Source Code for Module PyMata.pymata_serial

  1  __author__ = 'Copyright (c) 2013 Alan Yorinks All rights reserved.' 
  2  """ 
  3  Created on Tue Sep  3 07:12:01 2013 
  4   
  5  @author: Alan Yorinks 
  6  Copyright (c) 2013-14 Alan Yorinks All rights reserved. 
  7   
  8  This program is free software; you can redistribute it and/or 
  9  modify it under the terms of the GNU  General Public 
 10  License as published by the Free Software Foundation; either 
 11  version 3 of the License, or (at your option) any later version. 
 12   
 13  This library is distributed in the hope that it will be useful, 
 14  but WITHOUT ANY WARRANTY; without even the implied warranty of 
 15  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 16  Lesser General Public License for more details. 
 17   
 18  You should have received a copy of the GNU Lesser General Public 
 19  License along with this library; if not, write to the Free Software 
 20  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 
 21  """ 
 22   
 23  import threading 
 24  import serial 
 25   
 26   
 27 -class PyMataSerial(threading.Thread): 
 28      """ 
 29       This class manages the serial port for Arduino serial communications 
 30      """ 
 31   
 32      # class variables 
 33      arduino = serial.Serial() 
 34   
 35      port_id = "" 
 36      baud_rate = 57600 
 37      timeout = 1 
 38      command_deque = None 
 39   
 40   
 41 -    def __init__(self, port_id, command_deque): 
 42          """ 
 43          Constructor: 
 44          @param command_deque: A reference to the deque shared with the _command_handler 
 45          """ 
 46          self.port_id = port_id 
 47          self.command_deque = command_deque 
 48   
 49          threading.Thread.__init__(self) 
 50          self.daemon = True 
 51          self.arduino = serial.Serial(self.port_id, self.baud_rate, 
 52                                       timeout=int(self.timeout)) 
 53                                        
 54          self.stop_event = threading.Event() 
 55   
 56 -    def stop( self ): 
 57          self.stop_event.set() 
 58   
 59 -    def is_stopped( self ): 
 60          return self.stop_event.is_set() 
 61   
 62 -    def open(self): 
 63          """ 
 64          open the serial port using the configuration data 
 65          returns a reference to this instance 
 66          """ 
 67          # open a serial port 
 68          print '\nOpening Arduino Serial port %s ' % self.port_id 
 69   
 70          try: 
 71   
 72              # in case the port is already open, let's close it and then 
 73              #reopen it 
 74              self.arduino.close() 
 75              self.arduino.open() 
 76              return self.arduino 
 77   
 78          except Exception: 
 79              # opened failed - will report back to caller 
 80              raise 
 81               
 82 -    def close(self): 
 83          """ 
 84              Close the serial port 
 85              return: None 
 86          """ 
 87          self.arduino.close() 
 88   
 89 -    def write(self, data): 
 90          """ 
 91              write the data to the serial port 
 92              return: None 
 93          """ 
 94          self.arduino.write(data) 
 95           
 96 -    def run(self): 
 97          """ 
 98          This method continually runs. If an incoming character is available on the serial port 
 99          it is read and placed on the _command_deque 
100          @return: Never Returns 
101          """ 
102          while not self.is_stopped(): 
103              # we can get an OSError: [Errno9] Bad file descriptor when shutting down 
104              # just ignore it 
105              try: 
106                  if self.arduino.inWaiting(): 
107                      c = self.arduino.read() 
108                      self.command_deque.append(ord(c)) 
109              except OSError: 
110                  pass 
111               
112          self.close() 
113