Pregunta

Estoy tratando de conectarme a mi teléfono desde mi PC con Windows 7 usando Pyserial con el siguiente código:

import wmi
import serial

c = wmi.WMI()
modem = c.query("SELECT * FROM Win32_POTSModem").pop()
ser = serial.Serial(modem.AttachedTo, modem.MaxBaudRateToSerialPort)

try:
    ser.write('at \r\n')
    print ser.readline()
finally:
    ser.close()

Pero obtenga el siguiente error en la llamada de escritura:

Traceback (most recent call last):
  File "D:\Alasdair\Documents\Python Scripts\Phone Interface\test.py", line 14, in <module>
    ser.write('at \r\n')
  File "C:\Python26\Lib\site-packages\serial\serialwin32.py", line 255, in write
    raise SerialException("WriteFile failed (%s)" % ctypes.WinError())
SerialException: WriteFile failed ([Error 6] The handle is invalid.)

He intentado conectarme con Teraterm y eso funciona bien, por lo que no es un problema con la conexión al teléfono en sí.

He estado buscando en busca de años tratando de encontrar una solución, pero no he encontrado nada que funcione. ¿Algunas ideas?

¿Fue útil?

Solución

Estoy en Windows 7 de 64 bits, con Python 2.6, y me está dando el mismo error.

ser = serial.Serial(3,115200,timeout=1)
ser.read()
#or ser.write("whatever")

Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>
    ser.read(1)
  File "build\bdist.win-amd64\egg\serial\serialwin32.py", line 236, in read
    raise SerialException("ReadFile failed (%s)" % ctypes.WinError())
SerialException: ReadFile failed ([Error 6] The handle is invalid.)

Cuando se usa un programa similar usando la biblioteca de CA, el mismo puerto responde correctamente. ¿Qué pasa aquí? Suena como un error en Pyserial o Ctypes. ¿Estás usando 64 bit también?

El código fuente para escribir en pyserial se ve muy simple

def write(self, data):
        """Output the given string over the serial port."""
        if not self.hComPort: raise portNotOpenError
        #~ if not isinstance(data, (bytes, bytearray)):
            #~ raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data)))
        # convert data (needed in case of memoryview instance: Py 3.1 io lib), ctypes doesn't like memoryview
        data = bytes(data)
        if data:
            #~ win32event.ResetEvent(self._overlappedWrite.hEvent)
            n = win32.DWORD()
            err = win32.WriteFile(self.hComPort, data, len(data), ctypes.byref(n), self._overlappedWrite)
            if not err and win32.GetLastError() != win32.ERROR_IO_PENDING:
                raise SerialException("WriteFile failed (%s)" % ctypes.WinError())

¿Quizás un problema con ctypes de 64 bits?


Actualización: definitivamente un problema de 64 bits al menos para mí. Acabo de instalar una versión x86 de Python (3.1 esta vez), y ahora funciona bien. Aeligando CTYPES de 64 bits solo puede importar bibliotecas de 64 bits. Sin embargo, suena muy extraño no poder llegar a las bibliotecas del sistema operativo.

Otros consejos

Acabo de solucionar este problema en Windows de 64 bits (XP, Vista y 7).

Este problema es causado por la fundición del mango no válido que descarta el valor superior de 32 bits de 64 bits debido a las antiguas funciones de Python-Win32. Si enfrentó este tipo de problema, utilice las nuevas funciones Python-Win32 que se incluye en los módulos Win32File, etc. Escriba el siguiente código a través de los paquetes de sitio Serial Serialwin32.py.

#! python
# Python Serial Port Extension for Win32, Linux, BSD, Jython
# serial driver for win32
# see __init__.py
#
# (C) 2001-2009 Chris Liechti <cliechti@gmx.net>
# this is distributed under a free software license, see license.txt
#
# Initial patch to use ctypes by Giovanni Bajo <rasky@develer.com>

import ctypes
import win32
import win32file
import win32con
import pywintypes

from serialutil import *

def device(portnum):
    """Turn a port number into a device name"""
    return 'COM%d' % (portnum+1) # numbers are transformed to a string

class Win32Serial(SerialBase):
    """Serial port implementation for Win32 based on ctypes."""

    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
                 9600, 19200, 38400, 57600, 115200)

    def __init__(self, *args, **kwargs):
        self.hComPort = None
        SerialBase.__init__(self, *args, **kwargs)

    def open(self):
        """Open port with current settings. This may throw a SerialException
           if the port cannot be opened."""
        if self._port is None:
            raise SerialException("Port must be configured before it can be used.")
        # the "\\.\COMx" format is required for devices other than COM1-COM8
        # not all versions of windows seem to support this properly
        # so that the first few ports are used with the DOS device name
        port = self.portstr
        try:
            if port.upper().startswith('COM') and int(port[3:]) > 8:
                port = '\\\\.\\' + port
        except ValueError:
            # for like COMnotanumber
            pass
        self.hComPort = win32file.CreateFile(port,
               win32con.GENERIC_READ | win32con.GENERIC_WRITE,
               0, # exclusive access
               None, # no security
               win32con.OPEN_EXISTING,
               win32con.FILE_ATTRIBUTE_NORMAL | win32con.FILE_FLAG_OVERLAPPED,
               0)
        if self.hComPort == win32.INVALID_HANDLE_VALUE:
            self.hComPort = None    # 'cause __del__ is called anyway
            raise SerialException("could not open port %s: %s" % (self.portstr, ctypes.WinError()))

        # Setup a 4k buffer
        win32file.SetupComm(self.hComPort, 4096, 4096)

        # Save original timeout values:
        tos = win32file.GetCommTimeouts(self.hComPort)
        self._orgTimeouts = win32.COMMTIMEOUTS(*tos)
        self._rtsState = win32.RTS_CONTROL_ENABLE
        self._dtrState = win32.DTR_CONTROL_ENABLE

        self._reconfigurePort()

        # Clear buffers:
        # Remove anything that was there
        win32file.PurgeComm(self.hComPort,
                            win32.PURGE_TXCLEAR | win32.PURGE_TXABORT |
                            win32.PURGE_RXCLEAR | win32.PURGE_RXABORT)

        self._overlappedRead = pywintypes.OVERLAPPED()
        self._overlappedRead.hEvent = win32.CreateEvent(None, 1, 0, None)
        self._overlappedWrite = pywintypes.OVERLAPPED()
        #~ self._overlappedWrite.hEvent = win32.CreateEvent(None, 1, 0, None)
        self._overlappedWrite.hEvent = win32.CreateEvent(None, 0, 0, None)
        self._isOpen = True

    def _reconfigurePort(self):
        """Set communication parameters on opened port."""
        if not self.hComPort:
            raise SerialException("Can only operate on a valid port handle")

        # Set Windows timeout values
        # timeouts is a tuple with the following items:
        # (ReadIntervalTimeout,ReadTotalTimeoutMultiplier,
        #  ReadTotalTimeoutConstant,WriteTotalTimeoutMultiplier,
        #  WriteTotalTimeoutConstant)
        if self._timeout is None:
            timeouts = (0, 0, 0, 0, 0)
        elif self._timeout == 0:
            timeouts = (win32.MAXDWORD, 0, 0, 0, 0)
        else:
            timeouts = (0, 0, int(self._timeout*1000), 0, 0)
        if self._timeout != 0 and self._interCharTimeout is not None:
            timeouts = (int(self._interCharTimeout * 1000),) + timeouts[1:]

        if self._writeTimeout is None:
            pass
        elif self._writeTimeout == 0:
            timeouts = timeouts[:-2] + (0, win32.MAXDWORD)
        else:
            timeouts = timeouts[:-2] + (0, int(self._writeTimeout*1000))
        win32file.SetCommTimeouts(self.hComPort, timeouts)

        win32file.SetCommMask(self.hComPort, win32.EV_ERR)

        # Setup the connection info.
        # Get state and modify it:
        comDCB = win32file.GetCommState(self.hComPort)
        comDCB.BaudRate = self._baudrate

        if self._bytesize == FIVEBITS:
            comDCB.ByteSize     = 5
        elif self._bytesize == SIXBITS:
            comDCB.ByteSize     = 6
        elif self._bytesize == SEVENBITS:
            comDCB.ByteSize     = 7
        elif self._bytesize == EIGHTBITS:
            comDCB.ByteSize     = 8
        else:
            raise ValueError("Unsupported number of data bits: %r" % self._bytesize)

        if self._parity == PARITY_NONE:
            comDCB.Parity       = win32.NOPARITY
            comDCB.fParity      = 0 # Disable Parity Check
        elif self._parity == PARITY_EVEN:
            comDCB.Parity       = win32.EVENPARITY
            comDCB.fParity      = 1 # Enable Parity Check
        elif self._parity == PARITY_ODD:
            comDCB.Parity       = win32.ODDPARITY
            comDCB.fParity      = 1 # Enable Parity Check
        elif self._parity == PARITY_MARK:
            comDCB.Parity       = win32.MARKPARITY
            comDCB.fParity      = 1 # Enable Parity Check
        elif self._parity == PARITY_SPACE:
            comDCB.Parity       = win32.SPACEPARITY
            comDCB.fParity      = 1 # Enable Parity Check
        else:
            raise ValueError("Unsupported parity mode: %r" % self._parity)

        if self._stopbits == STOPBITS_ONE:
            comDCB.StopBits     = win32.ONESTOPBIT
        elif self._stopbits == STOPBITS_ONE_POINT_FIVE:
            comDCB.StopBits     = win32.ONE5STOPBITS
        elif self._stopbits == STOPBITS_TWO:
            comDCB.StopBits     = win32.TWOSTOPBITS
        else:
            raise ValueError("Unsupported number of stop bits: %r" % self._stopbits)

        comDCB.fBinary          = 1 # Enable Binary Transmission
        # Char. w/ Parity-Err are replaced with 0xff (if fErrorChar is set to TRUE)
        if self._rtscts:
            comDCB.fRtsControl  = win32.RTS_CONTROL_HANDSHAKE
        else:
            comDCB.fRtsControl  = self._rtsState
        if self._dsrdtr:
            comDCB.fDtrControl  = win32.DTR_CONTROL_HANDSHAKE
        else:
            comDCB.fDtrControl  = self._dtrState
        comDCB.fOutxCtsFlow     = self._rtscts
        comDCB.fOutxDsrFlow     = self._dsrdtr
        comDCB.fOutX            = self._xonxoff
        comDCB.fInX             = self._xonxoff
        comDCB.fNull            = 0
        comDCB.fErrorChar       = 0
        comDCB.fAbortOnError    = 0
        comDCB.XonChar          = XON
        comDCB.XoffChar         = XOFF
        win32file.SetCommState(self.hComPort, comDCB)

    #~ def __del__(self):
        #~ self.close()

    def close(self):
        """Close port"""
        if self._isOpen:
            if self.hComPort:
                # Restore original timeout values:
                win32file.SetCommTimeouts(self.hComPort, self._orgTimeouts)
                # Close COM-Port:
                win32file.CloseHandle(self.hComPort)
                win32file.CloseHandle(self._overlappedRead.hEvent)
                win32file.CloseHandle(self._overlappedWrite.hEvent)
                self.hComPort = None
            self._isOpen = False

    def makeDeviceName(self, port):
        return device(port)

    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

    def inWaiting(self):
        """Return the number of characters currently in the input buffer."""
        flags = win32.DWORD()
        comstat = win32.COMSTAT()
        if not win32file.ClearCommError(self.hComPort, ctypes.byref(flags), ctypes.byref(comstat)):
            raise SerialException('call to ClearCommError failed')
        return comstat.cbInQue

    def read(self, size=1):
        """Read size bytes from the serial port. If a timeout is set it may
           return less characters as requested. With no timeout it will block
           until the requested number of bytes is read."""
        if not self.hComPort: raise portNotOpenError
        if size > 0:
            win32.ResetEvent(self._overlappedRead.hEvent)
            if not win32file.ClearCommError(self.hComPort):
                raise SerialException('call to ClearCommError failed')
            if self.timeout == 0:
                n = min(comstat.cbInQue, size)
                if n > 0:
                    rc,buf = win32file.ReadFile(self.hComPort, n, self._overlappedRead)
                    if win32.GetLastError() != win32.ERROR_IO_PENDING:
                        raise SerialException("ReadFile failed (%s)" % ctypes.WinError())
                    err = win32.WaitForSingleObject(self._overlappedRead.hEvent, win32.INFINITE)
                    read = buf[:rc]
                else:
                    read = bytes()
            else:
                rc,buf = win32file.ReadFile(self.hComPort, size, self._overlappedRead)
                rc = win32file.GetOverlappedResult(self.hComPort, self._overlappedRead, True)
                read = buf[:rc]
        else:
            read = bytes()
        return bytes(read)

    def write(self, data):
        """Output the given string over the serial port."""
        if not self.hComPort: raise portNotOpenError
        #~ if not isinstance(data, (bytes, bytearray)):
            #~ raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data)))
        # convert data (needed in case of memoryview instance: Py 3.1 io lib), ctypes doesn't like memoryview
        if data:
            #~ win32event.ResetEvent(self._overlappedWrite.hEvent)
            err,n = win32file.WriteFile(self.hComPort, data, self._overlappedWrite)
            if not err and win32.GetLastError() != win32.ERROR_IO_PENDING:
                raise SerialException("WriteFile failed (%s)" % ctypes.WinError())
            # Wait for the write to complete.
            #~ win32.WaitForSingleObject(self._overlappedWrite.hEvent, win32.INFINITE)
            n = win32file.GetOverlappedResult(self.hComPort, self._overlappedWrite, True)
            if n != len(data):
                raise writeTimeoutError
            return n
        else:
            return 0

    def flushInput(self):
        """Clear input buffer, discarding all that is in the buffer."""
        if not self.hComPort: raise portNotOpenError
        win32.PurgeComm(self.hComPort, win32.PURGE_RXCLEAR | win32.PURGE_RXABORT)

    def flushOutput(self):
        """Clear output buffer, aborting the current output and
        discarding all that is in the buffer."""
        if not self.hComPort: raise portNotOpenError
        win32.PurgeComm(self.hComPort, win32.PURGE_TXCLEAR | win32.PURGE_TXABORT)

    def sendBreak(self, duration=0.25):
        """Send break condition. Timed, returns to idle state after given duration."""
        if not self.hComPort: raise portNotOpenError
        import time
        win32.SetCommBreak(self.hComPort)
        time.sleep(duration)
        win32.ClearCommBreak(self.hComPort)

    def setBreak(self, level=1):
        """Set break: Controls TXD. When active, to transmitting is possible."""
        if not self.hComPort: raise portNotOpenError
        if level:
            win32.SetCommBreak(self.hComPort)
        else:
            win32.ClearCommBreak(self.hComPort)

    def setRTS(self, level=1):
        """Set terminal status line: Request To Send"""
        if not self.hComPort: raise portNotOpenError
        if level:
            self._rtsState = win32.RTS_CONTROL_ENABLE
            win32.EscapeCommFunction(self.hComPort, win32.SETRTS)
        else:
            self._rtsState = win32.RTS_CONTROL_DISABLE
            win32.EscapeCommFunction(self.hComPort, win32.CLRRTS)

    def setDTR(self, level=1):
        """Set terminal status line: Data Terminal Ready"""
        if not self.hComPort: raise portNotOpenError
        if level:
            self._dtrState = win32.DTR_CONTROL_ENABLE
            win32.EscapeCommFunction(self.hComPort, win32.SETDTR)
        else:
            self._dtrState = win32.DTR_CONTROL_DISABLE
            win32.EscapeCommFunction(self.hComPort, win32.CLRDTR)

    def _GetCommModemStatus(self):
        stat = win32.DWORD()
        win32.GetCommModemStatus(self.hComPort, ctypes.byref(stat))
        return stat.value

    def getCTS(self):
        """Read terminal status line: Clear To Send"""
        if not self.hComPort: raise portNotOpenError
        return win32.MS_CTS_ON & self._GetCommModemStatus() != 0

    def getDSR(self):
        """Read terminal status line: Data Set Ready"""
        if not self.hComPort: raise portNotOpenError
        return win32.MS_DSR_ON & self._GetCommModemStatus() != 0

    def getRI(self):
        """Read terminal status line: Ring Indicator"""
        if not self.hComPort: raise portNotOpenError
        return win32.MS_RING_ON & self._GetCommModemStatus() != 0

    def getCD(self):
        """Read terminal status line: Carrier Detect"""
        if not self.hComPort: raise portNotOpenError
        return win32.MS_RLSD_ON & self._GetCommModemStatus() != 0

    # - - platform specific - - - -

    def setXON(self, level=True):
        """Platform specific - set flow state."""
        if not self.hComPort: raise portNotOpenError
        if level:
            win32.EscapeCommFunction(self.hComPort, win32.SETXON)
        else:
            win32.EscapeCommFunction(self.hComPort, win32.SETXOFF)

    def outWaiting(self):
        """return how many characters the in the outgoing buffer"""
        flags = win32.DWORD()
        comstat = win32.COMSTAT()
        if not win32.ClearCommError(self.hComPort, ctypes.byref(flags), ctypes.byref(comstat)):
            raise SerialException('call to ClearCommError failed')
        return comstat.cbOutQue

# assemble Serial class with the platform specific implementation and the base
# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
# library, derive from io.RawIOBase
try:
    import io
except ImportError:
    # classic version with our own file-like emulation
    class Serial(Win32Serial, FileLike):
        pass
else:
    # io library present
    class Serial(Win32Serial, io.RawIOBase):
        pass

# Nur Testfunktion!!
if __name__ == '__main__':
    s = Serial(0)
    sys.stdout.write("%s\n" % s)

    s = Serial()
    sys.stdout.write("%s\n" % s)

    s.baudrate = 19200
    s.databits = 7
    s.close()
    s.port = 0
    s.open()
    sys.stdout.write("%s\n" % s)

Observé este problema con Python 2.7 Win7 X64 y Pyserial 2.5 instalado automáticamente desde Easy_install.exe

El problema no está allí con Pyserial 2.4, por lo que si su código es compatible con 2.4, solo use ese en su lugar y el problema se resuelva. Observe que debe usar Pywin32 también y eligió la versión que corresponde a su Python (por ejemplo, PYWIN32-216.WIN-AMD64-PY2.7.EXE).

Ver también https://sourceforge.net/tracker/?func=detail&aid=2921959&group_id=46487&atid=446302%5D2921959

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