python串⼝库函数_python串⼝库
pySerialpython怎么读取串口数据
Featuressame class based interface on all supported platforms
access to the port settings through Python 2.2+ properties
port numbering starts at zero, no need to know the port name in the user program
port string (device name) can be specified if access through numbering is inappropriate
support for different bytesizes, stopbits, parity and flow control with RTS/CTS and/or Xon/Xoff
working with or without receive timeout
file like API with "read" and "write" ("readline" etc. also supported)
The files in this package are 100% pure Python. They depend on non standard but common packages on Windows
(pywin32) and Jython (JavaComm). POSIX (Linux, BSD) uses only modules from the standard Python distribution)
The port is set up for binary transmission. No NULL byte stripping, CR-LF translation etc. (which are many times enabled
for POSIX.) This makes this module universally useful.
RequirementsPython 2.2 or newer
pywin32 extensions on Windows
"Java Communications" (JavaComm) or compatible extension for Java/Jython
Installation
from sourceExtract files from the archive, open a shell/console in that directory and let Distutils do the rest:python setup.py installThe files get installed in the "Lib/site-packages" directory.
windows installerThere is also a Windows installer for end users. It is located in theDownload PageD
evelopers may be interested to get the source archive, because it contains examples and the readme.
Short introductionOpen port 0 at "9600,8,N,1", no timeout>>> import serial >>> ser = serial.Serial(0) # open first serial port >>> print ser.portstr # check which port was really used >>> ser.write("hello") # write a string >>> ser.close() # close portOpen named port at "19200,8,N,1", 1s timeout>>> ser = serial.Serial('/dev/ttyS1', 19200, timeout=1) >>> x = ad() # read one byte >>> s = ad(10) # read up to ten bytes (timeout) >>> line = adline() # read a '\n' terminated line >>>
ser.close()Open second port at "38400,8,E,1", non blocking HW handshaking>>> ser = serial.Serial(1, 38400, timeout=0, ... parity=serial.PARITY_EVEN, rtscts=1) >>> s = ad(100) # read up to one hundred bytes ... # or as much is in the bufferGet a Serial instance and configure/open it later>>> ser = serial.Serial() >>> ser.baudrate = 19200 >>> ser.port = 0 >>> ser Serial(port='COM1', baudrate=19200, bytesize=8, parity='N', stopbits=1, timeout=None, xonxoff=0, rtscts=0) >>>
ser.open() >>> ser.isOpen() True >>> ser.close() >>> ser.isOpen() FalseBe carefully when using "readline". Do specify a
timeout when opening the serial port otherwise it could block forever if no newline character is received. Also note that "readlines" only works with a timeout. "readlines" depends on having a timeout and interprets that as EOF (end of file). It raises an exception if the port is not opened correctly.Do also have a look at the example files in the examples directory in the source distribution or online.
Parameters for the Serial classser = serial.Serial( port=None, # number of device, numbering starts at # zero. if everything fails, the user # can specify a device string, note # that this isn't portable anymore # if no port is specified an unconfigured # an closed serial port object is created baudrate=9600, # baud rate bytesize=EIGHTBITS, # number of databits
parity=PARITY_NONE, # enable parity checking stopbits=STOPBITS_ONE, # number of stopbits timeout=None, # set a timeout value, None for waiting forever xonxoff=0, # enable software flow control rtscts=0, # enable RTS/CTS flow control interCharTimeout=None # Inter-character timeout, None to disable )The port is immediately opened on object creation, if a port is given. It is not opened if port is None.Options for read timeout:timeout=None # wait forever timeout=0 # non-blocking mode (return immediately on read) timeout=x # set timeout to x seconds (float allowed)
Methods of Serial instancesopen() # open port close() # close port immediately setBaudrate(baudrate) # change baud rate on an open port inWaiting() # return the number of chars in the receive buffer read(size=1) # read "size" characters write(s) # write the string s to the port flushInput() # flush input buffer, discarding all it's contents flushOutput() # flush output buffer, abort output sendBreak() # send break condition setRTS(level=1) # set RTS line to specified logic level
setDTR(level=1) # set DTR line to specified logic level getCTS() # return the state of the CTS line getDSR() # return the state of the DSR line getRI() # return the state of the RI line getCD() # return the state of the CD line
Attributes of Serial instancesRead Only:portstr # device name BAUDRATES # list of valid baudrates BYTESIZES # list of valid byte sizes PARITIES # list of valid parities STOPBITS # list of valid stop bit widthsNew values can be assigned to the following attributes, the port will be reconfigured, even if it's opened at that time:port # port name/number as set by the user baudrate # current baud rate setting bytesize # byte size in bits parity # parity setting stopbits # stop bit with (1,2) timeout # timeout setting xonxoff # if Xon/Xoff flow control is enabled rtscts # if hardware flow control is enabled
Exceptionsserial.SerialException
Constantsparity:serial.PARITY_NONE serial.PARITY_EVEN serial.PARITY_ODDstopbits:serial.STOPBITS_ONE
serial.STOPBITS_TWObytesize:serial.FIVEBITS serial.SIXBITS serial.SEVENBITS serial.EIGHTBITS

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