PN532 serial not found connected to Raspberry Pi

In step 2 of http://learn.adafruit.com/adafruit-nfc-rfid-on-raspberry-pi/building-libnfc you have modified the source code to get /dev/ttyAMA recognized. A similar step is required for nfcpy, you'll find the place in nfc/dev/__init__.py line 146. Replace ttyUSB with ttyAMA and if it then works please let me know.

Hi Stephen,

I've amended the code like you said but I still get the same message. Is there somewhere else that I need to change this?

I changed nfc/dev/__init__.py on line 146. Replace ttyUSB with ttyAMA .

This is how it looks

else:
                    log.info("searching for a usb tty reader")
                    for devname in glob.glob("/dev/ttyAMA[0-9]"):
                        log.debug("trying usb tty reader {0}".format(devname))
                        for module in ("arygon_tty", "pn53x_tty"):
                            driver = import_driver(module)

Thanks

Adam

Hi Stephen

Just thought I would try one more thing and it is now working. There was another place just above where you said with ttyUSB(0) so I changed that to ttyAMA(0). Here is where I mean.

 match = re.match(r"tty(?:\:(usb|com))?(?:\:([0-9]{1,2}))?$", path)
        if match is not None or path == "":
            line, port = match.groups() if match else (None, None)
            if line is None or line == "usb":
                if port is not None:
                    devname = "/dev/ttyAMA{0}".format(port) #THIS LINE IS THE ONE I CHANGED
                    log.debug("trying usb tty reader {0}".format(devname))
                    for module in ("arygon_tty", "pn53x_tty"):
                        driver = import_driver(module)
                        device = driver.init(devname)
                        if device is not None:
                            device._path = "tty:usb:{0}".format(port)
                            return device
                else:
                    log.info("searching for a usb tty reader")
                    for devname in glob.glob("/dev/ttyAMA[0-9]"):
                        log.debug("trying usb tty reader {0}".format(devname))
                        for module in ("arygon_tty", "pn53x_tty"):
                            driver = import_driver(module)
                            device = driver.init(devname)
                            if device is not None:
                                port = devname[-1]
                                device._path = "tty:usb:{0}".format(port)
                                return device

Thanks for your help. Now to see what I can do.

Adam

Hi, I made the same changes in the __init__.py but it finds the reader (PN532 breakout board connected over UART) only after I comunicate with the reader using libnfc (eg. nfc-poll) after reboot. Once it communicates with the device it works like a charm (even after soft-reset) but after pluggin the rpi off the plug it does not find the reader. Any hints how to fix this behavior?

Using latest pyusb-1.0.0a2.

If you're still having the problem please try again with the latest trunk revision. The driver architecture got some changes as well as the serial port implementation. You no longer have to change source code to get a ttyAMA recognized, just tell tagtool or any of the other example programs to use '--device tty:AMA0:pn53x'. The last part tells the driver to use on that port, this seems to be a safer aproach for serial connections as they do not really tell about the device connected, like USB does.