class Tunnel_DAC(Instrument): def __init__(self, name, serial=None, channel='A0', numdacs=3, delay=1e-3): ''' discover and initialize Tunnel_DAC hardware Input: serial - serial number of the FTDI converter channel - 2 character channel id the DAC is connected to; the first byte identifies the channel (A..D for current devices) the second byte identifies the bit within that channel (0..7) numdacs - number of DACs daisy-chained on that line delay - communications delay assumed between PC and the USB converter ''' logging.info(__name__ + ': Initializing instrument Tunnel_DAC') Instrument.__init__(self, name, tags=['physical']) self._conn = Ftdi() # VIDs and PIDs of converters used vps = [ (0x0403, 0x6011), # FTDI UM4232H 4ch (0x0403, 0x6014) # FTDI UM232H 1ch ] # explicitly clear device cache of UsbTools #UsbTools.USBDEVICES = [] # find all devices and obtain serial numbers devs = self._conn.find_all(vps) # filter list by serial number if provided if (serial != None): devs = [dev for dev in devs if dev[2] == serial] if (len(devs) == 0): logging.error(__name__ + ': failed to find matching FTDI devices.') elif (len(devs) > 1): logging.error( __name__ + ': more than one converter found and no serial number given.') logging.info(__name__ + ': available devices are: %s.' % str([dev[2] for dev in devs])) vid, pid, self._serial, channels, description = devs[0] # parse channel string if (len(channel) != 2): logging.error( __name__ + ': channel identifier must be a string of length 2. ex. A0, D5.' ) self._channel = 1 + ord(channel[0]) - ord('A') self._bit = ord(channel[1]) - ord('0') if ((self._channel < 1) or (self._channel > channels)): logging.error(__name__ + ': channel %c is not supported by this device.' % (chr(ord('A') + self._channel - 1))) if ((self._bit < 0) or (self._bit > 7)): logging.error(__name__ + ': subchannel must be between 0 and 7, not %d.' % self._bit) # open device self._conn.open(vid, pid, interface=self._channel, serial=self._serial) logging.info(__name__ + ': using converter with serial #%s' % self._serial) self._conn.set_bitmode(0xFF, Ftdi.BITMODE_BITBANG) # 80k generates bit durations of 12.5us, 80 is magic :( # magic?: 4 from incorrect BITBANG handling of pyftdi, 2.5 from 120MHz instead of 48MHz clock of H devices # original matlab code uses 19kS/s self._conn.set_baudrate(19000 / 80) # house keeping self._numdacs = numdacs self._sleeptime = ( 10. + 16. * self._numdacs ) * 12.5e-6 + delay # 1st term from hardware parameters, 2nd term from USB self._minval = -5000. self._maxval = 5000. self._resolution = 16 # DAC resolution in bits self._voltages = [0.] * numdacs self.add_parameter('voltage', type=types.FloatType, flags=Instrument.FLAG_SET, channels=(1, self._numdacs), minval=self._minval, maxval=self._maxval, units='mV', format='%.02f') # tags=['sweep'] self.add_function('set_voltages') self.add_function('commit') def _encode(self, data, channel=0, bits_per_item=16, big_endian=True): ''' convert binary data into line symbols the tunnel electronic DAC logic box triggers on rising signal edges and samples data after 18us. we use a line code with three bits of duration 12us, where a logical 1 is encoded as B"110" and a logical 0 is encoded as B"100". the line data is returned as a byte string with three bytes/symbol. Input: data - a vector of data entities (usually a string or list of integers) channel - a number in [0, 7] specifying the output bit on the USB-to-UART chip bits_per_item - number of bits to extract from each element of the data vector ''' # build line code for the requested channel line_1 = chr(1 << channel) line_0 = chr(0) line_code = [ ''.join([line_0, line_1, line_1]), ''.join([line_0, line_1, line_0]) ] # do actual encoding result = [] result.append(10 * line_0) for item in data: for bit in (range(bits_per_item - 1, -1, -1) if big_endian else range(0, bits_per_item)): result.append(line_code[1 if (item & (1 << bit)) else 0]) result.append(10 * line_0) return ''.join(result) def commit(self): ''' send updated parameter values to the physical DACs via USB ''' # normalize, scale, clip voltages voltages = [ -1 + 2 * (x - self._minval) / (self._maxval - self._minval) for x in self._voltages ] voltages = [ max( -2**(self._resolution - 1), min(2**(self._resolution - 1) - 1, int(2**(self._resolution - 1) * x))) for x in voltages ] # encode and send data = self._encode(reversed(voltages), self._bit, self._resolution) self._conn.write_data(data) # wait for the FTDI fifo to clock the data to the DACs sleep(self._sleeptime) def do_set_voltage(self, value, channel): ''' immediately update voltage on channel ch parameter checking is done by qtlab ''' self._voltages[channel - 1] = value self.commit() def set_voltages(self, valuedict): ''' update voltages on several channels simultaneously todo: update instrument panel display ''' for channel, value in valuedict.iteritems(): # bounds checking & clipping if ((channel < 1) or (channel > self._numdacs)): logging.error(__name__ + ': channel %d out of range.' % channel) continue value = float(value) if ((value < self._minval) or (value >= self._maxval)): logging.error(__name__ + ': value %f out of range. clipping.' % value) value = max(self._minval, min(self._maxval, value)) # does not handle maxval correctly self._voltages[channel - 1] = value self.commit()
class Tunnel_DAC(Instrument): def __init__(self, name, serial = None, channel = 'A0', numdacs=3, delay = 1e-3): ''' discover and initialize Tunnel_DAC hardware Input: serial - serial number of the FTDI converter channel - 2 character channel id the DAC is connected to; the first byte identifies the channel (A..D for current devices) the second byte identifies the bit within that channel (0..7) numdacs - number of DACs daisy-chained on that line delay - communications delay assumed between PC and the USB converter ''' logging.info(__name__+ ': Initializing instrument Tunnel_DAC') Instrument.__init__(self, name, tags=['physical']) self._conn = Ftdi() # VIDs and PIDs of converters used vps = [ (0x0403, 0x6011), # FTDI UM4232H 4ch (0x0403, 0x6014) # FTDI UM232H 1ch ] # explicitly clear device cache of UsbTools #UsbTools.USBDEVICES = [] # find all devices and obtain serial numbers devs = self._conn.find_all(vps) # filter list by serial number if provided if(serial != None): devs = [dev for dev in devs if dev[2] == serial] if(len(devs) == 0): logging.error(__name__ + ': failed to find matching FTDI devices.') elif(len(devs) > 1): logging.error(__name__ + ': more than one converter found and no serial number given.') logging.info(__name__ + ': available devices are: %s.'%str([dev[2] for dev in devs])) vid, pid, self._serial, channels, description = devs[0] # parse channel string if(len(channel) != 2): logging.error(__name__ + ': channel identifier must be a string of length 2. ex. A0, D5.') self._channel = 1 + ord(channel[0]) - ord('A') self._bit = ord(channel[1]) - ord('0') if((self._channel < 1) or (self._channel > channels)): logging.error(__name__ + ': channel %c is not supported by this device.'%(chr(ord('A')+self._channel-1))) if((self._bit < 0) or (self._bit > 7)): logging.error(__name__ + ': subchannel must be between 0 and 7, not %d.'%self._bit) # open device self._conn.open(vid, pid, interface = self._channel, serial = self._serial) logging.info(__name__ + ': using converter with serial #%s'%self._serial) self._conn.set_bitmode(0xFF, Ftdi.BITMODE_BITBANG) # 80k generates bit durations of 12.5us, 80 is magic :( # magic?: 4 from incorrect BITBANG handling of pyftdi, 2.5 from 120MHz instead of 48MHz clock of H devices # original matlab code uses 19kS/s self._conn.set_baudrate(19000/80) # house keeping self._numdacs = numdacs self._sleeptime = (10. + 16.*self._numdacs)*12.5e-6 + delay # 1st term from hardware parameters, 2nd term from USB self._minval = -5000. self._maxval = 5000. self._resolution = 16 # DAC resolution in bits self._voltages = [0.]*numdacs self.add_parameter('voltage', type=types.FloatType, flags=Instrument.FLAG_SET, channels=(1, self._numdacs), minval = self._minval, maxval = self._maxval, units='mV', format = '%.02f') # tags=['sweep'] self.add_function('set_voltages') self.add_function('commit') def _encode(self, data, channel = 0, bits_per_item = 16, big_endian = True): ''' convert binary data into line symbols the tunnel electronic DAC logic box triggers on rising signal edges and samples data after 18us. we use a line code with three bits of duration 12us, where a logical 1 is encoded as B"110" and a logical 0 is encoded as B"100". the line data is returned as a byte string with three bytes/symbol. Input: data - a vector of data entities (usually a string or list of integers) channel - a number in [0, 7] specifying the output bit on the USB-to-UART chip bits_per_item - number of bits to extract from each element of the data vector ''' # build line code for the requested channel line_1 = chr(1<<channel) line_0 = chr(0) line_code = [''.join([line_0, line_1, line_1]), ''.join([line_0, line_1, line_0])] # do actual encoding result = [] result.append(10*line_0) for item in data: for bit in (range(bits_per_item-1, -1, -1) if big_endian else range(0, bits_per_item)): result.append(line_code[1 if(item & (1<<bit)) else 0]) result.append(10*line_0) return ''.join(result) def commit(self): ''' send updated parameter values to the physical DACs via USB ''' # normalize, scale, clip voltages voltages = [-1+2*(x-self._minval)/(self._maxval-self._minval) for x in self._voltages] voltages = [max(-2**(self._resolution-1), min(2**(self._resolution-1)-1, int(2**(self._resolution-1)*x))) for x in voltages] # encode and send data = self._encode(reversed(voltages), self._bit, self._resolution) self._conn.write_data(data) # wait for the FTDI fifo to clock the data to the DACs sleep(self._sleeptime) def do_set_voltage(self, value, channel): ''' immediately update voltage on channel ch parameter checking is done by qtlab ''' self._voltages[channel-1] = value self.commit() def set_voltages(self, valuedict): ''' update voltages on several channels simultaneously todo: update instrument panel display ''' for channel, value in valuedict.iteritems(): # bounds checking & clipping if((channel < 1) or (channel > self._numdacs)): logging.error(__name__ + ': channel %d out of range.'%channel) continue value = float(value) if((value < self._minval) or (value >= self._maxval)): logging.error(__name__ + ': value %f out of range. clipping.'%value) value = max(self._minval, min(self._maxval, value)) # does not handle maxval correctly self._voltages[channel-1] = value self.commit()
class USBDevice(Device): """ `AD2USB`_ device utilizing PyFTDI's interface. """ # Constants PRODUCT_IDS = ((0x0403, 0x6001), (0x0403, 0x6015)) """List of Vendor and Product IDs used to recognize `AD2USB`_ devices.""" DEFAULT_VENDOR_ID = PRODUCT_IDS[0][0] """Default Vendor ID used to recognize `AD2USB`_ devices.""" DEFAULT_PRODUCT_ID = PRODUCT_IDS[0][1] """Default Product ID used to recognize `AD2USB`_ devices.""" # Deprecated constants FTDI_VENDOR_ID = DEFAULT_VENDOR_ID """DEPRECATED: Vendor ID used to recognize `AD2USB`_ devices.""" FTDI_PRODUCT_ID = DEFAULT_PRODUCT_ID """DEPRECATED: Product ID used to recognize `AD2USB`_ devices.""" BAUDRATE = 115200 """Default baudrate for `AD2USB`_ devices.""" __devices = [] __detect_thread = None @classmethod def find_all(cls, vid=None, pid=None): """ Returns all FTDI devices matching our vendor and product IDs. :returns: list of devices :raises: :py:class:`~alarmdecoder.util.CommError` """ if not have_pyftdi: raise ImportError( 'The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.' ) cls.__devices = [] query = cls.PRODUCT_IDS if vid and pid: query = [(vid, pid)] try: cls.__devices = Ftdi.find_all(query, nocache=True) except (usb.core.USBError, FtdiError) as err: raise CommError( 'Error enumerating AD2USB devices: {0}'.format(str(err)), err) return cls.__devices @classmethod def devices(cls): """ Returns a cached list of `AD2USB`_ devices located on the system. :returns: cached list of devices found """ return cls.__devices @classmethod def find(cls, device=None): """ Factory method that returns the requested :py:class:`USBDevice` device, or the first device. :param device: Tuple describing the USB device to open, as returned by find_all(). :type device: tuple :returns: :py:class:`USBDevice` object utilizing the specified device :raises: :py:class:`~alarmdecoder.util.NoDeviceError` """ if not have_pyftdi: raise ImportError( 'The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.' ) cls.find_all() if len(cls.__devices) == 0: raise NoDeviceError('No AD2USB devices present.') if device is None: device = cls.__devices[0] vendor, product, sernum, ifcount, description = device return USBDevice(interface=sernum, vid=vendor, pid=product) @classmethod def start_detection(cls, on_attached=None, on_detached=None): """ Starts the device detection thread. :param on_attached: function to be called when a device is attached **Callback definition:** *def callback(thread, device)* :type on_attached: function :param on_detached: function to be called when a device is detached **Callback definition:** *def callback(thread, device)* :type on_detached: function """ if not have_pyftdi: raise ImportError( 'The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.' ) cls.__detect_thread = USBDevice.DetectThread(on_attached, on_detached) try: cls.find_all() except CommError: pass cls.__detect_thread.start() @classmethod def stop_detection(cls): """ Stops the device detection thread. """ if not have_pyftdi: raise ImportError( 'The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.' ) try: cls.__detect_thread.stop() except Exception: pass @property def interface(self): """ Retrieves the interface used to connect to the device. :returns: the interface used to connect to the device """ return self._interface @interface.setter def interface(self, value): """ Sets the interface used to connect to the device. :param value: may specify either the serial number or the device index :type value: string or int """ self._interface = value if isinstance(value, int): self._device_number = value else: self._serial_number = value @property def serial_number(self): """ Retrieves the serial number of the device. :returns: serial number of the device """ return self._serial_number @serial_number.setter def serial_number(self, value): """ Sets the serial number of the device. :param value: serial number of the device :type value: string """ self._serial_number = value @property def description(self): """ Retrieves the description of the device. :returns: description of the device """ return self._description @description.setter def description(self, value): """ Sets the description of the device. :param value: description of the device :type value: string """ self._description = value def __init__(self, interface=0, vid=None, pid=None): """ Constructor :param interface: May specify either the serial number or the device index. :type interface: string or int """ if not have_pyftdi: raise ImportError( 'The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.' ) Device.__init__(self) self._device = Ftdi() self._interface = 0 self._device_number = 0 self._serial_number = None self._vendor_id = USBDevice.DEFAULT_VENDOR_ID if vid: self._vendor_id = vid self._product_id = USBDevice.DEFAULT_PRODUCT_ID if pid: self._product_id = pid self._endpoint = 0 self._description = None self.interface = interface def open(self, baudrate=BAUDRATE, no_reader_thread=False): """ Opens the device. :param baudrate: baudrate to use :type baudrate: int :param no_reader_thread: whether or not to automatically start the reader thread. :type no_reader_thread: bool :raises: :py:class:`~alarmdecoder.util.NoDeviceError` """ # Set up defaults if baudrate is None: baudrate = USBDevice.BAUDRATE self._read_thread = Device.ReadThread(self) # Open the device and start up the thread. try: self._device.open(self._vendor_id, self._product_id, self._endpoint, self._device_number, self._serial_number, self._description) self._device.set_baudrate(baudrate) if not self._serial_number: self._serial_number = self._get_serial_number() self._id = self._serial_number except (usb.core.USBError, FtdiError) as err: raise NoDeviceError('Error opening device: {0}'.format(str(err)), err) except KeyError as err: raise NoDeviceError( 'Unsupported device. ({0:04x}:{1:04x}) You probably need a newer version of pyftdi.' .format(err[0][0], err[0][1])) else: self._running = True self.on_open() if not no_reader_thread: self._read_thread.start() return self def close(self): """ Closes the device. """ try: Device.close(self) # HACK: Probably should fork pyftdi and make this call in .close() self._device.usb_dev.attach_kernel_driver(self._device_number) except Exception: pass def fileno(self): """ File number not supported for USB devices. :raises: NotImplementedError """ raise NotImplementedError('USB devices do not support fileno()') def write(self, data): """ Writes data to the device. :param data: data to write :type data: string :raises: :py:class:`~alarmdecoder.util.CommError` """ try: self._device.write_data(data) self.on_write(data=data) except FtdiError as err: raise CommError('Error writing to device: {0}'.format(str(err)), err) def read(self): """ Reads a single character from the device. :returns: character read from the device :raises: :py:class:`~alarmdecoder.util.CommError` """ ret = None try: ret = self._device.read_data(1) except (usb.core.USBError, FtdiError) as err: raise CommError('Error reading from device: {0}'.format(str(err)), err) return ret def read_line(self, timeout=0.0, purge_buffer=False): """ Reads a line from the device. :param timeout: read timeout :type timeout: float :param purge_buffer: Indicates whether to purge the buffer prior to reading. :type purge_buffer: bool :returns: line that was read :raises: :py:class:`~alarmdecoder.util.CommError`, :py:class:`~alarmdecoder.util.TimeoutError` """ def timeout_event(): """Handles read timeout event""" timeout_event.reading = False timeout_event.reading = True if purge_buffer: self._buffer = b'' got_line, ret = False, None timer = threading.Timer(timeout, timeout_event) if timeout > 0: timer.start() try: while timeout_event.reading: buf = self._device.read_data(1) if buf != b'': ub = bytes_hack(buf) self._buffer += ub if ub == b"\n": self._buffer = self._buffer.rstrip(b"\r\n") if len(self._buffer) > 0: got_line = True break else: time.sleep(0.01) except (usb.core.USBError, FtdiError) as err: raise CommError('Error reading from device: {0}'.format(str(err)), err) else: if got_line: ret, self._buffer = self._buffer, b'' self.on_read(data=ret) else: raise TimeoutError( 'Timeout while waiting for line terminator.') finally: timer.cancel() return ret def purge(self): """ Purges read/write buffers. """ self._device.purge_buffers() def _get_serial_number(self): """ Retrieves the FTDI device serial number. :returns: string containing the device serial number """ return usb.util.get_string(self._device.usb_dev, 64, self._device.usb_dev.iSerialNumber) class DetectThread(threading.Thread): """ Thread that handles detection of added/removed devices. """ on_attached = event.Event( "This event is called when an `AD2USB`_ device has been detected.\n\n**Callback definition:** def callback(thread, device*" ) on_detached = event.Event( "This event is called when an `AD2USB`_ device has been removed.\n\n**Callback definition:** def callback(thread, device*" ) def __init__(self, on_attached=None, on_detached=None): """ Constructor :param on_attached: Function to call when a device is attached **Callback definition:** *def callback(thread, device)* :type on_attached: function :param on_detached: Function to call when a device is detached **Callback definition:** *def callback(thread, device)* :type on_detached: function """ threading.Thread.__init__(self) if on_attached: self.on_attached += on_attached if on_detached: self.on_detached += on_detached self._running = False def stop(self): """ Stops the thread. """ self._running = False def run(self): """ The actual detection process. """ self._running = True last_devices = set() while self._running: try: current_devices = set(USBDevice.find_all()) for dev in current_devices.difference(last_devices): self.on_attached(device=dev) for dev in last_devices.difference(current_devices): self.on_detached(device=dev) last_devices = current_devices except CommError: pass time.sleep(0.25)
class USBDevice(Device): """ `AD2USB`_ device utilizing PyFTDI's interface. """ # Constants PRODUCT_IDS = ((0x0403, 0x6001), (0x0403, 0x6015)) """List of Vendor and Product IDs used to recognize `AD2USB`_ devices.""" DEFAULT_VENDOR_ID = PRODUCT_IDS[0][0] """Default Vendor ID used to recognize `AD2USB`_ devices.""" DEFAULT_PRODUCT_ID = PRODUCT_IDS[0][1] """Default Product ID used to recognize `AD2USB`_ devices.""" # Deprecated constants FTDI_VENDOR_ID = DEFAULT_VENDOR_ID """DEPRECATED: Vendor ID used to recognize `AD2USB`_ devices.""" FTDI_PRODUCT_ID = DEFAULT_PRODUCT_ID """DEPRECATED: Product ID used to recognize `AD2USB`_ devices.""" BAUDRATE = 115200 """Default baudrate for `AD2USB`_ devices.""" __devices = [] __detect_thread = None @classmethod def find_all(cls, vid=None, pid=None): """ Returns all FTDI devices matching our vendor and product IDs. :returns: list of devices :raises: :py:class:`~alarmdecoder.util.CommError` """ if not have_pyftdi: raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.') cls.__devices = [] query = cls.PRODUCT_IDS if vid and pid: query = [(vid, pid)] try: cls.__devices = Ftdi.find_all(query, nocache=True) except (usb.core.USBError, FtdiError) as err: raise CommError('Error enumerating AD2USB devices: {0}'.format(str(err)), err) return cls.__devices @classmethod def devices(cls): """ Returns a cached list of `AD2USB`_ devices located on the system. :returns: cached list of devices found """ return cls.__devices @classmethod def find(cls, device=None): """ Factory method that returns the requested :py:class:`USBDevice` device, or the first device. :param device: Tuple describing the USB device to open, as returned by find_all(). :type device: tuple :returns: :py:class:`USBDevice` object utilizing the specified device :raises: :py:class:`~alarmdecoder.util.NoDeviceError` """ if not have_pyftdi: raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.') cls.find_all() if len(cls.__devices) == 0: raise NoDeviceError('No AD2USB devices present.') if device is None: device = cls.__devices[0] vendor, product, sernum, ifcount, description = device return USBDevice(interface=sernum, vid=vendor, pid=product) @classmethod def start_detection(cls, on_attached=None, on_detached=None): """ Starts the device detection thread. :param on_attached: function to be called when a device is attached **Callback definition:** *def callback(thread, device)* :type on_attached: function :param on_detached: function to be called when a device is detached **Callback definition:** *def callback(thread, device)* :type on_detached: function """ if not have_pyftdi: raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.') cls.__detect_thread = USBDevice.DetectThread(on_attached, on_detached) try: cls.find_all() except CommError: pass cls.__detect_thread.start() @classmethod def stop_detection(cls): """ Stops the device detection thread. """ if not have_pyftdi: raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.') try: cls.__detect_thread.stop() except Exception: pass @property def interface(self): """ Retrieves the interface used to connect to the device. :returns: the interface used to connect to the device """ return self._interface @interface.setter def interface(self, value): """ Sets the interface used to connect to the device. :param value: may specify either the serial number or the device index :type value: string or int """ self._interface = value if isinstance(value, int): self._device_number = value else: self._serial_number = value @property def serial_number(self): """ Retrieves the serial number of the device. :returns: serial number of the device """ return self._serial_number @serial_number.setter def serial_number(self, value): """ Sets the serial number of the device. :param value: serial number of the device :type value: string """ self._serial_number = value @property def description(self): """ Retrieves the description of the device. :returns: description of the device """ return self._description @description.setter def description(self, value): """ Sets the description of the device. :param value: description of the device :type value: string """ self._description = value def __init__(self, interface=0, vid=None, pid=None): """ Constructor :param interface: May specify either the serial number or the device index. :type interface: string or int """ if not have_pyftdi: raise ImportError('The USBDevice class has been disabled due to missing requirement: pyftdi or pyusb.') Device.__init__(self) self._device = Ftdi() self._interface = 0 self._device_number = 0 self._serial_number = None self._vendor_id = USBDevice.DEFAULT_VENDOR_ID if vid: self._vendor_id = vid self._product_id = USBDevice.DEFAULT_PRODUCT_ID if pid: self._product_id = pid self._endpoint = 0 self._description = None self.interface = interface def open(self, baudrate=BAUDRATE, no_reader_thread=False): """ Opens the device. :param baudrate: baudrate to use :type baudrate: int :param no_reader_thread: whether or not to automatically start the reader thread. :type no_reader_thread: bool :raises: :py:class:`~alarmdecoder.util.NoDeviceError` """ # Set up defaults if baudrate is None: baudrate = USBDevice.BAUDRATE self._read_thread = Device.ReadThread(self) # Open the device and start up the thread. try: self._device.open(self._vendor_id, self._product_id, self._endpoint, self._device_number, self._serial_number, self._description) self._device.set_baudrate(baudrate) if not self._serial_number: self._serial_number = self._get_serial_number() self._id = self._serial_number except (usb.core.USBError, FtdiError) as err: raise NoDeviceError('Error opening device: {0}'.format(str(err)), err) except KeyError as err: raise NoDeviceError('Unsupported device. ({0:04x}:{1:04x}) You probably need a newer version of pyftdi.'.format(err[0][0], err[0][1])) else: self._running = True self.on_open() if not no_reader_thread: self._read_thread.start() return self def close(self): """ Closes the device. """ try: Device.close(self) # HACK: Probably should fork pyftdi and make this call in .close() self._device.usb_dev.attach_kernel_driver(self._device_number) except Exception: pass def fileno(self): """ File number not supported for USB devices. :raises: NotImplementedError """ raise NotImplementedError('USB devices do not support fileno()') def write(self, data): """ Writes data to the device. :param data: data to write :type data: string :raises: :py:class:`~alarmdecoder.util.CommError` """ try: self._device.write_data(data) self.on_write(data=data) except FtdiError as err: raise CommError('Error writing to device: {0}'.format(str(err)), err) def read(self): """ Reads a single character from the device. :returns: character read from the device :raises: :py:class:`~alarmdecoder.util.CommError` """ ret = None try: ret = self._device.read_data(1) except (usb.core.USBError, FtdiError) as err: raise CommError('Error reading from device: {0}'.format(str(err)), err) return ret def read_line(self, timeout=0.0, purge_buffer=False): """ Reads a line from the device. :param timeout: read timeout :type timeout: float :param purge_buffer: Indicates whether to purge the buffer prior to reading. :type purge_buffer: bool :returns: line that was read :raises: :py:class:`~alarmdecoder.util.CommError`, :py:class:`~alarmdecoder.util.TimeoutError` """ def timeout_event(): """Handles read timeout event""" timeout_event.reading = False timeout_event.reading = True if purge_buffer: self._buffer = b'' got_line, ret = False, None timer = threading.Timer(timeout, timeout_event) if timeout > 0: timer.start() try: while timeout_event.reading: buf = self._device.read_data(1) if buf != b'': ub = bytes_hack(buf) self._buffer += ub if ub == b"\n": self._buffer = self._buffer.rstrip(b"\r\n") if len(self._buffer) > 0: got_line = True break else: time.sleep(0.01) except (usb.core.USBError, FtdiError) as err: raise CommError('Error reading from device: {0}'.format(str(err)), err) else: if got_line: ret, self._buffer = self._buffer, b'' self.on_read(data=ret) else: raise TimeoutError('Timeout while waiting for line terminator.') finally: timer.cancel() return ret def purge(self): """ Purges read/write buffers. """ self._device.purge_buffers() def _get_serial_number(self): """ Retrieves the FTDI device serial number. :returns: string containing the device serial number """ return usb.util.get_string(self._device.usb_dev, 64, self._device.usb_dev.iSerialNumber) class DetectThread(threading.Thread): """ Thread that handles detection of added/removed devices. """ on_attached = event.Event("This event is called when an `AD2USB`_ device has been detected.\n\n**Callback definition:** def callback(thread, device*") on_detached = event.Event("This event is called when an `AD2USB`_ device has been removed.\n\n**Callback definition:** def callback(thread, device*") def __init__(self, on_attached=None, on_detached=None): """ Constructor :param on_attached: Function to call when a device is attached **Callback definition:** *def callback(thread, device)* :type on_attached: function :param on_detached: Function to call when a device is detached **Callback definition:** *def callback(thread, device)* :type on_detached: function """ threading.Thread.__init__(self) if on_attached: self.on_attached += on_attached if on_detached: self.on_detached += on_detached self._running = False def stop(self): """ Stops the thread. """ self._running = False def run(self): """ The actual detection process. """ self._running = True last_devices = set() while self._running: try: current_devices = set(USBDevice.find_all()) for dev in current_devices.difference(last_devices): self.on_attached(device=dev) for dev in last_devices.difference(current_devices): self.on_detached(device=dev) last_devices = current_devices except CommError: pass time.sleep(0.25)