Unable to connect to ACR122U-A2 / ACR122U-A9

Please run "examples/tagtool.py -d nfc" and post the debug output.

Hi Stephen,

Sorry for the lag in getting back to post this.

I think I actually have it working now, but will post again later today with my findings. (and/or close this ticket)

Thanks!
Steve

Ok, so to follow up, a few odd notes:

1) In general I have to specify the full vendor string in connect methods, just 'usb' never seems to find the device.

2) It seems like my device has a hard time initializing or something. For instance, when I first plug it in and try it nothing happens and the LED stays off. But if I do the following it works:
  - Plug it in
  - sudo /etc/init.d/pcscd start
  - sudo /etc/init.d/pcscd stop
  - sudo 'whatever ncfpy code'

It feels like pcscd is initing or something, I've checked that pcscd is stopped before initially plugging the reader in.

I am attaching the output tagtool.py

I'm getting the same issue. Interestingly however, when I use VirtualBox with a windowsXP VM, I dont face this issue !

[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 1.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6b050000000000000000ff00480000
[nfc.dev.transport] <<< 830a000000000002810041435231323255323133
[nfc.dev.acr122] GetFirmwareVersion called with timeout 100 ms
[nfc.dev.transport] >>> 6b070000000000000000ff00000002d402
[nfc.dev.transport] <<< 830a000000000002810041435231323255323133
Traceback (most recent call last):
  File "examples/tagtool.py", line 439, in <module>
    TagTool().run()
  File "/home/user/Downloads/shared/code/nfcpy/examples/cli.py", line 283, in run
    while self.run_once() and self.options.loop:
  File "/home/user/Downloads/shared/code/nfcpy/examples/cli.py", line 230, in run_once
    try: clf = nfc.ContactlessFrontend(device)
  File "/home/user/Downloads/shared/code/nfcpy/nfc/clf.py", line 105, in __init__
    if path and not self.open(path):
  File "/home/user/Downloads/shared/code/nfcpy/nfc/clf.py", line 156, in open
    self.dev = nfc.dev.connect(path)
  File "/home/user/Downloads/shared/code/nfcpy/nfc/dev/__init__.py", line 64, in connect
    device = driver.init(usb)
  File "/home/user/Downloads/shared/code/nfcpy/nfc/dev/acr122.py", line 92, in init
    chipset = Chipset(transport)
  File "/home/user/Downloads/shared/code/nfcpy/nfc/dev/acr122.py", line 50, in __init__
    super(Chipset, self).__init__(transport)
  File "/home/user/Downloads/shared/code/nfcpy/nfc/dev/pn53x.py", line 126, in __init__
    ic, ver, rev, support = self.get_firmware_version()
  File "/home/user/Downloads/shared/code/nfcpy/nfc/dev/pn53x.py", line 243, in get_firmware_version
    else: ic, ver, rev, support = data
ValueError: too many values to unpack

When all of the above is happening, the red LED on my device does NOT light up.

However - if I DONT blacklist pn533 , then the red LED lights up. Then I can do "modprobe -r pn533" and then all of nfcpy works perfectly.

I think there is an initialization step missing.

I can now confirm initialisation issues with an ACR122U213 (labelled ACR122U-A9).

Glad that folks can reproduce this. Let me know if there is anything I can do to help move this forward. I'm not sure if I have enough background knowledge to fix it, but if you can point me in the right direction in the code, I might be able to poke around a bit.

Cheers,
Steve

Fix committed and tested to work with an ACR122U-A9.

Thanks Stephen! I'll be trying this out tonight.

-Steve

Awesome, things are working great with this fix. Thanks so much, I really appreciate your work on this project!

-Steve

I'm afraid I'm still stuck here:

# python tagtool.py -d nfc
[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6f050000000000000000ff00480000
[nfc.dev.transport] <<< 800a000000000002810041435231323255323133
Traceback (most recent call last):
  File "tagtool.py", line 479, in <module>
    TagTool().run()
  File "/home/joggler/nfc/nfcpy/examples/cli.py", line 283, in run
    while self.run_once() and self.options.loop:
  File "/home/joggler/nfc/nfcpy/examples/cli.py", line 230, in run_once
    try: clf = nfc.ContactlessFrontend(device)
  File "/home/joggler/nfc/nfcpy/nfc/clf.py", line 105, in __init__
    if path and not self.open(path):
  File "/home/joggler/nfc/nfcpy/nfc/clf.py", line 156, in open
    self.dev = nfc.dev.connect(path)
  File "/home/joggler/nfc/nfcpy/nfc/dev/__init__.py", line 64, in connect
    device = driver.init(usb)
  File "/home/joggler/nfc/nfcpy/nfc/dev/acr122.py", line 121, in init
    chipset = Chipset(transport)
  File "/home/joggler/nfc/nfcpy/nfc/dev/acr122.py", line 40, in __init__
    reader_version = self.ccid_xfr_block(bytearray.fromhex("FF00480000"))
  File "/home/joggler/nfc/nfcpy/nfc/dev/acr122.py", line 81, in ccid_xfr_block
    if len(frame) != 10 + struct.unpack("<I", frame[1:5])[0]:
struct.error: unpack requires a string argument of length 4

Running as root for time being to test, but always the same result.

What is your python version? And could you check if the following works:

$ python
>>> import struct
>>> struct.unpack("<I", "\x0A\x00\x00\x00")
(10,)
>>> struct.unpack("<I", bytearray("\x0A\x00\x00\x00"))
(10,)

Hello everyone.

When running :

$ sudo python tagtool.py -d nfc, I get the follow dump

[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 0.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
[nfc.dev.transport] >>> 6f050000000000000000ff00480000
[nfc.dev.transport] <<< 800a000000000002810041435231323255323034
Traceback (most recent call last):
  File "tagtool.py", line 479, in <module>
    TagTool().run()
  File "/lhome/kasper/temp/pynfc/nfcpy/examples/cli.py", line 283, in run
    while self.run_once() and self.options.loop:
  File "/lhome/kasper/temp/pynfc/nfcpy/examples/cli.py", line 230, in run_once
    try: clf = nfc.ContactlessFrontend(device)
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/clf.py", line 105, in __init__
    if path and not self.open(path):
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/clf.py", line 156, in open
    self.dev = nfc.dev.connect(path)
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/dev/__init__.py", line 64, in connect
    device = driver.init(usb)
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/dev/acr122.py", line 121, in init
    chipset = Chipset(transport)
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/dev/acr122.py", line 40, in __init__
    reader_version = self.ccid_xfr_block(bytearray.fromhex("FF00480000"))
  File "/lhome/kasper/temp/pynfc/nfcpy/nfc/dev/acr122.py", line 81, in ccid_xfr_block
    if len(frame) != 10 + struct.unpack("<I", frame[1:5])[0]:
struct.error: unpack requires a string argument of length 4

I've tried the commands

Python 2.7.3 (default, Sep 26 2013, 20:03:06)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
>>> struct.unpack("<I", "\x0A\x00\x00\x00")
(10,)
>>> struct.unpack("<I", bytearray("\x0A\x00\x00\x00"))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
struct.error: unpack requires a string argument of length 4
>>>

So have I got a wrong python version ?

Thanks in advance

This is indeed an issue with the Python version. As this is different from the original bug I filed a new bug:1274973. and a fix will come in a minute or so.

I'm running into similar issues. I have the following:
 - Raspberry Pi
 - pyusb 1.0.0b2
 - Python 2.7.3 (default, Mar 18 2014, 05:13:23)
 - Using ACR-122U-A9 NFC reader

When running python check I get this:
>>> import struct
>>> struct.unpack("<I", "\x0A\x00\x00\x00")
(10,)
>>> struct.unpack("<I", bytearray("\x0A\x00\x00\x00"))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
struct.error: unpack requires a string argument of length 4

Here is the output from tag tool.py

pi@bmipi1 ~/Downloads/nfcpy/examples $ sudo python tagtool.py -d nfc
[main] enable debug output for module 'nfc'
[nfc.clf] searching for reader with path 'usb'
[nfc.dev.transport] using pyusb version 1.x
[nfc.dev.transport] path matches '^(usb|)$'
[nfc.dev] trying usb:072f:2200
[nfc.dev] import nfc.dev.acr122
Traceback (most recent call last):
  File "tagtool.py", line 516, in <module>
    TagTool().run()
  File "/home/pi/Downloads/nfcpy/examples/cli.py", line 283, in run
    while self.run_once() and self.options.loop:
  File "/home/pi/Downloads/nfcpy/examples/cli.py", line 230, in run_once
    try: clf = nfc.ContactlessFrontend(device)
  File "/home/pi/Downloads/nfcpy/nfc/clf.py", line 105, in __init__
    if path and not self.open(path):
  File "/home/pi/Downloads/nfcpy/nfc/clf.py", line 156, in open
    self.dev = nfc.dev.connect(path)
  File "/home/pi/Downloads/nfcpy/nfc/dev/__init__.py", line 63, in connect
    usb = transport.USB(bus, dev)
  File "/home/pi/Downloads/nfcpy/nfc/dev/transport.py", line 207, in __init__
    self.open(bus_id, dev_id)
  File "/home/pi/Downloads/nfcpy/nfc/dev/transport.py", line 275, in _PYUSB1_open
    self.usb_out.write('')
  File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 349, in write
    return self.device.write(self, data, timeout)
  File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 870, in write
    intf, ep = self._ctx.setup_request(self, endpoint)
  File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 190, in setup_request
    self.managed_claim_interface(device, intf)
  File "/usr/local/lib/python2.7/dist-packages/usb/core.py", line 146, in managed_claim_interface
    self.backend.claim_interface(self.handle, i)
  File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 747, in claim_interface
    _check(self.lib.libusb_claim_interface(dev_handle.handle, intf))
  File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 552, in _check
    raise USBError(_strerror(ret), ret, _libusb_errno[ret])
  File "/usr/local/lib/python2.7/dist-packages/usb/backend/libusb1.py", line 541, in _strerror
    return _lib.libusb_strerror(errcode).decode('utf8')
  File "/usr/lib/python2.7/ctypes/__init__.py", line 378, in __getattr__
    func = self.__getitem__(name)
  File "/usr/lib/python2.7/ctypes/__init__.py", line 383, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: /lib/arm-linux-gnueabihf/libusb-1.0.so.0: undefined symbol: libusb_strerror

Is there an issue with the Python version?

This is not a Python version issue but related to libus/pyusb. The root cause seems to be that libusb fails to claim the interface for the USB device and returns some error code that the _check() method in pyusb wants to raise up the stack. Then conversion of the error code to an error string fails because the libusb dynamic library doesn't have the libusb_strerror function.

Without knowing what pyUSB wants to say about the problem with claim_interface, it's speculative to say what might have caused the issue first place. However, a common cause would be that some another process has already claimed it or there are insufficient access permissions.