GY_US42.hpp 3.51 KB
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/**
 * @file GY_US42.cpp
 *
 * Driver for the GY-US42 sonar range finder on I2C.
 */

#pragma once

#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/i2c_spi_buses.h>
#include <lib/drivers/rangefinder/PX4Rangefinder.hpp>
#include <drivers/device/i2c.h>
#include <drivers/drv_hrt.h>
#include <lib/perf/perf_counter.h>

/* Configuration Constants */
#define GY_US42_BASEADDR 				0x70 	// 7-bit address. 8-bit address is 0xE0.

/* GY_US42 Registers addresses */
#define GY_US42_TAKE_RANGE_REG			0x51	// Measure range Register.
#define GY_US42_SET_ADDRESS_CMD1			0xAA	// Change address 1 cmd.
#define GY_US42_SET_ADDRESS_CMD2			0xA5	// Change address 2 cmd.

/* Device limits */
#define GY_US42_MIN_DISTANCE 			(0.20f)
#define GY_US42_MAX_DISTANCE 			(7.2f)

#define GY_US42_CONVERSION_INTERVAL 		50000	// 50ms for one sonar.

class GY_US42 : public device::I2C, public I2CSPIDriver<GY_US42>
{
public:
	GY_US42(I2CSPIBusOption bus_option, const int bus, const uint8_t rotation, int bus_frequency,
		int address = GY_US42_BASEADDR);
	~GY_US42() override;

	static I2CSPIDriverBase *instantiate(const BusCLIArguments &cli, const BusInstanceIterator &iterator,
					     int runtime_instance);
	static void print_usage();

	int init() override;
	void print_status() override;

	void RunImpl();

private:

	enum class STATE : uint8_t {
		INIT,
		POWERON_WAIT,
		MEASURE_WAIT,
		MODIFYADDR_WAIT
	};
	STATE _state{STATE::INIT};

	int collect();
	int measure();

	/**
	 * Test whether the device supported by the driver is present at a
	 * specific address.
	 * @param address The I2C bus address to probe.
	 * @return True if the device is present.
	 */

	PX4Rangefinder _px4_rangefinder;

	perf_counter_t _comms_errors{perf_alloc(PC_COUNT, MODULE_NAME": com_err")};
	perf_counter_t _sample_perf{perf_alloc(PC_ELAPSED,  MODULE_NAME": read")};
};