478 lines
20 KiB
Python
478 lines
20 KiB
Python
#! python
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#
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# backend for Windows ("win32" incl. 32/64 bit support)
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#
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# (C) 2001-2020 Chris Liechti <cliechti@gmx.net>
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#
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# This file is part of pySerial. https://github.com/pyserial/pyserial
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# SPDX-License-Identifier: BSD-3-Clause
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#
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# Initial patch to use ctypes by Giovanni Bajo <rasky@develer.com>
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from __future__ import absolute_import
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# pylint: disable=invalid-name,too-few-public-methods
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import ctypes
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import time
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from serial import win32
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import serial
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from serial.serialutil import SerialBase, SerialException, to_bytes, PortNotOpenError, SerialTimeoutException
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class Serial(SerialBase):
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"""Serial port implementation for Win32 based on ctypes."""
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BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
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9600, 19200, 38400, 57600, 115200)
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def __init__(self, *args, **kwargs):
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self._port_handle = None
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self._overlapped_read = None
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self._overlapped_write = None
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super(Serial, self).__init__(*args, **kwargs)
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def open(self):
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"""\
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Open port with current settings. This may throw a SerialException
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if the port cannot be opened.
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"""
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if self._port is None:
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raise SerialException("Port must be configured before it can be used.")
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if self.is_open:
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raise SerialException("Port is already open.")
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# the "\\.\COMx" format is required for devices other than COM1-COM8
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# not all versions of windows seem to support this properly
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# so that the first few ports are used with the DOS device name
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port = self.name
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try:
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if port.upper().startswith('COM') and int(port[3:]) > 8:
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port = '\\\\.\\' + port
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except ValueError:
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# for like COMnotanumber
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pass
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self._port_handle = win32.CreateFile(
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port,
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win32.GENERIC_READ | win32.GENERIC_WRITE,
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0, # exclusive access
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None, # no security
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win32.OPEN_EXISTING,
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win32.FILE_ATTRIBUTE_NORMAL | win32.FILE_FLAG_OVERLAPPED,
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0)
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if self._port_handle == win32.INVALID_HANDLE_VALUE:
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self._port_handle = None # 'cause __del__ is called anyway
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raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))
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try:
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self._overlapped_read = win32.OVERLAPPED()
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self._overlapped_read.hEvent = win32.CreateEvent(None, 1, 0, None)
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self._overlapped_write = win32.OVERLAPPED()
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#~ self._overlapped_write.hEvent = win32.CreateEvent(None, 1, 0, None)
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self._overlapped_write.hEvent = win32.CreateEvent(None, 0, 0, None)
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# Setup a 4k buffer
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win32.SetupComm(self._port_handle, 4096, 4096)
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# Save original timeout values:
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self._orgTimeouts = win32.COMMTIMEOUTS()
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win32.GetCommTimeouts(self._port_handle, ctypes.byref(self._orgTimeouts))
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self._reconfigure_port()
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# Clear buffers:
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# Remove anything that was there
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win32.PurgeComm(
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self._port_handle,
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win32.PURGE_TXCLEAR | win32.PURGE_TXABORT |
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win32.PURGE_RXCLEAR | win32.PURGE_RXABORT)
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except:
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try:
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self._close()
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except:
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# ignore any exception when closing the port
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# also to keep original exception that happened when setting up
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pass
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self._port_handle = None
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raise
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else:
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self.is_open = True
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def _reconfigure_port(self):
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"""Set communication parameters on opened port."""
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if not self._port_handle:
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raise SerialException("Can only operate on a valid port handle")
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# Set Windows timeout values
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# timeouts is a tuple with the following items:
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# (ReadIntervalTimeout,ReadTotalTimeoutMultiplier,
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# ReadTotalTimeoutConstant,WriteTotalTimeoutMultiplier,
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# WriteTotalTimeoutConstant)
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timeouts = win32.COMMTIMEOUTS()
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if self._timeout is None:
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pass # default of all zeros is OK
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elif self._timeout == 0:
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timeouts.ReadIntervalTimeout = win32.MAXDWORD
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else:
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timeouts.ReadTotalTimeoutConstant = max(int(self._timeout * 1000), 1)
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if self._timeout != 0 and self._inter_byte_timeout is not None:
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timeouts.ReadIntervalTimeout = max(int(self._inter_byte_timeout * 1000), 1)
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if self._write_timeout is None:
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pass
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elif self._write_timeout == 0:
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timeouts.WriteTotalTimeoutConstant = win32.MAXDWORD
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else:
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timeouts.WriteTotalTimeoutConstant = max(int(self._write_timeout * 1000), 1)
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win32.SetCommTimeouts(self._port_handle, ctypes.byref(timeouts))
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win32.SetCommMask(self._port_handle, win32.EV_ERR)
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# Setup the connection info.
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# Get state and modify it:
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comDCB = win32.DCB()
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win32.GetCommState(self._port_handle, ctypes.byref(comDCB))
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comDCB.BaudRate = self._baudrate
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if self._bytesize == serial.FIVEBITS:
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comDCB.ByteSize = 5
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elif self._bytesize == serial.SIXBITS:
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comDCB.ByteSize = 6
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elif self._bytesize == serial.SEVENBITS:
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comDCB.ByteSize = 7
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elif self._bytesize == serial.EIGHTBITS:
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comDCB.ByteSize = 8
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else:
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raise ValueError("Unsupported number of data bits: {!r}".format(self._bytesize))
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if self._parity == serial.PARITY_NONE:
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comDCB.Parity = win32.NOPARITY
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comDCB.fParity = 0 # Disable Parity Check
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elif self._parity == serial.PARITY_EVEN:
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comDCB.Parity = win32.EVENPARITY
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comDCB.fParity = 1 # Enable Parity Check
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elif self._parity == serial.PARITY_ODD:
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comDCB.Parity = win32.ODDPARITY
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comDCB.fParity = 1 # Enable Parity Check
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elif self._parity == serial.PARITY_MARK:
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comDCB.Parity = win32.MARKPARITY
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comDCB.fParity = 1 # Enable Parity Check
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elif self._parity == serial.PARITY_SPACE:
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comDCB.Parity = win32.SPACEPARITY
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comDCB.fParity = 1 # Enable Parity Check
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else:
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raise ValueError("Unsupported parity mode: {!r}".format(self._parity))
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if self._stopbits == serial.STOPBITS_ONE:
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comDCB.StopBits = win32.ONESTOPBIT
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elif self._stopbits == serial.STOPBITS_ONE_POINT_FIVE:
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comDCB.StopBits = win32.ONE5STOPBITS
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elif self._stopbits == serial.STOPBITS_TWO:
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comDCB.StopBits = win32.TWOSTOPBITS
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else:
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raise ValueError("Unsupported number of stop bits: {!r}".format(self._stopbits))
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comDCB.fBinary = 1 # Enable Binary Transmission
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# Char. w/ Parity-Err are replaced with 0xff (if fErrorChar is set to TRUE)
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if self._rs485_mode is None:
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if self._rtscts:
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comDCB.fRtsControl = win32.RTS_CONTROL_HANDSHAKE
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else:
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comDCB.fRtsControl = win32.RTS_CONTROL_ENABLE if self._rts_state else win32.RTS_CONTROL_DISABLE
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comDCB.fOutxCtsFlow = self._rtscts
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else:
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# checks for unsupported settings
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# XXX verify if platform really does not have a setting for those
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if not self._rs485_mode.rts_level_for_tx:
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raise ValueError(
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'Unsupported value for RS485Settings.rts_level_for_tx: {!r} (only True is allowed)'.format(
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self._rs485_mode.rts_level_for_tx,))
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if self._rs485_mode.rts_level_for_rx:
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raise ValueError(
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'Unsupported value for RS485Settings.rts_level_for_rx: {!r} (only False is allowed)'.format(
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self._rs485_mode.rts_level_for_rx,))
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if self._rs485_mode.delay_before_tx is not None:
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raise ValueError(
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'Unsupported value for RS485Settings.delay_before_tx: {!r} (only None is allowed)'.format(
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self._rs485_mode.delay_before_tx,))
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if self._rs485_mode.delay_before_rx is not None:
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raise ValueError(
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'Unsupported value for RS485Settings.delay_before_rx: {!r} (only None is allowed)'.format(
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self._rs485_mode.delay_before_rx,))
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if self._rs485_mode.loopback:
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raise ValueError(
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'Unsupported value for RS485Settings.loopback: {!r} (only False is allowed)'.format(
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self._rs485_mode.loopback,))
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comDCB.fRtsControl = win32.RTS_CONTROL_TOGGLE
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comDCB.fOutxCtsFlow = 0
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if self._dsrdtr:
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comDCB.fDtrControl = win32.DTR_CONTROL_HANDSHAKE
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else:
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comDCB.fDtrControl = win32.DTR_CONTROL_ENABLE if self._dtr_state else win32.DTR_CONTROL_DISABLE
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comDCB.fOutxDsrFlow = self._dsrdtr
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comDCB.fOutX = self._xonxoff
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comDCB.fInX = self._xonxoff
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comDCB.fNull = 0
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comDCB.fErrorChar = 0
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comDCB.fAbortOnError = 0
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comDCB.XonChar = serial.XON
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comDCB.XoffChar = serial.XOFF
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if not win32.SetCommState(self._port_handle, ctypes.byref(comDCB)):
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raise SerialException(
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'Cannot configure port, something went wrong. '
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'Original message: {!r}'.format(ctypes.WinError()))
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#~ def __del__(self):
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#~ self.close()
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def _close(self):
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"""internal close port helper"""
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if self._port_handle is not None:
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# Restore original timeout values:
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win32.SetCommTimeouts(self._port_handle, self._orgTimeouts)
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if self._overlapped_read is not None:
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self.cancel_read()
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win32.CloseHandle(self._overlapped_read.hEvent)
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self._overlapped_read = None
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if self._overlapped_write is not None:
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self.cancel_write()
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win32.CloseHandle(self._overlapped_write.hEvent)
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self._overlapped_write = None
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win32.CloseHandle(self._port_handle)
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self._port_handle = None
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def close(self):
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"""Close port"""
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if self.is_open:
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self._close()
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self.is_open = False
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# - - - - - - - - - - - - - - - - - - - - - - - -
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@property
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def in_waiting(self):
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"""Return the number of bytes currently in the input buffer."""
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flags = win32.DWORD()
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comstat = win32.COMSTAT()
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if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)):
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raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError()))
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return comstat.cbInQue
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def read(self, size=1):
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"""\
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Read size bytes from the serial port. If a timeout is set it may
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return less characters as requested. With no timeout it will block
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until the requested number of bytes is read.
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"""
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if not self.is_open:
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raise PortNotOpenError()
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if size > 0:
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win32.ResetEvent(self._overlapped_read.hEvent)
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flags = win32.DWORD()
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comstat = win32.COMSTAT()
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if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)):
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raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError()))
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n = min(comstat.cbInQue, size) if self.timeout == 0 else size
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if n > 0:
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buf = ctypes.create_string_buffer(n)
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rc = win32.DWORD()
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read_ok = win32.ReadFile(
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self._port_handle,
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buf,
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n,
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ctypes.byref(rc),
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ctypes.byref(self._overlapped_read))
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if not read_ok and win32.GetLastError() not in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING):
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raise SerialException("ReadFile failed ({!r})".format(ctypes.WinError()))
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result_ok = win32.GetOverlappedResult(
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self._port_handle,
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ctypes.byref(self._overlapped_read),
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ctypes.byref(rc),
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True)
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if not result_ok:
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if win32.GetLastError() != win32.ERROR_OPERATION_ABORTED:
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raise SerialException("GetOverlappedResult failed ({!r})".format(ctypes.WinError()))
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read = buf.raw[:rc.value]
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else:
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read = bytes()
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else:
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read = bytes()
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return bytes(read)
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def write(self, data):
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"""Output the given byte string over the serial port."""
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if not self.is_open:
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raise PortNotOpenError()
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#~ if not isinstance(data, (bytes, bytearray)):
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#~ raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data)))
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# convert data (needed in case of memoryview instance: Py 3.1 io lib), ctypes doesn't like memoryview
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data = to_bytes(data)
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if data:
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#~ win32event.ResetEvent(self._overlapped_write.hEvent)
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n = win32.DWORD()
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success = win32.WriteFile(self._port_handle, data, len(data), ctypes.byref(n), self._overlapped_write)
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if self._write_timeout != 0: # if blocking (None) or w/ write timeout (>0)
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if not success and win32.GetLastError() not in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING):
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raise SerialException("WriteFile failed ({!r})".format(ctypes.WinError()))
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# Wait for the write to complete.
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#~ win32.WaitForSingleObject(self._overlapped_write.hEvent, win32.INFINITE)
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win32.GetOverlappedResult(self._port_handle, self._overlapped_write, ctypes.byref(n), True)
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if win32.GetLastError() == win32.ERROR_OPERATION_ABORTED:
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return n.value # canceled IO is no error
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if n.value != len(data):
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raise SerialTimeoutException('Write timeout')
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return n.value
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else:
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errorcode = win32.ERROR_SUCCESS if success else win32.GetLastError()
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if errorcode in (win32.ERROR_INVALID_USER_BUFFER, win32.ERROR_NOT_ENOUGH_MEMORY,
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win32.ERROR_OPERATION_ABORTED):
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return 0
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elif errorcode in (win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING):
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# no info on true length provided by OS function in async mode
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return len(data)
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else:
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raise SerialException("WriteFile failed ({!r})".format(ctypes.WinError()))
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else:
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return 0
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def flush(self):
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"""\
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Flush of file like objects. In this case, wait until all data
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is written.
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"""
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while self.out_waiting:
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time.sleep(0.05)
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# XXX could also use WaitCommEvent with mask EV_TXEMPTY, but it would
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# require overlapped IO and it's also only possible to set a single mask
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# on the port---
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def reset_input_buffer(self):
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"""Clear input buffer, discarding all that is in the buffer."""
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if not self.is_open:
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raise PortNotOpenError()
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win32.PurgeComm(self._port_handle, win32.PURGE_RXCLEAR | win32.PURGE_RXABORT)
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def reset_output_buffer(self):
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"""\
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Clear output buffer, aborting the current output and discarding all
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that is in the buffer.
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"""
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if not self.is_open:
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raise PortNotOpenError()
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win32.PurgeComm(self._port_handle, win32.PURGE_TXCLEAR | win32.PURGE_TXABORT)
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def _update_break_state(self):
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"""Set break: Controls TXD. When active, to transmitting is possible."""
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if not self.is_open:
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raise PortNotOpenError()
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if self._break_state:
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win32.SetCommBreak(self._port_handle)
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else:
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win32.ClearCommBreak(self._port_handle)
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def _update_rts_state(self):
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"""Set terminal status line: Request To Send"""
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if self._rts_state:
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win32.EscapeCommFunction(self._port_handle, win32.SETRTS)
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else:
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win32.EscapeCommFunction(self._port_handle, win32.CLRRTS)
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def _update_dtr_state(self):
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"""Set terminal status line: Data Terminal Ready"""
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if self._dtr_state:
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win32.EscapeCommFunction(self._port_handle, win32.SETDTR)
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else:
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win32.EscapeCommFunction(self._port_handle, win32.CLRDTR)
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def _GetCommModemStatus(self):
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if not self.is_open:
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raise PortNotOpenError()
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stat = win32.DWORD()
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win32.GetCommModemStatus(self._port_handle, ctypes.byref(stat))
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return stat.value
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@property
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def cts(self):
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"""Read terminal status line: Clear To Send"""
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return win32.MS_CTS_ON & self._GetCommModemStatus() != 0
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@property
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def dsr(self):
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"""Read terminal status line: Data Set Ready"""
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return win32.MS_DSR_ON & self._GetCommModemStatus() != 0
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@property
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def ri(self):
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"""Read terminal status line: Ring Indicator"""
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return win32.MS_RING_ON & self._GetCommModemStatus() != 0
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@property
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def cd(self):
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"""Read terminal status line: Carrier Detect"""
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return win32.MS_RLSD_ON & self._GetCommModemStatus() != 0
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# - - platform specific - - - -
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def set_buffer_size(self, rx_size=4096, tx_size=None):
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"""\
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Recommend a buffer size to the driver (device driver can ignore this
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value). Must be called after the port is opened.
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"""
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if tx_size is None:
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tx_size = rx_size
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win32.SetupComm(self._port_handle, rx_size, tx_size)
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def set_output_flow_control(self, enable=True):
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"""\
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Manually control flow - when software flow control is enabled.
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This will do the same as if XON (true) or XOFF (false) are received
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from the other device and control the transmission accordingly.
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WARNING: this function is not portable to different platforms!
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"""
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if not self.is_open:
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raise PortNotOpenError()
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if enable:
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win32.EscapeCommFunction(self._port_handle, win32.SETXON)
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else:
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win32.EscapeCommFunction(self._port_handle, win32.SETXOFF)
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@property
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def out_waiting(self):
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"""Return how many bytes the in the outgoing buffer"""
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flags = win32.DWORD()
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comstat = win32.COMSTAT()
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if not win32.ClearCommError(self._port_handle, ctypes.byref(flags), ctypes.byref(comstat)):
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raise SerialException("ClearCommError failed ({!r})".format(ctypes.WinError()))
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return comstat.cbOutQue
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def _cancel_overlapped_io(self, overlapped):
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|
"""Cancel a blocking read operation, may be called from other thread"""
|
|
# check if read operation is pending
|
|
rc = win32.DWORD()
|
|
err = win32.GetOverlappedResult(
|
|
self._port_handle,
|
|
ctypes.byref(overlapped),
|
|
ctypes.byref(rc),
|
|
False)
|
|
if not err and win32.GetLastError() in (win32.ERROR_IO_PENDING, win32.ERROR_IO_INCOMPLETE):
|
|
# cancel, ignoring any errors (e.g. it may just have finished on its own)
|
|
win32.CancelIoEx(self._port_handle, overlapped)
|
|
|
|
def cancel_read(self):
|
|
"""Cancel a blocking read operation, may be called from other thread"""
|
|
self._cancel_overlapped_io(self._overlapped_read)
|
|
|
|
def cancel_write(self):
|
|
"""Cancel a blocking write operation, may be called from other thread"""
|
|
self._cancel_overlapped_io(self._overlapped_write)
|
|
|
|
@SerialBase.exclusive.setter
|
|
def exclusive(self, exclusive):
|
|
"""Change the exclusive access setting."""
|
|
if exclusive is not None and not exclusive:
|
|
raise ValueError('win32 only supports exclusive access (not: {})'.format(exclusive))
|
|
else:
|
|
serial.SerialBase.exclusive.__set__(self, exclusive)
|