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 "modules/core/abi.h"
#include "mcu_periph/uart.h"
#include "pprzlink/messages.h"
#include "modules/datalink/downlink.h"
#include "modules/datalink/telemetry.h"

Include dependency graph for airspeed_ms45xx_i2c.c:

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Macros
#define	AIRSPEED_MS45XX_SEND_ABI   true
#define	MS45XX_I2C_DEV   i2c2
	Default I2C device. More...
#define	MS45XX_I2C_ADDR   0x50
	Sensor I2C slave address (existing defaults 0x50, 0x6C and 0x8C) More...
#define	MS45XX_PRESSURE_OUTPUT_TYPE_InH2O   0
	MS45xx sensors pressure output type can be in PSI or InH2O, as defined in the datasheet if not defined to be MS45XX_PRESSURE_OUTPUT_TYPE_InH2O then PSI is used. More...
#define	MS45XX_PRESSURE_RANGE   1
	MS45xx pressure range in PSI or InH2O The sensor is available in many ranges, the datasheet of your pressure sensor will tell which one and what this range represents. More...
#define	MS45XX_PRESSURE_TYPE   0
	Pressure Type 0 = Differential, 1 = Gauge note there are theoretical more types than 2, e.g. More...
#define	USE_AIRSPEED_LOWPASS_FILTER   TRUE
	Use low pass filter on pressure values. More...
#define	MS45XX_OUTPUT_TYPE   0
	MS45xx output Type. More...
#define	InH2O_TO_PA   249.08891
	Conversion factor from InH2O to Pa. More...
#define	PSI_TO_PA   6894.75729
	Conversion factor from psi to Pa. More...
#define	OutputPressureToPa   PSI_TO_PA
#define	MS45XX_PRESSURE_SCALE   (2 * MS45XX_PRESSURE_RANGE / (0.8 * 16383) * OutputPressureToPa)
#define	MS45XX_PRESSURE_OFFSET   (16383 / 2)
#define	MS45XX_RHO_DIV_2   1.6327
	Quadratic scale factor for indicated 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...
#define	AUTOSET_NB_MAX   20

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 to be one of the versions with 14bit pressure and 11bit temperature.

Definition in file airspeed_ms45xx_i2c.c.

Macro Definition Documentation

AIRSPEED_MS45XX_SEND_ABI

#define AIRSPEED_MS45XX_SEND_ABI   true

Definition at line 44 of file airspeed_ms45xx_i2c.c.

AUTOSET_NB_MAX

#define AUTOSET_NB_MAX   20

Definition at line 230 of file airspeed_ms45xx_i2c.c.

InH2O_TO_PA

#define InH2O_TO_PA   249.08891

Conversion factor from InH2O to Pa.

Definition at line 95 of file airspeed_ms45xx_i2c.c.

MS45XX_I2C_ADDR

#define MS45XX_I2C_ADDR   0x50

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

Definition at line 56 of file airspeed_ms45xx_i2c.c.

MS45XX_I2C_DEV

#define MS45XX_I2C_DEV   i2c2

Default I2C device.

Definition at line 50 of file airspeed_ms45xx_i2c.c.

MS45XX_LOWPASS_TAU

#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 158 of file airspeed_ms45xx_i2c.c.

MS45XX_OUTPUT_TYPE

#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 91 of file airspeed_ms45xx_i2c.c.

MS45XX_PRESSURE_OFFSET

#define MS45XX_PRESSURE_OFFSET   (16383 / 2)

Definition at line 121 of file airspeed_ms45xx_i2c.c.

MS45XX_PRESSURE_OUTPUT_TYPE_InH2O

#define MS45XX_PRESSURE_OUTPUT_TYPE_InH2O   0

MS45xx sensors pressure output type can be in PSI or InH2O, as defined in the datasheet if not defined to be MS45XX_PRESSURE_OUTPUT_TYPE_InH2O then PSI is used.

Definition at line 63 of file airspeed_ms45xx_i2c.c.

MS45XX_PRESSURE_RANGE

#define MS45XX_PRESSURE_RANGE   1

MS45xx pressure range in PSI or InH2O The sensor is available in many ranges, the datasheet of your pressure sensor will tell which one and what this range represents.

Definition at line 71 of file airspeed_ms45xx_i2c.c.

MS45XX_PRESSURE_SCALE

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

Definition at line 118 of file airspeed_ms45xx_i2c.c.

MS45XX_PRESSURE_TYPE

#define MS45XX_PRESSURE_TYPE   0

Pressure Type 0 = Differential, 1 = Gauge note there are theoretical more types than 2, e.g.

Absolute not implemented

Definition at line 77 of file airspeed_ms45xx_i2c.c.

MS45XX_RHO_DIV_2

#define MS45XX_RHO_DIV_2   1.6327

Quadratic scale factor for indicated 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 151 of file airspeed_ms45xx_i2c.c.

OutputPressureToPa

#define OutputPressureToPa   PSI_TO_PA

Definition at line 103 of file airspeed_ms45xx_i2c.c.

PSI_TO_PA

#define PSI_TO_PA   6894.75729

Conversion factor from psi to Pa.

Definition at line 98 of file airspeed_ms45xx_i2c.c.

USE_AIRSPEED_LOWPASS_FILTER

#define USE_AIRSPEED_LOWPASS_FILTER   TRUE

Use low pass filter on pressure values.

Definition at line 83 of file airspeed_ms45xx_i2c.c.

Function Documentation

ms45xx_downlink()

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

static

Definition at line 181 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, dev, ms45xx, MS45XX_SENDER_ID, AirspeedMs45xx::pressure, AirspeedMs45xx::pressure_offset, AirspeedMs45xx::raw_p, and AirspeedMs45xx::temperature.

Referenced by ms45xx_i2c_init().

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ms45xx_i2c_event()

void ms45xx_i2c_event

(

void

)

Definition at line 232 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, AUTOSET_NB_MAX, AirspeedMs45xx::autoset_offset, i2c_transaction::buf, I2CTransDone, I2CTransFailed, I2CTransSuccess, ms45xx, ms45xx_filter, MS45XX_RHO_DIV_2, MS45XX_SENDER_ID, ms45xx_trans, AirspeedMs45xx::offset_set, AirspeedMs45xx::pressure, AirspeedMs45xx::pressure_offset, AirspeedMs45xx::pressure_scale, AirspeedMs45xx::raw_p, sign(), i2c_transaction::status, status, AirspeedMs45xx::temperature, and update_butterworth_2_low_pass().

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ms45xx_i2c_init()

void ms45xx_i2c_init

(

void

)

Definition at line 194 of file airspeed_ms45xx_i2c.c.

References AirspeedMs45xx::airspeed, DefaultPeriodic, I2CTransDone, init_butterworth_2_low_pass(), ms45xx, ms45xx_downlink(), ms45xx_filter, MS45XX_LOWPASS_TAU, MS45XX_PRESSURE_OFFSET, MS45XX_PRESSURE_SCALE, MS45XX_PRESSURE_TYPE, ms45xx_trans, AirspeedMs45xx::offset_set, preflight_check_register(), AirspeedMs45xx::pressure, AirspeedMs45xx::pressure_offset, AirspeedMs45xx::pressure_scale, AirspeedMs45xx::pressure_type, AirspeedMs45xx::raw_p, register_periodic_telemetry(), i2c_transaction::status, and AirspeedMs45xx::temperature.

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ms45xx_i2c_periodic()

void ms45xx_i2c_periodic

(

void

)

Definition at line 222 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

ms45xx

struct AirspeedMs45xx ms45xx

Definition at line 1 of file airspeed_ms45xx_i2c.c.

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

ms45xx_filter

Butterworth2LowPass ms45xx_filter

static

Definition at line 164 of file airspeed_ms45xx_i2c.c.

Referenced by ms45xx_i2c_event(), and ms45xx_i2c_init().

ms45xx_trans

struct i2c_transaction ms45xx_trans

static

Definition at line 1 of file airspeed_ms45xx_i2c.c.

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