mirror of https://github.com/ArduPilot/ardupilot
380 lines
9.5 KiB
C++
380 lines
9.5 KiB
C++
/*
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SUMD decoder, based on PX4Firmware/src/rc/lib/rc/sumd.c from PX4Firmware
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modified for use in AP_HAL_* by Andrew Tridgell
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*/
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/****************************************************************************
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*
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* Copyright (c) 2015 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/*
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* @file sumd.h
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*
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* RC protocol definition for Graupner HoTT transmitter (SUMD/SUMH Protocol)
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*
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* @author Marco Bauer <marco@wtns.de>
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <AP_Math/crc.h>
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#include "sumd.h"
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#define SUMD_MAX_CHANNELS 32
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#define SUMD_HEADER_LENGTH 3
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#define SUMD_HEADER_ID 0xA8
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#define SUMD_ID_SUMH 0x00
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#define SUMD_ID_SUMD 0x01
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#define SUMD_ID_FAILSAFE 0x81
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#pragma pack(push, 1)
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typedef struct {
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uint8_t header; ///< 0xA8 for a valid packet
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uint8_t status; ///< 0x01 valid and live SUMD data frame / 0x00 = SUMH / 0x81 = Failsafe
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uint8_t length; ///< Channels
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uint8_t sumd_data[SUMD_MAX_CHANNELS * 2]; ///< ChannelData (High Byte/ Low Byte)
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uint8_t crc16_high; ///< High Byte of 16 Bit CRC
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uint8_t crc16_low; ///< Low Byte of 16 Bit CRC
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uint8_t telemetry; ///< Telemetry request
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uint8_t crc8; ///< SUMH CRC8
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} ReceiverFcPacketHoTT;
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#pragma pack(pop)
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enum SUMD_DECODE_STATE {
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SUMD_DECODE_STATE_UNSYNCED = 0,
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SUMD_DECODE_STATE_GOT_HEADER,
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SUMD_DECODE_STATE_GOT_STATE,
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SUMD_DECODE_STATE_GOT_LEN,
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SUMD_DECODE_STATE_GOT_DATA,
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SUMD_DECODE_STATE_GOT_CRC,
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SUMD_DECODE_STATE_GOT_CRC16_BYTE_1,
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SUMD_DECODE_STATE_GOT_CRC16_BYTE_2
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};
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/*
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const char *decode_states[] = {"UNSYNCED",
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"GOT_HEADER",
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"GOT_STATE",
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"GOT_LEN",
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"GOT_DATA",
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"GOT_CRC",
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"GOT_CRC16_BYTE_1",
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"GOT_CRC16_BYTE_2"
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};
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*/
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static uint8_t _crc8 = 0x00;
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static uint16_t _crc16 = 0x0000;
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static bool _sumd = true;
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static bool _crcOK = false;
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static bool _debug = false;
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/* define range mapping here, -+100% -> 1000..2000 */
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#define SUMD_RANGE_MIN 0.0f
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#define SUMD_RANGE_MAX 4096.0f
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#define SUMD_TARGET_MIN 1000.0f
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#define SUMD_TARGET_MAX 2000.0f
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/* pre-calculate the floating point stuff as far as possible at compile time */
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#define SUMD_SCALE_FACTOR ((SUMD_TARGET_MAX - SUMD_TARGET_MIN) / (SUMD_RANGE_MAX - SUMD_RANGE_MIN))
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#define SUMD_SCALE_OFFSET (int)(SUMD_TARGET_MIN - (SUMD_SCALE_FACTOR * SUMD_RANGE_MIN + 0.5f))
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static enum SUMD_DECODE_STATE _decode_state = SUMD_DECODE_STATE_UNSYNCED;
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static uint8_t _rxlen;
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static ReceiverFcPacketHoTT _rxpacket;
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static uint8_t sumd_crc8(uint8_t crc, uint8_t value)
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{
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crc += value;
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return crc;
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}
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int sumd_decode(uint8_t byte, uint8_t *rssi, uint8_t *rx_count, uint16_t *channel_count, uint16_t *channels,
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uint16_t max_chan_count)
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{
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int ret = 1;
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switch (_decode_state) {
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case SUMD_DECODE_STATE_UNSYNCED:
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if (_debug) {
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printf(" SUMD_DECODE_STATE_UNSYNCED \n") ;
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}
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if (byte == SUMD_HEADER_ID) {
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_rxpacket.header = byte;
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_sumd = true;
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_rxlen = 0;
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_crc16 = 0x0000;
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_crc8 = 0x00;
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_crcOK = false;
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_crc16 = crc_xmodem_update(_crc16, byte);
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_crc8 = sumd_crc8(_crc8, byte);
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_decode_state = SUMD_DECODE_STATE_GOT_HEADER;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_HEADER: %x \n", byte) ;
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}
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} else {
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ret = 3;
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}
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break;
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case SUMD_DECODE_STATE_GOT_HEADER:
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if (byte == SUMD_ID_SUMD || byte == SUMD_ID_SUMH) {
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_rxpacket.status = byte;
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if (byte == SUMD_ID_SUMH) {
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_sumd = false;
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}
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if (_sumd) {
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_crc16 = crc_xmodem_update(_crc16, byte);
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} else {
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_crc8 = sumd_crc8(_crc8, byte);
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}
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_decode_state = SUMD_DECODE_STATE_GOT_STATE;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_STATE: %x \n", byte) ;
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}
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} else {
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_decode_state = SUMD_DECODE_STATE_UNSYNCED;
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}
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break;
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case SUMD_DECODE_STATE_GOT_STATE:
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if (byte >= 2 && byte <= SUMD_MAX_CHANNELS) {
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_rxpacket.length = byte;
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if (_sumd) {
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_crc16 = crc_xmodem_update(_crc16, byte);
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} else {
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_crc8 = sumd_crc8(_crc8, byte);
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}
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_rxlen++;
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_decode_state = SUMD_DECODE_STATE_GOT_LEN;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_LEN: %x (%d) \n", byte, byte) ;
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}
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} else {
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_decode_state = SUMD_DECODE_STATE_UNSYNCED;
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}
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break;
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case SUMD_DECODE_STATE_GOT_LEN:
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_rxpacket.sumd_data[_rxlen] = byte;
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if (_sumd) {
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_crc16 = crc_xmodem_update(_crc16, byte);
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} else {
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_crc8 = sumd_crc8(_crc8, byte);
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}
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_rxlen++;
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if (_rxlen <= ((_rxpacket.length * 2))) {
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_DATA[%d]: %x\n", _rxlen - 2, byte) ;
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}
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} else {
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_decode_state = SUMD_DECODE_STATE_GOT_DATA;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_DATA -- finish --\n") ;
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}
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}
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break;
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case SUMD_DECODE_STATE_GOT_DATA:
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_rxpacket.crc16_high = byte;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_CRC16[1]: %x [%x]\n", byte, ((_crc16 >> 8) & 0xff)) ;
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}
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if (_sumd) {
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_decode_state = SUMD_DECODE_STATE_GOT_CRC;
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} else {
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_decode_state = SUMD_DECODE_STATE_GOT_CRC16_BYTE_1;
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}
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break;
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case SUMD_DECODE_STATE_GOT_CRC16_BYTE_1:
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_rxpacket.crc16_low = byte;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_CRC16[2]: %x [%x]\n", byte, (_crc16 & 0xff)) ;
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}
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_decode_state = SUMD_DECODE_STATE_GOT_CRC16_BYTE_2;
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break;
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case SUMD_DECODE_STATE_GOT_CRC16_BYTE_2:
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_rxpacket.telemetry = byte;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_SUMH_TELEMETRY: %x\n", byte) ;
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}
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_decode_state = SUMD_DECODE_STATE_GOT_CRC;
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break;
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case SUMD_DECODE_STATE_GOT_CRC:
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if (_sumd) {
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_rxpacket.crc16_low = byte;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_CRC[2]: %x [%x]\n\n", byte, (_crc16 & 0xff)) ;
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}
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if (_crc16 == (uint16_t)(_rxpacket.crc16_high << 8) + _rxpacket.crc16_low) {
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_crcOK = true;
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}
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} else {
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_rxpacket.crc8 = byte;
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if (_debug) {
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printf(" SUMD_DECODE_STATE_GOT_CRC8_SUMH: %x [%x]\n\n", byte, _crc8) ;
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}
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if (_crc8 == _rxpacket.crc8) {
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_crcOK = true;
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}
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}
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if (_crcOK) {
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if (_debug) {
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printf(" CRC - OK \n") ;
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}
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if (_sumd) {
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if (_debug) {
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printf(" Got valid SUMD Packet\n") ;
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}
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} else {
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if (_debug) {
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printf(" Got valid SUMH Packet\n") ;
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}
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}
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if (_debug) {
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printf(" RXLEN: %d [Chans: %d] \n\n", _rxlen - 1, (_rxlen - 1) / 2) ;
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}
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ret = 0;
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unsigned i;
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uint8_t _cnt = *rx_count + 1;
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*rx_count = _cnt;
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*rssi = 100;
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/* received Channels */
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if ((uint16_t)_rxpacket.length > max_chan_count) {
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_rxpacket.length = (uint8_t) max_chan_count;
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}
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*channel_count = (uint16_t)_rxpacket.length;
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/* decode the actual packet */
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/* reorder first 4 channels */
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/* ch1 = roll -> sumd = ch2 */
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channels[0] = (uint16_t)((_rxpacket.sumd_data[1 * 2 + 1] << 8) | _rxpacket.sumd_data[1 * 2 + 2]) >> 3;
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/* ch2 = pitch -> sumd = ch2 */
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channels[1] = (uint16_t)((_rxpacket.sumd_data[2 * 2 + 1] << 8) | _rxpacket.sumd_data[2 * 2 + 2]) >> 3;
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/* ch3 = throttle -> sumd = ch2 */
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channels[2] = (uint16_t)((_rxpacket.sumd_data[0 * 2 + 1] << 8) | _rxpacket.sumd_data[0 * 2 + 2]) >> 3;
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/* ch4 = yaw -> sumd = ch2 */
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channels[3] = (uint16_t)((_rxpacket.sumd_data[3 * 2 + 1] << 8) | _rxpacket.sumd_data[3 * 2 + 2]) >> 3;
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/* we start at channel 5(index 4) */
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unsigned chan_index = 4;
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for (i = 4; i < _rxpacket.length; i++) {
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if (_debug) {
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printf("ch[%d] : %x %x [ %x %d ]\n", i + 1, _rxpacket.sumd_data[i * 2 + 1], _rxpacket.sumd_data[i * 2 + 2],
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((_rxpacket.sumd_data[i * 2 + 1] << 8) | _rxpacket.sumd_data[i * 2 + 2]) >> 3,
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((_rxpacket.sumd_data[i * 2 + 1] << 8) | _rxpacket.sumd_data[i * 2 + 2]) >> 3);
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}
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channels[chan_index] = (uint16_t)((_rxpacket.sumd_data[i * 2 + 1] << 8) | _rxpacket.sumd_data[i * 2 + 2]) >> 3;
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/* convert values to 1000-2000 ppm encoding in a not too sloppy fashion */
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//channels[chan_index] = (uint16_t)(channels[chan_index] * SUMD_SCALE_FACTOR + .5f) + SUMD_SCALE_OFFSET;
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chan_index++;
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}
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} else {
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/* decoding failed */
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ret = 4;
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if (_debug) {
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printf(" CRC - fail \n") ;
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}
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}
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_decode_state = SUMD_DECODE_STATE_UNSYNCED;
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break;
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}
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return ret;
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}
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