API for the LSM303AGR 3-Axis Geomagnetic Sensor. More...

Detailed Description

ID: lsm303agr
Name: Ultra-compact high-performance eCompass module
Category: compass
Manufacturer: stmicro
Connection: i2c gpio
Link: http://www.st.com/en/mems-and-sensors/lsm303agr.html

The LSM303AGR is an ultra-low-power high-performance system-in-package featuring a 3D digital linear acceleration sensor and a 3D digital magnetic sensor. The LSM303AGR has linear acceleration full scales of 2g/4g/8g/16g and a magnetic field dynamic range of 50 Gauss.

Not all functionality of this chip has been implemented in this driver, however all the pieces are present to add any desired functionality. This driver supports only I2C operation.

This device requires 3.3v operation.

    // Instantiate an LSM303AGR using default I2C parameters
    upm::LSM303AGR sensor;
    // now output data every 250 milliseconds
    while (shouldRun) {
        float x, y, z;
        sensor.update();
        sensor.getAccelerometer(&x, &y, &z);
        cout << "Accelerometer x: " << x << " y: " << y << " z: " << z << " g" << endl;
        sensor.getMagnetometer(&x, &y, &z);
        cout << "Magnetometer x: " << x << " y: " << y << " z: " << z << " uT" << endl;
        cout << "Temperature: " << sensor.getTemperature() << " C" << endl;
        cout << endl;
        upm_delay_us(250000);
    }

Public Member Functions
	LSM303AGR (int bus=LSM303AGR_DEFAULT_I2C_BUS, int acc_addr=LSM303AGR_DEFAULT_ACC_ADDR, int mag_addr=LSM303AGR_DEFAULT_MAG_ADDR)

	~LSM303AGR ()

void	update ()

void	getMagnetometer (float x, float y, float *z)

std::vector< float >	getMagnetometer ()

void	getAccelerometer (float x, float y, float *z)

std::vector< float >	getAccelerometer ()

float	getTemperature ()

void	init (LSM303AGR_POWER_MODE_T usage=LSM303AGR_POWER_HIGH_RESOLUTION)

void	setFullScale (LSM303AGR_A_FS_T fs)

void	setPowerMode (LSM303AGR_POWER_MODE_T mode)

void	setAccelerometerODR (LSM303AGR_A_ODR_T odr)

void	setMagnetometerODR (LSM303AGR_CFG_A_M_ODR_T odr)

uint8_t	getAccelerometerInt1Config ()

uint8_t	getAccelerometerInt2Config ()

void	setAccelerometerInt1Config (uint8_t bits)

void	setAccelerometerInt2Config (uint8_t bits)

uint8_t	getMagnetometerIntConfig ()

void	setMagnetometerIntConfig (uint8_t bits)

uint8_t	getAccelerometerInt1Src ()

uint8_t	getAccelerometerInt2Src ()

uint8_t	getMagnetometerIntSrc ()

void	installISR (LSM303AGR_INTERRUPT_PINS_T intr, int gpio, mraa::Edge level, void(isr)(void ), void *arg)

void	uninstallISR (LSM303AGR_INTERRUPT_PINS_T intr)

Protected Member Functions
uint8_t	readReg (uint8_t reg)

int	readRegs (uint8_t reg, uint8_t *buffer, int len)

void	writeReg (uint8_t reg, uint8_t val)

Protected Attributes
lsm303agr_context	m_lsm303agr

Constructor & Destructor Documentation

LSM303AGR	(	int	bus = `LSM303AGR_DEFAULT_I2C_BUS`,
		int	acc_addr = `LSM303AGR_DEFAULT_ACC_ADDR`,
		int	mag_addr = `LSM303AGR_DEFAULT_MAG_ADDR`
	)

LSM303AGR constructor

This driver can only support I2C. SPI requires support for 3-wire SPI which we cannot currently handle. Only the basic capabilities of the device are supported, however there is a full register map defined (lsm303agr_defs.h), and with access to the bus read/write functions, any desired additional functionality can be implemented.

Parameters

bus	I2C bus to use
acc_addr	The I2C address of the accelerometer. Use -1 if you do not wish to use the accelerometer.
mag_addr	The I2C address of the magnetometer. Use -1 if you do not wish to use the magnetometer.

Returns: The device context, or NULL if an error occurred

Exceptions

std::runtime_error on failure.

~LSM303AGR ( )

LSM303AGR Destructor

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Member Function Documentation

void update ( void )

Update the internal stored values from sensor data. This method must be called before querying the acceleration, magnetometer, or temperature.

Exceptions

std::runtime_error on failure

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void getMagnetometer	(	float *	x,
		float *	y,
		float *	z
	)

Return magnetometer data in micro-Teslas (uT). update() must have been called prior to calling this method.

Parameters

x	Pointer to a floating point value that will have the current x component placed into it
y	Pointer to a floating point value that will have the current y component placed into it
z	Pointer to a floating point value that will have the current z component placed into it

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std::vector< float > getMagnetometer ( )

Return magnetometer data in micro-Teslas (uT) in the form of a floating point vector. update() must have been called prior to calling this method.

Returns: A floating point vector containing x, y, and z in that order

void getAccelerometer	(	float *	x,
		float *	y,
		float *	z
	)

Return acceleration data in gravities. update() must have been called prior to calling this method.

Parameters

x	Pointer to a floating point value that will have the current x component placed into it
y	Pointer to a floating point value that will have the current y component placed into it
z	Pointer to a floating point value that will have the current z component placed into it

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std::vector< float > getAccelerometer ( )

Return acceleration data in gravities in the form of a floating point vector. update() must have been called prior to calling this method.

Returns: A floating point vector containing x, y, and z in that order

float getTemperature ( void )

Return temperature data in degrees Celsius. NOTE: This is not the ambient room temperature. update() must have been called prior to calling this method.

Returns: Temperature in degrees Celsius

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void init ( LSM303AGR_POWER_MODE_T usage = LSM303AGR_POWER_HIGH_RESOLUTION )

Initialize the device and start operation. This function is called from the constructor so it will not typically need to be called by a user unless the device is reset. It will initialize the accelerometer and magnetometer (if enabled) to certain default running modes.

For the accelerometer, the full scale will be set to 2G, mode continuous, all axes enabled, BDU enabled, temperature measurement enabled, and an output data rate (ODR) of 100Hz with the power mode set at high resolution.

For the magnetometer, temperature compensation will be enabled, mode continuous, and an output data rate of 10Hz with the power mode set at high resolution.

Parameters

usage One of the LSM303AGR_POWER_MODE_T values. The default is LSM303AGR_POWER_HIGH_RESOLUTION.

Exceptions

std::runtime_error on failure

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void setFullScale ( LSM303AGR_A_FS_T fs )

Set the full scale (sensitivity) value for the accelerometer. This device supports 2G, 4G, 8G, and 16G full scale modes.

Parameters

fs	One of the LSM303AGR_A_FS_T values

Exceptions

std::runtime_error on failure

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void setPowerMode ( LSM303AGR_POWER_MODE_T mode )

Set an operating power mode. There are 3 modes available: low power, normal, and high resolution.

Parameters

mode	One of the LSM303AGR_POWER_MODE_T values. The default set at initialization time is LSM303AGR_POWER_HIGH_RESOLUTION.

Exceptions

std::runtime_error on failure

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void setAccelerometerODR ( LSM303AGR_A_ODR_T odr )

Set the accelerometer output data rate (ODR)

Parameters

odr	One of the LSM303AGR_A_ODR_T values. The default set at initialization time is LSM303AGR_A_ODR_100HZ.

Exceptions

std::runtime_error on failure

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void setMagnetometerODR ( LSM303AGR_CFG_A_M_ODR_T odr )

Set the magnetometer output data rate (ODR)

Parameters

odr	One of the LSM303AGR_CFG_A_M_ODR_T values. The default set at initialization time is LSM303AGR_CFG_A_M_ODR_10HZ.

Exceptions

std::runtime_error on failure

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uint8_t getAccelerometerInt1Config ( )

Return the accelerometer interrupt 1 config register. This register allows you to enable various interrupt conditions. See the datasheet for details.

Returns: A bitmask of LSM303AGR_INT_CFG_A_BITS_T bits

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uint8_t getAccelerometerInt2Config ( )

Return the accelerometer interrupt 2 config register. This register allows you to enable various interrupt conditions. See the datasheet for details.

Returns: A bitmask of LSM303AGR_INT_CFG_A_BITS_T bits

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void setAccelerometerInt1Config ( uint8_t bits )

Set the accelerometer interrupt 1 config register. See the datasheet for details.

Parameters

dev	The device context
bits	A bitmask of LSM303AGR_INT_CFG_A_BITS_T bits

Exceptions

std::runtime_error on failure

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void setAccelerometerInt2Config ( uint8_t bits )

Set the accelerometer interrupt 2 config register. See the datasheet for details.

Parameters

dev	The device context
bits	A bitmask of LSM303AGR_INT_CFG_A_BITS_T bits

Exceptions

std::runtime_error on failure

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uint8_t getMagnetometerIntConfig ( )

Return the magnetometer interrupt config register. See the datasheet for details.

Returns: A bitmask of LSM303AGR_INT_CTRL_REG_M_BITS_T bits

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void setMagnetometerIntConfig ( uint8_t bits )

Set the magnetometer (mag) interrupt config register. See the datasheet for details.

Parameters

bits	A bitmask of LSM303AGR_INT_CTRL_REG_M_BITS_T bits

Exceptions

std::runtime_error on failure

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uint8_t getAccelerometerInt1Src ( )

Return the accelerometer interrupt 1 source register. This register indicates which interrupts have been triggered. See the datasheet for details.

Returns: a bitmask of LSM303AGR_INT_SRC_A_BITS_T bits

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uint8_t getAccelerometerInt2Src ( )

Return the accelerometer interrupt 2 source register. This register indicates which interrupts have been triggered. See the datasheet for details.

Returns: a bitmask of LSM303AGR_INT_SRC_A_BITS_T bits

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uint8_t getMagnetometerIntSrc ( )

Return the magnetometer (mag) interrupt source register. This register indicates which interrupts have been triggered. See the datasheet for details.

Parameters

dev	The device context

Returns: a bitmask of LSM303AGR_INT_SRC_REG_M_BITS_T bits

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void installISR	(	LSM303AGR_INTERRUPT_PINS_T	intr,
		int	gpio,
		mraa::Edge	level,
		void()(void )	isr,
		void *	arg
	)

Install an interrupt handler

Parameters

intr	One of the LSM303AGR_INTERRUPT_PINS_T values specifying which interrupt pin you are installing
gpio	GPIO pin to use as interrupt pin
level	The interrupt trigger level (one of mraa::Edge values). Make sure that you have configured the interrupt pin properly for whatever level you choose.
isr	The interrupt handler, accepting a void * argument
arg	The argument to pass the the interrupt handler