CanServo/Protocol/LongMessage

Long Message

• 각 패킷마다 Tail Byte를 붙여서 긴 메시지를 여러 패킷으로 분리하여 전달하는 방식입니다.

• This content refers to the message format of UAVCAN.
  • Thanks to UAVCAN

• Note:
  • CRC16 : byte order : low byte first, little endian

• Reference:
  • Code/CRC16

CAN 2.0

• Packaging the message to be sent.
  • If the message to be sent is 8 bytes or more, CRC16 is added.

• Packet's Data Format
  • < Data : max 7 byte, cut from packed Message >, <Check Byte>
  • Check Byte
    • bit 7 = first packet
    • bit 6 = last packet
    • bit 5 = Toggle, first packet = 1, toggle bit on each packet
    • bit 4:0 = Seq, 0 ~ 31, inc 1 on each message

• Messages less than 8 bytes long are transmitted as one packet.

• CRC starting value is 0xFFFF (-1)

CAN-FD

• CAN-FD data 는 64바이트까지 확장됩니다.
  • 0~8, 12, 16, 20, 24, 32, 48, 64

CAN ID

• CAN ID = 0x7FE = Host -> Servo
• CAN ID = 0x7FF = Servo -> Host
• CAN ID = Servo ID2 + 1