Index: DialityCoreCanProtocol.py
===================================================================
diff -u -r6c057347d02b98f98260ccefca3ffada9c7d628d -rc172ebf4d713b654fb5a75113c96bf7f5ef5d858
--- DialityCoreCanProtocol.py	(.../DialityCoreCanProtocol.py)	(revision 6c057347d02b98f98260ccefca3ffada9c7d628d)
+++ DialityCoreCanProtocol.py	(.../DialityCoreCanProtocol.py)	(revision c172ebf4d713b654fb5a75113c96bf7f5ef5d858)
@@ -19,6 +19,7 @@
 import can
 import math
 from time import sleep
+from ctypes import c_int8
 
 
 class DenaliMessage:
@@ -36,8 +37,30 @@
     HEADER_LENGTH = 4
 
     PACKET_LENGTH = 8
+    CRC_LENGTH = 1
     MAX_MSG_ID_NUMBER = 65535
 
+    MAX_NUMBER_OF_PAYLOAD_BYTES = 254
+
+    CRC_LIST = [
+        0, 49, 98, 83, 196, 245, 166, 151, 185, 136, 219, 234, 125, 76, 31, 46,
+        67, 114, 33, 16, 135, 182, 229, 212, 250, 203, 152, 169, 62, 15, 92, 109,
+        134, 183, 228, 213, 66, 115, 32, 17, 63, 14, 93, 108, 251, 202, 153, 168,
+        197, 244, 167, 150, 1, 48, 99, 82, 124, 77, 30, 47, 184, 137, 218, 235,
+        61, 12, 95, 110, 249, 200, 155, 170, 132, 181, 230, 215, 64, 113, 34, 19,
+        126, 79, 28, 45, 186, 139, 216, 233, 199, 246, 165, 148, 3, 50, 97, 80,
+        187, 138, 217, 232, 127, 78, 29, 44, 2, 51, 96, 81, 198, 247, 164, 149,
+        248, 201, 154, 171, 60, 13, 94, 111, 65, 112, 35, 18, 133, 180, 231, 214,
+        122, 75, 24, 41, 190, 143, 220, 237, 195, 242, 161, 144, 7, 54, 101, 84,
+        57, 8, 91, 106, 253, 204, 159, 174, 128, 177, 226, 211, 68, 117, 38, 23,
+        252, 205, 158, 175, 56, 9, 90, 107, 69, 116, 39, 22, 129, 176, 227, 210,
+        191, 142, 221, 236, 123, 74, 25, 40, 6, 55, 100, 85, 194, 243, 160, 145,
+        71, 118, 37, 20, 131, 178, 225, 208, 254, 207, 156, 173, 58, 11, 88, 105,
+        4, 53, 102, 87, 192, 241, 162, 147, 189, 140, 223, 238, 121, 72, 27, 42,
+        193, 240, 163, 146, 5, 52, 103, 86, 120, 73, 26, 43, 188, 141, 222, 239,
+        130, 179, 224, 209, 70, 119, 36, 21, 59, 10, 89, 104, 255, 206, 157, 172
+    ]
+
     @staticmethod
     def buildBasicMessage(channel_id=0, message=None):
         """
@@ -64,13 +87,13 @@
 
         if payload is None:
             payload = []
-        message = [DenaliCanMessenger.START_BYTE]
+        #message = [DenaliCanMessenger.START_BYTE]
 
         if 0 <= message_id <= DenaliMessage.MAX_MSG_ID_NUMBER:
             # Make sure an unsigned int was passed
             message_id_in_bytes = message_id.to_bytes(2, byteorder=DenaliMessage.BYTE_ORDER)
 
-            message += [message_id_in_bytes[0]]
+            message = [message_id_in_bytes[0]]
             message += [message_id_in_bytes[1]]
 
         else:
@@ -81,19 +104,33 @@
         payload_length = len(payload)
 
         # if payload is larger than 255 return nothing
-        if payload_length <= 255:
+        if payload_length <= DenaliMessage.MAX_NUMBER_OF_PAYLOAD_BYTES:
             # payload has to be a list
             message += [payload_length]
         else:
             return []
 
         message += payload
 
+        message += DenaliMessage.crc8(message)
+
+        message = [DenaliCanMessenger.START_BYTE] + message
+
         message = DenaliMessage.__padMessageWithZeros(message)
 
         return DenaliMessage.buildBasicMessage(channel_id=channel_id, message=message)
 
     @staticmethod
+    def crc8(message):
+        crc = 0
+
+        for byte in message:
+            unsigned_byte = int(byte) ^ crc
+            crc = DenaliMessage.CRC_LIST[unsigned_byte]
+
+        return bytes(c_int8(crc))
+
+    @staticmethod
     def __padMessageWithZeros(message):
         """
         returns a packet padded with zeros that guarantees that the packet is a multiple of 8 bytes.
@@ -177,7 +214,7 @@
         the_message = message if is_array else message['message']
 
         return math.ceil((the_message[DenaliMessage.PAYLOAD_LENGTH_INDEX] +
-                          DenaliMessage.HEADER_LENGTH) /
+                          DenaliMessage.HEADER_LENGTH + DenaliMessage.CRC_LENGTH) /
                           DenaliMessage.PACKET_LENGTH)
 
 
@@ -334,12 +371,12 @@
                     self.__dialinMessage = self.__longMessageBuilders[channel_id].push(can_data)
 
                 elif can_data[0] == self.START_BYTE and \
-                     message_length <= DenaliMessage.PAYLOAD_LENGTH_FIRST_PACKET:  # This is a short packet
+                        message_length <= DenaliMessage.PAYLOAD_LENGTH_FIRST_PACKET:  # This is a short packet
                     # This is the first time that we are building a message
                     self.__dialinMessage = can_data  # deliver the packet
 
                 elif can_data[0] == self.START_BYTE and \
-                     message_length > DenaliMessage.PAYLOAD_LENGTH_FIRST_PACKET:  # Long packet start
+                        message_length > DenaliMessage.PAYLOAD_LENGTH_FIRST_PACKET:  # Long packet start
                     # We are starting to build a long message, include it in the lonMsgChannelIDSet
                     self.__longMsgChannelIDSet.add(channel_id)
 
@@ -350,6 +387,8 @@
                     else:  # if we do have a builder.  This is the first time
                         self.__dialinMessage = self.__longMessageBuilders[channel_id].push(can_data, first_packet=True)
 
+                # Need to verify CRC at this point
+
                 # At this point we have a complete (long or short) Diality Packet
 
                 if self.__dialinMessage is not None: