.text .imp { font-weight: bold; color: red; }
- >>> 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
Open named port at "19200,8,N,1", 1s timeout
.text .imp { font-weight: bold; color: red; }
- >>> 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()
Open second port at "38400,8,E,1", non blocking HW handshaking
.text .imp { font-weight: bold; color: red; }
- >>> 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
Get a Serial instance and configure/open it later
.text .imp { font-weight: bold; color: red; }
- >>> ser = serial.Serial()
- >>> ser.baudrate = 19200
- >>> ser.port = 0
- >>> ser
- Serial<id=0xa81c10, open=False>(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
Be 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.
Examples
Please look in the SVN Repository. There is an example directory where you can find a simple terminal and more.
http://pyserial.svn.sourceforge.net/viewvc/pyserial/trunk/pyserial/examples/Parameters for the Serial class
.text .imp { font-weight: bold; color: red; }
- 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
- )
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:
.text .imp { font-weight: bold; color: red; }
- 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
.text .imp { font-weight: bold; color: red; }
- 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
Read Only:
.text .imp { font-weight: bold; color: red; }
- 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
New values can be assigned to the following attributes, the port will be reconfigured, even if it's opened at that time:
.text .imp { font-weight: bold; color: red; }
- 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
.text .imp { font-weight: bold; color: red; }
Constants
parity:
.text .imp { font-weight: bold; color: red; }
- serial.PARITY_NONE
- serial.PARITY_EVEN
- serial.PARITY_ODD
stopbits:
.text .imp { font-weight: bold; color: red; }
- serial.STOPBITS_ONE
- al.STOPBITS_TWO
bytesize:
.text .imp { font-weight: bold; color: red; }
- serial.FIVEBITS
- serial.SIXBITS
- serial.SEVENBITS
- serial.EIGHTBITS