ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_PWM.h

68 lines
2.1 KiB
C++

/*
This program 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 program 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/>.
*/
#pragma once
#include "RangeFinder.h"
#include "RangeFinder_Backend.h"
class AP_RangeFinder_PWM : public AP_RangeFinder_Backend
{
public:
// constructor
AP_RangeFinder_PWM(RangeFinder::RangeFinder_State &_state,
AP_RangeFinder_Params &_params,
float &_estimated_terrain_height);
// destructor
~AP_RangeFinder_PWM(void) {};
// static detection function
static bool detect();
// update state
void update(void) override;
protected:
bool get_reading(uint16_t &reading_cm);
MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override {
return MAV_DISTANCE_SENSOR_UNKNOWN;
}
private:
int8_t last_pin; // last pin used for reading pwm (used to recognise change in pin assignment)
// the following three members are updated by the interrupt handler
uint32_t irq_value_us; // some of calculated pwm values (irq copy)
uint16_t irq_sample_count; // number of pwm values in irq_value_us (irq copy)
uint32_t irq_pulse_start_us; // system time of start of pulse
void irq_handler(uint8_t pin, bool pin_high, uint32_t timestamp_us);
void check_pin();
void check_stop_pin();
void check_pins();
uint8_t last_stop_pin = -1;
float &estimated_terrain_height;
// return true if we are beyond the power saving range
bool out_of_range(void) const;
bool was_out_of_range = -1; // this odd initialisation ensures we transition to new state
};