L3GD20 Tri-axis Digital Gyroscope API. More...

Detailed Description

ID: l3gd20
Name: Tri-axis Digital Gyroscope
Category: gyroscope
Manufacturer: stmicro
Connection: iio i2c
Link: http://www.st.com/en/mems-and-sensors/l3gd20.html

The L3GD20 The L3GD20 is a low-power three-axis angular rate sensor. This driver supports IIO and I2C modes. Some methods will only work in one mode or the other. See the documentation on the methods to determine whether a given method is operation in a given mode. Both the I2C and IIO mechanisms make use of the calibration and denoise algorithms.

For I2C mode, not all capabilities of the device are supported, but a complete register map and low level read/write methods are provided to add any missing functionality.

Example using IIO

    upm::L3GD20 gyroscope(3);
    // Instantiate a L3GD20 Gyroscope Sensor on iio device 3
    // Available scales are 0.000153(250dps), 0.000305(500dps), and
    // 0.001222(2000dps)
    gyroscope.setScale(0.001222);
    // Available sampling frequency are 95, 190, 380, and 760
    gyroscope.setSamplingFrequency(95.0);
    gyroscope.enable3AxisChannel();
    gyroscope.installISR(data_callback, &gyroscope);
    gyroscope.enableBuffer(16);
    while (shouldRun) {
        upm_delay(1);
    }
    gyroscope.disableBuffer();

Example using I2C

    // Instantiate an L3GD20 using default parameters
    upm::L3GD20 sensor(L3GD20_DEFAULT_I2C_BUS, L3GD20_DEFAULT_I2C_ADDR);
    // set some parameters (these are already the defaults, but are
    // provided here as an example)
    // 250 deg/s sensitivity
    sensor.setRange(sensor.FS_250);
    // Set ODR to 95Hz, 25Hz cut-off
    sensor.setODR(sensor.ODR_CUTOFF_95_25);
    // If you already have calibration data, you can specify it here
    //  sensor.loadCalibratedData(-0.0296269637, -0.0080939643, -0.0077121737);
    // now output data every 100 milliseconds
    while (shouldRun) {
        float x, y, z;
        sensor.update();
        cout << "Calibrated: " << sensor.getCalibratedStatus() << endl;
        // output is in radians/s
        sensor.getGyroscope(&x, &y, &z);
        cout << fixed << setprecision(1) << "Gyroscope x: " << x << " y: " << y << " z: " << z
             << " radians" << endl;
        // same data converted to degrees/s
        cout << "Gyroscope x: " << rad2deg(x) << " y: " << rad2deg(y) << " z: " << rad2deg(z)
             << " degrees" << endl;
        // we show both C and F for temperature
        cout << "Compensation Temperature: " << sensor.getTemperature(false) << " C / "
             << sensor.getTemperature(true) << " F" << endl;
        cout << endl;
        upm_delay_us(100000);
    }
    // dump the calibration values if we managed to calibrate
    if (sensor.getCalibratedStatus()) {
        float calX, calY, calZ;
        sensor.getCalibratedData(&calX, &calY, &calZ);
        cout << setprecision(10) << "Calibration values x: " << calX << " y: " << calY
             << " z: " << calZ << endl;
    }
    cout << "Exiting..." << endl;

Data Structures
struct	filter_median_t

struct	gyro_cal_t

Public Types
enum	L3GD20_REGS_T { REG_WHO_AM_I = 0x0f, REG_CTRL_REG1 = 0x20, REG_CTRL_REG2 = 0x21, REG_CTRL_REG3 = 0x22, REG_CTRL_REG4 = 0x23, REG_CTRL_REG5 = 0x24, REG_REFERENCE = 0x25, REG_OUT_TEMPERATURE = 0x26, REG_STATUS_REG = 0x27, REG_OUT_X_L = 0x28, REG_OUT_X_H = 0x29, REG_OUT_Y_L = 0x2a, REG_OUT_Y_H = 0x2b, REG_OUT_Z_L = 0x2c, REG_OUT_Z_H = 0x2d, REG_FIFO_CTRL_REG = 0x2e, REG_FIFO_SRC_REG = 0x2f, REG_INT1_CFG = 0x30, REG_INT1_SRC = 0x31, REG_INT1_TSH_XH = 0x32, REG_INT1_TSH_XL = 0x33, REG_INT1_TSH_YH = 0x34, REG_INT1_TSH_YL = 0x35, REG_INT1_TSH_ZH = 0x36, REG_INT1_TSH_ZL = 0x37, REG_INT1_DURATION = 0x38 }

enum	CTRL_REG1_BITS_T { CTRL_REG1_YEN = 0x01, CTRL_REG1_XEN = 0x02, CTRL_REG1_ZEN = 0x04, CTRL_REG1_PD = 0x08, CTRL_REG1_BW0 = 0x10, CTRL_REG1_BW1 = 0x20, _CTRL_REG1_BW_MASK = 3, _CTRL_REG1_BW_SHIFT = 4, CTRL_REG1_DR0 = 0x40, CTRL_REG1_DR1 = 0x80, _CTRL_REG1_DR_MASK = 3, _CTRL_REG1_DR_SHIFT = 6, _CTRL_REG1_ODR_CUTOFF0 = 0x10, _CTRL_REG1_ODR_CUTOFF1 = 0x20, _CTRL_REG1_ODR_CUTOFF2 = 0x40, _CTRL_REG1_ODR_CUTOFF3 = 0x80, _CTRL_REG1_ODR_CUTOFF_MASK = 15, _CTRL_REG1_ODR_CUTOFF_SHIFT = 4 }

enum	ODR_CUTOFF_T { ODR_CUTOFF_95_12_5 = 0, ODR_CUTOFF_95_25 = 1, ODR_CUTOFF_190_12_5 = 4, ODR_CUTOFF_190_25 = 5, ODR_CUTOFF_190_50 = 6, ODR_CUTOFF_190_70 = 7, ODR_CUTOFF_380_20 = 8, ODR_CUTOFF_380_25 = 9, ODR_CUTOFF_380_50 = 10, ODR_CUTOFF_380_100 = 11, ODR_CUTOFF_760_30 = 12, ODR_CUTOFF_760_35 = 13, ODR_CUTOFF_760_50 = 14, ODR_CUTOFF_760_100 = 15 }

enum	POWER_MODES_T { POWER_DOWN, POWER_SLEEP, POWER_NORMAL }

enum	CTRL_REG2_BITS_T { _CTRL_REG2_RESERVED_BITS = 0x40 \| 0x80, CTRL_REG2_HPCF0 = 0x01, CTRL_REG2_HPCF1 = 0x02, CTRL_REG2_HPCF2 = 0x04, CTRL_REG2_HPCF3 = 0x08, _CTRL_REG2_HPCF_MASK = 15, _CTRL_REG2_HPCF_SHIFT = 0, CTRL_REG2_HPM0 = 0x10, CTRL_REG2_HPM1 = 0x20, _CTRL_REG2_HPM_MASK = 3, _CTRL_REG2_HPM_SHIFT = 4 }

enum	HPCF_T { HPCF_7_2 = 0, HPCF_3_5 = 1, HPCF_1_8 = 2, HPCF_0_9 = 3, HPCF_0_45 = 4, HPCF_0_18 = 5, HPCF_0_09 = 6, HPCF_0_045 = 7, HPCF_0_018 = 8, HPCF_0_009 = 9 }

enum	HPM_T { HPM_NORMAL_RESET_FILTER = 0, HPM_REFERENCE_SIGNAL = 1, HPM_NORMAL = 2, HPM_AUTORESET_ON_INT = 3 }

enum	CTRL_REG3_BITS_T { CTRL_REG3_I2_EMPTY = 0x01, CTRL_REG3_I2_ORUN = 0x02, CTRL_REG3_I2_WTM = 0x04, CTRL_REG3_I2_DRDY = 0x08, CTRL_REG3_PP_OD = 0x10, CTRL_REG3_H_LACTIVE = 0x20, CTRL_REG3_I1_BOOT = 0x40, CTRL_REG3_I1_INT1 = 0x80 }

enum	CTRL_REG4_BITS_T { _CTRL_REG4_RESERVED_BITS = 0x02 \| 0x04 \| 0x08, CTRL_REG4_SIM = 0x01, CTRL_REG4_FS0 = 0x10, CTRL_REG4_FS1 = 0x20, _CTRL_REG4_FS_MASK = 3, _CTRL_REG4_FS_SHIFT = 4, CTRL_REG4_BLE = 0x40, CTRL_REG4_BDU = 0x80 }

enum	FS_T { FS_250 = 0, FS_500 = 1, FS_2000 = 2 }

enum	CTRL_REG5_BITS_T { _CTRL_REG5_RESERVED_BITS = 0x20, CTRL_REG5_OUT_SEL0 = 0x01, CTRL_REG5_OUT_SEL1 = 0x02, _CTRL_REG5_OUT_SEL_MASK = 3, _CTRL_REG5_OUT_SEL_SHIFT = 0, CTRL_REG5_INT1_SEL0 = 0x04, CTRL_REG5_INT1_SEL1 = 0x08, _CTRL_REG5_INT1_SEL_MASK = 3, _CTRL_REG5_INT1_SEL_SHIFT = 2, CTRL_REG5_HPEN = 0x10, CTRL_REG5_FIFO_EN = 0x40, CTRL_REG5_BOOT = 0x80 }

enum	STATUS_REG_BITS_T { STATUS_REG_XDA = 0x01, STATUS_REG_YDA = 0x02, STATUS_REG_ZDA = 0x04, STATUS_REG_ZYXDA = 0x08, STATUS_REG_XOR = 0x10, STATUS_REG_YOR = 0x20, STATUS_REG_ZOR = 0x40, STATUS_REG_ZYXOR = 0x80 }

enum	FIFO_CTRL_REG_BITS_T { FIFO_CTRL_REG_WTM0 = 0x01, FIFO_CTRL_REG_WTM1 = 0x02, FIFO_CTRL_REG_WTM2 = 0x04, FIFO_CTRL_REG_WTM3 = 0x08, FIFO_CTRL_REG_WTM4 = 0x10, _FIFO_CTRL_REG_WTM_MASK = 31, _FIFO_CTRL_REG_WTM_SHIFT = 0, FIFO_CTRL_REG_FM0 = 0x20, FIFO_CTRL_REG_FM1 = 0x40, FIFO_CTRL_REG_FM2 = 0x80, _FIFO_CTRL_REG_FM_MASK = 7, _FIFO_CTRL_REG_FM_SHIFT = 5 }

enum	FIFO_MODE_T { FIFO_MODE_BYPASS = 0, FIFO_MODE_FIFO = 1, FIFO_MODE_STREAM = 2, FIFO_MODE_STREAM_TO_FIFO = 3, FIFO_MODE_BYPASS_TO_STREAM = 4 }

enum	FIFO_SRC_BITS_T { FIFO_SRC_REG_FSS0 = 0x01, FIFO_SRC_REG_FSS1 = 0x02, FIFO_SRC_REG_FSS2 = 0x04, FIFO_SRC_REG_FSS3 = 0x08, FIFO_SRC_REG_FSS4 = 0x10, _FIFO_SRC_REG_FSS_MASK = 31, _FIFO_SRC_REG_FSS_SHIFT = 0, FIFO_SRC_REG_EMPTY = 0x20, FIFO_SRC_REG_OVRN = 0x40, FIFO_SRC_REG_WTM = 0x80 }

enum	INT1_CFG_BITS_T { INT1_CFG_XLIE = 0x01, INT1_CFG_XHIE = 0x02, INT1_CFG_YLIE = 0x04, INT1_CFG_YHIE = 0x08, INT1_CFG_ZLIE = 0x10, INT1_CFG_ZHIE = 0x20, INT1_CFG_LIR = 0x40, INT1_CFG_AND_OR = 0x80 }

enum	INT1_SRC_BITS_T { _INT1_SRC_RESERVED_BITS = 0x80, INT1_SRC_XL = 0x01, INT1_SRC_XH = 0x02, INT1_SRC_YL = 0x04, INT1_SRC_YH = 0x08, INT1_SRC_ZL = 0x10, INT1_SRC_ZH = 0x20, INT1_SRC_IA = 0x40 }

enum	INT1_DURATION_BITS_T { INT1_DURATION_D0 = 0x01, INT1_DURATION_D1 = 0x02, INT1_DURATION_D2 = 0x04, INT1_DURATION_D3 = 0x08, INT1_DURATION_D4 = 0x10, INT1_DURATION_D5 = 0x20, INT1_DURATION_D6 = 0x40, INT1_DURATION_WAIT = 0x80 }

Public Member Functions
	L3GD20 (int device)

	L3GD20 (int bus, int addr)

	~L3GD20 ()

uint8_t	getChipID ()

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

void	setPowerMode (POWER_MODES_T mode)

void	setRange (FS_T range)

void	update ()

float	getTemperature (bool fahrenheit=false)

void	setODR (ODR_CUTOFF_T odr)

void	enableBDU (bool enable)

uint8_t	getStatusBits ()

void	installISR (void(isr)(char , void ), void arg)

int64_t	getChannelValue (unsigned char input, mraa_iio_channel chan)

bool	enableBuffer (int length)

bool	disableBuffer ()

bool	setScale (const float scale)

bool	setSamplingFrequency (const float sampling_frequency)

bool	enable3AxisChannel ()

bool	extract3Axis (char data, float x, float y, float z)

void	initCalibrate ()

bool	getCalibratedStatus ()

void	getCalibratedData (float bias_x, float bias_y, float *bias_z)

void	loadCalibratedData (float bias_x, float bias_y, float bias_z)

uint8_t	readReg (uint8_t reg)

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

void	writeReg (uint8_t reg, uint8_t val)

bool	gyroCollect (float x, float y, float z)

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

float	median (float *queue, unsigned int size)

unsigned int	partition (float *list, unsigned int left, unsigned int right, unsigned int pivot_index)

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

Protected Attributes
mraa::I2c *	m_i2c

float	m_gyrScale

float	m_gyrX

float	m_gyrY

float	m_gyrZ

float	m_temperature

Member Enumeration Documentation

enum L3GD20_REGS_T

L3GD20 registers (i2c)

enum CTRL_REG1_BITS_T

CTRL_REG1 bits

enum ODR_CUTOFF_T

CTRL_REG1_ODR_CUTOFF values

enum POWER_MODES_T

CTRL_REG1 power modes. Power is controlled via the PD, Zen, Yen, and Xen bitfields.

enum CTRL_REG2_BITS_T

CTRL_REG2 bits

enum HPCF_T

CTRL_REG2_HPCF values (see table 26 in the datasheet)

enum HPM_T

CTRL_REG2_HPM values

enum CTRL_REG3_BITS_T

CTRL_REG3 bits

enum CTRL_REG4_BITS_T

CTRL_REG4 bits

enum FS_T

CTRL_REG4_FS values

enum CTRL_REG5_BITS_T

CTRL_REG5 bits

enum STATUS_REG_BITS_T

STATUS_REG bits

enum FIFO_CTRL_REG_BITS_T

FIFO_CTRL_REG bits

enum FIFO_MODE_T

FIFO_CTRL_REG_FM (FIFO mode) values

enum FIFO_SRC_BITS_T

FIFO_SRC_REG bits

enum INT1_CFG_BITS_T

INT1_CFG bits

enum INT1_SRC_BITS_T

INT1_SRC bits

enum INT1_DURATION_BITS_T

INT1_DURATION bits

Constructor & Destructor Documentation

L3GD20 ( int device )

L3GD20 Tri-axis Digital Gyroscope Contructor for IIO operation

Parameters

device iio device number

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L3GD20	(	int	bus,
		int	addr
	)

L3GD20 Tri-axis Digital Gyroscope Contructor for I2C operation

Parameters

bus	i2c bus
addr	I2C address

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~L3GD20 ( )

L3GD20 destructor

Member Function Documentation

uint8_t getChipID ( )

Return the chip ID. I2C only.

Returns: The chip ID (L3GD20_DEFAULT_CHIP_ID).

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

Return gyroscope data in radians per second. update() must have been called prior to calling this method. I2C only.

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.

void setPowerMode ( POWER_MODES_T mode )

Set the power mode of the device. I2C only.

Parameters

mode	One of the POWER_MODES_T values.

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void setRange ( FS_T range )

Set the gyroscope detection scaling range. This device supports 250, 500 and 2000 degree/s ranges. I2C only.

Parameters

range One of the FS_T values.

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void update ( void )

Update the internal stored values from sensor data. This method must be called before querying any data (getTemperature() and getGyroscope()). I2C only.

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float getTemperature ( bool fahrenheit = false )

Return the current measured temperature. Note, this is not ambient temperature. update() must have been called prior to calling this method. I2C only.

Parameters

fahrenheit true to return data in Fahrenheit, false for Celicus. Celsius is the default.

Returns: The temperature in degrees Celsius or Fahrenheit.

void setODR ( ODR_CUTOFF_T odr )

Set the output data rate and cut off frequency of the device. I2C only.

Parameters

odr	One of the ODR_CUTOFF_T values.

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void enableBDU ( bool enable )

Enable or disable Block Data Update. When enabled, this ensures that LSB's or MSB's of a given axis are not being updated while the other is being read. This is enabled by default. I2C only.

Parameters

enable true to enable, false to disable

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uint8_t getStatusBits ( )

Return the bitfields of the Status register. This register provides information on the status of data gathering. I2C only.

Returns: The contents of the REG_STATUS_REG register.

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void installISR	(	void()(char , void *)	isr,
		void *	arg
	)

Installs an interrupt service routine (ISR) to be called when an interrupt occurs. IIO only.

Parameters

isr	Pointer to a function to be called on interrupt
arg	Pointer to an object to be supplied as an argument to the ISR.

int64_t getChannelValue	(	unsigned char *	input,
		mraa_iio_channel *	chan
	)

Extract the channel value based on channel type. IIO only.

Parameters

input	Channel data
chan	MRAA iio-layer channel info

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bool enableBuffer ( int length )

Enable trigger buffer. IIO only.

Parameters

length buffer length in integer

bool disableBuffer ( )

Disable trigger buffer. IIO only.

bool setScale ( const float scale )

Set scale. IIO only. For I2C operation, use setRange() with the appropriate FS_T value.

Parameters

scale in float Available scales are 0.000153(250dps), 0.000305(500dps), and 0.001222(2000dps) Default scale is 0.000153

bool setSamplingFrequency ( const float sampling_frequency )

Set sampling frequency. IIO only. For I2C operation, use the setODR() method with the appropriate ODR_CUTOFF_T value.

Parameters

sampling_frequency sampling frequency in float Available sampling frequency are 95, 190, 380, and 760 Default sampling frequency is 95

bool enable3AxisChannel ( )

Enable 3 axis scan element. IIO only.

bool extract3Axis	(	char *	data,
		float *	x,
		float *	y,
		float *	z
	)

Process enabled channel buffer and return x, y, z axis. IIO only.

Parameters

data	Enabled channel data, 6 bytes, each axis 2 bytes
x	X-Axis
y	Y-Axis
z	Z-Axis

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void initCalibrate ( )

Reset calibration data and start collect calibration data again

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bool getCalibratedStatus ( )

Get calibrated status, return true if calibrate successfully

void getCalibratedData	(	float *	bias_x,
		float *	bias_y,
		float *	bias_z
	)

Get calibrated data

void loadCalibratedData	(	float	bias_x,
		float	bias_y,
		float	bias_z
	)

Load calibrated data

uint8_t readReg ( uint8_t reg )

Read a register. I2C mode only.

Parameters

reg	The register to read.

Returns: The value of the register.

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

Read contiguous registers into a buffer. I2C mode only.

Parameters

buffer	The buffer to store the results.
len	The number of registers to read.

Returns: The number of bytes read.

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void writeReg	(	uint8_t	reg,
		uint8_t	val
	)

Write to a register. I2C mode only.

Parameters

reg	The register to write to.
val	The value to write.

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bool gyroCollect	(	float	x,
		float	y,
		float	z
	)

Calibrate gyro

Parameters

x	X-Axis
y	Y-Axis
z	Z-Axis

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

Denoise gyro

Parameters

x	X-Axis
y	Y-Axis
z	Z-Axis

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float median	(	float *	queue,
		unsigned int	size
	)

median algorithm

Parameters

queue
size

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unsigned int partition	(	float *	list,
		unsigned int	left,
		unsigned int	right,
		unsigned int	pivot_index
	)

partition algorithm

Parameters

list
left
right
pivot_index

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

Clamp Gyro Readings to Zero

Parameters

x	X-Axis
y	Y-Axis
z	Z-Axis

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The documentation for this class was generated from the following files:

src/l3gd20/l3gd20.hpp
src/l3gd20/l3gd20.cxx

Detailed Description

Data Structures

Public Types

Public Member Functions

Protected Attributes

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation