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import serial

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import exceptions

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from threading import Lock

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import time

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class LPCProtoError(exceptions.Exception):

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        """Exception class"""

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        def __init__(self, msg):

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                self.msg = msg

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        def __str__(self):

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                return "Exception in PLC protocol : " + str(self.msg)

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class LPCProto:

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    def __init__(self, port, rate, timeout):

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        # serialize access lock

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        self.TransactionLock = Lock()

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        if BMZ_DBG:

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            # Debugging serial stuff

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            self._serialPort = serial.Serial( port, rate, timeout = timeout, writeTimeout = timeout )

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            class myser:

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                def readline(self_):

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                    res = self._serialPort.readline() 

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                    print 'Recv :"', res, '"' 

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                    return res

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                def read(self_,cnt):

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                    res = self._serialPort.read(cnt)

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                    if len(res) > 16:

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                        print "Recv :", map(hex,map(ord,res[:16])), "[...]"

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                    else:

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                        print "Recv :", map(hex,map(ord,res))

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                    return res

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                def write(self_, string):

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                    lstr=len(string)

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                    if lstr > 16:

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                        print "Send :", map(hex,map(ord,string[:16])), "[...]"

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                    else:

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                        print "Send :", map(hex,map(ord,string))

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                    return self._serialPort.write(string)

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                    # while len(string)>0:

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                    #     i = self._serialPort.write(string[:4096])

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                    #     print ".",

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                    #     string = string[i:]

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                    # print

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                    #return lstr

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                def flush(self_):

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                    return self._serialPort.flush()

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                def close(self_):

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                    self._serialPort.close()

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            self.serialPort = myser()

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        else:

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            # open serial port

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            self.serialPort = serial.Serial( port, rate, timeout = timeout )

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        # start with empty buffer

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        self.serialPort.flush()

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    def __del__(self):

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        if self.serialPort:

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            self.serialPort.close()

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    def close(self):

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        self.serialPort.close()

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        self.serialPort = None