X8-DataPacket

Repository for keeping track of data packets needed.

Battlestation -> Main Micro Packet

Byte #	Description	Type
00	Header	0x12 - 18 decimal
01	Control	0x01 == Control
02	X-1	Signed int (2 bytes), High order
03	X-2	Signed int (2 bytes), Low order
04	Y-1	Signed int (2 bytes), High order
05	Y-2	Signed int (2 bytes), Low order
06	Z-1	Signed int (2 bytes), High order
07	Z-2	Signed int (2 bytes), Low order
08	Roll-1	Signed int (2 bytes), High order
09	Roll-2	Signed int (2 bytes), Low order
10	Pitch-1	Signed int (2 bytes), High order
11	Pitch-2	Signed int (2 bytes), Low order
12	Yaw-1	Signed int (2 bytes), High order
13	Yaw-2	Signed int (2 bytes), Low order
14	Solenoids	1 byte (2 bits per solonoid)
15	Hydaulics Pump	1 byte (0 to 255 PWM Val)
16	LEDs	1 byte (0 to 255 PWM Val)
17	Thrusters	1 byte - Controls thruster's on status
18	PID Control	1 byte - bool for pid / manual control
19	PID Tuning A-1	Signed int (2 bytes), High order
20	PID Tuning A-2	Signed int (2 bytes), Low order
21	PID Tuning B-1	Signed int (2 bytes), High order
22	PID Tuning B-2	Signed int (2 bytes), Low order
23	PID Tuning C-1	Signed int (2 bytes), High order
24	PID Tuning C-2	Signed int (2 bytes), Low order
25	PID Pivot X	Signed int (1 byte)
26	PID Pivot Y	Signed int (1 byte)
27	PID Pivot Z	Signed int (1 byte)
28	CRC8 Check	Use 0xD5 as polynomial
29	Tail Byte	0x13 - 19 decimal

Always set command to 0x01. In the future, there will be further options to program options are ask for certain data using this byte, but nothing is set yet.

Main Micro -> Battlestation Packet

Byte #	Description	Type
00	Header	0x12 - 18 decimal
01	Thruster Status	1 bit per thruster
02	Pressure-1	Signed int (2 bytes), High order
03	Pressure-2	Signed int (2 bytes), Low order
04	Temp-1	32-bit float, Highest order
05	Temp-2	32-bit float, High order
06	Temp-3	32-bit float, Low order
07	Temp-4	32-bit float, Lowest order
08	IMU A-1	Signed int (2 bytes), High order
09	IMU A-2	Signed int (2 bytes), Low order
10	IMU B-1	Signed int (2 bytes), High order
11	IMU B-2	Signed int (2 bytes), Low order
12	IMU C-1	Signed int (2 bytes), High order
13	IMU C-2	Signed int (2 bytes), Low order
14	IMU D-1	Signed int (2 bytes), High order
15	IMU D-2	Signed int (2 bytes), Low order
16	IMU E-1	Signed int (2 bytes), High order
17	IMU E-2	Signed int (2 bytes), Low order
18	IMU F-1	Signed int (2 bytes), High order
19	IMU F-2	Signed int (2 bytes), Low order
20	IMU G-1	Signed int (2 bytes), High order
21	IMU G-2	Signed int (2 bytes), Low order
22	IMU H-1	Signed int (2 bytes), High order
23	IMU H-2	Signed int (2 bytes), Low order
24	IMU I-1	Signed int (2 bytes), High order
25	IMU I-2	Signed int (2 bytes), Low order
26	CRC8 Check	Use 0xD5 as polynomial
27	Tail Byte	0x13 - 19 decimal

C :: CRC-8 Checksum Code

//loops over array of bytes and returns checksum
//skips first and last two bytes (header, checksum, tail)
char crc8(char bytes[], int size) {
  char crc = 0;
  char val;
  char mix;
  for (int i = 1; i < size - 2; ++i) {
    val = bytes[i];
    for (int j = 8; j; --j) {
      mix = (crc ^ val) & 0x01;
      crc >>= 1;
      if (mix) {
        crc ^= 0xD5;
      }
      val >>= 1;
    }
  }
  return crc;
}