airspeed_ms45xx_i2c.c File Reference

Airspeed sensor module using the MS45xxDO digital pressure sensor via I2C. More...

#include "std.h"
#include "mcu_periph/i2c.h"
#include "modules/sensors/airspeed_ms45xx_i2c.h"
#include "filters/low_pass_filter.h"
#include "subsystems/abi.h"
#include "mcu_periph/uart.h"
#include "pprzlink/messages.h"
#include "subsystems/datalink/downlink.h"
#include "subsystems/datalink/telemetry.h"

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Macros
#define	MS45XX_I2C_DEV   i2c2
	Default I2C device. More...
#define	MS45XX_I2C_ADDR   0x50
	Sensor I2C slave address (defaults 0x50, 0x6C and 0x8C) More...
#define	MS45XX_PRESSURE_RANGE   1
	MS45xx pressure range in psi. More...
#define	MS45XX_OUTPUT_TYPE   0
	MS45xx output Type. More...
#define	PSI_TO_PA   6894.75729
	Conversion factor from psi to Pa. More...
#define	MS45XX_PRESSURE_SCALE   (2 * MS45XX_PRESSURE_RANGE / (0.8 * 16383) * PSI_TO_PA)
#define	MS45XX_PRESSURE_OFFSET   (1.25 * MS45XX_PRESSURE_RANGE * PSI_TO_PA)
#define	MS45XX_SYNC_SEND   FALSE
	Send a AIRSPEED_MS45XX message with every new measurement. More...
#define	MS45XX_AIRSPEED_SCALE   1.6327
	Quadratic scale factor for airspeed. More...
#define	MS45XX_LOWPASS_TAU   0.15
	Time constant for second order Butterworth low pass filter Default of 0.15 should give cut-off freq of 1/(2*pi*tau) ~= 1Hz. More...

Functions
static void	ms45xx_downlink (struct transport_tx *trans, struct link_device *dev)
void	ms45xx_i2c_init (void)
void	ms45xx_i2c_periodic (void)
void	ms45xx_i2c_event (void)

Variables
struct AirspeedMs45xx	ms45xx
static struct i2c_transaction	ms45xx_trans
static Butterworth2LowPass	ms45xx_filter

Detailed Description

Airspeed sensor module using the MS45xxDO digital pressure sensor via I2C.

Needs one of the differential versions with 14bit pressure and 11bit temperature.

Definition in file airspeed_ms45xx_i2c.c.

Macro Definition Documentation

#define MS45XX_AIRSPEED_SCALE   1.6327

Quadratic scale factor for airspeed.

airspeed = sqrt(2*p_diff/density) With p_diff in Pa and standard air density of 1.225 kg/m^3, default airspeed scale is 2/1.225

Definition at line 125 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_init().

#define MS45XX_I2C_ADDR   0x50

Sensor I2C slave address (defaults 0x50, 0x6C and 0x8C)

Definition at line 61 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_periodic().

#define MS45XX_I2C_DEV   i2c2

Default I2C device.

Definition at line 56 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_periodic().

#define MS45XX_LOWPASS_TAU   0.15

Time constant for second order Butterworth low pass filter Default of 0.15 should give cut-off freq of 1/(2*pi*tau) ~= 1Hz.

Definition at line 132 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_init().

#define MS45XX_OUTPUT_TYPE   0

MS45xx output Type.

0 = Output Type A with 10% to 90% 1 = Output Type B with 5% to 95%

Definition at line 77 of file airspeed_ms45xx_i2c.c.

#define MS45XX_PRESSURE_OFFSET   (1.25 * MS45XX_PRESSURE_RANGE * PSI_TO_PA)

Definition at line 98 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_init().

#define MS45XX_PRESSURE_RANGE   1

MS45xx pressure range in psi.

The sensor is available in 1, 2, 5, 15, 30, 50, 100, 150 psi ranges. 1 psi max range should be ~100m/s max airspeed.

Definition at line 69 of file airspeed_ms45xx_i2c.c.

#define MS45XX_PRESSURE_SCALE   (2 * MS45XX_PRESSURE_RANGE / (0.8 * 16383) * PSI_TO_PA)

Definition at line 95 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_init().

#define MS45XX_SYNC_SEND   FALSE

Send a AIRSPEED_MS45XX message with every new measurement.

Mainly for debug, use with caution, sends message at ~100Hz.

Definition at line 116 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_init().

#define PSI_TO_PA   6894.75729

Conversion factor from psi to Pa.

Definition at line 81 of file airspeed_ms45xx_i2c.c.

Function Documentation

static void ms45xx_downlink ( struct transport_tx *  trans, struct link_device *  dev  )

static

Definition at line 140 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, AirspeedMs45xx::diff_pressure, ms45xx, and AirspeedMs45xx::temperature.

Referenced by ms45xx_i2c_event(), and ms45xx_i2c_init().

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void ms45xx_i2c_event

(

void

)

Definition at line 175 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, AirspeedMs45xx::airspeed_scale, i2c_transaction::buf, DefaultChannel, DefaultDevice, AirspeedMs45xx::diff_pressure, I2CTransDone, I2CTransFailed, I2CTransSuccess, Max, ms45xx, ms45xx_downlink(), MS45XX_SENDER_ID, ms45xx_trans, AirspeedMs45xx::pressure_offset, AirspeedMs45xx::pressure_scale, stateSetAirspeed_f(), i2c_transaction::status, AirspeedMs45xx::sync_send, AirspeedMs45xx::temperature, and update_butterworth_2_low_pass().

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void ms45xx_i2c_init

(

void

)

Definition at line 147 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, AirspeedMs45xx::airspeed_scale, DefaultPeriodic, AirspeedMs45xx::diff_pressure, I2CTransDone, init_butterworth_2_low_pass(), ms45xx, MS45XX_AIRSPEED_SCALE, ms45xx_downlink(), MS45XX_LOWPASS_TAU, MS45XX_PRESSURE_OFFSET, MS45XX_PRESSURE_SCALE, MS45XX_SYNC_SEND, ms45xx_trans, AirspeedMs45xx::pressure_offset, AirspeedMs45xx::pressure_scale, register_periodic_telemetry(), i2c_transaction::status, AirspeedMs45xx::sync_send, and AirspeedMs45xx::temperature.

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void ms45xx_i2c_periodic

(

void

)

Definition at line 167 of file airspeed_ms45xx_i2c.c.

References i2c_receive(), I2CTransDone, MS45XX_I2C_ADDR, MS45XX_I2C_DEV, ms45xx_trans, and i2c_transaction::status.

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Variable Documentation

struct AirspeedMs45xx ms45xx

Definition at line 135 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_downlink(), ms45xx_i2c_event(), and ms45xx_i2c_init().

Butterworth2LowPass ms45xx_filter

static

Definition at line 137 of file airspeed_ms45xx_i2c.c.

struct i2c_transaction ms45xx_trans

static

Definition at line 136 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_event(), ms45xx_i2c_init(), and ms45xx_i2c_periodic().