901 lines
34 KiB
Python
901 lines
34 KiB
Python
#!/usr/bin/env python
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#
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# backend for serial IO for POSIX compatible systems, like Linux, OSX
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#
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# This file is part of pySerial. https://github.com/pyserial/pyserial
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# (C) 2001-2020 Chris Liechti <cliechti@gmx.net>
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#
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# SPDX-License-Identifier: BSD-3-Clause
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#
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# parts based on code from Grant B. Edwards <grante@visi.com>:
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# ftp://ftp.visi.com/users/grante/python/PosixSerial.py
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#
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# references: http://www.easysw.com/~mike/serial/serial.html
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# Collection of port names (was previously used by number_to_device which was
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# removed.
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# - Linux /dev/ttyS%d (confirmed)
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# - cygwin/win32 /dev/com%d (confirmed)
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# - openbsd (OpenBSD) /dev/cua%02d
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# - bsd*, freebsd* /dev/cuad%d
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# - darwin (OS X) /dev/cuad%d
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# - netbsd /dev/dty%02d (NetBSD 1.6 testing by Erk)
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# - irix (IRIX) /dev/ttyf%d (partially tested) names depending on flow control
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# - hp (HP-UX) /dev/tty%dp0 (not tested)
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# - sunos (Solaris/SunOS) /dev/tty%c (letters, 'a'..'z') (confirmed)
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# - aix (AIX) /dev/tty%d
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from __future__ import absolute_import
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# pylint: disable=abstract-method
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import errno
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import fcntl
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import os
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import select
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import struct
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import sys
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import termios
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import serial
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from serial.serialutil import SerialBase, SerialException, to_bytes, \
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PortNotOpenError, SerialTimeoutException, Timeout
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class PlatformSpecificBase(object):
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BAUDRATE_CONSTANTS = {}
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def _set_special_baudrate(self, baudrate):
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raise NotImplementedError('non-standard baudrates are not supported on this platform')
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def _set_rs485_mode(self, rs485_settings):
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raise NotImplementedError('RS485 not supported on this platform')
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def set_low_latency_mode(self, low_latency_settings):
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raise NotImplementedError('Low latency not supported on this platform')
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def _update_break_state(self):
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"""\
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Set break: Controls TXD. When active, no transmitting is possible.
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"""
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if self._break_state:
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fcntl.ioctl(self.fd, TIOCSBRK)
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else:
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fcntl.ioctl(self.fd, TIOCCBRK)
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# some systems support an extra flag to enable the two in POSIX unsupported
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# paritiy settings for MARK and SPACE
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CMSPAR = 0 # default, for unsupported platforms, override below
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# try to detect the OS so that a device can be selected...
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# this code block should supply a device() and set_special_baudrate() function
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# for the platform
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plat = sys.platform.lower()
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if plat[:5] == 'linux': # Linux (confirmed) # noqa
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import array
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# extra termios flags
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CMSPAR = 0o10000000000 # Use "stick" (mark/space) parity
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# baudrate ioctls
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TCGETS2 = 0x802C542A
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TCSETS2 = 0x402C542B
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BOTHER = 0o010000
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# RS485 ioctls
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TIOCGRS485 = 0x542E
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TIOCSRS485 = 0x542F
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SER_RS485_ENABLED = 0b00000001
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SER_RS485_RTS_ON_SEND = 0b00000010
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SER_RS485_RTS_AFTER_SEND = 0b00000100
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SER_RS485_RX_DURING_TX = 0b00010000
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class PlatformSpecific(PlatformSpecificBase):
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BAUDRATE_CONSTANTS = {
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0: 0o000000, # hang up
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50: 0o000001,
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75: 0o000002,
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110: 0o000003,
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134: 0o000004,
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150: 0o000005,
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200: 0o000006,
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300: 0o000007,
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600: 0o000010,
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1200: 0o000011,
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1800: 0o000012,
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2400: 0o000013,
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4800: 0o000014,
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9600: 0o000015,
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19200: 0o000016,
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38400: 0o000017,
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57600: 0o010001,
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115200: 0o010002,
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230400: 0o010003,
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460800: 0o010004,
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500000: 0o010005,
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576000: 0o010006,
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921600: 0o010007,
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1000000: 0o010010,
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1152000: 0o010011,
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1500000: 0o010012,
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2000000: 0o010013,
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2500000: 0o010014,
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3000000: 0o010015,
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3500000: 0o010016,
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4000000: 0o010017
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}
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def set_low_latency_mode(self, low_latency_settings):
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buf = array.array('i', [0] * 32)
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try:
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# get serial_struct
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fcntl.ioctl(self.fd, termios.TIOCGSERIAL, buf)
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# set or unset ASYNC_LOW_LATENCY flag
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if low_latency_settings:
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buf[4] |= 0x2000
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else:
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buf[4] &= ~0x2000
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# set serial_struct
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fcntl.ioctl(self.fd, termios.TIOCSSERIAL, buf)
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except IOError as e:
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raise ValueError('Failed to update ASYNC_LOW_LATENCY flag to {}: {}'.format(low_latency_settings, e))
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def _set_special_baudrate(self, baudrate):
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# right size is 44 on x86_64, allow for some growth
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buf = array.array('i', [0] * 64)
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try:
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# get serial_struct
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fcntl.ioctl(self.fd, TCGETS2, buf)
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# set custom speed
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buf[2] &= ~termios.CBAUD
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buf[2] |= BOTHER
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buf[9] = buf[10] = baudrate
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# set serial_struct
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fcntl.ioctl(self.fd, TCSETS2, buf)
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except IOError as e:
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raise ValueError('Failed to set custom baud rate ({}): {}'.format(baudrate, e))
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def _set_rs485_mode(self, rs485_settings):
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buf = array.array('i', [0] * 8) # flags, delaytx, delayrx, padding
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try:
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fcntl.ioctl(self.fd, TIOCGRS485, buf)
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buf[0] |= SER_RS485_ENABLED
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if rs485_settings is not None:
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if rs485_settings.loopback:
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buf[0] |= SER_RS485_RX_DURING_TX
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else:
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buf[0] &= ~SER_RS485_RX_DURING_TX
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if rs485_settings.rts_level_for_tx:
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buf[0] |= SER_RS485_RTS_ON_SEND
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else:
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buf[0] &= ~SER_RS485_RTS_ON_SEND
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if rs485_settings.rts_level_for_rx:
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buf[0] |= SER_RS485_RTS_AFTER_SEND
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else:
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buf[0] &= ~SER_RS485_RTS_AFTER_SEND
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if rs485_settings.delay_before_tx is not None:
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buf[1] = int(rs485_settings.delay_before_tx * 1000)
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if rs485_settings.delay_before_rx is not None:
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buf[2] = int(rs485_settings.delay_before_rx * 1000)
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else:
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buf[0] = 0 # clear SER_RS485_ENABLED
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fcntl.ioctl(self.fd, TIOCSRS485, buf)
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except IOError as e:
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raise ValueError('Failed to set RS485 mode: {}'.format(e))
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elif plat == 'cygwin': # cygwin/win32 (confirmed)
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class PlatformSpecific(PlatformSpecificBase):
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BAUDRATE_CONSTANTS = {
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128000: 0x01003,
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256000: 0x01005,
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500000: 0x01007,
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576000: 0x01008,
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921600: 0x01009,
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1000000: 0x0100a,
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1152000: 0x0100b,
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1500000: 0x0100c,
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2000000: 0x0100d,
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2500000: 0x0100e,
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3000000: 0x0100f
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}
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elif plat[:6] == 'darwin': # OS X
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import array
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IOSSIOSPEED = 0x80045402 # _IOW('T', 2, speed_t)
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class PlatformSpecific(PlatformSpecificBase):
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osx_version = os.uname()[2].split('.')
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TIOCSBRK = 0x2000747B # _IO('t', 123)
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TIOCCBRK = 0x2000747A # _IO('t', 122)
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# Tiger or above can support arbitrary serial speeds
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if int(osx_version[0]) >= 8:
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def _set_special_baudrate(self, baudrate):
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# use IOKit-specific call to set up high speeds
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buf = array.array('i', [baudrate])
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fcntl.ioctl(self.fd, IOSSIOSPEED, buf, 1)
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def _update_break_state(self):
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"""\
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Set break: Controls TXD. When active, no transmitting is possible.
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"""
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if self._break_state:
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fcntl.ioctl(self.fd, PlatformSpecific.TIOCSBRK)
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else:
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fcntl.ioctl(self.fd, PlatformSpecific.TIOCCBRK)
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elif plat[:3] == 'bsd' or \
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plat[:7] == 'freebsd' or \
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plat[:6] == 'netbsd' or \
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plat[:7] == 'openbsd':
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class ReturnBaudrate(object):
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def __getitem__(self, key):
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return key
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class PlatformSpecific(PlatformSpecificBase):
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# Only tested on FreeBSD:
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# The baud rate may be passed in as
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# a literal value.
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BAUDRATE_CONSTANTS = ReturnBaudrate()
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TIOCSBRK = 0x2000747B # _IO('t', 123)
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TIOCCBRK = 0x2000747A # _IO('t', 122)
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def _update_break_state(self):
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"""\
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Set break: Controls TXD. When active, no transmitting is possible.
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"""
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if self._break_state:
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fcntl.ioctl(self.fd, PlatformSpecific.TIOCSBRK)
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else:
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fcntl.ioctl(self.fd, PlatformSpecific.TIOCCBRK)
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else:
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class PlatformSpecific(PlatformSpecificBase):
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pass
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# load some constants for later use.
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# try to use values from termios, use defaults from linux otherwise
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TIOCMGET = getattr(termios, 'TIOCMGET', 0x5415)
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TIOCMBIS = getattr(termios, 'TIOCMBIS', 0x5416)
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TIOCMBIC = getattr(termios, 'TIOCMBIC', 0x5417)
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TIOCMSET = getattr(termios, 'TIOCMSET', 0x5418)
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# TIOCM_LE = getattr(termios, 'TIOCM_LE', 0x001)
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TIOCM_DTR = getattr(termios, 'TIOCM_DTR', 0x002)
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TIOCM_RTS = getattr(termios, 'TIOCM_RTS', 0x004)
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# TIOCM_ST = getattr(termios, 'TIOCM_ST', 0x008)
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# TIOCM_SR = getattr(termios, 'TIOCM_SR', 0x010)
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TIOCM_CTS = getattr(termios, 'TIOCM_CTS', 0x020)
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TIOCM_CAR = getattr(termios, 'TIOCM_CAR', 0x040)
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TIOCM_RNG = getattr(termios, 'TIOCM_RNG', 0x080)
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TIOCM_DSR = getattr(termios, 'TIOCM_DSR', 0x100)
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TIOCM_CD = getattr(termios, 'TIOCM_CD', TIOCM_CAR)
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TIOCM_RI = getattr(termios, 'TIOCM_RI', TIOCM_RNG)
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# TIOCM_OUT1 = getattr(termios, 'TIOCM_OUT1', 0x2000)
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# TIOCM_OUT2 = getattr(termios, 'TIOCM_OUT2', 0x4000)
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if hasattr(termios, 'TIOCINQ'):
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TIOCINQ = termios.TIOCINQ
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else:
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TIOCINQ = getattr(termios, 'FIONREAD', 0x541B)
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TIOCOUTQ = getattr(termios, 'TIOCOUTQ', 0x5411)
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TIOCM_zero_str = struct.pack('I', 0)
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TIOCM_RTS_str = struct.pack('I', TIOCM_RTS)
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TIOCM_DTR_str = struct.pack('I', TIOCM_DTR)
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TIOCSBRK = getattr(termios, 'TIOCSBRK', 0x5427)
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TIOCCBRK = getattr(termios, 'TIOCCBRK', 0x5428)
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class Serial(SerialBase, PlatformSpecific):
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"""\
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Serial port class POSIX implementation. Serial port configuration is
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done with termios and fcntl. Runs on Linux and many other Un*x like
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systems.
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"""
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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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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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self.fd = None
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# open
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try:
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self.fd = os.open(self.portstr, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK)
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except OSError as msg:
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self.fd = None
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raise SerialException(msg.errno, "could not open port {}: {}".format(self._port, msg))
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#~ fcntl.fcntl(self.fd, fcntl.F_SETFL, 0) # set blocking
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self.pipe_abort_read_r, self.pipe_abort_read_w = None, None
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self.pipe_abort_write_r, self.pipe_abort_write_w = None, None
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try:
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self._reconfigure_port(force_update=True)
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try:
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if not self._dsrdtr:
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self._update_dtr_state()
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if not self._rtscts:
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self._update_rts_state()
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except IOError as e:
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# ignore Invalid argument and Inappropriate ioctl
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if e.errno not in (errno.EINVAL, errno.ENOTTY):
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raise
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self._reset_input_buffer()
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self.pipe_abort_read_r, self.pipe_abort_read_w = os.pipe()
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self.pipe_abort_write_r, self.pipe_abort_write_w = os.pipe()
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fcntl.fcntl(self.pipe_abort_read_r, fcntl.F_SETFL, os.O_NONBLOCK)
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fcntl.fcntl(self.pipe_abort_write_r, fcntl.F_SETFL, os.O_NONBLOCK)
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except BaseException:
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try:
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os.close(self.fd)
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except Exception:
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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.fd = None
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if self.pipe_abort_read_w is not None:
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os.close(self.pipe_abort_read_w)
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self.pipe_abort_read_w = None
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if self.pipe_abort_read_r is not None:
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os.close(self.pipe_abort_read_r)
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self.pipe_abort_read_r = None
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if self.pipe_abort_write_w is not None:
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os.close(self.pipe_abort_write_w)
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self.pipe_abort_write_w = None
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if self.pipe_abort_write_r is not None:
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os.close(self.pipe_abort_write_r)
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self.pipe_abort_write_r = None
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raise
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self.is_open = True
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def _reconfigure_port(self, force_update=False):
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"""Set communication parameters on opened port."""
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if self.fd is None:
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raise SerialException("Can only operate on a valid file descriptor")
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# if exclusive lock is requested, create it before we modify anything else
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if self._exclusive is not None:
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if self._exclusive:
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try:
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fcntl.flock(self.fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
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except IOError as msg:
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raise SerialException(msg.errno, "Could not exclusively lock port {}: {}".format(self._port, msg))
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else:
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fcntl.flock(self.fd, fcntl.LOCK_UN)
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custom_baud = None
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vmin = vtime = 0 # timeout is done via select
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if self._inter_byte_timeout is not None:
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vmin = 1
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vtime = int(self._inter_byte_timeout * 10)
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try:
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orig_attr = termios.tcgetattr(self.fd)
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iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr
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except termios.error as msg: # if a port is nonexistent but has a /dev file, it'll fail here
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raise SerialException("Could not configure port: {}".format(msg))
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# set up raw mode / no echo / binary
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cflag |= (termios.CLOCAL | termios.CREAD)
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lflag &= ~(termios.ICANON | termios.ECHO | termios.ECHOE |
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termios.ECHOK | termios.ECHONL |
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termios.ISIG | termios.IEXTEN) # |termios.ECHOPRT
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for flag in ('ECHOCTL', 'ECHOKE'): # netbsd workaround for Erk
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if hasattr(termios, flag):
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lflag &= ~getattr(termios, flag)
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oflag &= ~(termios.OPOST | termios.ONLCR | termios.OCRNL)
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iflag &= ~(termios.INLCR | termios.IGNCR | termios.ICRNL | termios.IGNBRK)
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if hasattr(termios, 'IUCLC'):
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iflag &= ~termios.IUCLC
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if hasattr(termios, 'PARMRK'):
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iflag &= ~termios.PARMRK
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# setup baud rate
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try:
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ispeed = ospeed = getattr(termios, 'B{}'.format(self._baudrate))
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except AttributeError:
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try:
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ispeed = ospeed = self.BAUDRATE_CONSTANTS[self._baudrate]
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except KeyError:
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#~ raise ValueError('Invalid baud rate: %r' % self._baudrate)
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# See if BOTHER is defined for this platform; if it is, use
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# this for a speed not defined in the baudrate constants list.
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try:
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ispeed = ospeed = BOTHER
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except NameError:
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# may need custom baud rate, it isn't in our list.
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ispeed = ospeed = getattr(termios, 'B38400')
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try:
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custom_baud = int(self._baudrate) # store for later
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except ValueError:
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raise ValueError('Invalid baud rate: {!r}'.format(self._baudrate))
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else:
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if custom_baud < 0:
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raise ValueError('Invalid baud rate: {!r}'.format(self._baudrate))
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# setup char len
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cflag &= ~termios.CSIZE
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if self._bytesize == 8:
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cflag |= termios.CS8
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elif self._bytesize == 7:
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cflag |= termios.CS7
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elif self._bytesize == 6:
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cflag |= termios.CS6
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elif self._bytesize == 5:
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cflag |= termios.CS5
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else:
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raise ValueError('Invalid char len: {!r}'.format(self._bytesize))
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# setup stop bits
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if self._stopbits == serial.STOPBITS_ONE:
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cflag &= ~(termios.CSTOPB)
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elif self._stopbits == serial.STOPBITS_ONE_POINT_FIVE:
|
|
cflag |= (termios.CSTOPB) # XXX same as TWO.. there is no POSIX support for 1.5
|
|
elif self._stopbits == serial.STOPBITS_TWO:
|
|
cflag |= (termios.CSTOPB)
|
|
else:
|
|
raise ValueError('Invalid stop bit specification: {!r}'.format(self._stopbits))
|
|
# setup parity
|
|
iflag &= ~(termios.INPCK | termios.ISTRIP)
|
|
if self._parity == serial.PARITY_NONE:
|
|
cflag &= ~(termios.PARENB | termios.PARODD | CMSPAR)
|
|
elif self._parity == serial.PARITY_EVEN:
|
|
cflag &= ~(termios.PARODD | CMSPAR)
|
|
cflag |= (termios.PARENB)
|
|
elif self._parity == serial.PARITY_ODD:
|
|
cflag &= ~CMSPAR
|
|
cflag |= (termios.PARENB | termios.PARODD)
|
|
elif self._parity == serial.PARITY_MARK and CMSPAR:
|
|
cflag |= (termios.PARENB | CMSPAR | termios.PARODD)
|
|
elif self._parity == serial.PARITY_SPACE and CMSPAR:
|
|
cflag |= (termios.PARENB | CMSPAR)
|
|
cflag &= ~(termios.PARODD)
|
|
else:
|
|
raise ValueError('Invalid parity: {!r}'.format(self._parity))
|
|
# setup flow control
|
|
# xonxoff
|
|
if hasattr(termios, 'IXANY'):
|
|
if self._xonxoff:
|
|
iflag |= (termios.IXON | termios.IXOFF) # |termios.IXANY)
|
|
else:
|
|
iflag &= ~(termios.IXON | termios.IXOFF | termios.IXANY)
|
|
else:
|
|
if self._xonxoff:
|
|
iflag |= (termios.IXON | termios.IXOFF)
|
|
else:
|
|
iflag &= ~(termios.IXON | termios.IXOFF)
|
|
# rtscts
|
|
if hasattr(termios, 'CRTSCTS'):
|
|
if self._rtscts:
|
|
cflag |= (termios.CRTSCTS)
|
|
else:
|
|
cflag &= ~(termios.CRTSCTS)
|
|
elif hasattr(termios, 'CNEW_RTSCTS'): # try it with alternate constant name
|
|
if self._rtscts:
|
|
cflag |= (termios.CNEW_RTSCTS)
|
|
else:
|
|
cflag &= ~(termios.CNEW_RTSCTS)
|
|
# XXX should there be a warning if setting up rtscts (and xonxoff etc) fails??
|
|
|
|
# buffer
|
|
# vmin "minimal number of characters to be read. 0 for non blocking"
|
|
if vmin < 0 or vmin > 255:
|
|
raise ValueError('Invalid vmin: {!r}'.format(vmin))
|
|
cc[termios.VMIN] = vmin
|
|
# vtime
|
|
if vtime < 0 or vtime > 255:
|
|
raise ValueError('Invalid vtime: {!r}'.format(vtime))
|
|
cc[termios.VTIME] = vtime
|
|
# activate settings
|
|
if force_update or [iflag, oflag, cflag, lflag, ispeed, ospeed, cc] != orig_attr:
|
|
termios.tcsetattr(
|
|
self.fd,
|
|
termios.TCSANOW,
|
|
[iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
|
|
|
|
# apply custom baud rate, if any
|
|
if custom_baud is not None:
|
|
self._set_special_baudrate(custom_baud)
|
|
|
|
if self._rs485_mode is not None:
|
|
self._set_rs485_mode(self._rs485_mode)
|
|
|
|
def close(self):
|
|
"""Close port"""
|
|
if self.is_open:
|
|
if self.fd is not None:
|
|
os.close(self.fd)
|
|
self.fd = None
|
|
os.close(self.pipe_abort_read_w)
|
|
os.close(self.pipe_abort_read_r)
|
|
os.close(self.pipe_abort_write_w)
|
|
os.close(self.pipe_abort_write_r)
|
|
self.pipe_abort_read_r, self.pipe_abort_read_w = None, None
|
|
self.pipe_abort_write_r, self.pipe_abort_write_w = None, None
|
|
self.is_open = False
|
|
|
|
# - - - - - - - - - - - - - - - - - - - - - - - -
|
|
|
|
@property
|
|
def in_waiting(self):
|
|
"""Return the number of bytes currently in the input buffer."""
|
|
#~ s = fcntl.ioctl(self.fd, termios.FIONREAD, TIOCM_zero_str)
|
|
s = fcntl.ioctl(self.fd, TIOCINQ, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0]
|
|
|
|
# select based implementation, proved to work on many systems
|
|
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.is_open:
|
|
raise PortNotOpenError()
|
|
read = bytearray()
|
|
timeout = Timeout(self._timeout)
|
|
while len(read) < size:
|
|
try:
|
|
ready, _, _ = select.select([self.fd, self.pipe_abort_read_r], [], [], timeout.time_left())
|
|
if self.pipe_abort_read_r in ready:
|
|
os.read(self.pipe_abort_read_r, 1000)
|
|
break
|
|
# If select was used with a timeout, and the timeout occurs, it
|
|
# returns with empty lists -> thus abort read operation.
|
|
# For timeout == 0 (non-blocking operation) also abort when
|
|
# there is nothing to read.
|
|
if not ready:
|
|
break # timeout
|
|
buf = os.read(self.fd, size - len(read))
|
|
except OSError as e:
|
|
# this is for Python 3.x where select.error is a subclass of
|
|
# OSError ignore BlockingIOErrors and EINTR. other errors are shown
|
|
# https://www.python.org/dev/peps/pep-0475.
|
|
if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR):
|
|
raise SerialException('read failed: {}'.format(e))
|
|
except select.error as e:
|
|
# this is for Python 2.x
|
|
# ignore BlockingIOErrors and EINTR. all errors are shown
|
|
# see also http://www.python.org/dev/peps/pep-3151/#select
|
|
if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR):
|
|
raise SerialException('read failed: {}'.format(e))
|
|
else:
|
|
# read should always return some data as select reported it was
|
|
# ready to read when we get to this point.
|
|
if not buf:
|
|
# Disconnected devices, at least on Linux, show the
|
|
# behavior that they are always ready to read immediately
|
|
# but reading returns nothing.
|
|
raise SerialException(
|
|
'device reports readiness to read but returned no data '
|
|
'(device disconnected or multiple access on port?)')
|
|
read.extend(buf)
|
|
|
|
if timeout.expired():
|
|
break
|
|
return bytes(read)
|
|
|
|
def cancel_read(self):
|
|
if self.is_open:
|
|
os.write(self.pipe_abort_read_w, b"x")
|
|
|
|
def cancel_write(self):
|
|
if self.is_open:
|
|
os.write(self.pipe_abort_write_w, b"x")
|
|
|
|
def write(self, data):
|
|
"""Output the given byte string over the serial port."""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
d = to_bytes(data)
|
|
tx_len = length = len(d)
|
|
timeout = Timeout(self._write_timeout)
|
|
while tx_len > 0:
|
|
try:
|
|
n = os.write(self.fd, d)
|
|
if timeout.is_non_blocking:
|
|
# Zero timeout indicates non-blocking - simply return the
|
|
# number of bytes of data actually written
|
|
return n
|
|
elif not timeout.is_infinite:
|
|
# when timeout is set, use select to wait for being ready
|
|
# with the time left as timeout
|
|
if timeout.expired():
|
|
raise SerialTimeoutException('Write timeout')
|
|
abort, ready, _ = select.select([self.pipe_abort_write_r], [self.fd], [], timeout.time_left())
|
|
if abort:
|
|
os.read(self.pipe_abort_write_r, 1000)
|
|
break
|
|
if not ready:
|
|
raise SerialTimeoutException('Write timeout')
|
|
else:
|
|
assert timeout.time_left() is None
|
|
# wait for write operation
|
|
abort, ready, _ = select.select([self.pipe_abort_write_r], [self.fd], [], None)
|
|
if abort:
|
|
os.read(self.pipe_abort_write_r, 1)
|
|
break
|
|
if not ready:
|
|
raise SerialException('write failed (select)')
|
|
d = d[n:]
|
|
tx_len -= n
|
|
except SerialException:
|
|
raise
|
|
except OSError as e:
|
|
# this is for Python 3.x where select.error is a subclass of
|
|
# OSError ignore BlockingIOErrors and EINTR. other errors are shown
|
|
# https://www.python.org/dev/peps/pep-0475.
|
|
if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR):
|
|
raise SerialException('write failed: {}'.format(e))
|
|
except select.error as e:
|
|
# this is for Python 2.x
|
|
# ignore BlockingIOErrors and EINTR. all errors are shown
|
|
# see also http://www.python.org/dev/peps/pep-3151/#select
|
|
if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR):
|
|
raise SerialException('write failed: {}'.format(e))
|
|
if not timeout.is_non_blocking and timeout.expired():
|
|
raise SerialTimeoutException('Write timeout')
|
|
return length - len(d)
|
|
|
|
def flush(self):
|
|
"""\
|
|
Flush of file like objects. In this case, wait until all data
|
|
is written.
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
termios.tcdrain(self.fd)
|
|
|
|
def _reset_input_buffer(self):
|
|
"""Clear input buffer, discarding all that is in the buffer."""
|
|
termios.tcflush(self.fd, termios.TCIFLUSH)
|
|
|
|
def reset_input_buffer(self):
|
|
"""Clear input buffer, discarding all that is in the buffer."""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
self._reset_input_buffer()
|
|
|
|
def reset_output_buffer(self):
|
|
"""\
|
|
Clear output buffer, aborting the current output and discarding all
|
|
that is in the buffer.
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
termios.tcflush(self.fd, termios.TCOFLUSH)
|
|
|
|
def send_break(self, duration=0.25):
|
|
"""\
|
|
Send break condition. Timed, returns to idle state after given
|
|
duration.
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
termios.tcsendbreak(self.fd, int(duration / 0.25))
|
|
|
|
def _update_rts_state(self):
|
|
"""Set terminal status line: Request To Send"""
|
|
if self._rts_state:
|
|
fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_RTS_str)
|
|
else:
|
|
fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_RTS_str)
|
|
|
|
def _update_dtr_state(self):
|
|
"""Set terminal status line: Data Terminal Ready"""
|
|
if self._dtr_state:
|
|
fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str)
|
|
else:
|
|
fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str)
|
|
|
|
@property
|
|
def cts(self):
|
|
"""Read terminal status line: Clear To Send"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0] & TIOCM_CTS != 0
|
|
|
|
@property
|
|
def dsr(self):
|
|
"""Read terminal status line: Data Set Ready"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0] & TIOCM_DSR != 0
|
|
|
|
@property
|
|
def ri(self):
|
|
"""Read terminal status line: Ring Indicator"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0] & TIOCM_RI != 0
|
|
|
|
@property
|
|
def cd(self):
|
|
"""Read terminal status line: Carrier Detect"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0] & TIOCM_CD != 0
|
|
|
|
# - - platform specific - - - -
|
|
|
|
@property
|
|
def out_waiting(self):
|
|
"""Return the number of bytes currently in the output buffer."""
|
|
#~ s = fcntl.ioctl(self.fd, termios.FIONREAD, TIOCM_zero_str)
|
|
s = fcntl.ioctl(self.fd, TIOCOUTQ, TIOCM_zero_str)
|
|
return struct.unpack('I', s)[0]
|
|
|
|
def fileno(self):
|
|
"""\
|
|
For easier use of the serial port instance with select.
|
|
WARNING: this function is not portable to different platforms!
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
return self.fd
|
|
|
|
def set_input_flow_control(self, enable=True):
|
|
"""\
|
|
Manually control flow - when software flow control is enabled.
|
|
This will send XON (true) or XOFF (false) to the other device.
|
|
WARNING: this function is not portable to different platforms!
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
if enable:
|
|
termios.tcflow(self.fd, termios.TCION)
|
|
else:
|
|
termios.tcflow(self.fd, termios.TCIOFF)
|
|
|
|
def set_output_flow_control(self, enable=True):
|
|
"""\
|
|
Manually control flow of outgoing data - when hardware or software flow
|
|
control is enabled.
|
|
WARNING: this function is not portable to different platforms!
|
|
"""
|
|
if not self.is_open:
|
|
raise PortNotOpenError()
|
|
if enable:
|
|
termios.tcflow(self.fd, termios.TCOON)
|
|
else:
|
|
termios.tcflow(self.fd, termios.TCOOFF)
|
|
|
|
def nonblocking(self):
|
|
"""DEPRECATED - has no use"""
|
|
import warnings
|
|
warnings.warn("nonblocking() has no effect, already nonblocking", DeprecationWarning)
|
|
|
|
|
|
class PosixPollSerial(Serial):
|
|
"""\
|
|
Poll based read implementation. Not all systems support poll properly.
|
|
However this one has better handling of errors, such as a device
|
|
disconnecting while it's in use (e.g. USB-serial unplugged).
|
|
"""
|
|
|
|
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.is_open:
|
|
raise PortNotOpenError()
|
|
read = bytearray()
|
|
timeout = Timeout(self._timeout)
|
|
poll = select.poll()
|
|
poll.register(self.fd, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL)
|
|
poll.register(self.pipe_abort_read_r, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL)
|
|
if size > 0:
|
|
while len(read) < size:
|
|
# print "\tread(): size",size, "have", len(read) #debug
|
|
# wait until device becomes ready to read (or something fails)
|
|
for fd, event in poll.poll(None if timeout.is_infinite else (timeout.time_left() * 1000)):
|
|
if fd == self.pipe_abort_read_r:
|
|
break
|
|
if event & (select.POLLERR | select.POLLHUP | select.POLLNVAL):
|
|
raise SerialException('device reports error (poll)')
|
|
# we don't care if it is select.POLLIN or timeout, that's
|
|
# handled below
|
|
if fd == self.pipe_abort_read_r:
|
|
os.read(self.pipe_abort_read_r, 1000)
|
|
break
|
|
buf = os.read(self.fd, size - len(read))
|
|
read.extend(buf)
|
|
if timeout.expired() \
|
|
or (self._inter_byte_timeout is not None and self._inter_byte_timeout > 0) and not buf:
|
|
break # early abort on timeout
|
|
return bytes(read)
|
|
|
|
|
|
class VTIMESerial(Serial):
|
|
"""\
|
|
Implement timeout using vtime of tty device instead of using select.
|
|
This means that no inter character timeout can be specified and that
|
|
the error handling is degraded.
|
|
|
|
Overall timeout is disabled when inter-character timeout is used.
|
|
|
|
Note that this implementation does NOT support cancel_read(), it will
|
|
just ignore that.
|
|
"""
|
|
|
|
def _reconfigure_port(self, force_update=True):
|
|
"""Set communication parameters on opened port."""
|
|
super(VTIMESerial, self)._reconfigure_port()
|
|
fcntl.fcntl(self.fd, fcntl.F_SETFL, 0) # clear O_NONBLOCK
|
|
|
|
if self._inter_byte_timeout is not None:
|
|
vmin = 1
|
|
vtime = int(self._inter_byte_timeout * 10)
|
|
elif self._timeout is None:
|
|
vmin = 1
|
|
vtime = 0
|
|
else:
|
|
vmin = 0
|
|
vtime = int(self._timeout * 10)
|
|
try:
|
|
orig_attr = termios.tcgetattr(self.fd)
|
|
iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr
|
|
except termios.error as msg: # if a port is nonexistent but has a /dev file, it'll fail here
|
|
raise serial.SerialException("Could not configure port: {}".format(msg))
|
|
|
|
if vtime < 0 or vtime > 255:
|
|
raise ValueError('Invalid vtime: {!r}'.format(vtime))
|
|
cc[termios.VTIME] = vtime
|
|
cc[termios.VMIN] = vmin
|
|
|
|
termios.tcsetattr(
|
|
self.fd,
|
|
termios.TCSANOW,
|
|
[iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
|
|
|
|
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.is_open:
|
|
raise PortNotOpenError()
|
|
read = bytearray()
|
|
while len(read) < size:
|
|
buf = os.read(self.fd, size - len(read))
|
|
if not buf:
|
|
break
|
|
read.extend(buf)
|
|
return bytes(read)
|
|
|
|
# hack to make hasattr return false
|
|
cancel_read = property()
|