串口通讯的python模块——pySerial

pySerial

Overview

This module encapsulates the access for the serial port. It provides backends for Python running on Windows, Linux, BSD (possibly any POSIX compliant system), Jython and IronPython (.NET and Mono). The module named "serial" automatically selects the appropriate backend.

It is released under a free software license, see LICENSE.txt for more details.
(C) 2001-2008 Chris Liechti cliechti@gmx.net 

The project page on SourceForge and here is the SVN repository and the Download Page .
The homepage is on http://pyserial.sf.net/ 

Features

• same 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.

Requirements

• Python 2.2 or newer
• pywin32 extensions on Windows
• "Java Communications" (JavaComm) or compatible extension for Java/Jython

Installation

from source

Extract files from the archive, open a shell/console in that directory and let Distutils do the rest:
python setup.py install 

The files get installed in the "Lib/site-packages" directory.

easy_install

An EGG is available from the Python Package Index: http://pypi.python.org/pypi/pyserial 
easy_install pyserial 

windows installer

There is also a Windows installer for end users. It is located in the Download Page 
Developers may be interested to get the source archive, because it contains examples and the readme.

Short introduction

Open 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 port

>>> ser = serial.Serial('/dev/ttyS1', 19200, timeout=1) >>> x = ser.read() # read one byte >>> s = ser.read(10) # read up to ten bytes (timeout) >>> line = ser.readline() # read a '/n' terminated line >>> ser.close()

>>> ser = serial.Serial(1, 38400, timeout=0, ... parity=serial.PARITY_EVEN, rtscts=1) >>> s = ser.read(100) # read up to one hundred bytes ... # or as much is in the buffer

>>> 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() False

Examples

Parameters for the Serial class

ser = 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 )

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 instances

open() # 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 instances

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 widths

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

Exceptions

serial.SerialException

Constants

serial.PARITY_NONE serial.PARITY_EVEN serial.PARITY_ODD

serial.STOPBITS_ONE serial.STOPBITS_TWO

serial.FIVEBITS serial.SIXBITS serial.SEVENBITS serial.EIGHTBITS