/*
* Copyright (C) 2016 Intel Corporation. All rights reserved.
*
* 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 .
*/
#include
#include
#include
#include "AP_RangeFinder_MaxsonarSerialLV.h"
#define MAXSONAR_SERIAL_LV_BAUD_RATE 9600
extern const AP_HAL::HAL& hal;
/*
The constructor also initialises the rangefinder. Note that this
constructor is not called until detect() returns true, so we
already know that we should setup the rangefinder
*/
AP_RangeFinder_MaxsonarSerialLV::AP_RangeFinder_MaxsonarSerialLV(RangeFinder::RangeFinder_State &_state,
AP_SerialManager &serial_manager) :
AP_RangeFinder_Backend(_state, MAV_DISTANCE_SENSOR_ULTRASOUND)
{
uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Lidar, 0);
if (uart != nullptr) {
uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Lidar, 0));
}
}
/*
detect if a MaxSonar rangefinder is connected. We'll detect by
trying to take a reading on Serial. If we get a result the sensor is
there.
*/
bool AP_RangeFinder_MaxsonarSerialLV::detect(AP_SerialManager &serial_manager)
{
return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Lidar, 0) != nullptr;
}
// read - return last value measured by sensor
bool AP_RangeFinder_MaxsonarSerialLV::get_reading(uint16_t &reading_cm)
{
if (uart == nullptr) {
return false;
}
int32_t sum = 0;
int16_t nbytes = uart->available();
uint16_t count = 0;
while (nbytes-- > 0) {
char c = uart->read();
if (c == '\r') {
linebuf[linebuf_len] = 0;
sum += (int)atoi(linebuf);
count++;
linebuf_len = 0;
} else if (isdigit(c)) {
linebuf[linebuf_len++] = c;
if (linebuf_len == sizeof(linebuf)) {
// too long, discard the line
linebuf_len = 0;
}
}
}
if (count == 0) {
return false;
}
// This sonar gives the metrics in inches, so we have to transform this to centimeters
reading_cm = 2.54f * sum / count;
return true;
}
/*
update the state of the sensor
*/
void AP_RangeFinder_MaxsonarSerialLV::update(void)
{
if (get_reading(state.distance_cm)) {
// update range_valid state based on distance measured
last_reading_ms = AP_HAL::millis();
update_status();
} else if (AP_HAL::millis() - last_reading_ms > 500) {
set_status(RangeFinder::RangeFinder_NoData);
}
}