ardupilot/libraries/AP_RCProtocol/AP_RCProtocol_SUMD.h

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/*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Code by Andrew Tridgell and Siddharth Bharat Purohit
*/
#pragma once
#include "AP_RCProtocol.h"
#include "SoftSerial.h"
#define SUMD_MAX_CHANNELS 32
#define SUMD_FRAME_MAXLEN 40
class AP_RCProtocol_SUMD : public AP_RCProtocol_Backend {
public:
AP_RCProtocol_SUMD(AP_RCProtocol &_frontend) : AP_RCProtocol_Backend(_frontend) {}
void process_pulse(uint32_t width_s0, uint32_t width_s1) override;
void process_byte(uint8_t byte, uint32_t baudrate) override;
private:
void _process_byte(uint32_t timestamp_us, uint8_t byte);
static uint16_t sumd_crc16(uint16_t crc, uint8_t value);
static uint8_t sumd_crc8(uint8_t crc, uint8_t value);
#pragma pack(push, 1)
typedef struct {
uint8_t header; ///< 0xA8 for a valid packet
uint8_t status; ///< 0x01 valid and live SUMD data frame / 0x00 = SUMH / 0x81 = Failsafe
uint8_t length; ///< Channels
uint8_t sumd_data[(SUMD_MAX_CHANNELS+1) * 2]; ///< ChannelData (High Byte/ Low Byte)
uint8_t crc16_high; ///< High Byte of 16 Bit CRC
uint8_t crc16_low; ///< Low Byte of 16 Bit CRC
uint8_t telemetry; ///< Telemetry request
uint8_t crc8; ///< SUMH CRC8
} ReceiverFcPacketHoTT;
#pragma pack(pop)
enum SUMD_DECODE_STATE {
SUMD_DECODE_STATE_UNSYNCED = 0,
SUMD_DECODE_STATE_GOT_HEADER,
SUMD_DECODE_STATE_GOT_STATE,
SUMD_DECODE_STATE_GOT_LEN,
SUMD_DECODE_STATE_GOT_DATA,
SUMD_DECODE_STATE_GOT_CRC,
SUMD_DECODE_STATE_GOT_CRC16_BYTE_1,
SUMD_DECODE_STATE_GOT_CRC16_BYTE_2
};
enum SUMD_DECODE_STATE _decode_state = SUMD_DECODE_STATE_UNSYNCED;
uint8_t _rxlen;
ReceiverFcPacketHoTT _rxpacket;
uint8_t _crc8 = 0x00;
uint16_t _crc16 = 0x0000;
bool _sumd = true;
bool _crcOK = false;
uint32_t last_packet_us;
SoftSerial ss{115200, SoftSerial::SERIAL_CONFIG_8N1};
};