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	Camera Servo	Signed int (1 byte), Offset from 0
15	Solenoids	1 byte (2 bits per solonoid)
16	Thrusters	1 byte - Controls thruster's on status
17	Stabilization	1 byte - bool for pid / manual control
18	Rotation P Val	Signed int (2 bytes), High order
19	Rotation P Val	Signed int (2 bytes), Low order
20	Rotation I Val	Signed int (2 bytes), High order
21	Rotation I Val	Signed int (2 bytes), Low order
22	Location P Val	Signed int (2 bytes), High order
23	Location P Val	Signed int (2 bytes), Low order
24	Location I Val	Signed int (2 bytes), High order
25	Location I Val	Signed int (2 bytes), Low order
26	CRC8 Check	Use 0xD5 as polynomial
27	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.

Stabilization Byte Acting Axis

Bit #	Description
00	Rx
01	Ry
02	Rz
03	Lx
04	Ly
05	Lz
06	Unused
07	Unused

Main Micro -> Battlestation Packet

Byte #	Description	Type
00	Header	0x12 - 18 decimal
01	Packet Type	0x01 == Sensor Data
02	Thruster Status	1 bit per thruster
03	Pressure-1	32-bit float
04	Pressure-2	32-bit float
05	Pressure-3	32-bit float
06	Pressure-4	32-bit float
07	Temp-1	32-bit float
08	Temp-2	32-bit float
09	Temp-3	32-bit float
10	Temp-4	32-bit float
11	IMU-Lx	Signed int (2 bytes), High order
12	IMU-Lx	Signed int (2 bytes), Low order
13	IMU-Ly	Signed int (2 bytes), High order
14	IMU-Ly	Signed int (2 bytes), Low order
15	IMU-Lz	Signed int (2 bytes), High order
16	IMU-Lz	Signed int (2 bytes), Low order
17	IMU-Rx	Signed int (2 bytes), High order
18	IMU-Rx	Signed int (2 bytes), Low order
19	IMU-Ry	Signed int (2 bytes), High order
20	IMU-Ry	Signed int (2 bytes), Low order
21	IMU-Rz	Signed int (2 bytes), High order
22	IMU-Rz	Signed int (2 bytes), Low order
23	Thruster 1	Thruster Value, Offset from 0
24	Thruster 2	Thruster Value, Offset from 0
25	Thruster 3	Thruster Value, Offset from 0
26	Thruster 4	Thruster Value, Offset from 0
27	Thruster 5	Thruster Value, Offset from 0
28	Thruster 6	Thruster Value, Offset from 0
29	Thruster 7	Thruster Value, Offset from 0
30	Thruster 8	Thruster Value, Offset from 0
31	CRC8 Check	Use 0xD5 as polynomial
32	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;
}