libraries/AP_Frsky_Telem/AP_Frsky_MAVlite_SPortToMAVlite.h

   1 #pragma once
   2
   3 #include "AP_Frsky_MAVlite_Message.h"
   4 #include "AP_Frsky_SPort.h"
   5
   6 #include <stdint.h>
   7
   8 #if HAL_WITH_FRSKY_TELEM_BIDIRECTIONAL
   9 /*
  10  * An instance of this class decodes a stream of SPort packets into a
  11  * MAVlite message (see AP_Frsky_MAVlite_Message.h).  It is expected
  12  * that the same rxmsg is passed into process() multiple times, each
  13  * time with a new sport packet.  If a packet is successfully decodes
  14  * then process() will return true and rxmsg can be used as a MAVlite
  15  * message.
  16  *
  17  * See AP_Frsky_MAVlite.h for a description of the encoding of a
  18  * MAVlite message in SPort packets.
  19  */
  20 class AP_Frsky_MAVlite_SPortToMAVlite {
  21 public:
  22
  23     bool process(AP_Frsky_MAVlite_Message &rxmsg,
  24                  const AP_Frsky_SPort::sport_packet_t &packet) WARN_IF_UNUSED;
  25
  26 private:
  27
  28     void reset();
  29
  30     uint8_t expected_seq;
  31     uint8_t payload_next_byte;
  32
  33     enum class State : uint8_t {
  34         IDLE=0,
  35         ERROR,
  36         WANT_LEN,
  37         WANT_MSGID,
  38         WANT_PAYLOAD,
  39         WANT_CHECKSUM,
  40         MESSAGE_RECEIVED,
  41     };
  42     State parse_state = State::IDLE;
  43
  44     AP_Frsky_MAVlite_Message _rxmsg;
  45     void parse(const uint8_t byte);
  46
  47     int16_t checksum;                       // sent at end of packet
  48     void update_checksum(const uint8_t c);
  49 };
  50 #endif