LidarLitePWM.cpp 4 KB
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/**
 * @file LidarLitePWM.h
 * @author Johan Jansen <jnsn.johan@gmail.com>
 * @author Ban Siesta <bansiesta@gmail.com>
 *
 * Driver for the PulsedLight Lidar-Lite range finders connected via PWM.
 *
 * This driver accesses the pwm_input published by the pwm_input driver.
 */

#include "LidarLitePWM.h"

#ifdef LIDAR_LITE_PWM_SUPPORTED

#include <px4_arch/io_timer.h>

LidarLitePWM::LidarLitePWM(const uint8_t rotation) :
	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::hp_default),
	_px4_rangefinder(0 /* no device type for PWM input */, rotation)
{
	_px4_rangefinder.set_min_distance(LL40LS_MIN_DISTANCE);
	_px4_rangefinder.set_max_distance(LL40LS_MAX_DISTANCE);
	_px4_rangefinder.set_fov(0.008); // Divergence 8 mRadian
	px4_arch_configgpio(io_timer_channel_get_gpio_output(GPIO_VDD_RANGEFINDER_EN_CHAN));

	_px4_rangefinder.set_device_type(DRV_DIST_DEVTYPE_LL40LS);
}

LidarLitePWM::~LidarLitePWM()
{
	stop();
	perf_free(_sample_perf);
	perf_free(_comms_errors);
	perf_free(_sensor_resets);
	perf_free(_sensor_zero_resets);
}

int
LidarLitePWM::init()
{
	start();

	return PX4_OK;
}

void
LidarLitePWM::start()
{
	ScheduleOnInterval(get_measure_interval());
}

void
LidarLitePWM::stop()
{
	ScheduleClear();
}

void
LidarLitePWM::Run()
{
	measure();
}

int
LidarLitePWM::measure()
{
	perf_begin(_sample_perf);

	const hrt_abstime timestamp_sample = hrt_absolute_time();

	if (PX4_OK != collect()) {
		PX4_DEBUG("collection error");
		perf_count(_comms_errors);
		perf_end(_sample_perf);
		return PX4_ERROR;
	}

	const float current_distance = float(_pwm.pulse_width) * 1e-3f;   /* 10 usec = 1 cm distance for LIDAR-Lite */

	/* Due to a bug in older versions of the LidarLite firmware, we have to reset sensor on (distance == 0) */
	if (current_distance <= 0.0f) {
		perf_count(_sensor_zero_resets);
		perf_end(_sample_perf);
	}

	_px4_rangefinder.update(timestamp_sample, current_distance);

	perf_end(_sample_perf);
	return PX4_OK;
}

int
LidarLitePWM::collect()
{
	pwm_input_s pwm_input;

	if (_sub_pwm_input.update(&pwm_input)) {

		_pwm = pwm_input;

		return PX4_OK;
	}

	return EAGAIN;
}

void
LidarLitePWM::print_info()
{
	perf_print_counter(_sample_perf);
	perf_print_counter(_comms_errors);
	perf_print_counter(_sensor_resets);
	perf_print_counter(_sensor_zero_resets);
	printf("poll interval:  %u \n", get_measure_interval());
}

#endif