mirror of https://github.com/ArduPilot/ardupilot
104 lines
3.4 KiB
C++
104 lines
3.4 KiB
C++
/*
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* Copyright (C) 2016 Intel Corporation. All rights reserved.
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*
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <AP_HAL/AP_HAL.h>
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#include <AP_SerialManager/AP_SerialManager.h>
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#include <ctype.h>
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#include "AP_RangeFinder_MaxsonarSerialLV.h"
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#define MAXSONAR_SERIAL_LV_BAUD_RATE 9600
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extern const AP_HAL::HAL& hal;
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/*
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The constructor also initialises the rangefinder. Note that this
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constructor is not called until detect() returns true, so we
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already know that we should setup the rangefinder
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*/
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AP_RangeFinder_MaxsonarSerialLV::AP_RangeFinder_MaxsonarSerialLV(RangeFinder::RangeFinder_State &_state,
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AP_RangeFinder_Params &_params,
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AP_SerialManager &serial_manager,
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uint8_t serial_instance) :
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AP_RangeFinder_Backend(_state, _params)
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{
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uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
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if (uart != nullptr) {
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uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance));
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}
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}
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/*
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detect if a MaxSonar rangefinder is connected. We'll detect by
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trying to take a reading on Serial. If we get a result the sensor is
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there.
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*/
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bool AP_RangeFinder_MaxsonarSerialLV::detect(AP_SerialManager &serial_manager, uint8_t serial_instance)
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{
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return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != nullptr;
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}
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// read - return last value measured by sensor
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bool AP_RangeFinder_MaxsonarSerialLV::get_reading(uint16_t &reading_cm)
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{
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if (uart == nullptr) {
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return false;
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}
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int32_t sum = 0;
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int16_t nbytes = uart->available();
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uint16_t count = 0;
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while (nbytes-- > 0) {
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char c = uart->read();
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if (c == '\r') {
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linebuf[linebuf_len] = 0;
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sum += (int)atoi(linebuf);
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count++;
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linebuf_len = 0;
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} else if (isdigit(c)) {
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linebuf[linebuf_len++] = c;
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if (linebuf_len == sizeof(linebuf)) {
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// too long, discard the line
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linebuf_len = 0;
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}
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}
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}
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if (count == 0) {
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return false;
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}
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// This sonar gives the metrics in inches, so we have to transform this to centimeters
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reading_cm = 2.54f * sum / count;
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return true;
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}
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/*
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update the state of the sensor
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*/
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void AP_RangeFinder_MaxsonarSerialLV::update(void)
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{
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if (get_reading(state.distance_cm)) {
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// update range_valid state based on distance measured
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state.last_reading_ms = AP_HAL::millis();
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update_status();
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} else if (AP_HAL::millis() - state.last_reading_ms > 500) {
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set_status(RangeFinder::RangeFinder_NoData);
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}
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}
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