L3Gxxxx 3-axis gyroscope sensor family

Device Driver for ST L3Gxxxx 3-axis gyroscope sensor family. More...

Detailed Description

Device Driver for ST L3Gxxxx 3-axis gyroscope sensor family.

Driver for ST L3Gxxxx 3-axis gyroscope sensor family

Table of contents

1. Overview
   1. About the sensor
   2. Supported features
2. Measurement Process
   1. Sensor modes
   2. Output Data Rates and Filters
3. Using the driver (basic functionality)
   1. Initialization
   2. Output data format
   3. Fetching data
4. Using the FIFO
   1. Configuration of the FIFO
   2. Reading data from the FIFO
5. Using Interrupts
   1. [Data interrupts (data ready and FIFO status) on signal INT2/DRDY] (#l3gxxxx_data_interrupt)
   2. [Event interrupts (Axes movement and wake-up) on signal INT1] (#l3gxxxx_event_interrupt)
   3. Interrupt context problem
   4. Interrupt signal properties
6. Power Saving
7. Low level functions
8. Default configuration

Overview

About the sensor

ST L3Gxxxx sensors are low-power 3-axis angular rate sensors connected to I2C or SPI with a full scale of up to 2000 dps. It supports different measuring rates with a user selectable bandwidth.

Main features of the sensor are:

• 3 selectable full scales of ±245, ±500, and ±2000 dps
• 7 measuring rates from 12.5 Hz to 800 Hz with 4 bandwidths
• 16 bit angular rate value data output
• 2 dedicated interrupt signals for data and event interrupts
• integrated high-pass filters with 3 modes and 10 different cutoff frequencies
• embedded temperature sensor with 8 bit data output
• embedded 32 levels of 16 bit data output FIFO
• I2C and SPI digital interface
• embedded power-down and sleep mode with fast power-on and wake-up

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Supported Features

The driver supports the following sensors of the L3Gxxxx 3-axis gyro sensor family. Used sensor variant has to be specified by using the respective pseudomodule.

Sensor Variant	Pseudomodule	Vendor Status
L3GD20H	l3gd20h	Not recommended for new designs
L3GD20	l3gd20	Obsolete
L3G4200D	l3g4200_ng	Obsolete
A3G4250D	a3g4250d	Active
I3G4250D	i3g4250d	Active

The driver is modular and supports different levels of functionality, which can be enabled using pseudomodules according to the requirements of the application. This ensures that the driver only uses as much ROM and RAM as really needed.

As basic functionality the driver supports

• a static configuration of the sensor by a default configuration parameter set of type l3gxxxx_params_t as defined in the file l3gxxxx_params.h
• the polling of raw output data or angular rates in millidegrees per second (mdps)
• the power-down and power-up of the sensor
• the use of the I2C or SPI interface

The following pseudomodules are used to enable additional functionalities:

Pseudomodule	Functionality
l3gxxxx_i2c	I2C interface enabled
l3gxxxx_spi	SPI interface enabled
l3gxxxx_low_odr	Low output data rates enabled (L3GD20H only)
l3gxxxx_fifo	32 level FIFO enabled
l3gxxxx_irq_data	Data interrupt (INT2/DRDY) handling enabled
l3gxxxx_irq_event	Event interrupt (INT1) handling enabled
l3gxxxx_sleep	Sleep and wake-up functions enabled
l3gxxxx_config	Functions for changing configurations at runtime nabled

The following table shows the mapping of which modules have to be used to enable which functions of the L3Gxxxx.

Feature	Module
16 bit angular rate data output (raw and angular rate)	l3gxxxx
Full scales of ±245, ±500, and ±2000 dps	l3gxxxx
Using high-pass filter (HPF) and low-pass filter (LPF1/LPF2)	l3gxxxx
Output data rates (ODR) from 100 Hz to 800 Hz	l3gxxxx
Output data rates (ODR) from 12.5 Hz to 50 Hz (L3GD20H only)	l3gxxxx_low_odr
Polling data	l3gxxxx
SAUL sensor interface	l3gxxxx
Power-down and power-up functionality	l3gxxxx
Sleep and wake-up functionality	l3gxxxx_sleep
32 level FIFO handling	l3gxxxx_fifo
Data interrupt (INT2/DRDY) handling (data ready and FIFO)	l3gxxxx_irq_data
Event interrupt (INT1) handling (Axes movement and wake-up)	l3gxxxx_irq_event
Configuration of all sensor functions at runtime	l3gxxxx_config
I2C interface	l3gxxxx_i2c
SPI interface (SPI mode 3)	l3gxxxx_spi

Note

• Multiple L3Gxxxx sensors of same type with both SPI and I2C interfaces can be used simultaneously. If neither the I2C nor the SPI interface are enabled by using the modules l3gxxxx_i2c or l3gxxxx_spi, the I2C interface is used by default.
  
  
• In default configuration, the sensor is configured with an output data rate (ODR) of 100 Hz with a LPF2 cutoff frequency of 25 Hz (L3GXXXX_ODR_100_25) and a full scale of 245 dps (L3GXXXX_SCALE_245_DPS). The data are filtered with HPF and LPF2, where the HPF is used in normal mode with reset (L3GXXXX_HPF_NORMAL) and a cutoff frequency of 8 Hz (see l3gxxxx_config_hpf).
  
  This configuration can either be changed by overriding default parameters CONFIG_L3GXXXX_ODR, CONFIG_L3GXXXX_SCALE, CONFIG_L3GXXXX_FILTER_SEL, CONFIG_L3GXXXX_HPF_MODE and CONFIG_L3GXXXX_HPF_CUTOFF or by using functions l3gxxxx_set_mode, l3gxxxx_set_scale, l3gxxxx_select_output_filter, l3gxxxx_config_hpf if module l3gxxxx_config is enabled.
  
  
• If module 'l3gxxxx_fifo' is used, the FIFO is enabled in mode L3GXXXX_FIFO with a watermark level (threshold) of 23, i.e. the interrupt L3GXXXX_INT_FIFO_WATERMARK is triggered (if enabled) when the 24th sample is stored in the FIFO.
  
  This configuration can be changed either by overriding the default configuration parameters CONFIG_L3GXXXX_FIFO_MODE and CONFIG_L3GXXXX_FIFO_WATERMARK or by function l3gxxxx_set_fifo_mode if module l3gxxxx_config is used.
  
  
• If the handling of data interrupts on signal INT2/DRDY is enabled by module l3gxxxx_irq_data, it depends on whether module l3gxxxx_fifo is used, which data interrupts are enabled by default. If l3gxxxx_fifo is used, L3GXXXX_INT_FIFO_WATERMARK and L3GXXXX_INT_FIFO_OVERRUN interrupts are enabled by default. Otherwise only L3GXXXX_INT_DATA_READY is enabled by default.
  
  This configuration can be changed using function l3gxxxx_enable_int.
  
  
• If the handling of event interrupts on signal INT1 is enabled by module l3gxxxx_irq_event, the high event interrupt is enabled by default for all axes. This means that for each individual axis an interrupt is generated when the absolute value of its angular rate exceeds a threshold value of ~30 dps (high event).
  
  The axis data are filtered with HPF and LPF2. The interrupt signal INT1 is triggered when the data for one axis becomes greater than the specified threshold (OR condition). The interrupt is latched by default.
  
  This configuration can be changed either by overriding the default configuration parameters CONFIG_L3GXXXX_INT1_X_THRESH, CONFIG_L3GXXXX_INT1_Y_THRESH, CONFIG_L3GXXXX_INT1_Z_THRESH, CONFIG_L3GXXXX_INT1_X_LT_THRESH, CONFIG_L3GXXXX_INT1_X_GT_THRESH, CONFIG_L3GXXXX_INT1_Y_LT_THRESH, CONFIG_L3GXXXX_INT1_Y_GT_THRESH, CONFIG_L3GXXXX_INT1_Z_LT_THRESH, CONFIG_L3GXXXX_INT1_Z_GT_THRESH, CONFIG_L3GXXXX_INT1_FILTER, CONFIG_L3GXXXX_INT1_AND and CONFIG_L3GXXXX_INT1_LATCH or at runtime using function l3gxxxx_set_int_event_cfg function.
  
  The INT1 signal is a HIGH active push/pull output.

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Measurement Process

Sensor modes

L3Gxxxx sensors provide different operating modes.

• Power-down mode is configured automatically after power up boot sequence. In this mode, all gyros are switched off. Therefore, it takes up to 100 ms to switch to another mode. The power consumption in this mode is about 1 uA.
• Normal mode is the normal measurement mode. All gyros are switched on and at least one axis is enabled for measurements. Measurements are performed at a defined output data rate (ODR). The power consumption in this mode is about 5 mA.
• Sleep mode is the normal mode when no axes era enabled for measurement. In this modes, all gyros are kept switched on. Therefore, it only takes 1/ODR to switch to normal mode if low pass filtering is disabled or 6/ODR if low pass filtering is enabled. The power consumption in this mode is about 2.5 mA.

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Output Data Rates and Filters

In normal mode, measurements are performed at a defined output rate (ODR) with a user selectable bandwidth.

Used filter selection

L3Gxxxx sensors integrate a combination of two low pass filters (LPF) and one high pass filter (HPF).

                                 +--------------->   L3GXXXX_NO_FILTER
                                 |    +----- +
                    +------------+--->|      |--->   L3GXXXX_LPF2_ONLY
                    |                 | LPF2 |
+-----+   +------+  |   +-----+  +--->|      |--->   L3GXXXX_HPF_AND_LPF2
|     |   |      |  |   |     |  |    +------+
| ADC |-->| LPF1 |--+-->| HPF |--+--------------->   L3GXXXX_HPF_ONLY
|     |   |      |      |     |
+-----+   +------+      +-----+

First, raw sensor data are always filtered by LPF1 with a cutoff frequency that is fixed for the selected output data rate (ODR), see l3gxxxx_odr_t. Resulting data can then optionally be filtered by HPF and/or LPF2. Both filters can be used or bypassed.

The figure above shows possible filter selections and the driver symbols defined by l3gxxxx_filter_sel_t. These can be used to set the filter combination separately for the output data and the data for event interrupt generation.

Driver symbol	High pass filter (HPF) used	Low pass filter 2 (LPF2) used
L3GXXXX_NO_FILTER	-	-
L3GXXXX_HPF_ONLY	x	-
L3GXXXX_LPF2_ONLY	-	x
L3GXXXX_HPF_AND_LPF2	x	x

The default filter selection for the output data is L3GXXXX_HPF_AND_LPF2 and is defined by the default configuration parameter CONFIG_L3GXXXX_FILTER_SEL. If the module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_select_output_filter.

The default filter selection for event interrupt generation is L3GXXXX_HPF_AND_LPF2 and is defined by default configuration parameter CONFIG_L3GXXXX_INT1_FILTER. It can be changed at runtime with function l3gxxxx_set_int_event_cfg.

Note

Since same filters are used for the output data as well as the data used for event interrupt generation (selective axes movement / wake-up), the configuration of the filters always affects both data. If the HPF is enabled for filtering the output data, it is also active for filtering the sensor data used for interrupt generation if the LPF2 is enabled for interrupt generation. The other way around, the HPF is also active for filtering the output data when it is enabled for interrupt generation and when the LPF2 is enabled for the output data.

High pass filter mode

The high pass filter (HPF) can be used in different modes.

Driver symbol	HPF mode
L3GXXXX_HPF_NORMAL	Normal mode
L3GXXXX_HPF_REFERENCE	Reference mode
L3GXXXX_HPF_AUTORESET	Auto-reset on interrupt

In normal mode, the HPF can be reset by reading the REFERENCE register, which instantly deletes the DC component of the angular rate. In reference mode, output data are the difference of raw sensor data and the contents of the REFERENCE register. In autoreset mode, HPF is automatically reset when a configured event interrupt occurs.

The default HPF mode is L3GXXXX_HPF_NORMAL and is defined by the default configuration parameter CONFIG_L3GXXXX_HPF_MODE. If module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_config_hpf.

Output data rates and filter cutoff frequencies

The cutoff frequencies of LPF1 and LPF2 are determined by used output data rate l3gxxxx_odr_t. The following output data rates (ODR) and the LPF1/LPF2 cutoff frequencies are defined (Reference: Application Note AN4506):

Mode	ODR [Hz]	LPF1 cutoff [Hz]	LPF2 cutoff [Hz]	Driver symbol
Normal	100	32	12.5	L3GXXXX_ODR_100_12
Normal	100	32	25	L3GXXXX_ODR_100_25
Normal	200	63.3	12.5	L3GXXXX_ODR_200_12
Normal	200	63.3	25	L3GXXXX_ODR_200_25
Normal	200	63.3	50	L3GXXXX_ODR_200_50
Normal	200	63.3	70	L3GXXXX_ODR_200_70
Normal	400	128	20	L3GXXXX_ODR_400_20
Normal	400	128	25	L3GXXXX_ODR_400_25
Normal	400	128	50	L3GXXXX_ODR_400_50
Normal	400	128	110	L3GXXXX_ODR_400_110
Normal	800	211	30	L3GXXXX_ODR_800_30
Normal	800	211	35	L3GXXXX_ODR_800_35
Normal	800	211	30	L3GXXXX_ODR_800_30
Normal	800	211	100	L3GXXXX_ODR_800_100
Low ODR	12.5	3.9	-	L3GXXXX_ODR_12
Low ODR	25	7.8	-	L3GXXXX_ODR_25
Low ODR	50	16	16.6	L3GXXXX_ODR_50

Note

Low ODRs are only available on L3GD20H and if module l3gxxxx_low_odr is used.

The default output data rate (ODR) is L3GXXXX_ODR_100_12 and defined by the default configuration parameter CONFIG_L3GXXXX_ODR. If module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_set_mode, for example:

l3gxxxx_set_mode(&dev, L3GXXXX_ODR_400_20, true, true, false);

The cutoff frequencies of the HPF depend on the selected output data rate (ODR) and are specified by an index from 0 to 9, as shown in the following table. All frequencies are given in Hz.

ODR [Hz]	12.5	25	50	100	200	400	800
0	1	2	4	8	15	30	56
1	0.5	1	2	4	8	15	30
2	0.2	0.5	1	2	4	8	15
3	0.1	0.2	0.5	1	2	4	8
4	0.05	0.1	0.2	0.5	1	2	4
5	0.02	0.05	0.1	0.2	0.5	1	2
6	0.01	0.02	0.05	0.1	0.2	0.5	1
7	0.005	0.01	0.02	0.05	0.1	0.2	0.5
8	0.002	0.005	0.01	0.02	0.05	0.1	0.2
9	0.001	0.002	0.005	0.01	0.02	0.05	0.1

The default cutoff frequency of HPF is 8 Hz (index 0) and set by the default configuration parameter CONFIG_L3GXXXX_HPF_CUTOFF. If module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_config_hpf, for example:

l3gxxxx_config_hpf(&dev, L3GXXXX_HPF_NORMAL, 0);

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Using the driver

Initialization

The easiest way to use the driver is simply to initialize the sensor with function l3gxxxx_init using the default configuration parameter set l3gxxxx_params as defined in file l3gxxxx_params.h.

static l3gxxxx_t dev;
 
if (l3gxxxx_init(&dev, &l3gxxxx_params[0]) != L3DG20H_OK) {
    ... // error handling
}

After this initialization, the sensor is fully operational and data can be fetched either by polling or interrupt driven.

Note

Function l3gxxxx_init resets the sensor completely. All registers are reset to default values and the embedded FIFO is cleared.

The default configuration parameter set defines

• the communication interface,
• the output data rate (ODR) including LPF1/LPF2 cutoff frequencies,
• the filter combination and HPF cutoff frequency,
• the sensitivity level selected by full scale,
• the FIFO parameters if module l3gxxxx_fifo is used,
• the data interrupt (INT2/DRDY) pin if module l3gxxxx_irq_data is used, and
• the event interrupt (INT1) configuration if module l3gxxxx_irq_event is used.

Most of these configuration parameters can also be changed at runtime by respective functions if the module l3gxxxx_config is used or by overriding default configuration parameters. Detailed information about the default configuration can be found in section Configuration.

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Output data format

In normal mode, the sensor determines periodically the angular rate for all axes that are enabled for measurement and produces raw output data with the selected output data rate (ODR).

These raw output data are 16-bit signed integer values in two’s complement representation. Their range and their resolution depend on the sensitivity of the sensor which is selected by the full scale value. L3Gxxxx sensors allow to select the following full scales:

Full Scale	Sensitivity	Driver symbol	Remark
±245 dps	8.75 mdps	L3GXXXX_SCALE_245_DPS
±500 dps	17.50 mdps	L3GXXXX_SCALE_500_DPS	not available on A3G4250D
±2000 dps	70.00 mdps	L3GXXXX_SCALE_2000_DPS	not available on A3G4250D

Note

On the A34250D, only 245 dps (L3GXXXX_SCALE_245_DPS) is available as full scale value.

The default full scale value is ±245 dps which is defined by the default configuration parameter CONFIG_L3GXXXX_SCALE. If module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_set_scale, for example:

l3gxxxx_set_scale(&dev, L3GXXXX_SCALE_500_DPS);

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Fetching data

To get the information whether new data are available, the user task can either use

• the function l3gxxxx_data_ready to check periodically whether new output data are available, or
• the data ready interrupt (INT2/DRDY) which is triggered as soon as new output data are available (see below).

Last measurement results can then be fetched either

• as 16 bit raw output data of type l3gxxxx_raw_data_t using function l3gxxxx_read_raw or
• as 32 bit integer angular rates type l3gxxxx_data_t in millidegrees per second (mdps) using function l3gxxxx_read.

It is recommended to use function l3gxxxx_read since the driver already converts raw output data to angular rates according to the selected full scale value.

while (1)
{
    l3gxxxx_data_t data;
 
    // execute task every 20 ms
    xtimer_usleep(20 * US_PER_MS);
    ...
    // test for new data and fetch them if available
    if ((l3gxxxx_data_ready(&dev) > 0) &&
        (l3gxxxx_read(&dev, &data) == L3GXXXX_OK)) {
        // do something with data
        ...
    }
}

Note

The functions l3gxxxx_read and l3gxxxx_read_raw always return the last available results. If these functions are called more often than measurements are performed, some measurement results are retrieved multiple times. If these functions are called too rarely, some measurement results will be lost.

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Using the FIFO

In order to limit the rate at which the host processor has to fetch the data, L3Gxxxx sensors embed a FIFO buffer. This is in particular helpful at high output data rates. The FIFO buffer can work in seven different modes and is able to store up to 32 data samples. Please refer the datasheet or application note for more details.

Driver symbol	FIFO mode	Remark
L3GXXXX_BYPASS	Bypass mode	FIFO is not used
L3GXXXX_FIFO	FIFO mode
L3GXXXX_STREAM	Stream mode
L3GXXXX_STREAM_TO_FIFO	Stream-to-FIFO mode	L3GD20H and L3GD20 only
L3GXXXX_BYPASS_TO_STREAM	Bypass-to-Stream mode	L3GD20H and L3GD20 only
L3GXXXX_DYNAMIC_STREAM	Dynamic Stream mode	L3GD20H only
L3GXXXX_BYPASS_TO_FIFO	Bypass to FIFO mode	L3GD20H only

A watermark level (threshold) can be set for the FIFO. If the number of data samples in the FIFO exceeds this value, the watermark flag is set and the interrupt L3GXXXX_INT_FIFO_WATERMARK is triggered, if enabled. This interrupt can be used to gather a minimum number of samples of raw output data before the data are fetched as a single read operation from the sensor.

Configuration of the FIFO

The default FIFO mode is defined by the default configuration parameter CONFIG_L3GXXXX_FIFO_MODE. The default watermark level (threshold) of the FIFO is defined by the default configuration parameter CONFIG_L3GXXXX_FIFO_WATERMARK.

If module l3gxxxx_config is used, both configuration parameters can be changed at runtime with function l3gxxxx_set_fifo_mode. This function takes two parameters, the FIFO mode and the watermark level.

...
// set the FIFO mode with a watermark level (threshold) of 10, i.e. the
// watermark flag is set or the interrupt is triggered for the 11th sample
l3gxxxx_set_fifo_mode(&dev, L3GXXXX_STREAM, 10);
...

Note

To clear the FIFO at any time, set the FIFO mode to L3GXXXX_BYPASS and back to the desired FIFO mode.

l3gxxxx_set_fifo_mode(&dev, L3GXXXX_BYPASS, 0);
l3gxxxx_set_fifo_mode(&dev, L3GXXXX_STREAM, 10);

Reading data from FIFO

To read data from the FIFO, just use either

• function l3gxxxx_read_raw_fifo to get all raw output data stored in the FIFO or
• function l3gxxxx_read_fifo to get all data stored in the FIFO and converted to angular rates in mdps (millidegrees per second).

Both functions clear the FIFO and return the number of samples read from the FIFO.

l3gxxxx_data_fifo_t  data;
 
while (1)
{
    // execute task every 500 ms
    xtimer_usleep(500 * US_PER_MS);
    ...
    // test for new data
    if (l3gxxxx_data_ready(&dev) > 0) {
 
        // fetch data from fifo
        int num = l3gxxxx_read_fifo(dev, data);
 
        for (int i = 0; i < num; i++) {
           // do something with data[i] ...
        }
}

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Using Interrupts

L3Gxxxx sensors allow to activate interrupts on two different signals:

• for data (data ready and FIFO status) on signal INT2/DRDY, and
• for events (axis movement and wake-up) on signal INT1.

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Data interrupts (data ready and FIFO status) on signal INT2/DRDY

Interrupts on signal INT2/DRDY can be generated by the following sources:

Interrupt source	Driver symbol
Output data are ready to be read	L3GXXXX_INT_DATA_READY
FIFO content exceeds the watermark level	L3GXXXX_INT_FIFO_WATERMARK
FIFO is completely filled	L3GXXXX_INT_FIFO_OVERRUN
FIFO becomes empty	L3GXXXX_INT_FIFO_EMPTY

L3GXXXX_INT_DATA is the bitwise OR combination of these symbols.

Note

Using data interrupts requires to enable module l3gxxxx_irq_data.

Each interrupt source can be enabled or disabled separately with function l3gxxxx_enable_int.

l3gxxxx_enable_int(&dev, L3GXXXX_INT_DATA_READY, true);

If l3gxxxx_fifo is used, L3GXXXX_INT_FIFO_WATERMARK and L3GXXXX_INT_FIFO_OVERRUN interrupts are enabled by default. Otherwise only L3GXXXX_INT_DATA_READY is enabled by default.

The MCU GPIO pin used for the INT2/DRDY interrupt signal has to be defined by the hardware configuration parameter L3GXXXX_INT2_PIN.

Once a data interrupt is enabled, function l3gxxxx_wait_int can be used to wait for an interrupt on signal INT2/DRDY. This function returns a structure with the interrupt sources of type l3gxxxx_int_src_t which contains a flag for each possible data interrupt source in member l3gxxxx_int_src_t::data that can be tested for true.

l3gxxxx_int_src_t int_src = l3gxxxx_wait_int(&dev);
 
if (int_src.data.data_ready) {
    l3gxxxx_read(&dev, &data)
    ...
}

If module l3gxxxx_fifo is used, the corresponding interrupt sources can be tested.

l3gxxxx_int_src_t int_src = l3gxxxx_wait_int(&dev);
 
...
if (int_src.data.fifo_threshold) {
    l3gxxxx_read(&dev, &data);
    ...
}
if (int_src.data.fifo_overrun) {
    printf("FIFO overrun");
}

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Event interrupts (axes movement and wake-up) on signal INT1

This interrupt signal allows to recognize independent rotations of the X, Y and Z axes. For this purpose, a separate threshold can be defined for each axis. If activated, the angular rate of each axis is compared with its threshold to check whether it is below or above the threshold. The results of all activated comparisons are combined OR or AND to generate the interrupt signal.

The configuration of the thresholds, the activated comparisons and selected AND/OR combination allows to recognize special situations like selective axis movement (SA) or axes movement wake-up (WU).

• Selective axis movement recognition (SA) means that only one axis is rotating. This is the case if the angular rate of selected axis is above its threshold AND angular rates of all other axes are below their thresholds.
• Axis movement wake-up (WU) means that the angular rate of any axis is above its threshold (OR).

Note

Using event interrupts requires to enable module l3gxxxx_irq_event.

The MCU GPIO pin used for the INT1 interrupt signal is defined by the hardware configuration parameter L3GXXXX_INT1_PIN.

The default configuration for event interrupts is defined by L3GXXXX_INT1_PARAMS. This configuration can be changed either by overriding default configuration parameters CONFIG_L3GXXXX_INT1_X_THRESH, CONFIG_L3GXXXX_INT1_Y_THRESH, CONFIG_L3GXXXX_INT1_Z_THRESH, CONFIG_L3GXXXX_INT1_X_LT_THRESH, CONFIG_L3GXXXX_INT1_X_GT_THRESH, CONFIG_L3GXXXX_INT1_Y_LT_THRESH, CONFIG_L3GXXXX_INT1_Y_GT_THRESH, CONFIG_L3GXXXX_INT1_Z_LT_THRESH, CONFIG_L3GXXXX_INT1_Z_GT_THRESH, CONFIG_L3GXXXX_INT1_FILTER, CONFIG_L3GXXXX_INT1_AND and CONFIG_L3GXXXX_INT1_LATCH or at runtime using function l3gxxxx_set_int_event_cfg with a set of parameters of type l3gxxxx_int_event_cfg_t that contains the configuration. For example, selective axis movement recognition (SA) for the z-axis could be configured as following. With this configuration, the event interrupt is only triggered if all conditions are met.

l3gxxxx_int_event_cfg_t int_cfg;
 
// thresholds
int_cfg.x_threshold = 100;
int_cfg.y_threshold = 100;
int_cfg.z_threshold = 1000;
 
// X axis below threshold enabled
int_cfg.x_low_enabled  = true;
int_cfg.x_high_enabled = false;
 
// Y axis below threshold enabled
int_cfg.y_low_enabled  = true;
int_cfg.y_high_enabled = false;
 
// Z axis below threshold enabled
int_cfg.z_low_enabled  = false;
int_cfg.z_high_enabled = true;
 
// AND combination of all conditions
int_cfg.and_or = true;
 
// further parameters
int_cfg.filter = L3GXXXX_HPF_ONLY;
int_cfg.latch = true;
int_cfg.duration = 0;
int_cfg.wait = false;
 
// set the configuration and enable the interrupt
l3gxxxx_set_int_event_cfg(&dev, &int_cfg);
l3gxxxx_enable_int(&dev, L3GXXXX_INT_EVENT, true);

The data structure l3gxxxx_int_event_cfg_t defines

• whether the interrupt signal should be latched until the interrupt source is read by function l3gxxxx_wait_int,
• which filters are applied to the data used for interrupt generation,
• which time measured in 1/ODR an interrupt condition has to be given before the interrupt is generated, and
• whether this time is also used when interrupt condition is no longer given before interrupt signal is reset.

Note

• If the interrupt is configured to be latched, the interrupt signal is active until the interrupt source is read by function l3gxxxx_wait_int AND next raw output data are available. Otherwise the interrupt signal is active as long as the interrupt condition is satisfied.
• The driver function l3gxxxx_wait_int uses the leading flank of the interrupt signal to detect an interrupt and read the interrupt source.

Function l3gxxxx_enable_int is used to enable or disable the event interrupt generation (L3GXXXX_INT_EVENT).

As with data interrupts function l3gxxxx_wait_int can be used to wait for an interrupt on signal INT1 if event interrupts are enabled. This function returns a structure with the interrupt sources of type l3gxxxx_int_src_t which contains a flag for each possible event interrupt source in member l3gxxxx_int_src_t::event that can be tested for true.

l3gxxxx_int_src_t int_src = l3gxxxx_wait_int(&dev);
 
if (int_src.event.x_low) {
    printf("x below ");
}
if (int_src.event.x_high) {
    printf("x above ");
}
...

Activating all threshold comparisons and using the OR combination is the most flexible way to realize functions like selective axis movement by combining the different interrupt sources as required by the application.

l3gxxxx_int_event_cfg_t int_cfg;
 
// thresholds
int_cfg.x_threshold = 100;
int_cfg.y_threshold = 100;
int_cfg.z_threshold = 100;
 
// X axis below and above threshold enabled
int_cfg.x_low_enabled  = true;
int_cfg.x_high_enabled = true;
 
// Y axis below and above threshold enabled
int_cfg.y_low_enabled  = true;
int_cfg.y_high_enabled = true;
 
// Z axis below and above threshold enabled
int_cfg.z_low_enabled  = true;
int_cfg.z_high_enabled = true;
 
// OR combination of all conditions
int_cfg.and_or = false;
...
// set the configuration and enable the interrupt
l3gxxxx_set_int_event_cfg(&dev, &int_cfg);
l3gxxxx_enable_int(&dev, l3gxxxx_int_event, true);

Following example shows the selective axis movement recognition (SA) for the Z-axis.

l3gxxxx_int_src_t int_src = l3gxxxx_wait_int(&dev);
 
if (int_src.event.y_low && int_src.event.y_low && int_src.event.z_high) {
    // selective axis movement of Z-axis
    ...
}

Interrupt context problem

All functions of the driver require direct access to the sensor via I2C or SPI which does not work in interrupt context.

Therefore, the driver prevents the direct use of the interrupts and application specific ISRs. The only way to use interrupts is to call the function l3gxxxx_wait_int which enables the interrupt signals for the configured MCU GPIO pins and then blocks the calling thread until an interrupt is triggered.

Once an interrupt is triggered, the driver handles the interrupt with an internal ISR and then returns from the l3gxxxx_wait_int function. The return value is a structure with the interrupt sources of type l3gxxxx_int_src_t, which contains a flag for each possible interrupt source that can be tested for true.

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Interrupt signal properties

By default, interrupt signals are high active push/pull outputs.

Power Saving

L3Gxxxx sensors offer two modes for power saving:

• Power-down mode
• Sleep mode

While in power-down mode almost all internal blocks of the device including the gyros are switched off, in sleep mode only the measuring functions for all three axes are deactivated. Therefore, the time to continue measurements after sleep mode is drastically shorter than after power down.

Starting mode	Target mode	Turn-on time typical
Power-down	Normal	100 ms
Power-down	Sleep	100 ms
Sleep	Normal	1/ODR when LPF2 disabled 6/ODR when LPF2 enabled

L3Gxxxx sensors can be powered down when no measurements are required using the function l3gxxxx_power_down. The power consumption is reduced to some uA in power-down mode. To restart the L3Gxxxx in previous measurement mode, the l3gxxxx_power_up function can be used.

If module l3gxxxx_sleep is enabled, the sleep mode can be activated with function l3gxxxx_sleep. The power consumption is then reduced from 4.8 mA to 2.4 mA and thus to half. The l3gxxxx_wake_up function continues the measurement in previous operation mode.

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Low level functions

L3Gxxxx sensors are complex and flexible sensors with a lot of features. It can be used for a big number of different use cases. Since it is impossible to implement a high level interface which is generic enough to cover all the functionality of the sensor for all different use cases, there are two low level interface functions that allow direct read and write access to the registers of the sensor.

bool l3gxxxx_reg_read(l3gxxxx_sensor_t* dev, uint8_t reg, uint8_t *data, uint16_t len);
bool l3gxxxx_reg_write(l3gxxxx_sensor_t* dev, uint8_t reg, uint8_t *data, uint16_t len);

Warning

These functions should only be used to do something special that is not covered by the high level interface AND if you exactly know what you do and what it might affect. Please be aware that it might affect the high level interface.

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Default configuration

Default sensor hardware configurations are set in file l3gxxxx_params.h using the following defines:

Hardware configuration	Driver name	Default Value
I2C device	L3GXXXX_I2C_DEV	I2C_DEV(0)
I2C address	L3GXXXX_I2C_ADDR	L3GXXXX_I2C_ADDR_2
SPI device	L3GXXXX_SPI_DEV	SPI_DEV(0)
SPI clock frequency	L3GXXXX_SPI_CLK	SPI_CLK_1MHZ
SPI CS signal	L3GXXXX_SPI_CS	GPIO_PIN(0, 0)
INT1 MCU pin	L3GXXXX_INT1_PIN	GPIO_PIN(0, 1)
INT2/DRDY MCU pin	L3GXXXX_INT2_PIN	GPIO_PIN(0, 2)

These hardware configurations can be overridden either by the board definition or by defining them in the CFLAGS variable in the make command, for example:

DRIVER=l3gd20h USEMODULE='l3gxxxx_irq_data` \
CLFAGS='-DL3GXXXX_INT2_PIN=GPIO_PIN\‍(0, 5\‍)' \
BOARD=... make -C tests/drivers/l3gxxxx

The default configuration of the sensor is defined in file l3gxxxx_params.h using the following defines:

Configuration parameter	Driver name	Default Value
ODR and LPF2 cutoff frequency	CONFIG_L3GXXXX_ODR	L3GXXXX_ODR_100_25
Full scale	CONFIG_L3GXXXX_SCALE	L3GXXXX_SCALE_245_DPS
Filter selection used for output data	CONFIG_L3GXXXX_FILTER_SEL	L3GXXXX_HPF_AND_LPF2
HPF mode used for output data	CONFIG_L3GXXXX_HPF_MODE	L3GXXXX_HPF_NORMAL
HPF cutoff frequency 8 Hz	CONFIG_L3GXXXX_HPF_CUTOFF	0
FIFO mode if FIFO is used	CONFIG_L3GXXXX_FIFO_MODE	L3GXXXX_FIFO
FIFO threshold value if FIFO is used	CONFIG_L3GXXXX_FIFO_WATERMARK	23
INT1 threshold for X axis (~30 dps)	CONFIG_L3GXXXX_INT1_X_THRESH	4012
INT1 threshold for Y axis (~30 dps)	CONFIG_L3GXXXX_INT1_Y_THRESH	4012
INT1 threshold for Z axis (~30 dps)	CONFIG_L3GXXXX_INT1_Z_THRESH	4012
INT1 interrupt enable for X > X threshold	CONFIG_L3GXXXX_INT1_X_GT_THRESH	true
INT1 interrupt enable for Y > Y threshold	CONFIG_L3GXXXX_INT1_Y_GT_THRESH	true
INT1 interrupt enable for Z > Z threshold	CONFIG_L3GXXXX_INT1_Z_GT_THRESH	true
INT1 interrupt enable for X < X threshold	CONFIG_L3GXXXX_INT1_X_LT_THRESH	false
INT1 interrupt enable for Y < Y threshold	CONFIG_L3GXXXX_INT1_Y_LT_THRESH	false
INT1 interrupt enable for Z < Z threshold	CONFIG_L3GXXXX_INT1_Z_LT_THRESH	false
INT1 filter selection	CONFIG_L3GXXXX_INT1_FILTER	L3GXXXX_HPF_AND_LPF2
INT1 interrupt combination	CONFIG_L3GXXXX_INT1_AND	false
INT1 interrupt latch enabled	CONFIG_L3GXXXX_INT1_LATCH	true

Single or all parameters of the default configuration can be overridden either by defining them in the variable CFLAGS in the make command line or by placing a modified file l3gxxxx_params.h in the application directory, for example:

DRIVER=l3gd20h USEMODULE='l3gxxxx_low_odr l3gxxxx_irq_data` \
CLFAGS='-DCONFIG_L3GXXXX_ODR=L3GXXXX_ODR_12 -DL3GXXXX_INT2_PIN=GPIO_PIN\‍(0,5\‍)' \
BOARD=... make -C tests/drivers/l3gxxxx

Author

Gunar Schorcht gunar.nosp@m.@sch.nosp@m.orcht.nosp@m..net

Files
file	l3gxxxx.h
	Device Driver for ST L3Gxxxx 3-axis gyroscope sensor family.
file	l3gxxxx_params.h
	Default configuration for ST L3Gxxxx 3-axis gyroscope sensor family.
file	l3gxxxx_regs.h
	Register definitions for ST L3Gxxxx 3-axis gyroscope sensor family.

Data Structures
struct	l3gxxxx_int_event_cfg_t
	Event interrupt generator configuration (axis movement and wake-up) More...
union	l3gxxxx_int_event_src_t
	Event interrupt sources (axis movement and wake-up) More...
union	l3gxxxx_int_data_src_t
	Data interrupt sources (data ready and FIFO status) More...
struct	l3gxxxx_int_src_t
	Composite type for all possible interrupt sources. More...
struct	l3gxxxx_raw_data_t
	Raw output data set as two's complements. More...
struct	l3gxxxx_data_t
	Angular rates in millidegrees per seconds (mdps) More...
struct	l3gxxxx_i2c_params_t
	L3Gxxxx I2C interface parameters. More...
struct	l3gxxxx_spi_params_t
	L3Gxxxx SPI interface parameters. More...
struct	l3gxxxx_if_params_t
	L3Gxxxx Hardware interface parameters union. More...
struct	l3gxxxx_params_t
	L3Gxxxx device initialization parameters. More...
struct	l3gxxxx_t
	L3Gxxxx sensor device data structure type. More...

Macros
#define	L3GXXXX_INT_DATA
	Data interrupts (Data ready and FIFO status)

Typedefs
typedef l3gxxxx_raw_data_t	l3gxxxx_raw_data_fifo_t[32]
	Raw output data FIFO type.
typedef l3gxxxx_data_t	l3gxxxx_data_fifo_t[32]
	Angular rates FIFO type.

Enumerations
enum	l3gxxxx_error_codes_t {   L3GXXXX_OK , L3GXXXX_ERROR_I2C , L3GXXXX_ERROR_SPI , L3GXXXX_ERROR_WRONG_CHIP_ID ,   L3GXXXX_ERROR_INV_DEV , L3GXXXX_ERROR_INV_MODE , L3GXXXX_ERROR_INV_FIFO_MODE , L3GXXXX_ERROR_INV_INT_TYPE ,   L3GXXXX_ERROR_NO_NEW_DATA , L3GXXXX_ERROR_RAW_DATA , L3GXXXX_ERROR_RAW_DATA_FIFO , L3GXXXX_ERROR_NO_INT1_PIN ,   L3GXXXX_ERROR_NO_INT2_PIN , L3GXXXX_ERROR_BYPASS_MODE , L3GXXXX_ERROR_FIFO_MODE }
	Definition of error codes. More...
enum	l3gxxxx_odr_t {   L3GXXXX_ODR_100_12 = 0x00 , L3GXXXX_ODR_100_25 = 0x01 , L3GXXXX_ODR_200_12 = 0x04 , L3GXXXX_ODR_200_25 = 0x05 ,   L3GXXXX_ODR_200_50 = 0x06 , L3GXXXX_ODR_200_70 = 0x07 , L3GXXXX_ODR_400_20 = 0x08 , L3GXXXX_ODR_400_25 = 0x09 ,   L3GXXXX_ODR_400_50 = 0x0a , L3GXXXX_ODR_400_110 = 0x0b , L3GXXXX_ODR_800_30 = 0x0c , L3GXXXX_ODR_800_35 = 0x0d ,   L3GXXXX_ODR_800_50 = 0x0e , L3GXXXX_ODR_800_100 = 0x0f , L3GXXXX_ODR_12 = 0x10 , L3GXXXX_ODR_25 = 0x14 ,   L3GXXXX_ODR_50 = 0x18 }
	Sensor output data rates (ODR) and LPF2 cutoff frequencies. More...
enum	l3gxxxx_scale_t { L3GXXXX_SCALE_245_DPS = 0 , L3GXXXX_SCALE_500_DPS = 1 , L3GXXXX_SCALE_2000_DPS = 2 }
	Full scale in degrees per second (dps) More...
enum	l3gxxxx_fifo_mode_t {   L3GXXXX_BYPASS = 0 , L3GXXXX_FIFO = 1 , L3GXXXX_STREAM = 2 , L3GXXXX_STREAM_TO_FIFO = 3 ,   L3GXXXX_BYPASS_TO_STREAM = 4 , L3GXXXX_DYNAMIC_STREAM = 6 , L3GXXXX_BYPASS_TO_FIFO = 7 }
	FIFO mode. More...
enum	l3gxxxx_filter_sel_t { L3GXXXX_NO_FILTER = 0 , L3GXXXX_HPF_ONLY = 1 , L3GXXXX_LPF2_ONLY = 2 , L3GXXXX_HPF_AND_LPF2 = 3 }
	High pass filter (HPF) and low pass filter 2 (LPF2) selection. More...
enum	l3gxxxx_hpf_mode_t { L3GXXXX_HPF_NORMAL = 0 , L3GXXXX_HPF_REFERENCE = 1 , L3GXXXX_HPF_AUTORESET = 3 }
	HPF (high pass filter) modes. More...
enum	l3gxxxx_int_types_t {   L3GXXXX_INT_DATA_READY = L3GXXXX_INT2_DRDY , L3GXXXX_INT_FIFO_WATERMARK = L3GXXXX_INT2_WTM , L3GXXXX_INT_FIFO_OVERRUN = L3GXXXX_INT2_ORUN , L3GXXXX_INT_FIFO_EMPTY = L3GXXXX_INT2_EMPTY ,   L3GXXXX_INT_EVENT = L3GXXXX_INT1_IG }
	Interrupt types. More...
enum	l3gxxxx_int_pin_level_t { L3GXXXX_HIGH = 0 , L3GXXXX_LOW }
	INT1, INT2/DRDY sensor signal activity level More...
enum	l3gxxxx_int_pin_type_t { L3GXXXX_PUSH_PULL = 0 , L3GXXXX_OPEN_DRAIN }
	INT1, INT2/DRDY sensor signal type More...
enum	l3gxxxx_if_t { L3GXXXX_I2C , L3GXXXX_SPI }
	L3Gxxxx interface types. More...

Sensor initialization and configuration
int	l3gxxxx_init (l3gxxxx_t *dev, const l3gxxxx_params_t *params)
	Initialize the L3Gxxxx sensor device.
int	l3gxxxx_set_mode (l3gxxxx_t *dev, l3gxxxx_odr_t odr, bool x, bool y, bool z)
	Set sensor mode.
int	l3gxxxx_set_scale (l3gxxxx_t *dev, l3gxxxx_scale_t scale)
	Set full scale.

Power saving functions
int	l3gxxxx_power_down (l3gxxxx_t *dev)
	Power down the sensor.
int	l3gxxxx_power_up (l3gxxxx_t *dev)
	Power up the sensor.
int	l3gxxxx_sleep (l3gxxxx_t *dev)
	Sleep mode.
int	l3gxxxx_wake_up (l3gxxxx_t *dev)
	Wake-up the sensor.

Basic sensor data handling
int	l3gxxxx_data_ready (const l3gxxxx_t *dev)
	Data ready status function.
int	l3gxxxx_read (const l3gxxxx_t *dev, l3gxxxx_data_t *data)
	Read last sample of angular rates in millidegree per second (mpds)
int	l3gxxxx_read_raw (const l3gxxxx_t *dev, l3gxxxx_raw_data_t *raw)
	Read last sample of raw output data as 16 bit two's complements.

FIFO handling
int	l3gxxxx_set_fifo_mode (l3gxxxx_t *dev, l3gxxxx_fifo_mode_t mode, uint8_t watermark)
	Set FIFO mode and watermark level (threshold)
int	l3gxxxx_read_fifo (const l3gxxxx_t *dev, l3gxxxx_data_fifo_t data)
	Get all samples of angular rates stored in the FIFO (unit mdps)
int	l3gxxxx_read_raw_fifo (const l3gxxxx_t *dev, l3gxxxx_raw_data_fifo_t raw)
	Get all samples of raw output data stored in the FIFO.

Filter configuration and handling
int	l3gxxxx_select_output_filter (l3gxxxx_t *dev, l3gxxxx_filter_sel_t filter)
	Filter selection for raw output data.
int	l3gxxxx_config_hpf (const l3gxxxx_t *dev, l3gxxxx_hpf_mode_t mode, uint8_t cutoff)
	Config HPF (high pass filter) for output data.
int	l3gxxxx_set_hpf_ref (const l3gxxxx_t *dev, int8_t ref)
	Set HPF (high pass filter) reference.
int	l3gxxxx_get_hpf_ref (const l3gxxxx_t *dev, int8_t *ref)
	Get HPF (high pass filter) reference.

Interrupt configuration and handling
int	l3gxxxx_enable_int (const l3gxxxx_t *dev, l3gxxxx_int_types_t mask, bool enable)
	Enable or disable event and/or data interrupts on signal INT1 and INT2/DRDY
l3gxxxx_int_src_t	l3gxxxx_wait_int (l3gxxxx_t *dev)
	Wait for event and/or data interrupts on signals INT1 and INT2/DRDY
int	l3gxxxx_set_int_event_cfg (const l3gxxxx_t *dev, const l3gxxxx_int_event_cfg_t *cfg)
	Set new configuration for event interrupt generation.
int	l3gxxxx_get_int_event_cfg (const l3gxxxx_t *dev, l3gxxxx_int_event_cfg_t *cfg)
	Get current configuration of event interrupt generation.

Low level interface functions
int	l3gxxxx_reg_write (const l3gxxxx_t *dev, uint8_t reg, const uint8_t *data, uint8_t len)
	Direct write to register.
int	l3gxxxx_reg_read (const l3gxxxx_t *dev, uint8_t reg, uint8_t *data, uint8_t len)
	Direct read from register.

L3Gxxxx addresses
#define	L3GXXXX_I2C_ADDR_1   (0x68)
	SDO pin is low.
#define	L3GXXXX_I2C_ADDR_2   (0x69)
	SDO pin is high.

L3Gxxxx chip ids
#define	L3GXXXX_CHIP_ID_L3GD20H   (0xd7)
	Chip ID for L3GD20H.
#define	L3GXXXX_CHIP_ID_L3GD20   (0xd4)
	Chip ID for L3GD20.
#define	L3GXXXX_CHIP_ID_X3G42XXD   (0xd3)
	Chip ID for L3G4200D, I3G4250D, A3G4250D.

Macro Definition Documentation

L3GXXXX_CHIP_ID_L3GD20

#define L3GXXXX_CHIP_ID_L3GD20   (0xd4)

Chip ID for L3GD20.

Definition at line 1003 of file l3gxxxx.h.

L3GXXXX_CHIP_ID_L3GD20H

#define L3GXXXX_CHIP_ID_L3GD20H   (0xd7)

Chip ID for L3GD20H.

Definition at line 1002 of file l3gxxxx.h.

L3GXXXX_CHIP_ID_X3G42XXD

#define L3GXXXX_CHIP_ID_X3G42XXD   (0xd3)

Chip ID for L3G4200D, I3G4250D, A3G4250D.

Definition at line 1004 of file l3gxxxx.h.

L3GXXXX_I2C_ADDR_1

#define L3GXXXX_I2C_ADDR_1   (0x68)

SDO pin is low.

Definition at line 993 of file l3gxxxx.h.

L3GXXXX_I2C_ADDR_2

#define L3GXXXX_I2C_ADDR_2   (0x69)

SDO pin is high.

Definition at line 994 of file l3gxxxx.h.

L3GXXXX_INT_DATA

#define L3GXXXX_INT_DATA

Value:

                          (L3GXXXX_INT_DATA_READY | \
                          L3GXXXX_INT_FIFO_WATERMARK | \
                          L3GXXXX_INT_FIFO_OVERRUN | \
                          L3GXXXX_INT_FIFO_EMPTY)

Data interrupts (Data ready and FIFO status)

This define combines the data interrupt types of l3gxxxx_int_types_t that use the INT2/DRDY signal to an ORed value.

Definition at line 1253 of file l3gxxxx.h.

Typedef Documentation

l3gxxxx_data_fifo_t

typedef l3gxxxx_data_t l3gxxxx_data_fifo_t[32]

Angular rates FIFO type.

Definition at line 1380 of file l3gxxxx.h.

l3gxxxx_raw_data_fifo_t

typedef l3gxxxx_raw_data_t l3gxxxx_raw_data_fifo_t[32]

Raw output data FIFO type.

Definition at line 1375 of file l3gxxxx.h.

Enumeration Type Documentation

l3gxxxx_error_codes_t

enum l3gxxxx_error_codes_t

Definition of error codes.

Enumerator
L3GXXXX_OK	success
L3GXXXX_ERROR_I2C	I2C communication error.
L3GXXXX_ERROR_SPI	SPI communication error.
L3GXXXX_ERROR_WRONG_CHIP_ID	wrong chip id read from WHO_AM_I reg
L3GXXXX_ERROR_INV_DEV	invalid device type used
L3GXXXX_ERROR_INV_MODE	sensor mode is invalid or not available
L3GXXXX_ERROR_INV_FIFO_MODE	FIFO mode is invalid or not available.
L3GXXXX_ERROR_INV_INT_TYPE	invalid interrupt type used
L3GXXXX_ERROR_NO_NEW_DATA	no new data are available
L3GXXXX_ERROR_RAW_DATA	reading raw output data failed
L3GXXXX_ERROR_RAW_DATA_FIFO	reading raw output data from FIFO failed
L3GXXXX_ERROR_NO_INT1_PIN	INT1 signal pin not configured
L3GXXXX_ERROR_NO_INT2_PIN	INT2/DRDY signal pin not configured
L3GXXXX_ERROR_BYPASS_MODE	sensor is in bypass mode
L3GXXXX_ERROR_FIFO_MODE	sensor is in FIFO mode

Definition at line 1008 of file l3gxxxx.h.

l3gxxxx_fifo_mode_t

enum l3gxxxx_fifo_mode_t

FIFO mode.

The integrated FIFO with up to 32 data samples can be used in different modes. The mode defines the behavior of FIFO when it becomes full.

Enumerator
L3GXXXX_BYPASS	FIFO is not used (default)
L3GXXXX_FIFO	Data samples are stored in the FIFO until it is full.
L3GXXXX_STREAM	FIFO is used as ring buffer and newest data samples are stored continuously.
L3GXXXX_STREAM_TO_FIFO	FIFO is used in Stream mode until an interrupt, switches then to FIFO mode (L3GD20H and L3GD20 only)
L3GXXXX_BYPASS_TO_STREAM	FIFO is not used until an interrupt, switches then to Stream mode (L3GD20H and L3GD20 only)
L3GXXXX_DYNAMIC_STREAM	like Stream mode, but differs in reading the first data sample after emptying (L3GD20H only)
L3GXXXX_BYPASS_TO_FIFO	FIFO is not used until an interrupt, switches then to FIFO mode (L3GD20H only)

Definition at line 1112 of file l3gxxxx.h.

l3gxxxx_filter_sel_t

enum l3gxxxx_filter_sel_t

High pass filter (HPF) and low pass filter 2 (LPF2) selection.

L3Gxxxx sensors integrate a combination of two low pass filters (LPF) and one high pass filter (HPF).

First, raw sensor data are always filtered by LPF1 with a cutoff frequency that is fixed for the selected output data rate (ODR), see l3gxxxx_odr_t. Resulting data can then optionally be filtered by HPF and/or LPF2. Both filters can be used or bypassed.

                                 +--------------->   L3GXXXX_NO_FILTER
                                 |    +----- +
                    +------------+--->|      |--->   L3GXXXX_LPF2_ONLY
                    |                 | LPF2 |
+-----+   +------+  |   +-----+  +--->|      |--->   L3GXXXX_HPF_AND_LPF2
|     |   |      |  |   |     |  |    +------+
| ADC |-->| LPF1 |--+-->| HPF |--+--------------->   L3GXXXX_HPF_ONLY
|     |   |      |      |     |
+-----+   +------+      +-----+

l3gxxxx_filter_sel_t defines the possible filter combinations that can be used to select the filters for the output data and for the interrupt generation separately.

The default filter selection for the output data is L3GXXXX_HPF_AND_LPF2 and is defined by the default configuration parameter CONFIG_L3GXXXX_FILTER_SEL. If the module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_select_output_filter.

The default filter selection for event interrupt generation is L3GXXXX_HPF_AND_LPF2 and is defined by default configuration parameter CONFIG_L3GXXXX_INT1_FILTER. It can be changed at runtime with function l3gxxxx_set_int_event_cfg.

Note

Since same filters are used for the output data as well as the data used for event interrupt generation (selective axes movement / wake-up), the configuration of the filters always affects both data. If the HPF is enabled for filtering the output data, it is also active for filtering the sensor data used for interrupt generation if the LPF2 is enabled for interrupt generation. The other way around, the HPF is also active for filtering the output data when it is enabled for interrupt generation and when the LPF2 is enabled for the output data.

The cutoff frequencies of LPF1 and LPF2 are determined by the used output data rate l3gxxxx_odr_t, see section [Output Data Rates and Filters] (#l3gxxxx_odr_filters). The default cutoff frequency of HPF is 8 Hz and set by the default configuration parameter CONFIG_L3GXXXX_HPF_CUTOFF. If module l3gxxxx_config is used, it can be changed at runtime using function l3gxxxx_config_hpf.

Enumerator
L3GXXXX_NO_FILTER	HPF not used, LPF2 not used (default)
L3GXXXX_HPF_ONLY	HPF used, LPF2 not used.
L3GXXXX_LPF2_ONLY	HPF not used, LPF2 used.
L3GXXXX_HPF_AND_LPF2	HPF used, LPF2 used.

Definition at line 1189 of file l3gxxxx.h.

l3gxxxx_hpf_mode_t

enum l3gxxxx_hpf_mode_t

HPF (high pass filter) modes.

The high pass filter can be used in different modes.

Enumerator
L3GXXXX_HPF_NORMAL	Normal mode, HPF is reset by reading the REFERENCE register.
L3GXXXX_HPF_REFERENCE	Reference mode, output data are the difference to the REFERENCE register.
L3GXXXX_HPF_AUTORESET	Autoreset mode, HPF is automatically reset when a configured event interrupt occurs.

Definition at line 1201 of file l3gxxxx.h.

l3gxxxx_if_t

enum l3gxxxx_if_t

L3Gxxxx interface types.

Enumerator
L3GXXXX_I2C	I2C interface used.
L3GXXXX_SPI	SPI interface used.

Definition at line 1385 of file l3gxxxx.h.

l3gxxxx_int_pin_level_t

enum l3gxxxx_int_pin_level_t

INT1, INT2/DRDY sensor signal activity level

Enumerator
L3GXXXX_HIGH	INT signals are High active (default)
L3GXXXX_LOW	INT signals are Low active.

Definition at line 1341 of file l3gxxxx.h.

l3gxxxx_int_pin_type_t

enum l3gxxxx_int_pin_type_t

INT1, INT2/DRDY sensor signal type

Enumerator
L3GXXXX_PUSH_PULL	INT pins are push/pull outputs (default)
L3GXXXX_OPEN_DRAIN	INT pins are open-drain.

Definition at line 1349 of file l3gxxxx.h.

l3gxxxx_int_types_t

enum l3gxxxx_int_types_t

Interrupt types.

L3Gxxxx sensors support different types of interrupts. These are on the one hand the various data interrupts on signal INT2/DRDY and on the other hand event interrupts on signal INT1.

The enumeration values correspond to the according bits in register CTRL3 (L3GXXXX_REG_CTRL3).

L3GXXXX_INT_DATA combines the various data interrupts to an ORed value.

Enumerator
L3GXXXX_INT_DATA_READY	Data interrupt on signal INT2/DRDY: Output data are ready to be read.
L3GXXXX_INT_FIFO_WATERMARK	Data interrupt on signal INT2/DRDY: FIFO filling exceeds the watermark level (threshold)
L3GXXXX_INT_FIFO_OVERRUN	Data interrupt on signal INT2/DRDY: FIFO is completely filled.
L3GXXXX_INT_FIFO_EMPTY	Data interrupt on signal INT2/DRDY: FIFO becomes empty.
L3GXXXX_INT_EVENT	Event interrupt on signal INT1: Angular rate of one or more axes is lower or higher than the configured threshold.

Definition at line 1222 of file l3gxxxx.h.

l3gxxxx_odr_t

enum l3gxxxx_odr_t

Sensor output data rates (ODR) and LPF2 cutoff frequencies.

The following output data rates (ODR) and the LPF1/LPF2 cutoff frequencies are defined (Reference: Application Note AN4506):

Mode	ODR [Hz]	LPF1 cutoff [Hz]	LPF2 cutoff [Hz]
High ODR
L3GXXXX_ODR_100_12	100	32	12.5
L3GXXXX_ODR_100_25	100	32	25
L3GXXXX_ODR_200_12	200	63.3	12.5
L3GXXXX_ODR_200_25	200	63.3	25
L3GXXXX_ODR_200_50	200	63.3	50
L3GXXXX_ODR_200_70	200	63.3	70
L3GXXXX_ODR_400_20	400	128	20
L3GXXXX_ODR_400_25	400	128	25
L3GXXXX_ODR_400_50	400	128	50
L3GXXXX_ODR_400_110	400	128	110
L3GXXXX_ODR_800_30	800	211	30
L3GXXXX_ODR_800_35	800	211	35
L3GXXXX_ODR_800_50	800	211	50
L3GXXXX_ODR_800_100	800	211	100
Low ODR (L3GD20H only)
L3GXXXX_ODR_12	12.5	3.9	-
L3GXXXX_ODR_25	25	7.8	-
L3GXXXX_ODR_50	50	16	16.6

Detailed information about the filter chain and possible filter combinations can be found in the section Output data rates and filters.

While LPF1 is always used, LPF2 and HPF have to be explicitly enabled by the configuration parameter l3gxxxx_params_t::filter_sel or the l3gxxxx_select_output_filter function if module l3gxxxx_config is used. L3GXXXX_ODR_100_25 is used by the default configuration.

Note

Low data rates 12.5 Hz, 25 Hz and 50 Hz are only supported by L3GXXXX.

Enumerator
L3GXXXX_ODR_100_12	High ODR 100 Hz, LPF1 cutoff 32 Hz, LPF2 cutoff 12.5 Hz.
L3GXXXX_ODR_100_25	High ODR 100 Hz, LPF1 cutoff 32 Hz, LPF2 cutoff 25 Hz.
L3GXXXX_ODR_200_12	High ODR 200 Hz, LPF1 cutoff 63.3 Hz, LPF2 cutoff 12.5 Hz.
L3GXXXX_ODR_200_25	High ODR 200 Hz, LPF1 cutoff 63.3 Hz, LPF2 cutoff 25 Hz.
L3GXXXX_ODR_200_50	High ODR 200 Hz, LPF1 cutoff 63.3 Hz, LPF2 cutoff 50 Hz.
L3GXXXX_ODR_200_70	High ODR 200 Hz, LPF1 cutoff 63.3 Hz, LPF2 cutoff 70 Hz.
L3GXXXX_ODR_400_20	High ODR 400 Hz, LPF1 cutoff 128 Hz, LPF2 cutoff 20 Hz.
L3GXXXX_ODR_400_25	High ODR 400 Hz, LPF1 cutoff 128 Hz, LPF2 cutoff 25 Hz.
L3GXXXX_ODR_400_50	High ODR 400 Hz, LPF1 cutoff 128 Hz, LPF2 cutoff 50 Hz.
L3GXXXX_ODR_400_110	High ODR 400 Hz, LPF1 cutoff 128 Hz, LPF2 cutoff 110 Hz.
L3GXXXX_ODR_800_30	High ODR 400 Hz, LPF1 cutoff 211 Hz, LPF2 cutoff 30 Hz.
L3GXXXX_ODR_800_35	High ODR 400 Hz, LPF1 cutoff 211 Hz, LPF2 cutoff 35 Hz.
L3GXXXX_ODR_800_50	High ODR 400 Hz, LPF1 cutoff 211 Hz, LPF2 cutoff 50 Hz.
L3GXXXX_ODR_800_100	High ODR 400 Hz, LPF1 cutoff 211 Hz, LPF2 cutoff 100 Hz.
L3GXXXX_ODR_12	Low ODR 12.5 Hz, LPF1 cutoff 3.9 Hz, LPF2 not used.
L3GXXXX_ODR_25	Low ODR 25 Hz, LPF1 cutoff 7.8 Hz, LPF2 not used.
L3GXXXX_ODR_50	Low ODR 50 Hz, LPF1 cutoff 16 Hz, LPF2 cutoff 16.6 Hz.

Definition at line 1068 of file l3gxxxx.h.

l3gxxxx_scale_t

enum l3gxxxx_scale_t

Full scale in degrees per second (dps)

The full scale value determines the sensitivity of the sensor and thus the range and resolution of the sensor's output data. The resolution of the output data is about Full Scale/INT16_MAX.

Note

On the A34250D, only 245 dps (L3GXXXX_SCALE_245_DPS) is available as full scale value.

Enumerator
L3GXXXX_SCALE_245_DPS	245 dps (default)
L3GXXXX_SCALE_500_DPS	500 dps
L3GXXXX_SCALE_2000_DPS	2000 dps

Definition at line 1100 of file l3gxxxx.h.

Function Documentation

l3gxxxx_config_hpf()

int l3gxxxx_config_hpf	(	const l3gxxxx_t *	dev,
		l3gxxxx_hpf_mode_t	mode,
		uint8_t	cutoff
	)

Config HPF (high pass filter) for output data.

The cutoff frequency of the HPF depends on the selected output data rate (ODR). The following table shows the possible values of parameter cutoff and the cutoff frequencies for the according ODRs. All frequencies are given in Hz.

cutoff / ODR	12.5	25	50	100	200	400	800
0	1	2	4	8	15	30	56
1	0.5	1	2	4	8	15	30
2	0.2	0.5	1	2	4	8	15
3	0.1	0.2	0.5	1	2	4	8
4	0.05	0.1	0.2	0.5	1	2	4
5	0.02	0.05	0.1	0.2	0.5	1	2
6	0.01	0.02	0.05	0.1	0.2	0.5	1
7	0.005	0.01	0.02	0.05	0.1	0.2	0.5
8	0.002	0.005	0.01	0.02	0.05	0.1	0.2
9	0.001	0.002	0.005	0.01	0.02	0.05	0.1

Note

This function is available only if module l3gxxxx_config is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	mode	high pass filter mode, see l3gxxxx_hpf_mode_t
[in]	cutoff	cutoff frequency (depends on ODR) [0 ... 9]

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_data_ready()

int l3gxxxx_data_ready

(

const l3gxxxx_t *

dev

)

Data ready status function.

This function returns the number of new data samples that are ready to be read or 0 if no new data samples are available.

If the FIFO is not used or used in bypass mode (L3GXXXX_BYPASS), the maximum number of available data samples is 1. If another FIFO mode is used, the number of available data samples is equal to the number of new data samples in the FIFO.

Parameters

[in]

dev

device descriptor of the L3Gxxxx sensor

Returns

number of data samples available for read or negative error code, see l3gxxxx_error_codes_t

l3gxxxx_enable_int()

int l3gxxxx_enable_int	(	const l3gxxxx_t *	dev,
		l3gxxxx_int_types_t	mask,
		bool	enable
	)

Enable or disable event and/or data interrupts on signal INT1 and INT2/DRDY

This function is used to enable or disable interrupts. The parameter mask is the ORed value of the interrupts that are enabled or disabled by the function call.

Precondition

MCU GPIO pins for the INT1 signal respectively the INT2/DRDY signal have to be defined for enabled interrupts (l3gxxxx_params_t::int1_pin and l3gxxxx_params_t::int2_pin).

Note

This function is available only if module l3gxxxx_irq_data and/or module l3gxxxx_irq_event are used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	mask	interrupts to be enabled or disabled
[in]	enable	enable the interrupts if true, otherwise disable them

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_get_hpf_ref()

int l3gxxxx_get_hpf_ref	(	const l3gxxxx_t *	dev,
		int8_t *	ref
	)

Get HPF (high pass filter) reference.

Returns the content of the REFERENCE register. In normal mode L3GXXXX_HPF_NORMAL, it is also used to reset the HPF.

Note

This function is available only if module l3gxxxx_config is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[out]	ref	reference

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_get_int_event_cfg()

int l3gxxxx_get_int_event_cfg	(	const l3gxxxx_t *	dev,
		l3gxxxx_int_event_cfg_t *	cfg
	)

Get current configuration of event interrupt generation.

This function can be used to retrieve the configuration of interrupt conditions currently used to generate event interrupts. See l3gxxxx_int_event_cfg_t for details.

Note

This function is available only if module l3gxxxx_irq_event and module l3gxxxx_irq_config are used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[out]	cfg	event interrupt generator configuration

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_init()

int l3gxxxx_init	(	l3gxxxx_t *	dev,
		const l3gxxxx_params_t *	params
	)

Initialize the L3Gxxxx sensor device.

This function resets the sensor and initializes it according to the given configuration parameter set. All registers are reset to their default values. The FIFO is cleared.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor to be initialized
[in]	params	L3Gxxxx configuration parameters

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_power_down()

int l3gxxxx_power_down

(

l3gxxxx_t *

dev

)

Power down the sensor.

Changes the sensor operation mode to power-down mode. In this mode almost all internal blocks including the gyros are switched off. I2C and SPI interfaces are still active. The content of the configuration registers is preserved.

Parameters

[in]

dev

Device descriptor of L3Gxxxx device to read from

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_power_up()

int l3gxxxx_power_up

(

l3gxxxx_t *

dev

)

Power up the sensor.

Swichtes the sensor back into the last active operation mode. It takes up to 100 ms since the gyros have to be switched on.

Parameters

[in]

dev

Device descriptor of L3Gxxxx device to read from

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_read()

int l3gxxxx_read	(	const l3gxxxx_t *	dev,
		l3gxxxx_data_t *	data
	)

Read last sample of angular rates in millidegree per second (mpds)

Raw output data are read from the sensor and converted to angular rates in millidegrees per second (mdps). The resolution of the angular rates depends on the configured full scale value as follows:

Full Scale	Resolution	Driver symbol	Remark
±245 dps	8.75 mdps / LSB	L3GXXXX_SCALE_245_DPS
±500 dps	17.50 mdps / LSB	L3GXXXX_SCALE_500_DPS	not available on A3G4250D
±2000 dps	70.00 mdps / LSB	L3GXXXX_SCALE_2000_DPS	not available on A3G4250D

Note

If the FIFO is enabled by module l3gxxxxx_fifo, the function returns only the last sample. To read all samples from the FIFO, function l3gxxxx_read_fifo has to be used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[out]	data	last sample of angular rates in mdps

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_read_fifo()

int l3gxxxx_read_fifo	(	const l3gxxxx_t *	dev,
		l3gxxxx_data_fifo_t	data
	)

Get all samples of angular rates stored in the FIFO (unit mdps)

This function reads all samples of raw output data from the FIFO and converts them to angular rates in millidegrees per second (mdps) according to the configured full scale. For details about the resolution of these angular rates see l3gxxxx_read.

In bypass mode (L3GXXXX_BYPASS), it returns only the last sample.

Note

This function is available only if module l3gxxxx_fifo is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[out]	data	array for up to 32 samples of angular rates in mdps

Returns

number of data samples read on success, or negative error code, see l3gxxxx_error_codes_t

l3gxxxx_read_raw()

int l3gxxxx_read_raw	(	const l3gxxxx_t *	dev,
		l3gxxxx_raw_data_t *	raw
	)

Read last sample of raw output data as 16 bit two's complements.

Note

If the FIFO is enabled by module l3gxxxxx_fifo, the function returns only the last sample. To read all samples from the FIFO, function l3gxxxx_read_raw_fifo has to be used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
	raw	last sample of raw output data as 16 bit two's complements

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_read_raw_fifo()

int l3gxxxx_read_raw_fifo	(	const l3gxxxx_t *	dev,
		l3gxxxx_raw_data_fifo_t	raw
	)

Get all samples of raw output data stored in the FIFO.

This function reads all samples of raw output data from the FIFO. In bypass mode (L3GXXXX_BYPASS), it returns only the last raw output data sample.

Note

This function is available only if module l3gxxxx_fifo is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[out]	raw	array for up to 32 raw output data as two's complement

Returns

number of data samples read on success, or negative error code, see l3gxxxx_error_codes_t

l3gxxxx_reg_read()

int l3gxxxx_reg_read	(	const l3gxxxx_t *	dev,
		uint8_t	reg,
		uint8_t *	data,
		uint8_t	len
	)

Direct read from register.

Note

This function should only be used to do something special that is not covered by the high level interface AND if you exactly know what you do and what effects it might have. Please be aware that it might affect the high level interface.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	reg	address of the first register to be read
[out]	data	pointer to the data to be read from the register
[in]	len	number of bytes to be read from the register

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_reg_write()

int l3gxxxx_reg_write	(	const l3gxxxx_t *	dev,
		uint8_t	reg,
		const uint8_t *	data,
		uint8_t	len
	)

Direct write to register.

Note

This function should only be used to do something special that is not covered by the high level interface AND if you exactly know what you do and what effects it might have. Please be aware that it might affect the high level interface.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	reg	address of the first register to be changed
[in]	data	pointer to the data to be written to the register
[in]	len	number of bytes to be written to the register

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_select_output_filter()

int l3gxxxx_select_output_filter	(	l3gxxxx_t *	dev,
		l3gxxxx_filter_sel_t	filter
	)

Filter selection for raw output data.

L3Gxxxx supports a combination of a high pass filter (HPF) and a second low pass filter (LPF2). This function selects the combination of the HPF and the LPF2 applied to raw output data.

Note

• This function is available only if module l3gxxxx_config is used.
• The filter selection for the output data also affects the filter selection for event interrupt generation. If the HPF is enabled for filtering the output data, it is also active for filtering the sensor data used for interrupt generation if the LPF2 is enabled for interrupt generation.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	filter	selected filters for output values

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_set_fifo_mode()

int l3gxxxx_set_fifo_mode	(	l3gxxxx_t *	dev,
		l3gxxxx_fifo_mode_t	mode,
		uint8_t	watermark
	)

Set FIFO mode and watermark level (threshold)

The FIFO buffer can work in seven different modes and is able to store up to 32 data samples, see l3gxxxx_fifo_mode_t. The use of the FIFO allows to reduce the interaction events of the MCU with the sensor and thus to save power.

The watermark level can be used to define the number of raw output data samples that have to be stored in the FIFO before the watermark flag is set and the L3GXXXX_INT_FIFO_WATERMARK is triggered, if enabled. The watermark flag is set and the interrupt L3GXXXX_INT_FIFO_WATERMARK is triggered when the number of samples stored in the FIFO becomes greater than this watermark level (threshold).

Note

This function is available only if modules l3gxxxx_fifo and l3gxxxx_config are used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	mode	FIFO mode
[in]	watermark	FIFO watermark (ignored in bypass mode)

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_set_hpf_ref()

int l3gxxxx_set_hpf_ref	(	const l3gxxxx_t *	dev,
		int8_t	ref
	)

Set HPF (high pass filter) reference.

Used to set the reference for HPF in reference mode L3GXXXX_HPF_REFERENCE and to reset the HPF in autoreset mode L3GXXXX_HPF_AUTORESET. Reference is given as two's complement.

Note

This function is available only if module l3gxxxx_config is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	ref	reference in L3GXXXX_HPF_REFERENCE mode, otherwise ignored

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_set_int_event_cfg()

int l3gxxxx_set_int_event_cfg	(	const l3gxxxx_t *	dev,
		const l3gxxxx_int_event_cfg_t *	cfg
	)

Set new configuration for event interrupt generation.

The event interrupt generator produces interrupts (axis movement and wake-up) on signal INT1 whenever the angular rate of one or more axes becomes higher or lower than defined thresholds.

This function can be used at runtime to change the configuration of the interrupt conditions for event interrupt generation. This includes thresholds for all axes, enabled threshold interrupts, filter selection used for interrupt generation and other parameters, see l3gxxxx_int_event_cfg_t for details.

Note

This function is available only if module l3gxxxx_irq_event is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	cfg	event interrupt generator configuration

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_set_mode()

int l3gxxxx_set_mode	(	l3gxxxx_t *	dev,
		l3gxxxx_odr_t	odr,
		bool	x,
		bool	y,
		bool	z
	)

Set sensor mode.

Note

This function is available only if module l3gxxxx_config is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	odr	output data rate (ODR) and LPF2 cutoff frequency
[in]	x	enable X axis measurements if true
[in]	y	enable Y axis measurements if true
[in]	z	enable Z axis measurements if true

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_set_scale()

int l3gxxxx_set_scale	(	l3gxxxx_t *	dev,
		l3gxxxx_scale_t	scale
	)

Set full scale.

Note

This function is available only if module l3gxxxx_config is used.

Parameters

[in]	dev	device descriptor of the L3Gxxxx sensor
[in]	scale	fulle scale

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_sleep()

int l3gxxxx_sleep

(

l3gxxxx_t *

dev

)

Sleep mode.

Activates the sleep mode of the sensor. In this mode, measurements for all axes are disabled, but the gyroscopes remain on. To return from sleep mode, function l3gxxxx_wake_up is used.

Note

This function is available only if module l3gxxxx_sleep is used.

Parameters

[in]

dev

Device descriptor of L3Gxxxx device to read from

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_wait_int()

l3gxxxx_int_src_t l3gxxxx_wait_int

(

l3gxxxx_t *

dev

)

Wait for event and/or data interrupts on signals INT1 and INT2/DRDY

The function waits for a configured interrupt and returns the sources of triggered interrupts. Since data interrupts (data ready and FIFO status) and event interrupts (axis movement and wake-up) use different signals, both data and event interrupts can occur simultaneously. The return value of type l3gxxxx_int_src_t contains all sources for which the interrupt conditions are fulfilled at the same time.

Precondition

MCU GPIO pins for the INT1 signal respectively the INT2/DRDY signal have to be defined for enabled interrupts (l3gxxxx_params_t::int1_pin and l3gxxxx_params_t::int2_pin).

Note

This function is available only if module l3gxxxx_irq_data and/or module l3gxxxx_irq_event are used.

Parameters

[in]

dev

device descriptor of the L3Gxxxx sensor

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t

l3gxxxx_wake_up()

int l3gxxxx_wake_up

(

l3gxxxx_t *

dev

)

Wake-up the sensor.

Swichtes the sensor back into the last active operation mode. It takes only 1/ODR when LPF2 is disabled and 6/ODR when LPF2 is enabled to continue measurements.

Note

This function is available only if module l3gxxxx_sleep is used.

Parameters

[in]

dev

Device descriptor of L3Gxxxx device to read from

Return values

L3GXXXX_OK	on success
L3GXXXX_ERROR_*	negative error code, see l3gxxxx_error_codes_t