```
*-
* Free/Libre Near Field Communication (NFC) library
*
* Libnfc historical contributors:
* Copyright (C) 2009      Roel Verdult
* Copyright (C) 2009-2015 Romuald Conty
* Copyright (C) 2010-2012 Romain Tartière
* Copyright (C) 2010-2013 Philippe Teuwen
* Copyright (C) 2012-2013 Ludovic Rousseau
* Additional contributors:
* See AUTHORS file
-*
```

General Information
===================

libnfc is a library which allows userspace application access to NFC devices.

The official web site is:
  http://www.nfc-tools.org/

The official forum site is:
  http://www.libnfc.org/community/

The official development site is:
  https://github.com/nfc-tools/libnfc

Important note: this file covers POSIX systems, for Windows please read README-Windows.md

Requirements
============

Some NFC drivers depend on third party software:

* pn53x_usb & acr122_usb:

   - libusb-0.1 http://libusb.sf.net

* acr122_pcsc:

   - pcsc-lite http://pcsclite.alioth.debian.org/

The regression test suite depends on the cutter framework:
http://cutter.sf.net

Installation
============

See the file `INSTALL` for configure, build and install details.

Additionnally, you may need to grant permissions to your user to drive your device.
Under GNU/Linux systems, if you use udev, you could use the provided udev rules.
  e.g. under Debian, Ubuntu, etc.

    sudo cp contrib/udev/93-pn53x.rules /lib/udev/rules.d/

Under FreeBSD, if you use devd, there is also a rules file: contrib/devd/pn53x.conf.

Configuration
=============

In order to change the default behavior of the library, the libnfc uses a
configuration file located in sysconfdir (as provided to ./configure).

A sample commented file is available in sources: libnfc.conf.sample

If you have compiled using:

    ./configure --prefix=/usr --sysconfdir=/etc

you can make configuration directory and copy the sample file:

    sudo mkdir /etc/nfc
    sudo cp libnfc.conf.sample /etc/nfc/libnfc.conf

To configure multiple devices, you can either modify libnfc.conf or create a
file per device in a nfc/devices.d directory:

    sudo mkdir -p /etc/nfc/devices.d
    printf 'name = "My first device"\nconnstring = "pn532_uart:/dev/ttyACM0"\n' | sudo tee /etc/nfc/devices.d/first.conf
    printf 'name = "My second device"\nconnstring = "pn532_uart:/dev/ttyACM1"\n' | sudo tee /etc/nfc/devices.d/second.conf

How to report bugs
==================

To report a bug, visit https://github.com/nfc-tools/libnfc/issues and fill
out a bug report form.

If you have questions, remarks, we encourage you to post this in the developers
community:
http://www.libnfc.org/community

Please make sure to include:

* The version of libnfc

* Information about your system. For instance:

   - What operating system and version
   - For Linux, what version of the C library

  And anything else you think is relevant.

* A trace with debug activated.

  Reproduce the bug with debug, e.g. if it was:

        $ nfc-list -v

  run it as:

        $ LIBNFC_LOG_LEVEL=3 nfc-list -v

* How to reproduce the bug.

  Please include a short test program that exhibits the behavior.
  As a last resort, you can also provide a pointer to a larger piece
  of software that can be downloaded.

* If the bug was a crash, the exact text that was printed out
  when the crash occured.

* Further information such as stack traces may be useful, but
  is not necessary.

Patches
=======

Patches can be posted to https://github.com/nfc-tools/libnfc/issues

If the patch fixes a bug, it is usually a good idea to include
all the information described in "How to Report Bugs".

Building
========

It should be as simple as running these two commands:

    ./configure
    make

Troubleshooting
===============

Touchatag/ACR122:
-----------------
If your Touchatag or ACR122 device fails being detected by libnfc, make sure
that PCSC-lite daemon (`pcscd`) is installed and is running.

If your Touchatag or ACR122 device fails being detected by PCSC-lite daemon
(`pcsc_scan` doesn't see anything) then try removing the bogus firmware detection
of libccid: edit libccid_Info.plist configuration file (usually
`/etc/libccid_Info.plist`) and locate `<key>ifdDriverOptions</key>`, turn
`<string>0x0000</string>` value into `0x0004` to allow bogus devices and restart
pcscd daemon.

ACR122:
-------
Using an ACR122 device with libnfc and without tag (e.g. to use NFCIP modes or
card emulation) needs yet another PCSC-lite tweak: You need to allow usage of
CCID Exchange command.  To do this, edit `libccid_Info.plist` configuration file
(usually `/etc/libccid_Info.plist`) and locate `<key>ifdDriverOptions</key>`,
turn `<string>0x0000</string>` value into `0x0001` to allow CCID exchange or
`0x0005` to allow CCID exchange and bogus devices (cf previous remark) and
restart pcscd daemon.

Warning: if you use ACS CCID drivers (acsccid), configuration file is located
in something like: `/usr/lib/pcsc/drivers/ifd-acsccid.bundle/Contents/Info.plist`

SCL3711:
--------
Libnfc cannot be used concurrently with the PCSC proprietary driver of SCL3711.
Two possible solutions:
* Either you don't install SCL3711 driver at all
* Or you stop the PCSC daemon when you want to use libnfc-based tools

PN533 USB device on Linux >= 3.1:
---------------------------------
Since Linux kernel version 3.1, a few kernel-modules must not be loaded in order
to use libnfc : "nfc", "pn533" and "pn533_usb".
To prevent kernel from loading automatically these modules, you can blacklist
them in a modprobe conf file. This file is provided within libnfc archive:

    sudo cp contrib/linux/blacklist-libnfc.conf /etc/modprobe.d/blacklist-libnfc.conf

Proprietary Notes
=================

FeliCa is a registered trademark of the Sony Corporation.
MIFARE is a trademark of NXP Semiconductors.
Jewel Topaz is a trademark of Innovision Research & Technology.
All other trademarks are the property of their respective owners.
