Added methods to receive CAN messages
* Added a receiveMessage method to the PCan class * The PCan class can hold messages now, needed for updating message data and signal data after reception * Added a GetData method to the CanMessage class * Updated and extended the example program
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Christian Sltrop
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8363ddd5a8
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3a693ba35d
7 changed files with 165 additions and 56 deletions
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@ -116,6 +116,47 @@ class CanMessage(object):
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if tgtBitNo >= 8:
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tgtBitNo = 0
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tgtByteNo += 1
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'''
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Takes the CAN message data and decomposes it into its signals.
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This method is basically the reversion of the method composeData.
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'''
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def decomposeData(self):
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for sigKey in self.Signals:
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sig = self.Signals[sigKey]
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tgtBegin = 0 # writing the target data (to the signal) always starts at the first byte
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srcBegin = sig.Begin # where the target data is in the message is defined in the Begin field of the CanSignal object. Unit: bits
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tgtByteNo = tgtBegin/8 # will be 0 if tgtBegin == 0
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tgtBitNo = tgtBegin%8 # will be 0 if tgtBegin == 0
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srcByteNo = srcBegin/8 # get the byte and bit numbers
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srcBitNo = srcBegin%8 # for the source (the CanMessage object) array
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for i in range(0, sig.Length):
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# copy the source data bits into the target
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if srcByteNo >= self.Length:
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sys.exit('Signal data not in message (message too short)')
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tmp = (self.Data[srcByteNo] & (1<<tgtBitNo))
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if tmp != 0: # the bit shall be set
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sig.Data[tgtByteNo] |= (1<<tgtBitNo)
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else: # the bit shall be cleared
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sig.Data[tgtByteNo] &= ~(1<<tgtBitNo)
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# increment the counters
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srcBitNo += 1
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if srcBitNo >= 8: # on bit counter overflow, increment the byte counter and reset the bit counter
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srcBitNo = 0
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srcByteNo += 1
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tgtBitNo += 1
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if tgtBitNo >= 8:
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tgtBitNo = 0
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tgtByteNo += 1
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self.Signals[sigKey] = sig
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'''
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Calculate the CRC checksum over the whole message.
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@ -124,10 +165,9 @@ class CanMessage(object):
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If this is true for all checksums is not certain! Has been tested for mMotor_5 and mMotor_6 only!
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'''
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def calculateCRC(self):
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crc = Crc(width=8, poly=0x01, reflect_in = False, reflect_out = False, xor_in = 0xff, xor_out = 0xff)
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crc = Crc(width=8, poly=0x01, reflect_in = False, reflect_out = False, xor_in = 0xff, xor_out = 0xff) # configure the crc calculator according to the VW parameters
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self.composeData()
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data = self.Data.tostring()
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my_crc = crc.bit_by_bit_fast(data)
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#print ("%x" % my_crc)
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return my_crc
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Binary file not shown.
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@ -1,11 +1,13 @@
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# -*- coding: UTF-8 -*-
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'''
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Created on 06.07.2012
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@author: sueltrop
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@author: Christian Sültrop
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'''
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import sys
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import array
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#import sys
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#import array
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class CanSignal(object):
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@ -35,7 +37,7 @@ class CanSignal(object):
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def SetData(self, SignalData):
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'''
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Updated the data of the Signal.
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Update the data of the Signal.
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The data is given to the Signal as full bytes, but only the bits up to Length may be used!
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@param Data: An array of unsigned characters containing the data.
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'''
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@ -44,4 +46,18 @@ class CanSignal(object):
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tmpData = int((SignalData-self.Offset) / self.Scaling)
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self.Data = []
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for i in range(0, int(self.Length/8)+1):
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self.Data.append ( (tmpData >> (8*i) ) & 0xff )
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self.Data.append ( (tmpData >> (8*i) ) & 0xff )
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def GetData(self):
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'''
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'''
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tmpData = 0
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for i in range(0, int(self.Length/8)):
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#print 'Data[i]', self.Data[i]
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tmpData += ( self.Data[i] << (8*i) )
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tmpData = int( (tmpData * self.Scaling) + self.Offset )
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#tmpData = int( (tmpData - self.Offset ) / self.Scaling )
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#print tmpData
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return tmpData
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Binary file not shown.
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@ -3,7 +3,7 @@
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'''
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Created on 06.07.2012
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@author: Christan Sültrop
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@author: Christian Sültrop
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'''
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import PCANBasic # PCANBasic wrapper library provided by PEAK
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@ -24,21 +24,41 @@ class PcanAdapter (object):
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def __init__(self, Baudrate):
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'''
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Constructor.
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@param Baudrate: Baudrate from the PcanAdapter.Baudrate dictionary
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@param Baudrate: Baud rate from the PcanAdapter. Baud rate dictionary
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'''
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# Object variables:
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# Instance variables:
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self.Messages = {}
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self.Channel = PCANBasic.PCAN_USBBUS1
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self.Pcan = PCANBasic.PCANBasic()
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self.Baudrate = Baudrate # Baudrate from PCANBasic
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self.Baudrate = Baudrate # Baud rate from PCANBasic
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self.isInitialised = False
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def __del__(self):
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'''
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Destructor.
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Uninitializes the PCAN adapter.
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Uninitialises the PCAN adapter.
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'''
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print '\nDestructor:'
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self.uninitialize()
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def addMessage(self, CanMessage):
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'''
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Add a Message of type CanMessage to the list of messages.
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@param CanMessage: The message to add to the list of messages.
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'''
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self.Messages.update({CanMessage.Label: CanMessage})
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def removeMessage(self, CanMessageLabel):
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try:
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self.Messages.pop(CanMessageLabel)
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except:
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pass
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def clearMessages(self):
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self.Messages = {}
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def initialize(self):
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'''
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@ -48,9 +68,9 @@ class PcanAdapter (object):
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status = self.Pcan.Initialize(self.Channel, self.Baudrate)
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if status != PCANBasic.PCAN_ERROR_OK:
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print 'Error: ', self.Pcan.GetErrorText(status, 0)[1]
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sys.exit("PCAN initialization error")
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sys.exit("PCAN initialisation error")
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print("PCAN initialized")
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print("PCAN initialised")
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self.isInitialised = True
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channel, hwId = self.Pcan.GetValue( self.Channel, PCANBasic.PCAN_DEVICE_NUMBER )
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@ -64,9 +84,9 @@ class PcanAdapter (object):
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status = self.Pcan.Uninitialize(self.Channel)
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if status != PCANBasic.PCAN_ERROR_OK:
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print 'Error: ', self.Pcan.GetErrorText(status, 0)[1]
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sys.exit("PCAN deinitialization error")
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sys.exit("PCAN deinitialisation error")
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print("PCAN deinitialized")
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print("PCAN deinitialised")
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def sendMessage(self, Message):
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'''
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@ -80,7 +100,26 @@ class PcanAdapter (object):
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msg.ID = Message.Id # copy the ID
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msg.MSGTYPE = PCANBasic.PCAN_MESSAGE_STANDARD # Message type is standard (not extended)
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msg.LEN = Message.Length # copy the length
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msg.DATA[0:Message.Length] = Message.Data # copy the message data into the PCAN messge object
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msg.DATA[0:Message.Length] = Message.Data # copy the message data into the PCAN message object
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self.Pcan.Write(self.Channel, msg) # write it onto the Bus
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#print ('Message ' + Message.Label + ' written.')
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#print ('Message ' + Message.Label + ' written.')
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def receiveMessage(self):
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'''
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Tries to receive a CAN message and puts its data into the according CanMessage object's Data field.
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This method should be called frequently.
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'''
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result, msg, timestamp = self.Pcan.Read(self.Channel)
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if result == PCANBasic.PCAN_ERROR_OK:
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# loop through the messages and look for one that matches the received message:
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for msgKey in self.Messages:
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if self.Messages[msgKey].Id == msg.ID:
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if msg.LEN != self.Messages[msgKey].Length:
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# an error message could be posted at this point
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pass
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else:
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for i in range(0, self.Messages[msgKey].Length):
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self.Messages[msgKey].Data[i] = msg.DATA[i]
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self.Messages[msgKey].decomposeData()
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Binary file not shown.
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@ -9,53 +9,67 @@ Example for creating and sending CAN messages via PCAN using the CanMessage, Can
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from CanMessage import CanMessage
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from CanSignal import CanSignal
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from PCan import PcanAdapter
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print '\ncreate some messages'
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mMotor_1 = CanMessage(0x280, 8, 10, 'mMotor_1')
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print 'mMotor_1.Data', mMotor_1.Data
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mMotor_2 = CanMessage(0x288, 8, 20, 'mMotor_2')
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print 'mMotor_2.Data', mMotor_2.Data
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print '\ncreate some Signals'
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# for mMotor_1
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MO1_Leergas = CanSignal(0, 1, [0x01], 'MO1_Leergas')
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MO1_Sta_Pedal = CanSignal(1, 1, [0x01], 'MO1_Sta_Pedal')
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MO1_Mo_m_ex = CanSignal(8, 8, [0x00], 'MO1_Mo_m_ex')
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value = int(3000*0.25)
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MO1_Drehzahl = CanSignal(16, 16, [value>>8, value&0x00ff], 'MO1_Drehzahl') # split into two bytes
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mMotor_1.addSignal(MO1_Leergas)
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mMotor_1.addSignal(MO1_Sta_Pedal)
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mMotor_1.addSignal(MO1_Mo_m_ex)
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mMotor_1.addSignal(MO1_Drehzahl)
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print MO1_Drehzahl.Data
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# for mMotor_2
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MO2_Kuehlm_T = CanSignal(8, 8, [int(60*0.75)-48], 'MO2_Kuehlm_T')
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mMotor_2.addSignal( MO2_Kuehlm_T )
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mMotor_2.addSignal( CanSignal(24, 8, [0], 'MO2_GRA_Soll') )
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mMotor_2.addSignal( CanSignal(0, 6, [44], 'MO2_CAN_Vers') )
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print '\nManipulate Signals'
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# does not work yet! need a way to replace a Signal -> dictionary
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MO1_Leergas.SetData( [0x00] )
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mMotor_1.addSignal( MO1_Leergas )
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import time
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print '\nCreate a PCAN adapter'
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pcan = PcanAdapter(PcanAdapter.Baudrate['500k'])
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pcan.initialize()
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print '\ncreate some messages'
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mMotor_1 = CanMessage(0x280, 8, 10, 'mMotor_1')
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pcan.addMessage(mMotor_1)
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print 'mMotor_1.Data', pcan.Messages['mMotor_1'].Data
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mMotor_2 = CanMessage(0x288, 8, 20, 'mMotor_2')
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pcan.addMessage(mMotor_2)
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print 'mMotor_2.Data', pcan.Messages['mMotor_2'].Data
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print '\ncreate some Signals'
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# for mMotor_1
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MO1_Leergas = CanSignal(0, 1, 0, 1, 1, 'MO1_Leergas')
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MO1_Sta_Pedal = CanSignal(1, 1, 0, 1, 1, 'MO1_Sta_Pedal')
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MO1_Mo_m_ex = CanSignal(8, 8, 0, 1, 0, 'MO1_Mo_m_ex')
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value = 3000
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MO1_Drehzahl = CanSignal(16, 16, 0, 0.25, value, 'MO1_Drehzahl') # split into two bytes
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pcan.Messages['mMotor_1'].addSignal(MO1_Leergas)
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pcan.Messages['mMotor_1'].addSignal(MO1_Sta_Pedal)
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pcan.Messages['mMotor_1'].addSignal(MO1_Mo_m_ex)
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pcan.Messages['mMotor_1'].addSignal(MO1_Drehzahl)
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print pcan.Messages['mMotor_1'].Signals['MO1_Drehzahl'].Data
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# for mMotor_2
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MO2_Kuehlm_T = CanSignal(8, 8, -48, 0.75, 60, 'MO2_Kuehlm_T')
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pcan.Messages['mMotor_2'].addSignal( MO2_Kuehlm_T )
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pcan.Messages['mMotor_2'].addSignal( CanSignal(24, 8, 0, 1, 0, 'MO2_GRA_Soll') )
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pcan.Messages['mMotor_2'].addSignal( CanSignal(0, 6, 0, 1, 44, 'MO2_CAN_Vers') )
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print '\nManipulate Signals'
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pcan.Messages['mMotor_1'].Signals['MO1_Leergas'].SetData( 0 )
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print '\nSend the messages'
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mMotor_1.composeData()
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pcan.sendMessage(mMotor_1)
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pcan.Messages['mMotor_1'].composeData()
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print 'mMotor_1.Data', pcan.Messages['mMotor_1'].Data
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pcan.sendMessage(pcan.Messages['mMotor_1'])
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mMotor_2.composeData()
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pcan.sendMessage(mMotor_2)
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pcan.Messages['mMotor_2'].composeData()
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print 'mMotor_2.Data', pcan.Messages['mMotor_2'].Data
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pcan.sendMessage(pcan.Messages['mMotor_2'])
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# receive messages, if the signal MO1_Drehzahl has changed, print the new value
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while True:
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dataOld = pcan.Messages['mMotor_1'].Signals['MO1_Drehzahl'].GetData()
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pcan.receiveMessage()
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if pcan.Messages['mMotor_1'].Signals['MO1_Drehzahl'].GetData() != dataOld:
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print 'mMotor_1.Data', pcan.Messages['mMotor_1'].Data
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print 'GetData()', pcan.Messages['mMotor_1'].Signals['MO1_Drehzahl'].GetData()
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time.sleep(0.0005)
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# wait a while to make sure messages can be sent and end
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time.sleep(1)
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print 'end of program'
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