SDP3X.hpp

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/**
 * @file SDP3X.hpp
 *
 * Driver for Sensirion SDP3X Differential Pressure Sensor
 *
 * Datasheet: https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/8_Differential_Pressure/Sensirion_Differential_Pressure_Sensors_SDP3x_Digital_Datasheet_V0.8.pdf
 */

#ifndef DRIVERS_SDP3X_AIRSPEED_HPP_
#define DRIVERS_SDP3X_AIRSPEED_HPP_

#include <drivers/airspeed/airspeed.h>
#include <math.h>
#include <mathlib/math/filter/LowPassFilter2p.hpp>
#include <px4_platform_common/getopt.h>

#define I2C_ADDRESS_1_SDP3X     0x21
#define I2C_ADDRESS_2_SDP3X     0x22
#define I2C_ADDRESS_3_SDP3X     0x23

#define SDP3X_SCALE_TEMPERATURE     200.0f
#define SDP3X_RESET_ADDR        0x00
#define SDP3X_RESET_CMD         0x06
#define SDP3X_CONT_MEAS_AVG_MODE    0x3615

#define SDP3X_SCALE_PRESSURE_SDP31  60
#define SDP3X_SCALE_PRESSURE_SDP32  240
#define SDP3X_SCALE_PRESSURE_SDP33  20

#define PATH_SDP3X "/dev/sdp3x"

// Measurement rate is 20Hz
#define SPD3X_MEAS_RATE 100
#define SDP3X_MEAS_DRIVER_FILTER_FREQ 3.0f
#define CONVERSION_INTERVAL (1000000 / SPD3X_MEAS_RATE) /* microseconds */

class SDP3X : public Airspeed
{
public:
    SDP3X(int bus, int address = I2C_ADDRESS_1_SDP3X, const char *path = PATH_SDP3X) :
        Airspeed(bus, address, CONVERSION_INTERVAL, path)
    {
    }

private:

    /**
     * Perform a poll cycle; collect from the previous measurement
     * and start a new one.
     */
    void    Run() override;
    int measure() override { return 0; }
    int collect() override;
    int probe() override;

    math::LowPassFilter2p _filter{SPD3X_MEAS_RATE, SDP3X_MEAS_DRIVER_FILTER_FREQ};

    bool init_sdp3x();

    /**
     * Calculate the CRC8 for the sensor payload data
     */
    bool crc(const uint8_t data[], unsigned size, uint8_t checksum);

    /**
     * Write a command in Sensirion specific logic
     */
    int write_command(uint16_t command);

    uint16_t _scale{0};
};

#endif /* DRIVERS_SDP3X_AIRSPEED_HPP_ */