InvenSense ITG-3200 digital triaxial gyroscope.

This module implements a driver for the InvenSense ITG-3200 digital 3-axis MEMS gyroscope. The ITG-3200 provides digital-output x-, y-, and z-axis angular rate sensor readings with a sensitivity of 16 LSBs per deg/sec and a full-scale range of +/-2000 deg/sec.

The ITG-3200 consists of the following key blocks and functions:

 - Three-axis MEMS rate gyroscope sensors with individual 16-bit
   ADCs and signal conditioning

 - I2C serial communications interface

 - Clocking

 - Sensor Data Registers

 - Interrupts

 - Digital-Output Temperature Sensor

 - Bias and LDO

 - Charge Pump

 - Three-Axis MEMS Gyroscope with 16-bit ADCs and Signal Conditioning

The ITG-3200 consists of three independent vibratory MEMS gyroscopes, which detect rotational rate about the X (roll), Y (pitch), and Z (yaw) axes. When the gyros are rotated about any of the sense axes, the Coriolis Effect causes a deflection that is detected by a capacitive pickoff. The resulting signal is amplified, demodulated, and filtered to produce a voltage that is proportional to the angular rate. This voltage is digitized using individual on-chip 16-bit Analog-to-Digital Converters (ADCs) to sample each axis.

The full-scale range of the gyro sensors is preset to +/-2000 degrees per second (deg/sec). The ADC output rate is programmable up to a maximum of 8,000 samples per second down to 3.9 samples per second, and user-selectable low-pass filters enable a wide range of cut-off frequencies.

#include "itg3200.h"

Data Structures
struct	itg3200_event_t
	Interrupt Service Routine Data Descriptor. More...

Macros
#define	ITG3200_FS_RANGE (2000) /* fixed full-scale range (deg/sec) */

#define	ITG3200_RESOLUTION (16) /* axis data sample resolution (bits) */

#define	SCALE_LSB_PER_DPS (14375 / 1000)
	The ITG-3200 specification originally stated that the sensitivity scale factor was 16.4 LSB/deg/sec. More...

Functions
static bool	itg3200_default_init (sensor_hal_t *hal)
	InvenSense ITG-3200 gyroscope driver defaults. More...

static bool	itg3200_device_id (sensor_hal_t hal, sensor_data_t data)
	Read gyroscope device ID. More...

static bool	itg3200_event (sensor_t sensor, sensor_event_t sensor_event, sensor_event_callback_t callback, bool enable)
	Enable/disable ITG3200 sensor event. More...

static bool	itg3200_get_rotation (sensor_hal_t hal, sensor_data_t data)
	Read gyroscope angular rate axis data. More...

static bool	itg3200_get_temperature (sensor_hal_t hal, sensor_data_t data)
	Read gyroscope integrated temperature sensor data. More...

bool	itg3200_init (sensor_t *sensor, int resvd)
	InvenSense ITG-3200 gyroscope driver initialization. More...

static bool	itg3200_ioctl (sensor_t sensor, sensor_command_t cmd, void arg)
	ITG3200 ioctl control entry point. More...

static void	itg3200_isr (volatile void *arg)
	Invensense ITG3200 driver interrupt service routine. More...

static bool	itg3200_read (sensor_t sensor, sensor_read_t type, sensor_data_t data)
	Read sensor data. More...

static bool	itg3200_set_bandwidth (sensor_hal_t *hal, int16_t band)
	Set the ITG-3200 low-pass filter bandwidth. More...

static bool	itg3200_set_sample_rate (sensor_hal_t *hal, int16_t rate)
	Set the ITG-3200 sample rate. More...

static bool	itg3200_set_state (sensor_hal_t *hal, sensor_state_t state)
	Set the ITG-3200 execution mode. More...

Variables
static const sensor_map_t	band_table []
	InvenSense ITG-3200 low-pass Bandwidth Table (hertz, register value) More...

static sensor_event_callback_t	event_cb = {.handler = default_event_handler}
	Sensor Event Callback Descriptor. More...

#define ITG3200_FS_RANGE (2000) /* fixed full-scale range (deg/sec) */

Referenced by itg3200_init().

#define ITG3200_RESOLUTION (16) /* axis data sample resolution (bits) */

Referenced by itg3200_init().

#define SCALE_LSB_PER_DPS (14375 / 1000)

The ITG-3200 specification originally stated that the sensitivity scale factor was 16.4 LSB/deg/sec.

As of revision 1.4 of the specification, that has been modified to 14.375 LSB/deg/sec. The vendor may supply a way to interrogate ITG-3200 parts to determine which scale factor to use.

Referenced by itg3200_get_rotation(), and itg3200_isr().

static bool itg3200_default_init ( sensor_hal_t * hal )

inlinestatic

InvenSense ITG-3200 gyroscope driver defaults.

This is a convenience routine for setting the default device configuration during initialization or after reset.

Parameters

hal	Address of an initialized sensor hardware descriptor.

Returns: bool true if the sensor is ready for use, else false.

References sensor_hal::bus, DLPF_CFG_42HZ, FS_SEL_2000, ITG3200_DLPF_FS, ITG3200_ID_VAL, ITG3200_PWR_MGM, ITG3200_SMPLRT_DIV, ITG3200_WHOAMI, PWR_MGM_CLK_SEL_Z, PWR_MGM_H_RESET, sensor_bus_get, sensor_bus_put, status, bus_desc_t::status, and STATUS_OK.

Referenced by itg3200_init(), and itg3200_set_state().

static bool itg3200_device_id	(	sensor_hal_t *	hal,
		sensor_data_t *	data
	)

static

Read gyroscope device ID.

This function reads the gyroscope hardware identification registers and returns these values to the addresses specified in the function parameters.

Parameters

sensor	Address of an initialized sensor device descriptor.
data	Address of sensor_data_t structure to return values.

Returns: bool true if the call succeeds, else false is returned.

References sensor_data_t::device, ITG3200_WHOAMI, and sensor_bus_get.

Referenced by itg3200_read().

static bool itg3200_event	(	sensor_t *	sensor,
		sensor_event_t	sensor_event,
		sensor_event_callback_t *	callback,
		bool	enable
	)

static

Enable/disable ITG3200 sensor event.

Parameters

sensor	Address of an initialized sensor device descriptor
callback	Application-defined event callback handler descriptor
enable	Enable flag: true = enable event, false = disable event

Returns: bool true if the call succeeds, else false is returned

References sensor_desc::hal, INT_CFG_ANYRD_2CLEAR, INT_CFG_LATCH_INT_EN, INT_CFG_RAW_RDY_EN, ITG3200_INT_CFG, sensor_bus_put, SENSOR_EVENT_NEW_DATA, sensor_reg_bitclear, and status.

Referenced by itg3200_init(), and itg3200_ioctl().

static bool itg3200_get_rotation	(	sensor_hal_t *	hal,
		sensor_data_t *	data
	)

static

Read gyroscope angular rate axis data.

This function reads angular rate data for all 3 axes of an ITG-3200 gyroscope.

Parameters

sensor	Address of an initialized sensor device descriptor.
data	The address of a vector storing sensor axis data.

Returns: bool true if the call succeeds, else false is returned.

References sensor_data_t::axis, sensor_axis_vec_t::axis, ITG3200_GYRO_XOUT_H, sensor_hal::orientation, SCALE_LSB_PER_DPS, sensor_data_t::scaled, sensor_bus_read, sensor_axis_vec_t::sign, sensor_orient_t::x, sensor_orient_t::y, and sensor_orient_t::z.

Referenced by itg3200_ioctl(), and itg3200_read().

static bool itg3200_get_temperature	(	sensor_hal_t *	hal,
		sensor_data_t *	data
	)

static

Read gyroscope integrated temperature sensor data.

This function reads ITG-3200 integrated temperature sensor data. The temperature is always returned in scaled engineering units (degrees Celsius).

Parameters

sensor	Address of an initialized sensor device descriptor.
data	The address where temperature samples are returned.

Returns: bool true if the call succeeds, else false is returned.

References be16_to_cpu, ITG3200_TEMP_OUT_H, sensor_data_t::scaled, sensor_bus_read, TEMP_COUNTS_PER_DEG_C, TEMP_OFFSET, TEMP_REF_DEG, and sensor_data_t::temperature.

Referenced by itg3200_read().

bool itg3200_init	(	sensor_t *	sensor,
		int	resvd
	)

InvenSense ITG-3200 gyroscope driver initialization.

This is the main initialization function for the ITG-3200 device.

Parameters

sensor	Address of a sensor device descriptor.
resvd	Reserved value.

Returns: bool true if the sensor is ready for use, else false.

References ARRAYSIZE, band_table, sensor_hal::bandwidth, sensor_hal::burst_addr, sensor_desc::drv, sensor_device_t::func, sensor_desc::hal, itg3200_default_init(), itg3200_event(), ITG3200_FS_RANGE, ITG3200_INT_STATUS, itg3200_ioctl(), itg3200_isr(), itg3200_read(), ITG3200_RESOLUTION, sensor_hal::mcu_sigint, sensor_hal::range, sensor_funcs_t::read, sensor_hal::resolution, sensor_hal::sample_rate, SENSOR_CAPS_3_AXIS, SENSOR_CAPS_AUX_TEMP, sensor_irq_connect(), SENSOR_UNITS_deg_per_sec, SENSOR_VENDOR_INVENSENSE, and status.

static bool itg3200_ioctl	(	sensor_t *	sensor,
		sensor_command_t	cmd,
		void *	arg
	)

static

ITG3200 ioctl control entry point.

This function provides a general-purpose interface for performing various control operations on the sensor device.

Parameters

sensor	Address of an initialized sensor device descriptor.
cmd	Command to execute
arg	Argument for command (varies)

Returns: bool true if the call succeeds, else false is returned.

References sensor_data_t::axis, sensor_desc::err, sensor_desc::hal, itg3200_event(), itg3200_get_rotation(), itg3200_set_bandwidth(), itg3200_set_sample_rate(), itg3200_set_state(), sensor_data_t::scaled, SENSOR_DISABLE_EVENT, SENSOR_ENABLE_EVENT, SENSOR_ERR_UNSUPPORTED, SENSOR_READ_VECTOR, SENSOR_SET_BANDWIDTH, SENSOR_SET_SAMPLE_RATE, SENSOR_SET_STATE, vector3_t::x, vector3_t::y, and vector3_t::z.

Referenced by itg3200_init().

static void itg3200_isr ( volatile void * arg )

static

Invensense ITG3200 driver interrupt service routine.

This is the interrupt service routine for enabled ITG3200 interrupt events. Only the new data ("raw data ready") interrupt is supported.

Parameters

arg	The address of the driver sensor_hal_t descriptor.

Returns: Nothing.

References sensor_event_callback_t::arg, sensor_data_t::axis, sensor_axis_vec_t::axis, sensor_hal::burst_addr, sensor_hal::bus, sensor_event_data_t::data, sensor_event_data_t::event, sensor_event_callback_t::handler, bus_desc_t::no_wait, sensor_hal::orientation, SCALE_LSB_PER_DPS, sensor_data_t::scaled, sensor_bus_read, SENSOR_EVENT_NEW_DATA, sensor_timestamp(), sensor_axis_vec_t::sign, bus_desc_t::status, STATUS_OK, sensor_data_t::timestamp, sensor_orient_t::x, itg3200_event_t::x_hi, itg3200_event_t::x_lo, sensor_orient_t::y, itg3200_event_t::y_hi, itg3200_event_t::y_lo, sensor_orient_t::z, itg3200_event_t::z_hi, and itg3200_event_t::z_lo.

Referenced by itg3200_init().

static bool itg3200_read	(	sensor_t *	sensor,
		sensor_read_t	type,
		sensor_data_t *	data
	)

static

Read sensor data.

This routine calls the appropriate internal data function to obtain the specified type of data from the sensor device.

Parameters

sensor	Address of an initialized sensor device descriptor.
type	Type of sensor data to read.
data	The address where data values are returned.

Returns: bool true if the call succeeds, else false is returned.

References sensor_desc::err, sensor_desc::hal, itg3200_device_id(), itg3200_get_rotation(), itg3200_get_temperature(), SENSOR_ERR_FUNCTION, SENSOR_READ_ID, SENSOR_READ_ROTATION, and SENSOR_READ_TEMPERATURE.

Referenced by itg3200_init().

static bool itg3200_set_bandwidth	(	sensor_hal_t *	hal,
		int16_t	band
	)

static

Set the ITG-3200 low-pass filter bandwidth.

This routine sets the ITG-3200 low-pass filter bandwidth and the internal sample rate used by the device. This internal sample rate is then further scaled by the sample rate divider (SMPLRT_DIV) value to produce the gyro sample rate according to the formula:

* F_sample = F_internal / (divider + 1)

*

Valid filter bandwidths and the associated internal sample rate are as follows:

*          Low Pass Filter Bandwidth       Internal Sample Rate
*          ____________________________________________________
*              256Hz                           8kHz
*              188Hz                           1kHz
*              98Hz                            1kHz
*              42Hz                            1kHz
*              20Hz                            1kHz
*              10Hz                            1kHz
*              5Hz                             1kHz
* 

Parameters

hal	Address of an initialized sensor device descriptor.
band	The index of a driver-specific bandwidth table entry.

Returns: bool true if the call succeeds, else false is returned.

References sensor_hal::bandwidth, sensor_map_t::bandwidth_Hz, FS_SEL_2000, ITG3200_DLPF_FS, itg3200_set_sample_rate(), sensor_hal::sample_rate, and sensor_bus_put.

Referenced by itg3200_ioctl().

static bool itg3200_set_sample_rate	(	sensor_hal_t *	hal,
		int16_t	rate
	)

static

Set the ITG-3200 sample rate.

This routine sets the externally visible ITG-3200 sample rate for the device. This sets a divider that scaled down the internal 1Khz or 8 KHz sample rate to the specified frequency, according to the formula:

* F_sample = F_internal / (divider + 1)

*

The internal sampling rate is 1KHz for all filter bandwidths except 256Hz, which uses an 8KHz internal rate.

Parameters

hal	Address of an initialized sensor device descriptor.
rate	The externally visible sampling rate to be set

Returns: bool true if the call succeeds, else false is returned.

References sensor_hal::bandwidth, ITG3200_SMPLRT_DIV, and sensor_bus_put.

Referenced by itg3200_ioctl(), and itg3200_set_bandwidth().

static bool itg3200_set_state	(	sensor_hal_t *	hal,
		sensor_state_t	state
	)

static

Set the ITG-3200 execution mode.

This routine sets a specified ITG-3200 execution state to one of the following:

SENSOR_STATE_SLEEP or SENSOR_STATE_LOWEST_POWER Setting the sleep mode puts the device into very low power sleep mode. In this mode, only the serial interface and internal registers remain active.

SENSOR_STATE_NORMAL or SENSOR_STATE_HIGHEST_POWER Sets the device to a normal operational state.

SENSOR_STATE_RESET Sets the device and internal registers to the power-up default settings.

Parameters

sensor	Address of an initialized sensor device descriptor.
state	A specified sensor operational state.

Returns: bool true if the call succeeds, else false is returned.

References delay_ms, itg3200_default_init(), ITG3200_PWR_MGM, PWR_MGM_SLEEP, sensor_reg_bitclear, sensor_reg_bitset, SENSOR_STATE_HIGHEST_POWER, SENSOR_STATE_LOWEST_POWER, SENSOR_STATE_NORMAL, SENSOR_STATE_RESET, and SENSOR_STATE_SLEEP.

Referenced by itg3200_ioctl().

const sensor_map_t band_table[]

static

Initial value:

= {
    {{  5}, DLPF_CFG_5HZ  }, {{ 10}, DLPF_CFG_10HZ },
    {{ 20}, DLPF_CFG_20HZ }, {{ 42}, DLPF_CFG_42HZ },
    {{ 98}, DLPF_CFG_98HZ }, {{188}, DLPF_CFG_188HZ},
    {{256}, DLPF_CFG_256HZ} 
}

InvenSense ITG-3200 low-pass Bandwidth Table (hertz, register value)

Referenced by itg3200_init().

sensor_event_callback_t event_cb = {.handler = default_event_handler}

static

Sensor Event Callback Descriptor.

Microchip® Advanced Software Framework

Data Structures

Macros

Functions

Variables