mirror of https://github.com/ArduPilot/ardupilot
77 lines
2.7 KiB
C++
77 lines
2.7 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "RangeFinder.h"
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#include "RangeFinder_Backend.h"
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class AP_RangeFinder_NMEA : public AP_RangeFinder_Backend
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{
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public:
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// constructor
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AP_RangeFinder_NMEA(RangeFinder::RangeFinder_State &_state,
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AP_RangeFinder_Params &_params,
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uint8_t serial_instance);
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// static detection function
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static bool detect(uint8_t serial_instance);
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// update state
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void update(void) override;
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protected:
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virtual MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override {
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return MAV_DISTANCE_SENSOR_ULTRASOUND;
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}
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private:
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/// enum for handled messages
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enum sentence_types : uint8_t {
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SONAR_UNKNOWN = 0,
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SONAR_DBT,
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SONAR_DPT
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};
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// get a reading
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bool get_reading(uint16_t &reading_cm);
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// add a single character to the buffer and attempt to decode
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// returns true if a complete sentence was successfully decoded
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// distance should be pulled directly from _distance_m member
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bool decode(char c);
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// decode the just-completed term
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// returns true if new sentence has just passed checksum test and is validated
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bool decode_latest_term();
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// return the numeric value of an ascii hex character
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static int16_t char_to_hex(char a);
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AP_HAL::UARTDriver *uart = nullptr; // pointer to serial uart
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// message decoding related members
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char _term[15]; // buffer for the current term within the current sentence
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uint8_t _term_offset; // offset within the _term buffer where the next character should be placed
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uint8_t _term_number; // term index within the current sentence
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float _distance_m; // distance in meters parsed from a term, -1 if no distance
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uint8_t _checksum; // checksum accumulator
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bool _term_is_checksum; // current term is the checksum
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sentence_types _sentence_type; // the sentence type currently being processed
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};
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