Reconnecting to device with pySerial
pyserial, python, serial-port
Solution
You aren't releasing the serial port when you are finished. Use `ser.close()` to close the port before exiting your program, otherwise the port will stay locked indefinitely. I would suggest adding a method called `disconnect()` in your class for this.
If you are on Windows, to remedy the situation during testing, start Task Manager and kill any `python.exe` or `pythonw.exe` processes that may be locking the serial port.
Problem
I am currently having a problem with the pySerial module in Python. My problem relates to connecting and disconnecting to a device. I can successfully connect to my device and communicate with it for as long as I want to, and disconnect from it whenever I desire. However, I am unable to reconnect to the device once the connection has been severed. Here is the wrapper class that my program uses to interface with the serial port: ``` import serial, tkMessageBox class Controller: """ Wrapper class for managing the serial connection with the MS-2000. """ def __init__(self, settings): self.ser = None self.settings = settings def connect(self): """ Connect or disconnect to MS-2000. Return connection status.""" try: if self.ser == None: self.ser = serial.Serial(self.settings['PORT'], self.settings['BAUDRATE']) print "Successfully connected to port %r." % self.ser.port return True else: if self.ser.isOpen(): self.ser.close() print "Disconnected." return False else: self.ser.open() print "Connected." return True except serial.SerialException, e: return False def isConnected(self): '''Is the computer connected with the MS-2000?''' try: return self.ser.isOpen() except: return False def write(self, command): """ Sends command to MS-2000, appending a carraige return. """ try: self.ser.write(command + '\r') except Exception, e: tkMessageBox.showerror('Serial connection error', 'Error sending message "%s" to MS-2000:\n%s' % (command, e)) def read(self, chars): """ Reads specified number of characters from the serial port. """ return self.ser.read(chars) ``` Does anybody know the reason why this problem exists and what I could try to do to fix it?