocate communication sockets with socket() and spawn working threads to perform communication. The callback must return more or less immediately with True unless the logical link controller run loop is handled within the callback.

‘role’: string

Defines which role the local LLC shall take for the data exchange protocol activation. Possible values are ‘initiator’ and ‘target’. The default is to alternate between both roles until communication is established.

‘miu’: integer

Defines the maximum information unit size that will be supported and announced to the remote LLC. The default value is 128.

‘lto’: integer

Defines the link timeout value (in milliseconds) that will be announced to the remote LLC. The default value is 100 milliseconds.

‘agf’: boolean

Defines if the local LLC performs PDU aggregation and may thus send Aggregated Frame (AGF) PDUs to the remote LLC. The dafault is to use aggregation.

>>> import nfc
>>> import threading
>>> def worker(socket):
...     socket.sendto("Hi there!", address=16)
...     socket.close()
...
>>> def connected(llc):
...     socket = llc.socket(nfc.llcp.LOGICAL_DATA_LINK)
...     threading.Thread(target=worker, args=(socket,)).start()
...     return True
...
>>> clf = nfc.ContactlessFrontend()
>>> clf.connect(llcp={'on-connect': connected})

Card Emulation Options

‘targets’: sequence

A list of target specifications with each target of either type TTA, TTB, or TTF. The list of targets is processed sequentially. Defaults to an empty list.

‘on-startup’: function

A function that will be called with the list of targets (from ‘targets’) to emulate. Must return a list of one target choosen or None.

‘on-connect’: function

A function that will be called with an activated TagEmulation instance as first parameter and the first command received as the second parameter.

‘on-release’: function A function that will be called when the

activated tag has been released by it’s Initiator, basically that is when the tag has been removed from the Initiator’s RF field.

‘timeout’: integer

The timeout in seconds to wait for for each target to become initialized. The default value is 1 second.

>>> import nfc
>>>
>>> def connected(tag, command):
...     print tag
...     print str(command).encode("hex")
...
>>> clf = nfc.ContactlessFrontend()
>>> idm = bytearray.fromhex("01010501b00ac30b")
>>> pmm = bytearray.fromhex("03014b024f4993ff")
>>> sys = bytearray.fromhex("12fc")
>>> target = nfc.clf.TTF(212, idm, pmm, sys)
>>> clf.connect(card={'targets': [target], 'on-connect': connected})
Type3TagEmulation IDm=01010501b00ac30b PMm=03014b024f4993ff SYS=12fc
100601010501b00ac30b010b00018000
True

Connect returns None if no options were to execute, False if interrupted by a KeyboardInterrupt, or True if terminated normally and the ‘on-connect’ callback function had returned True. If the ‘on-connect’ callback had returned False the return value of connect() is the same parameters as were provided to the callback function.

Connect raises IOError(errno.ENODEV) if called before a contactless reader was opened.

sense(targets, **kwargs)¶

Send discovery and activation requests to find a target. Targets is a list of target specifications (TTA, TTB, TTF). Not all readers may support all possible target types. The return value is an activated target with a possibly updated specification (bitrate) or None.

Additional keyword arguments are driver specific.

Note

This is a direct interface to the driver and not needed if connect() is used.

listen(target, timeout)¶

Listen for timeout seconds to become initialized as a target. The target must be one of nfc.clf.TTA, nfc.clf.TTB, nfc.clf.TTF, or nfc.clf.DEP (note that target type support depends on the hardware capabilities). The return value is None if timeout elapsed without activation or a tuple (target, command) where target is the activated target (which may differ from the requested target, see below) and command is the first command received from the initiator.

If an activated target is returned, the target type and attributes may differ from the target requested. This is especically true if activation as a nfc.clf.DEP target is requested but the contactless frontend does not have a hardware implementation of the data exchange protocol and returns a nfc.clf.TTA or nfc.clf.TTF target instead.

Note

This is a direct interface to the driver and not needed if connect() is used.

exchange(send_data, timeout)¶

Exchange data with an activated target (data is a command frame) or as an activated target (data is a response frame). Returns a target response frame (if data is send to an activated target) or a next command frame (if data is send from an activated target). Returns None if the communication link broke during exchange (if data is sent as a target). The timeout is the number of seconds to wait for data to return, if the timeout expires an nfc.clf.TimeoutException is raised. Other nfc.clf.DigitalProtocolExceptions may be raised if an error is detected during communication.

Note

This is a direct interface to the driver and not needed if connect() is used.

set_communication_mode(brm, **kwargs)¶

Set the hardware communication mode. The effect of calling this method depends on the hardware support, some drivers may purposely ignore this function. If supported, the parameter brm specifies the communication mode to choose as a string composed of the bitrate and modulation type, for example ‘212F’ shall switch to 212 kbps Type F communication. Other communication parameters may be changed with optional keyword arguments. Currently implemented by the RC-S380 driver are the parameters ‘add-crc’ and ‘check-crc’ when running as initator. It is possible to set brm to an empty string if bitrate and modulation shall not be changed but only optional parameters executed.

Note

This is a direct interface to the driver and not needed if connect() is used.