Motor_PacketSpec.txt

Motor Controller Packet

0x12 	= Header byte
address = byte 
command = byte
arg1	= byte
arg2	= byte
crc8	= check sum byte
0x13 	= Tail byte

Address:
	Master: 0
	Motors:	1-8
	
Command: 
	0x01 (Control Motor)
	0x02 (Stop Motor)
	0x03 (Request fault data)
	0x04 (Reset H-bridge)
	
arg1/arg2
	0x01 (Control Motor)
		Arg1: Direction
			0 = reverse
			1 = forward
		
		Arg2: Speed (Any integer value between 0 and 255)
			0 = No speed
			255 = Full speed
			
	0x02 (STOP)
		Arg1: NA
		
		Arg2: NA
	
	0x03 (Request Fault Data)
		Arg1: NA
		
		Arg2: NA
	
	0x04 (Reset H-bridge)
		Arg1: NA
		
		Arg2: NA

Check Sum
	
	Takes an byte array of length 4 and creates a check sum.
	
	byte crc8(const byte *packet)
	{ 
	  byte crc = 0;
	  for(byte len = 0; len < 4; len++) {
		uint8_t inbyte = *packet++;
		for (byte i = 8; i; i--) {
		  byte mix = (crc ^ inbyte) & 0x01;
		  crc >>= 1;
		  if (mix) crc ^= 0xD5;
		  inbyte >>= 1;
		}
	  }
	  return crc;
	}