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#! /usr/bin/python
#Python Serial Port Extension for Win32, Linux, BSD, Jython
#module for serial IO for POSIX compatible systems, like Linux
#see __init__.py
#
#(C) 2001-2003 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
from serialutil import *
VERSION = "$Revision: 1.35 $".split()[1] #extract CVS version
#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...
plat = sys.platform.lower()
if plat[:5] == 'linux': #Linux (confirmed)
def device(port):
return '/dev/ttyS%d' % port
elif plat == 'cygwin': #cywin/win32 (confirmed)
def device(port):
return '/dev/com%d' % (port + 1)
elif plat == 'openbsd3': #BSD (confirmed)
def device(port):
return '/dev/ttyp%d' % port
elif plat[:3] == 'bsd' or \
plat[:7] == 'freebsd' or \
plat[:7] == 'openbsd' or \
plat[:6] == 'darwin': #BSD (confirmed for freebsd4: cuaa%d)
def device(port):
return '/dev/cuad%d' % port
elif plat[:6] == 'netbsd': #NetBSD 1.6 testing by Erk
def device(port):
return '/dev/dty%02d' % port
elif plat[:4] == 'irix': #IRIX (partialy tested)
def device(port):
return '/dev/ttyf%d' % (port+1) #XXX different device names depending on flow control
elif plat[:2] == 'hp': #HP-UX (not tested)
def device(port):
return '/dev/tty%dp0' % (port+1)
elif plat[:5] == 'sunos': #Solaris/SunOS (confirmed)
def device(port):
return '/dev/tty%c' % (ord('a')+port)
elif plat[:3] == 'aix': #aix
def device(port):
return '/dev/tty%d' % (port)
else:
#platform detection has failed...
print """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 paramter.
def device(portum):
return '/dev/ttyS%d' % portnum
#~ 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
TIOCINQ = hasattr(TERMIOS, 'FIONREAD') and TERMIOS.FIONREAD or 0x541B
TIOCM_zero_str = struct.pack('I', 0)
TIOCM_RTS_str = struct.pack('I', TIOCM_RTS)
TIOCM_DTR_str = struct.pack('I', TIOCM_DTR)
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
}
class Serial(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.")
self.fd = None
#open
try:
self.fd = os.open(self.portstr, os.O_RDWR|os.O_NOCTTY|os.O_NONBLOCK)
except Exception, msg:
self.fd = None
raise SerialException("could not open port %s: %s" % (self._port, msg))
#~ fcntl.fcntl(self.fd, FCNTL.F_SETFL, 0) #set blocking
try:
self._reconfigurePort()
except:
os.close(self.fd)
self.fd = None
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 port handle")
vmin = vtime = 0 #timeout is done via select
try:
iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self.fd)
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 baudrate
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)
#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 stopbits
if self._stopbits == STOPBITS_ONE:
cflag &= ~(TERMIOS.CSTOPB)
elif self._stopbits == STOPBITS_TWO:
cflag |= (TERMIOS.CSTOPB)
else:
raise ValueError('Invalid stopit 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)
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. = 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
termios.tcsetattr(self.fd, TERMIOS.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
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]
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 = ''
inp = None
if size > 0:
while len(read) < size:
#print "\tread(): size",size, "have", len(read) #debug
ready,_,_ = select.select([self.fd],[],[], self._timeout)
if not ready:
break #timeout
buf = os.read(self.fd, size-len(read))
read = read + buf
if self._timeout >= 0 and not buf:
break #early abort on timeout
return read
def write(self, data):
"""Output the given string over the serial port."""
if self.fd is None: raise portNotOpenError
if not isinstance(data, str):
raise TypeError('expected str, got %s' % type(data))
t = len(data)
d = data
while t > 0:
try:
if self._writeTimeout is not None and self._writeTimeout > 0:
_,ready,_ = select.select([],[self.fd],[], self._writeTimeout)
if not ready:
raise writeTimeoutError
n = os.write(self.fd, d)
if self._writeTimeout is not None and self._writeTimeout > 0:
_,ready,_ = select.select([],[self.fd],[], self._writeTimeout)
if not ready:
raise writeTimeoutError
d = d[n:]
t = t - n
except OSError,v:
if v.errno != errno.EAGAIN:
raise
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 self.fd is None:
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 self.fd is None:
raise portNotOpenError
termios.tcflush(self.fd, TERMIOS.TCOFLUSH)
def sendBreak(self, duration=0.25):
"""Send break condition."""
if self.fd is None:
raise portNotOpenError
termios.tcsendbreak(self.fd, int(duration/0.25))
def setRTS(self, level=1):
"""Set terminal status line: Request To Send"""
if self.fd is None: 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 self.fd is None: 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 self.fd is None: 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 self.fd is None: 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 self.fd is None: 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 self.fd is None: raise portNotOpenError
s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
return struct.unpack('I',s)[0] & TIOCM_CD != 0
# - - platform specific - - - -
def drainOutput(self):
"""internal - not portable!"""
if self.fd is None: raise portNotOpenError
termios.tcdrain(self.fd)
def nonblocking(self):
"""internal - not portable!"""
if self.fd is None:
raise portNotOpenError
fcntl.fcntl(self.fd, FCNTL.F_SETFL, FCNTL.O_NONBLOCK)
def fileno(self):
"""For easier of the serial port instance with select.
WARNING: this function is not portable to different platforms!"""
if self.fd is None: raise portNotOpenError
return self.fd
if __name__ == '__main__':
s = Serial(0,
baudrate=19200, #baudrate
bytesize=EIGHTBITS, #number of databits
parity=PARITY_EVEN, #enable parity checking
stopbits=STOPBITS_ONE, #number of stopbits
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')
print repr(s.read(5))
print s.inWaiting()
del s
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