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1.8.13
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Robot Control Library
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A userspace C interface for the invensense MPU6050, MPU6500, MPU9150, and MPU9250.
<rc/mpu.h>
This API allows the user to configure this IMU in two modes: NORMAL and DMP
The accelerometer, gyroscope, magnetometer, and thermometer can be read directly at any time. To use this mode, call rc_mpu_initialize() with your imu_config and imu_data structs as arguments as defined below. You can then call rc_mpu_read_accel, rc_mpu_read_gyro, rc_mpu_read_mag, or rc_mpu_read_temp at any time to get the latest sensor values.
Stands for Digital Motion Processor which is a feature of the MPU9250. in this mode, the DMP will sample the sensors internally and fill a FIFO buffer with the data at a fixed rate. Furthermore, the DMP will also calculate a filtered orientation quaternion which is placed in the same buffer. When new data is ready in the buffer, the IMU sends an interrupt to the BeagleBone triggering the buffer read followed by the execution of a function of your choosing set with the rc_mpu_set_dmp_callback() function.
Data Structures | |
| struct | rc_mpu_config_t |
| configuration of the mpu sensor More... | |
| struct | rc_mpu_data_t |
| data struct populated with new sensor data More... | |
Macros | |
| #define | RC_MPU_DEFAULT_I2C_ADDR 0x68 |
| default i2c address if AD0 is left low More... | |
| #define | RC_MPU_ALT_I2C_ADDR 0x69 |
| alternate i2c address if AD0 pin pulled high More... | |
| #define | TB_PITCH_X 0 |
| Index of the dmp_TaitBryan[] array corresponding to the Pitch (X) axis. More... | |
| #define | TB_ROLL_Y 1 |
| Index of the dmp_TaitBryan[] array corresponding to the Roll (Y) axis. More... | |
| #define | TB_YAW_Z 2 |
| Index of the dmp_TaitBryan[] array corresponding to the Yaw (Z) axis. More... | |
| #define | QUAT_W 0 |
| First index of the dmp_quat[] quaternion vector. More... | |
| #define | QUAT_X 1 |
| Second index of the dmp_quat[] quaternion vector. More... | |
| #define | QUAT_Y 2 |
| Third index of the dmp_quat[] quaternion vector. More... | |
| #define | QUAT_Z 3 |
| Fourth index of the dmp_quat[] quaternion vector. More... | |
| #define | DEG_TO_RAD 0.0174532925199 |
| multiply to convert degrees to radians More... | |
| #define | RAD_TO_DEG 57.295779513 |
| multiply to convert radians to degrees More... | |
| #define | MS2_TO_G 0.10197162129 |
| multiply to convert m/s^2 to G More... | |
| #define | G_TO_MS2 9.80665 |
| multiply to convert G to m/s^2, standard gravity definition More... | |
Typedefs | |
| typedef enum rc_mpu_accel_fsr_t | rc_mpu_accel_fsr_t |
| accelerometer full scale range options More... | |
| typedef enum rc_mpu_gyro_fsr_t | rc_mpu_gyro_fsr_t |
| gyroscope full scale range options More... | |
| typedef enum rc_mpu_accel_dlpf_t | rc_mpu_accel_dlpf_t |
| accelerometer digital low-pass filter options More... | |
| typedef enum rc_mpu_gyro_dlpf_t | rc_mpu_gyro_dlpf_t |
| gyroscope digital low-pass filter options More... | |
| typedef enum rc_mpu_orientation_t | rc_mpu_orientation_t |
| Orientation of the sensor. More... | |
| typedef struct rc_mpu_config_t | rc_mpu_config_t |
| configuration of the mpu sensor More... | |
| typedef struct rc_mpu_data_t | rc_mpu_data_t |
| data struct populated with new sensor data More... | |
common functions | |
| rc_mpu_config_t | rc_mpu_default_config (void) |
| Returns an rc_mpu_config_t struct with default settings. More... | |
| int | rc_mpu_set_config_to_default (rc_mpu_config_t *conf) |
| Resets a config struct to defaults. More... | |
| int | rc_mpu_power_off (void) |
| Powers off the MPU. More... | |
normal one-shot sampling functions | |
| int | rc_mpu_initialize (rc_mpu_data_t *data, rc_mpu_config_t conf) |
| Sets up the MPU in normal one-shot sampling mode. More... | |
| int | rc_mpu_read_accel (rc_mpu_data_t *data) |
| Reads accelerometer data from the MPU. More... | |
| int | rc_mpu_read_gyro (rc_mpu_data_t *data) |
| Reads gyroscope data from the MPU. More... | |
| int | rc_mpu_read_temp (rc_mpu_data_t *data) |
| Reads thermometer data from the MPU. More... | |
| int | rc_mpu_read_mag (rc_mpu_data_t *data) |
| Reads magnetometer data from the MPU. More... | |
interrupt-driven DMP mode functions | |
| int | rc_mpu_initialize_dmp (rc_mpu_data_t *data, rc_mpu_config_t conf) |
| Initializes the MPU in DMP mode, see rc_test_dmp example. More... | |
| int | rc_mpu_set_dmp_callback (void(*func)(void)) |
| Sets the callback function that will be triggered when new DMP data is ready. More... | |
| int | rc_mpu_block_until_dmp_data (void) |
| blocking function that returns once new DMP data is available More... | |
| int64_t | rc_mpu_nanos_since_last_dmp_interrupt (void) |
| calculates number of nanoseconds since the last DMP interrupt More... | |
| int | rc_mpu_set_tap_callback (void(*func)(int direction, int counter)) |
| sets the callback function triggered when a tap is detected More... | |
| int | rc_mpu_block_until_tap (void) |
| blocking function that returns when a tap is detected More... | |
| int64_t | rc_mpu_nanos_since_last_tap (void) |
| calculates nanoseconds since last tap was detected More... | |
calibration functions | |
| int | rc_mpu_calibrate_gyro_routine (rc_mpu_config_t conf) |
| Runs gyroscope calibration routine. More... | |
| int | rc_mpu_calibrate_mag_routine (rc_mpu_config_t conf) |
| Runs magnetometer calibration routine. More... | |
| int | rc_mpu_calibrate_accel_routine (rc_mpu_config_t conf) |
| Runs accelerometer calibration routine. More... | |
| int | rc_mpu_is_gyro_calibrated (void) |
| Checks if a gyro calibration file is saved to disk. More... | |
| int | rc_mpu_is_mag_calibrated (void) |
| Checks if a magnetometer calibration file is saved to disk. More... | |
| int | rc_mpu_is_accel_calibrated (void) |
| Checks if an accelerometer calibration file is saved to disk. More... | |
| #define RC_MPU_DEFAULT_I2C_ADDR 0x68 |
default i2c address if AD0 is left low
| #define RC_MPU_ALT_I2C_ADDR 0x69 |
alternate i2c address if AD0 pin pulled high
| #define TB_PITCH_X 0 |
Index of the dmp_TaitBryan[] array corresponding to the Pitch (X) axis.
| #define TB_ROLL_Y 1 |
Index of the dmp_TaitBryan[] array corresponding to the Roll (Y) axis.
| #define TB_YAW_Z 2 |
Index of the dmp_TaitBryan[] array corresponding to the Yaw (Z) axis.
| #define QUAT_W 0 |
First index of the dmp_quat[] quaternion vector.
| #define QUAT_X 1 |
Second index of the dmp_quat[] quaternion vector.
| #define QUAT_Y 2 |
Third index of the dmp_quat[] quaternion vector.
| #define QUAT_Z 3 |
Fourth index of the dmp_quat[] quaternion vector.
| #define DEG_TO_RAD 0.0174532925199 |
multiply to convert degrees to radians
| #define RAD_TO_DEG 57.295779513 |
multiply to convert radians to degrees
| #define MS2_TO_G 0.10197162129 |
multiply to convert m/s^2 to G
| #define G_TO_MS2 9.80665 |
multiply to convert G to m/s^2, standard gravity definition
| enum rc_mpu_accel_fsr_t |
accelerometer full scale range options
The user may choose from 4 full scale ranges of the accelerometer and gyroscope. They have units of gravity (G) and degrees per second (DPS) The defaults values are A_FSR_2G and G_FSR_2000DPS respectively.
| Enumerator | |
|---|---|
| ACCEL_FSR_2G | |
| ACCEL_FSR_4G | |
| ACCEL_FSR_8G | |
| ACCEL_FSR_16G | |
| enum rc_mpu_gyro_fsr_t |
gyroscope full scale range options
The user may choose from 4 full scale ranges of the accelerometer and gyroscope. They have units of gravity (G) and degrees per second (DPS) The defaults values are A_FSR_2G and G_FSR_2000DPS respectively.
| Enumerator | |
|---|---|
| GYRO_FSR_250DPS | |
| GYRO_FSR_500DPS | |
| GYRO_FSR_1000DPS | |
| GYRO_FSR_2000DPS | |
| enum rc_mpu_accel_dlpf_t |
accelerometer digital low-pass filter options
The user may choose from 7 digital low pass filter constants for the accelerometer and gyroscope. The filter runs at 1kz and helps to reduce sensor noise when sampling more slowly. The default values are ACCEL_DLPF_184 GYRO_DLPF_184. Lower cut-off frequencies incur phase-loss in measurements. Number is cutoff frequency in hz.
| Enumerator | |
|---|---|
| ACCEL_DLPF_OFF | |
| ACCEL_DLPF_460 | |
| ACCEL_DLPF_184 | |
| ACCEL_DLPF_92 | |
| ACCEL_DLPF_41 | |
| ACCEL_DLPF_20 | |
| ACCEL_DLPF_10 | |
| ACCEL_DLPF_5 | |
| enum rc_mpu_gyro_dlpf_t |
gyroscope digital low-pass filter options
The user may choose from 7 digital low pass filter constants for the accelerometer and gyroscope. The filter runs at 1kz and helps to reduce sensor noise when sampling more slowly. The default values are ACCEL_DLPF_184 GYRO_DLPF_184. Lower cut-off frequencies incur phase-loss in measurements. Number is cutoff frequency in hz.
| Enumerator | |
|---|---|
| GYRO_DLPF_OFF | |
| GYRO_DLPF_250 | |
| GYRO_DLPF_184 | |
| GYRO_DLPF_92 | |
| GYRO_DLPF_41 | |
| GYRO_DLPF_20 | |
| GYRO_DLPF_10 | |
| GYRO_DLPF_5 | |
| enum rc_mpu_orientation_t |
Orientation of the sensor.
This is only applicable when operating in DMP mode. This is the orientation that the DMP consideres neutral, aka where roll/pitch/yaw are zero.
| Enumerator | |
|---|---|
| ORIENTATION_Z_UP | |
| ORIENTATION_Z_DOWN | |
| ORIENTATION_X_UP | |
| ORIENTATION_X_DOWN | |
| ORIENTATION_Y_UP | |
| ORIENTATION_Y_DOWN | |
| ORIENTATION_X_FORWARD | |
| ORIENTATION_X_BACK | |
| rc_mpu_config_t rc_mpu_default_config | ( | void | ) |
Returns an rc_mpu_config_t struct with default settings.
Use this as a starting point and modify as you wish.
| int rc_mpu_set_config_to_default | ( | rc_mpu_config_t * | conf | ) |
Resets a config struct to defaults.
| [out] | conf | Pointer to config struct to be overwritten |
| int rc_mpu_power_off | ( | void | ) |
Powers off the MPU.
Only call this after powering on the MPU with rc_mpu_initialize or rc_mpu_initialize_dmp. This should geenrally be called at the end of your main function to make sure the MPU is put to sleep.
| int rc_mpu_initialize | ( | rc_mpu_data_t * | data, |
| rc_mpu_config_t | conf | ||
| ) |
Sets up the MPU in normal one-shot sampling mode.
First create an instance of the rc_mpu_data_t struct and pass its pointer to rc_mpu_initialize which will then write to. Also pass an rc_mpu_config_t struct with your configruation settings.
This function will populate the accel_to_ms2 and gyro_to_deg fields of the rc_mpu_data_t struct appropriately based on the user-configured full scale ranges.
After this, you may read sensor data at any time with the functions rc_mpu_read_accel(), rc_mpu_read_gyro(), and rc_mpu_read_temp(). The magentometer can also be read with rc_mpu_read_mag() if using an MPU9150 or MPU9250 and the enable_magnetometer field in the rc_mpu_config_t struct has been set to 1.
Be sure to power off the MPU at the end of your program with rc_mpu_power_off().
| data | pointer to user's data struct | |
| [in] | conf | user congiguration data |
| int rc_mpu_read_accel | ( | rc_mpu_data_t * | data | ) |
Reads accelerometer data from the MPU.
| data | Pointer to user's data struct where new data will be written |
| int rc_mpu_read_gyro | ( | rc_mpu_data_t * | data | ) |
Reads gyroscope data from the MPU.
| data | Pointer to user's data struct where new data will be written |
| int rc_mpu_read_temp | ( | rc_mpu_data_t * | data | ) |
Reads thermometer data from the MPU.
Note this is the internal termperature of the chip, not abient temperature.
| data | Pointer to user's data struct where new data will be written |
| int rc_mpu_read_mag | ( | rc_mpu_data_t * | data | ) |
Reads magnetometer data from the MPU.
Note this requires use of an MPU9150 or MPU9250, the MPU6050 and MPU6500 do not have magnetometers. Additionally, the enable_magnetometer flag must has been set in the user's rc_mpu_config_t when it was passed to rc_mpu_initialize()
| data | Pointer to user's data struct where new data will be written |
| int rc_mpu_initialize_dmp | ( | rc_mpu_data_t * | data, |
| rc_mpu_config_t | conf | ||
| ) |
Initializes the MPU in DMP mode, see rc_test_dmp example.
After calling this the user does not need to call the normal read functions rc_mpu_read_accel(), rc_mpu_read_gyro(), or rc_mpu_read mag(). Instead the data will automatically be read into the user's data struct at the dmp_sample_rate set in the config struct.
| data | Pointer to user's data struct where new data will be written | |
| [in] | conf | User's configuration struct |
| int rc_mpu_set_dmp_callback | ( | void(*)(void) | func | ) |
Sets the callback function that will be triggered when new DMP data is ready.
| [in] | func | user's callback function |
| int rc_mpu_block_until_dmp_data | ( | void | ) |
blocking function that returns once new DMP data is available
| int64_t rc_mpu_nanos_since_last_dmp_interrupt | ( | void | ) |
calculates number of nanoseconds since the last DMP interrupt
| int rc_mpu_set_tap_callback | ( | void(*)(int direction, int counter) | func | ) |
sets the callback function triggered when a tap is detected
| [in] | func | user's callback function |
| int rc_mpu_block_until_tap | ( | void | ) |
blocking function that returns when a tap is detected
| int64_t rc_mpu_nanos_since_last_tap | ( | void | ) |
calculates nanoseconds since last tap was detected
| int rc_mpu_calibrate_gyro_routine | ( | rc_mpu_config_t | conf | ) |
Runs gyroscope calibration routine.
This should generally not be used by the user unless they absolutely want to calibrate the gyroscope inside their own program. Instead call the rc_calibrate_gyro example program.
| [in] | conf | Config struct, only used to configure i2c bus and address. |
| int rc_mpu_calibrate_mag_routine | ( | rc_mpu_config_t | conf | ) |
Runs magnetometer calibration routine.
This should generally not be used by the user unless they absolutely want to calibrate the magnetometer inside their own program. Instead call the rc_calibrate_mag example program.
| [in] | conf | Config struct, only used to configure i2c bus and address. |
| int rc_mpu_calibrate_accel_routine | ( | rc_mpu_config_t | conf | ) |
Runs accelerometer calibration routine.
This should generally not be used by the user unless they absolutely want to calibrate the accelerometer inside their own program. Instead call the rc_calibrate_accel example program.
| [in] | conf | Config struct, only used to configure i2c bus and address. |
| int rc_mpu_is_gyro_calibrated | ( | void | ) |
Checks if a gyro calibration file is saved to disk.
generally used to warn the user that they are running a program without calibration. Can also be used to decide if calibration should be done at the beginning of user's program.
| int rc_mpu_is_mag_calibrated | ( | void | ) |
Checks if a magnetometer calibration file is saved to disk.
generally used to warn the user that they are running a program without calibration. Can also be used to decide if calibration should be done at the beginning of user's program.
| int rc_mpu_is_accel_calibrated | ( | void | ) |
Checks if an accelerometer calibration file is saved to disk.
generally used to warn the user that they are running a program without calibration. Can also be used to decide if calibration should be done at the beginning of user's program.
1.8.13