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Diffstat (limited to 'scripts/serial/serialposix.py')
| -rw-r--r-- | scripts/serial/serialposix.py | 730 |
1 files changed, 730 insertions, 0 deletions
diff --git a/scripts/serial/serialposix.py b/scripts/serial/serialposix.py new file mode 100644 index 0000000000..359ad1b877 --- /dev/null +++ b/scripts/serial/serialposix.py @@ -0,0 +1,730 @@ +#!/usr/bin/env python +# +# Python Serial Port Extension for Win32, Linux, BSD, Jython +# module for serial IO for POSIX compatible systems, like Linux +# see __init__.py +# +# (C) 2001-2010 Chris Liechti <cliechti@gmx.net> +# this is distributed under a free software license, see license.txt +# +# parts based on code from Grant B. Edwards <grante@visi.com>: +# ftp://ftp.visi.com/users/grante/python/PosixSerial.py +# +# references: http://www.easysw.com/~mike/serial/serial.html + +import sys, os, fcntl, termios, struct, select, errno, time +from serial.serialutil import * + +# Do check the Python version as some constants have moved. +if (sys.hexversion < 0x020100f0): + import TERMIOS +else: + TERMIOS = termios + +if (sys.hexversion < 0x020200f0): + import FCNTL +else: + FCNTL = fcntl + +# try to detect the OS so that a device can be selected... +# this code block should supply a device() and set_special_baudrate() function +# for the platform +plat = sys.platform.lower() + +if plat[:5] == 'linux': # Linux (confirmed) + + def device(port): + return '/dev/ttyS%d' % port + + TCGETS2 = 0x802C542A + TCSETS2 = 0x402C542B + BOTHER = 0o010000 + + def set_special_baudrate(port, baudrate): + # right size is 44 on x86_64, allow for some growth + import array + buf = array.array('i', [0] * 64) + + try: + # get serial_struct + FCNTL.ioctl(port.fd, TCGETS2, buf) + # set custom speed + buf[2] &= ~TERMIOS.CBAUD + buf[2] |= BOTHER + buf[9] = buf[10] = baudrate + + # set serial_struct + res = FCNTL.ioctl(port.fd, TCSETS2, buf) + except IOError, e: + raise ValueError('Failed to set custom baud rate (%s): %s' % (baudrate, e)) + + baudrate_constants = { + 0: 0000000, # hang up + 50: 0000001, + 75: 0000002, + 110: 0000003, + 134: 0000004, + 150: 0000005, + 200: 0000006, + 300: 0000007, + 600: 0000010, + 1200: 0000011, + 1800: 0000012, + 2400: 0000013, + 4800: 0000014, + 9600: 0000015, + 19200: 0000016, + 38400: 0000017, + 57600: 0010001, + 115200: 0010002, + 230400: 0010003, + 460800: 0010004, + 500000: 0010005, + 576000: 0010006, + 921600: 0010007, + 1000000: 0010010, + 1152000: 0010011, + 1500000: 0010012, + 2000000: 0010013, + 2500000: 0010014, + 3000000: 0010015, + 3500000: 0010016, + 4000000: 0010017 + } + +elif plat == 'cygwin': # cygwin/win32 (confirmed) + + def device(port): + return '/dev/com%d' % (port + 1) + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = { + 128000: 0x01003, + 256000: 0x01005, + 500000: 0x01007, + 576000: 0x01008, + 921600: 0x01009, + 1000000: 0x0100a, + 1152000: 0x0100b, + 1500000: 0x0100c, + 2000000: 0x0100d, + 2500000: 0x0100e, + 3000000: 0x0100f + } + +elif plat[:7] == 'openbsd': # OpenBSD + + def device(port): + return '/dev/cua%02d' % port + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:3] == 'bsd' or \ + plat[:7] == 'freebsd': + + def device(port): + return '/dev/cuad%d' % port + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:6] == 'darwin': # OS X + + version = os.uname()[2].split('.') + # Tiger or above can support arbitrary serial speeds + if int(version[0]) >= 8: + def set_special_baudrate(port, baudrate): + # use IOKit-specific call to set up high speeds + import array, fcntl + buf = array.array('i', [baudrate]) + IOSSIOSPEED = 0x80045402 #_IOW('T', 2, speed_t) + fcntl.ioctl(port.fd, IOSSIOSPEED, buf, 1) + else: # version < 8 + def set_special_baudrate(port, baudrate): + raise ValueError("baud rate not supported") + + def device(port): + return '/dev/cuad%d' % port + + baudrate_constants = {} + + +elif plat[:6] == 'netbsd': # NetBSD 1.6 testing by Erk + + def device(port): + return '/dev/dty%02d' % port + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:4] == 'irix': # IRIX (partially tested) + + def device(port): + return '/dev/ttyf%d' % (port+1) #XXX different device names depending on flow control + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:2] == 'hp': # HP-UX (not tested) + + def device(port): + return '/dev/tty%dp0' % (port+1) + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:5] == 'sunos': # Solaris/SunOS (confirmed) + + def device(port): + return '/dev/tty%c' % (ord('a')+port) + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +elif plat[:3] == 'aix': # AIX + + def device(port): + return '/dev/tty%d' % (port) + + def set_special_baudrate(port, baudrate): + raise ValueError("sorry don't know how to handle non standard baud rate on this platform") + + baudrate_constants = {} + +else: + # platform detection has failed... + sys.stderr.write("""\ +don't know how to number ttys on this system. +! Use an explicit path (eg /dev/ttyS1) or send this information to +! the author of this module: + +sys.platform = %r +os.name = %r +serialposix.py version = %s + +also add the device name of the serial port and where the +counting starts for the first serial port. +e.g. 'first serial port: /dev/ttyS0' +and with a bit luck you can get this module running... +""" % (sys.platform, os.name, VERSION)) + # no exception, just continue with a brave attempt to build a device name + # even if the device name is not correct for the platform it has chances + # to work using a string with the real device name as port parameter. + def device(portum): + return '/dev/ttyS%d' % portnum + def set_special_baudrate(port, baudrate): + raise SerialException("sorry don't know how to handle non standard baud rate on this platform") + baudrate_constants = {} + #~ raise Exception, "this module does not run on this platform, sorry." + +# whats up with "aix", "beos", .... +# they should work, just need to know the device names. + + +# load some constants for later use. +# try to use values from TERMIOS, use defaults from linux otherwise +TIOCMGET = hasattr(TERMIOS, 'TIOCMGET') and TERMIOS.TIOCMGET or 0x5415 +TIOCMBIS = hasattr(TERMIOS, 'TIOCMBIS') and TERMIOS.TIOCMBIS or 0x5416 +TIOCMBIC = hasattr(TERMIOS, 'TIOCMBIC') and TERMIOS.TIOCMBIC or 0x5417 +TIOCMSET = hasattr(TERMIOS, 'TIOCMSET') and TERMIOS.TIOCMSET or 0x5418 + +#TIOCM_LE = hasattr(TERMIOS, 'TIOCM_LE') and TERMIOS.TIOCM_LE or 0x001 +TIOCM_DTR = hasattr(TERMIOS, 'TIOCM_DTR') and TERMIOS.TIOCM_DTR or 0x002 +TIOCM_RTS = hasattr(TERMIOS, 'TIOCM_RTS') and TERMIOS.TIOCM_RTS or 0x004 +#TIOCM_ST = hasattr(TERMIOS, 'TIOCM_ST') and TERMIOS.TIOCM_ST or 0x008 +#TIOCM_SR = hasattr(TERMIOS, 'TIOCM_SR') and TERMIOS.TIOCM_SR or 0x010 + +TIOCM_CTS = hasattr(TERMIOS, 'TIOCM_CTS') and TERMIOS.TIOCM_CTS or 0x020 +TIOCM_CAR = hasattr(TERMIOS, 'TIOCM_CAR') and TERMIOS.TIOCM_CAR or 0x040 +TIOCM_RNG = hasattr(TERMIOS, 'TIOCM_RNG') and TERMIOS.TIOCM_RNG or 0x080 +TIOCM_DSR = hasattr(TERMIOS, 'TIOCM_DSR') and TERMIOS.TIOCM_DSR or 0x100 +TIOCM_CD = hasattr(TERMIOS, 'TIOCM_CD') and TERMIOS.TIOCM_CD or TIOCM_CAR +TIOCM_RI = hasattr(TERMIOS, 'TIOCM_RI') and TERMIOS.TIOCM_RI or TIOCM_RNG +#TIOCM_OUT1 = hasattr(TERMIOS, 'TIOCM_OUT1') and TERMIOS.TIOCM_OUT1 or 0x2000 +#TIOCM_OUT2 = hasattr(TERMIOS, 'TIOCM_OUT2') and TERMIOS.TIOCM_OUT2 or 0x4000 +if hasattr(TERMIOS, 'TIOCINQ'): + TIOCINQ = TERMIOS.TIOCINQ +else: + TIOCINQ = hasattr(TERMIOS, 'FIONREAD') and TERMIOS.FIONREAD or 0x541B +TIOCOUTQ = hasattr(TERMIOS, 'TIOCOUTQ') and TERMIOS.TIOCOUTQ or 0x5411 + +TIOCM_zero_str = struct.pack('I', 0) +TIOCM_RTS_str = struct.pack('I', TIOCM_RTS) +TIOCM_DTR_str = struct.pack('I', TIOCM_DTR) + +TIOCSBRK = hasattr(TERMIOS, 'TIOCSBRK') and TERMIOS.TIOCSBRK or 0x5427 +TIOCCBRK = hasattr(TERMIOS, 'TIOCCBRK') and TERMIOS.TIOCCBRK or 0x5428 + +CMSPAR = 010000000000 # Use "stick" (mark/space) parity + + +class PosixSerial(SerialBase): + """\ + Serial port class POSIX implementation. Serial port configuration is + done with termios and fcntl. Runs on Linux and many other Un*x like + systems. + """ + + 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.") + if self._isOpen: + raise SerialException("Port is already open.") + self.fd = None + # open + try: + self.fd = os.open(self.portstr, os.O_RDWR|os.O_NOCTTY|os.O_NONBLOCK) + except OSError, msg: + self.fd = None + raise SerialException(msg.errno, "could not open port %s: %s" % (self._port, msg)) + #~ fcntl.fcntl(self.fd, FCNTL.F_SETFL, 0) # set blocking + + try: + self._reconfigurePort() + except: + try: + os.close(self.fd) + except: + # ignore any exception when closing the port + # also to keep original exception that happened when setting up + pass + self.fd = None + raise + else: + self._isOpen = True + self.flushInput() + + + def _reconfigurePort(self): + """Set communication parameters on opened port.""" + if self.fd is None: + raise SerialException("Can only operate on a valid file descriptor") + custom_baud = None + + vmin = vtime = 0 # timeout is done via select + if self._interCharTimeout is not None: + vmin = 1 + vtime = int(self._interCharTimeout * 10) + try: + orig_attr = termios.tcgetattr(self.fd) + iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr + except termios.error, msg: # if a port is nonexistent but has a /dev file, it'll fail here + raise SerialException("Could not configure port: %s" % msg) + # set up raw mode / no echo / binary + cflag |= (TERMIOS.CLOCAL|TERMIOS.CREAD) + lflag &= ~(TERMIOS.ICANON|TERMIOS.ECHO|TERMIOS.ECHOE|TERMIOS.ECHOK|TERMIOS.ECHONL| + TERMIOS.ISIG|TERMIOS.IEXTEN) #|TERMIOS.ECHOPRT + for flag in ('ECHOCTL', 'ECHOKE'): # netbsd workaround for Erk + if hasattr(TERMIOS, flag): + lflag &= ~getattr(TERMIOS, flag) + + oflag &= ~(TERMIOS.OPOST) + iflag &= ~(TERMIOS.INLCR|TERMIOS.IGNCR|TERMIOS.ICRNL|TERMIOS.IGNBRK) + if hasattr(TERMIOS, 'IUCLC'): + iflag &= ~TERMIOS.IUCLC + if hasattr(TERMIOS, 'PARMRK'): + iflag &= ~TERMIOS.PARMRK + + # setup baud rate + try: + ispeed = ospeed = getattr(TERMIOS, 'B%s' % (self._baudrate)) + except AttributeError: + try: + ispeed = ospeed = baudrate_constants[self._baudrate] + except KeyError: + #~ raise ValueError('Invalid baud rate: %r' % self._baudrate) + # may need custom baud rate, it isn't in our list. + ispeed = ospeed = getattr(TERMIOS, 'B38400') + try: + custom_baud = int(self._baudrate) # store for later + except ValueError: + raise ValueError('Invalid baud rate: %r' % self._baudrate) + else: + if custom_baud < 0: + raise ValueError('Invalid baud rate: %r' % self._baudrate) + + # setup char len + cflag &= ~TERMIOS.CSIZE + if self._bytesize == 8: + cflag |= TERMIOS.CS8 + elif self._bytesize == 7: + cflag |= TERMIOS.CS7 + elif self._bytesize == 6: + cflag |= TERMIOS.CS6 + elif self._bytesize == 5: + cflag |= TERMIOS.CS5 + else: + raise ValueError('Invalid char len: %r' % self._bytesize) + # setup stop bits + if self._stopbits == STOPBITS_ONE: + cflag &= ~(TERMIOS.CSTOPB) + elif self._stopbits == STOPBITS_ONE_POINT_FIVE: + cflag |= (TERMIOS.CSTOPB) # XXX same as TWO.. there is no POSIX support for 1.5 + elif self._stopbits == STOPBITS_TWO: + cflag |= (TERMIOS.CSTOPB) + else: + raise ValueError('Invalid stop bit specification: %r' % self._stopbits) + # setup parity + iflag &= ~(TERMIOS.INPCK|TERMIOS.ISTRIP) + if self._parity == PARITY_NONE: + cflag &= ~(TERMIOS.PARENB|TERMIOS.PARODD) + elif self._parity == PARITY_EVEN: + cflag &= ~(TERMIOS.PARODD) + cflag |= (TERMIOS.PARENB) + elif self._parity == PARITY_ODD: + cflag |= (TERMIOS.PARENB|TERMIOS.PARODD) + elif self._parity == PARITY_MARK and plat[:5] == 'linux': + cflag |= (TERMIOS.PARENB|CMSPAR|TERMIOS.PARODD) + elif self._parity == PARITY_SPACE and plat[:5] == 'linux': + cflag |= (TERMIOS.PARENB|CMSPAR) + cflag &= ~(TERMIOS.PARODD) + else: + raise ValueError('Invalid parity: %r' % 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 ' % vmin) + cc[TERMIOS.VMIN] = vmin + # vtime + if vtime < 0 or vtime > 255: + raise ValueError('Invalid vtime: %r' % vtime) + cc[TERMIOS.VTIME] = vtime + # activate settings + if [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: + set_special_baudrate(self, custom_baud) + + def close(self): + """Close port""" + if self._isOpen: + if self.fd is not None: + os.close(self.fd) + self.fd = None + self._isOpen = False + + def makeDeviceName(self, port): + return device(port) + + # - - - - - - - - - - - - - - - - - - - - - - - - + + def inWaiting(self): + """Return the number of characters 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._isOpen: raise portNotOpenError + read = bytearray() + while len(read) < size: + try: + ready,_,_ = select.select([self.fd],[],[], self._timeout) + # 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)) + # 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) + except OSError, e: + # this is for Python 3.x where select.error is a subclass of OSError + # ignore EAGAIN errors. all other errors are shown + if e.errno != errno.EAGAIN: + raise SerialException('read failed: %s' % (e,)) + except select.error, e: + # this is for Python 2.x + # ignore EAGAIN errors. all other errors are shown + # see also http://www.python.org/dev/peps/pep-3151/#select + if e[0] != errno.EAGAIN: + raise SerialException('read failed: %s' % (e,)) + return bytes(read) + + def write(self, data): + """Output the given string over the serial port.""" + if not self._isOpen: raise portNotOpenError + d = to_bytes(data) + tx_len = len(d) + if self._writeTimeout is not None and self._writeTimeout > 0: + timeout = time.time() + self._writeTimeout + else: + timeout = None + while tx_len > 0: + try: + n = os.write(self.fd, d) + if timeout: + # when timeout is set, use select to wait for being ready + # with the time left as timeout + timeleft = timeout - time.time() + if timeleft < 0: + raise writeTimeoutError + _, ready, _ = select.select([], [self.fd], [], timeleft) + if not ready: + raise writeTimeoutError + else: + # wait for write operation + _, ready, _ = select.select([], [self.fd], [], None) + if not ready: + raise SerialException('write failed (select)') + d = d[n:] + tx_len -= n + except OSError, v: + if v.errno != errno.EAGAIN: + raise SerialException('write failed: %s' % (v,)) + return len(data) + + def flush(self): + """\ + Flush of file like objects. In this case, wait until all data + is written. + """ + self.drainOutput() + + def flushInput(self): + """Clear input buffer, discarding all that is in the buffer.""" + if not self._isOpen: raise portNotOpenError + termios.tcflush(self.fd, TERMIOS.TCIFLUSH) + + def flushOutput(self): + """\ + Clear output buffer, aborting the current output and discarding all + that is in the buffer. + """ + if not self._isOpen: raise portNotOpenError + termios.tcflush(self.fd, TERMIOS.TCOFLUSH) + + def sendBreak(self, duration=0.25): + """\ + Send break condition. Timed, returns to idle state after given + duration. + """ + if not self._isOpen: raise portNotOpenError + termios.tcsendbreak(self.fd, int(duration/0.25)) + + def setBreak(self, level=1): + """\ + Set break: Controls TXD. When active, no transmitting is possible. + """ + if self.fd is None: raise portNotOpenError + if level: + fcntl.ioctl(self.fd, TIOCSBRK) + else: + fcntl.ioctl(self.fd, TIOCCBRK) + + def setRTS(self, level=1): + """Set terminal status line: Request To Send""" + if not self._isOpen: raise portNotOpenError + if level: + fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_RTS_str) + else: + fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_RTS_str) + + def setDTR(self, level=1): + """Set terminal status line: Data Terminal Ready""" + if not self._isOpen: raise portNotOpenError + if level: + fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str) + else: + fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str) + + def getCTS(self): + """Read terminal status line: Clear To Send""" + if not self._isOpen: raise portNotOpenError + s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) + return struct.unpack('I',s)[0] & TIOCM_CTS != 0 + + def getDSR(self): + """Read terminal status line: Data Set Ready""" + if not self._isOpen: raise portNotOpenError + s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) + return struct.unpack('I',s)[0] & TIOCM_DSR != 0 + + def getRI(self): + """Read terminal status line: Ring Indicator""" + if not self._isOpen: raise portNotOpenError + s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) + return struct.unpack('I',s)[0] & TIOCM_RI != 0 + + def getCD(self): + """Read terminal status line: Carrier Detect""" + if not self._isOpen: raise portNotOpenError + s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) + return struct.unpack('I',s)[0] & TIOCM_CD != 0 + + # - - platform specific - - - - + + def outWaiting(self): + """Return the number of characters 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 drainOutput(self): + """internal - not portable!""" + if not self._isOpen: raise portNotOpenError + termios.tcdrain(self.fd) + + def nonblocking(self): + """internal - not portable!""" + if not self._isOpen: raise portNotOpenError + fcntl.fcntl(self.fd, FCNTL.F_SETFL, os.O_NONBLOCK) + + 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._isOpen: raise portNotOpenError + return self.fd + + def setXON(self, level=True): + """\ + Manually control flow - when software flow control is enabled. + This will send XON (true) and XOFF (false) to the other device. + WARNING: this function is not portable to different platforms! + """ + if not self.hComPort: raise portNotOpenError + if enable: + termios.tcflow(self.fd, TERMIOS.TCION) + else: + termios.tcflow(self.fd, TERMIOS.TCIOFF) + + def flowControlOut(self, enable): + """\ + 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._isOpen: raise portNotOpenError + if enable: + termios.tcflow(self.fd, TERMIOS.TCOON) + else: + termios.tcflow(self.fd, TERMIOS.TCOOFF) + + +# 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(PosixSerial, FileLike): + pass +else: + # io library present + class Serial(PosixSerial, io.RawIOBase): + pass + +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 self.fd is None: raise portNotOpenError + read = bytearray() + poll = select.poll() + poll.register(self.fd, 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(self._timeout*1000): + 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 + buf = os.read(self.fd, size - len(read)) + read.extend(buf) + if ((self._timeout is not None and self._timeout >= 0) or + (self._interCharTimeout is not None and self._interCharTimeout > 0)) and not buf: + break # early abort on timeout + return bytes(read) + + +if __name__ == '__main__': + s = Serial(0, + baudrate=19200, # baud rate + bytesize=EIGHTBITS, # number of data bits + parity=PARITY_EVEN, # enable parity checking + stopbits=STOPBITS_ONE, # number of stop bits + timeout=3, # set a timeout value, None for waiting forever + xonxoff=0, # enable software flow control + rtscts=0, # enable RTS/CTS flow control + ) + s.setRTS(1) + s.setDTR(1) + s.flushInput() + s.flushOutput() + s.write('hello') + sys.stdout.write('%r\n' % s.read(5)) + sys.stdout.write('%s\n' % s.inWaiting()) + del s + |