..
 #############################################################
 # This file was automatically generated on 2015-05-08.      #
 #                                                           #
 # If you have a bugfix for this file and want to commit it, #
 # please fix the bug in the generator. You can find a link  #
 # to the generators git repository on tinkerforge.com       #
 #############################################################


:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-c">Software</a> / C/C++ - IMU Brick

.. |device_identifier_constant| replace:: There is also a :ref:`constant <imu_brick_c_constants>` for the device identifier of this Brick.

.. _imu_brick_c:

C/C++ - IMU Brick
=================

This is the description of the :ref:`C/C++ API bindings <api_bindings_c>` for the :ref:`IMU Brick <imu_brick>`. General information and technical
specifications for the IMU Brick are summarized in its :ref:`hardware description
<imu_brick_description>`.

An :ref:`installation guide <api_bindings_c_install>` for the C/C++ API
bindings is part of their general description.

.. _imu_brick_c_examples:


Examples
--------

The example code below is `Public Domain (CC0 1.0)
<http://creativecommons.org/publicdomain/zero/1.0/>`__.

Simple
^^^^^^

`Download (example_simple.c) <https://github.com/Tinkerforge/imu-brick/raw/master/software/examples/c/example_simple.c>`__

.. literalinclude:: IMU_Brick_C_example_simple.c
 :language: c
 :linenos:
 :tab-width: 4

Callback
^^^^^^^^

`Download (example_callback.c) <https://github.com/Tinkerforge/imu-brick/raw/master/software/examples/c/example_callback.c>`__

.. literalinclude:: IMU_Brick_C_example_callback.c
 :language: c
 :linenos:
 :tab-width: 4

.. _imu_brick_c_api:

API
---

Every function of the C/C++ bindings returns an integer which describes an
error code. Data returned from the device, when a getter is called,
is handled via call by reference. These parameters are labeled with the
``ret_`` prefix.

Possible error codes are:

* E_OK = 0
* E_TIMEOUT = -1
* E_NO_STREAM_SOCKET = -2
* E_HOSTNAME_INVALID = -3
* E_NO_CONNECT = -4
* E_NO_THREAD = -5
* E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
* E_ALREADY_CONNECTED = -7
* E_NOT_CONNECTED = -8
* E_INVALID_PARAMETER = -9
* E_NOT_SUPPORTED = -10
* E_UNKNOWN_ERROR_CODE = -11

as defined in :file:`ip_connection.h`.

All functions listed below are thread-safe.




Basic Functions
^^^^^^^^^^^^^^^


.. c:function:: void imu_create(IMU *imu, const char *uid, IPConnection *ipcon)

 Creates the device object ``imu`` with the unique device ID ``uid`` and adds
 it to the IPConnection ``ipcon``:

 .. code-block:: c

    IMU imu;
    imu_create(&imu, "YOUR_DEVICE_UID", &ipcon);

 This device object can be used after the IP connection has been connected
 (see examples :ref:`above <imu_brick_c_examples>`).

.. c:function:: void imu_destroy(IMU *imu)

 Removes the device object ``imu`` from its IPConnection and destroys it.
 The device object cannot be used anymore afterwards.


.. c:function:: int imu_get_orientation(IMU *imu, int16_t *ret_roll, int16_t *ret_pitch, int16_t *ret_yaw)

 Returns the current orientation (roll, pitch, yaw) of the IMU Brick as Euler
 angles in one-hundredth degree. Note that Euler angles always experience a
 `gimbal lock <http://en.wikipedia.org/wiki/Gimbal_lock>`__.
 
 We recommend that you use quaternions instead.
 
 The order to sequence in which the orientation values should be applied is 
 roll, yaw, pitch. 
 
 If you want to get the orientation periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_ORIENTATION` and set the period with 
 :c:func:`imu_set_orientation_period`.
 
.. c:function:: int imu_get_quaternion(IMU *imu, float *ret_x, float *ret_y, float *ret_z, float *ret_w)

 Returns the current orientation (x, y, z, w) of the IMU as 
 `quaternions <http://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation>`__.
 
 You can go from quaternions to Euler angles with the following formula::
 
  xAngle = atan2(2*y*w - 2*x*z, 1 - 2*y*y - 2*z*z)
  yAngle = atan2(2*x*w - 2*y*z, 1 - 2*x*x - 2*z*z)
  zAngle =  asin(2*x*y + 2*z*w)
 
 This process is not reversible, because of the 
 `gimbal lock <http://en.wikipedia.org/wiki/Gimbal_lock>`__.
 
 It is also possible to calculate independent angles. You can calculate 
 yaw, pitch and roll in a right-handed vehicle coordinate system according to DIN70000
 with::
 
  yaw   =  atan2(2*x*y + 2*w*z, w*w + x*x - y*y - z*z)
  pitch = -asin(2*w*y - 2*x*z)
  roll  = -atan2(2*y*z + 2*w*x, -w*w + x*x + y*y - z*z))
 
 Converting the quaternions to an OpenGL transformation matrix is
 possible with the following formula::
 
  matrix = [[1 - 2*(y*y + z*z),     2*(x*y - w*z),     2*(x*z + w*y), 0],
            [    2*(x*y + w*z), 1 - 2*(x*x + z*z),     2*(y*z - w*x), 0],
            [    2*(x*z - w*y),     2*(y*z + w*x), 1 - 2*(x*x + y*y), 0],
            [                0,                 0,                 0, 1]]
 
 If you want to get the quaternions periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_QUATERNION` and set the period with 
 :c:func:`imu_set_quaternion_period`.
 
.. c:function:: int imu_leds_on(IMU *imu)

 Turns the orientation and direction LEDs of the IMU Brick on.
 
.. c:function:: int imu_leds_off(IMU *imu)

 Turns the orientation and direction LEDs of the IMU Brick off.
 
.. c:function:: int imu_are_leds_on(IMU *imu, bool *ret_leds)

 Returns *true* if the orientation and direction LEDs of the IMU Brick
 are on, *false* otherwise.
 
.. c:function:: int imu_set_convergence_speed(IMU *imu, uint16_t speed)

 Sets the convergence speed of the IMU Brick in °/s. The convergence speed 
 determines how the different sensor measurements are fused.
 
 If the orientation of the IMU Brick is off by 10° and the convergence speed is 
 set to 20°/s, it will take 0.5s until the orientation is corrected. However,
 if the correct orientation is reached and the convergence speed is too high,
 the orientation will fluctuate with the fluctuations of the accelerometer and
 the magnetometer.
 
 If you set the convergence speed to 0, practically only the gyroscope is used
 to calculate the orientation. This gives very smooth movements, but errors of the
 gyroscope will not be corrected. If you set the convergence speed to something
 above 500, practically only the magnetometer and the accelerometer are used to
 calculate the orientation. In this case the movements are abrupt and the values
 will fluctuate, but there won't be any errors that accumulate over time.
 
 In an application with high angular velocities, we recommend a high convergence
 speed, so the errors of the gyroscope can be corrected fast. In applications with
 only slow movements we recommend a low convergence speed. You can change the
 convergence speed on the fly. So it is possible (and recommended) to increase 
 the convergence speed before an abrupt movement and decrease it afterwards 
 again.
 
 You might want to play around with the convergence speed in the Brick Viewer to
 get a feeling for a good value for your application.
 
 The default value is 30.
 
.. c:function:: int imu_get_convergence_speed(IMU *imu, uint16_t *ret_speed)

 Returns the convergence speed as set by :c:func:`imu_set_convergence_speed`.
 


Advanced Functions
^^^^^^^^^^^^^^^^^^

.. c:function:: int imu_get_acceleration(IMU *imu, int16_t *ret_x, int16_t *ret_y, int16_t *ret_z)
 
 Returns the calibrated acceleration from the accelerometer for the 
 x, y and z axis in mG (G/1000, 1G = 9.80605m/s²).
 
 If you want to get the acceleration periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_ACCELERATION` and set the period with 
 :c:func:`imu_set_acceleration_period`.
 
.. c:function:: int imu_get_magnetic_field(IMU *imu, int16_t *ret_x, int16_t *ret_y, int16_t *ret_z)

 Returns the calibrated magnetic field from the magnetometer for the 
 x, y and z axis in mG (Milligauss or Nanotesla).
 
 If you want to get the magnetic field periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_MAGNETIC_FIELD` and set the period with 
 :c:func:`imu_set_magnetic_field_period`.
 
.. c:function:: int imu_get_angular_velocity(IMU *imu, int16_t *ret_x, int16_t *ret_y, int16_t *ret_z)

 Returns the calibrated angular velocity from the gyroscope for the 
 x, y and z axis in °/14.375s (you have to divide by 14.375 to
 get the value in °/s).
 
 If you want to get the angular velocity periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_ANGULAR_VELOCITY` and set the period with 
 :c:func:`imu_set_angular_velocity_period`.
 
.. c:function:: int imu_get_all_data(IMU *imu, int16_t *ret_acc_x, int16_t *ret_acc_y, int16_t *ret_acc_z, int16_t *ret_mag_x, int16_t *ret_mag_y, int16_t *ret_mag_z, int16_t *ret_ang_x, int16_t *ret_ang_y, int16_t *ret_ang_z, int16_t *ret_temperature)

 Returns the data from :c:func:`imu_get_acceleration`, :c:func:`imu_get_magnetic_field` 
 and :c:func:`imu_get_angular_velocity` as well as the temperature of the IMU Brick.
 
 The temperature is given in °C/100.
 
 If you want to get the data periodically, it is recommended 
 to use the callback :c:data:`IMU_CALLBACK_ALL_DATA` and set the period with 
 :c:func:`imu_set_all_data_period`.
 
.. c:function:: int imu_get_imu_temperature(IMU *imu, int16_t *ret_temperature)

 Returns the temperature of the IMU Brick. The temperature is given in 
 °C/100.
 
.. c:function:: int imu_set_acceleration_range(IMU *imu, uint8_t range)

 Not implemented yet.
 
.. c:function:: int imu_get_acceleration_range(IMU *imu, uint8_t *ret_range)

 Not implemented yet.
 
.. c:function:: int imu_set_magnetometer_range(IMU *imu, uint8_t range)

 Not implemented yet.
 
.. c:function:: int imu_get_magnetometer_range(IMU *imu, uint8_t *ret_range)

 Not implemented yet.
 
.. c:function:: int imu_set_calibration(IMU *imu, uint8_t typ, int16_t data[10])

 There are several different types that can be calibrated:
 
 .. csv-table::
  :header: "Type", "Description", "Values"
  :widths: 10, 30, 110
 
  "0",    "Accelerometer Gain", "``[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]``"
  "1",    "Accelerometer Bias", "``[bias x, bias y, bias z, 0, 0, 0, 0, 0, 0, 0]``"
  "2",    "Magnetometer Gain",  "``[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]``"
  "3",    "Magnetometer Bias",  "``[bias x, bias y, bias z, 0, 0, 0, 0, 0, 0, 0]``"
  "4",    "Gyroscope Gain",     "``[mul x, mul y, mul z, div x, div y, div z, 0, 0, 0, 0]``"
  "5",    "Gyroscope Bias",     "``[bias xl, bias yl, bias zl, temp l, bias xh, bias yh, bias zh, temp h, 0, 0]``"
 
 The calibration via gain and bias is done with the following formula::
 
  new_value = (bias + orig_value) * gain_mul / gain_div
 
 If you really want to write your own calibration software, please keep
 in mind that you first have to undo the old calibration (set bias to 0 and
 gain to 1/1) and that you have to average over several thousand values
 to obtain a usable result in the end.
 
 The gyroscope bias is highly dependent on the temperature, so you have to
 calibrate the bias two times with different temperatures. The values ``xl``,
 ``yl``, ``zl`` and ``temp l`` are the bias for ``x``, ``y``, ``z`` and the
 corresponding temperature for a low temperature. The values ``xh``, ``yh``,
 ``zh`` and ``temp h`` are the same for a high temperatures. The temperature
 difference should be at least 5°C. If you have a temperature where the
 IMU Brick is mostly used, you should use this temperature for one of the
 sampling points.
 
 .. note::
  We highly recommend that you use the Brick Viewer to calibrate your
  IMU Brick.
 
 The following defines are available for this function:
 
 * IMU_CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
 * IMU_CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
 * IMU_CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
 * IMU_CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
 * IMU_CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
 * IMU_CALIBRATION_TYPE_GYROSCOPE_BIAS = 5
 
.. c:function:: int imu_get_calibration(IMU *imu, uint8_t typ, int16_t ret_data[10])

 Returns the calibration for a given type as set by :c:func:`imu_set_calibration`.
 
 The following defines are available for this function:
 
 * IMU_CALIBRATION_TYPE_ACCELEROMETER_GAIN = 0
 * IMU_CALIBRATION_TYPE_ACCELEROMETER_BIAS = 1
 * IMU_CALIBRATION_TYPE_MAGNETOMETER_GAIN = 2
 * IMU_CALIBRATION_TYPE_MAGNETOMETER_BIAS = 3
 * IMU_CALIBRATION_TYPE_GYROSCOPE_GAIN = 4
 * IMU_CALIBRATION_TYPE_GYROSCOPE_BIAS = 5
 
.. c:function:: int imu_orientation_calculation_on(IMU *imu)

 Turns the orientation calculation of the IMU Brick on.
 
 As default the calculation is on.
 
 .. versionadded:: 2.0.2~(Firmware)
 
.. c:function:: int imu_orientation_calculation_off(IMU *imu)

 Turns the orientation calculation of the IMU Brick off.
 
 If the calculation is off, :c:func:`imu_get_orientation` will return
 the last calculated value until the calculation is turned on again.
 
 The trigonometric functions that are needed to calculate the orientation 
 are very expensive. We recommend to turn the orientation calculation
 off if the orientation is not needed, to free calculation time for the
 sensor fusion algorithm.
 
 As default the calculation is on.
 
 .. versionadded:: 2.0.2~(Firmware)
 
.. c:function:: int imu_is_orientation_calculation_on(IMU *imu, bool *ret_orientation_calculation_on)

 Returns *true* if the orientation calculation of the IMU Brick
 is on, *false* otherwise.
 
 .. versionadded:: 2.0.2~(Firmware)
 
.. c:function:: int imu_get_api_version(IMU *imu, uint8_t ret_api_version[3])

 Returns the version of the API definition (major, minor, revision) implemented
 by this API bindings. This is neither the release version of this API bindings
 nor does it tell you anything about the represented Brick or Bricklet.
 
.. c:function:: int imu_get_response_expected(IMU *imu, uint8_t function_id, bool *ret_response_expected)

 Returns the response expected flag for the function specified by the function
 ID parameter. It is *true* if the function is expected to send a response,
 *false* otherwise.
 
 For getter functions this is enabled by default and cannot be disabled,
 because those functions will always send a response. For callback configuration
 functions it is enabled by default too, but can be disabled by
 :c:func:`imu_set_response_expected`. For setter functions it is disabled by default
 and can be enabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 See :c:func:`imu_set_response_expected`
 for the list of function ID defines available for this function.
 
.. c:function:: int imu_set_response_expected(IMU *imu, uint8_t function_id, bool response_expected)

 Changes the response expected flag of the function specified by the
 function ID parameter. This flag can only be changed for setter (default value:
 *false*) and callback configuration functions (default value: *true*). For
 getter functions it is always enabled and callbacks it is always disabled.
 
 Enabling the response expected flag for a setter function allows to detect
 timeouts and other error conditions calls of this setter as well. The
 device will then send a response for this purpose. If this flag is disabled for
 a setter function then no response is send and errors are silently ignored,
 because they cannot be detected.
 
 The following function ID defines are available for this function:
 
 * IMU_FUNCTION_LEDS_ON = 8
 * IMU_FUNCTION_LEDS_OFF = 9
 * IMU_FUNCTION_SET_ACCELERATION_RANGE = 11
 * IMU_FUNCTION_SET_MAGNETOMETER_RANGE = 13
 * IMU_FUNCTION_SET_CONVERGENCE_SPEED = 15
 * IMU_FUNCTION_SET_CALIBRATION = 17
 * IMU_FUNCTION_SET_ACCELERATION_PERIOD = 19
 * IMU_FUNCTION_SET_MAGNETIC_FIELD_PERIOD = 21
 * IMU_FUNCTION_SET_ANGULAR_VELOCITY_PERIOD = 23
 * IMU_FUNCTION_SET_ALL_DATA_PERIOD = 25
 * IMU_FUNCTION_SET_ORIENTATION_PERIOD = 27
 * IMU_FUNCTION_SET_QUATERNION_PERIOD = 29
 * IMU_FUNCTION_ORIENTATION_CALCULATION_ON = 37
 * IMU_FUNCTION_ORIENTATION_CALCULATION_OFF = 38
 * IMU_FUNCTION_ENABLE_STATUS_LED = 238
 * IMU_FUNCTION_DISABLE_STATUS_LED = 239
 * IMU_FUNCTION_RESET = 243
 
.. c:function:: int imu_set_response_expected_all(IMU *imu, bool response_expected)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. c:function:: int imu_enable_status_led(IMU *imu)

 Enables the status LED.
 
 The status LED is the blue LED next to the USB connector. If enabled is is
 on and it flickers if data is transfered. If disabled it is always off.
 
 The default state is enabled.
 
 .. versionadded:: 2.3.1~(Firmware)
 
.. c:function:: int imu_disable_status_led(IMU *imu)

 Disables the status LED.
 
 The status LED is the blue LED next to the USB connector. If enabled is is
 on and it flickers if data is transfered. If disabled it is always off.
 
 The default state is enabled.
 
 .. versionadded:: 2.3.1~(Firmware)
 
.. c:function:: int imu_is_status_led_enabled(IMU *imu, bool *ret_enabled)

 Returns *true* if the status LED is enabled, *false* otherwise.
 
 .. versionadded:: 2.3.1~(Firmware)
 
.. c:function:: int imu_get_protocol1_bricklet_name(IMU *imu, char port, uint8_t *ret_protocol_version, uint8_t ret_firmware_version[3], char ret_name[40])

 Returns the firmware and protocol version and the name of the Bricklet for a
 given port.
 
 This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet
 plugins.
 
.. c:function:: int imu_get_chip_temperature(IMU *imu, int16_t *ret_temperature)

 Returns the temperature in °C/10 as measured inside the microcontroller. The
 value returned is not the ambient temperature!
 
 The temperature is only proportional to the real temperature and it has an
 accuracy of +-15%. Practically it is only useful as an indicator for
 temperature changes.
 
.. c:function:: int imu_reset(IMU *imu)

 Calling this function will reset the Brick. Calling this function
 on a Brick inside of a stack will reset the whole stack.
 
 After a reset you have to create new device objects,
 calling functions on the existing ones will result in
 undefined behavior!
 
.. c:function:: int imu_get_identity(IMU *imu, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

 Returns the UID, the UID where the Brick is connected to, 
 the position, the hardware and firmware version as well as the
 device identifier.
 
 The position can be '0'-'8' (stack position).
 
 The device identifier numbers can be found :ref:`here <device_identifier>`.
 |device_identifier_constant|
 


Callback Configuration Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


.. c:function:: void imu_register_callback(IMU *imu, uint8_t id, void *callback, void *user_data)

 Registers a callback with ID ``id`` to the function ``callback``. The
 ``user_data`` will be given as a parameter of the callback.

 The available IDs with corresponding function signatures are listed
 :ref:`below <imu_brick_c_callbacks>`.


.. c:function:: int imu_set_acceleration_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_ACCELERATION` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 The default value is 0.
 
.. c:function:: int imu_get_acceleration_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_acceleration_period`.
 
.. c:function:: int imu_set_magnetic_field_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_MAGNETIC_FIELD` callback is triggered
 periodically. A value of 0 turns the callback off.
 
.. c:function:: int imu_get_magnetic_field_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_magnetic_field_period`.
 
.. c:function:: int imu_set_angular_velocity_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_ANGULAR_VELOCITY` callback is triggered
 periodically. A value of 0 turns the callback off.
 
.. c:function:: int imu_get_angular_velocity_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_angular_velocity_period`.
 
.. c:function:: int imu_set_all_data_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_ALL_DATA` callback is triggered
 periodically. A value of 0 turns the callback off.
 
.. c:function:: int imu_get_all_data_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_all_data_period`.
 
.. c:function:: int imu_set_orientation_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_ORIENTATION` callback is triggered
 periodically. A value of 0 turns the callback off.
 
.. c:function:: int imu_get_orientation_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_orientation_period`.
 
.. c:function:: int imu_set_quaternion_period(IMU *imu, uint32_t period)

 Sets the period in ms with which the :c:data:`IMU_CALLBACK_QUATERNION` callback is triggered
 periodically. A value of 0 turns the callback off.
 
.. c:function:: int imu_get_quaternion_period(IMU *imu, uint32_t *ret_period)

 Returns the period as set by :c:func:`imu_set_quaternion_period`.
 


.. _imu_brick_c_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the :c:func:`imu_register_callback` function. The parameters consist of
the device object, the callback ID, the callback function and optional
user data:

 .. code-block:: c

    void my_callback(int p, void *user_data) {
        printf("parameter: %d\n", p);
    }

    imu_register_callback(&imu, IMU_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures
are described below.

.. note::
 Using callbacks for recurring events is *always* preferred
 compared to using getters. It will use less USB bandwidth and the latency
 will be a lot better, since there is no round trip time.

.. c:var:: IMU_CALLBACK_ACCELERATION

 .. code-block:: c

  void callback(int16_t x, int16_t y, int16_t z, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_acceleration_period`. The parameters are the acceleration
 for the x, y and z axis.
 
.. c:var:: IMU_CALLBACK_MAGNETIC_FIELD

 .. code-block:: c

  void callback(int16_t x, int16_t y, int16_t z, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_magnetic_field_period`. The parameters are the magnetic field
 for the x, y and z axis.
 
.. c:var:: IMU_CALLBACK_ANGULAR_VELOCITY

 .. code-block:: c

  void callback(int16_t x, int16_t y, int16_t z, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_angular_velocity_period`. The parameters are the angular velocity
 for the x, y and z axis.
 
.. c:var:: IMU_CALLBACK_ALL_DATA

 .. code-block:: c

  void callback(int16_t acc_x, int16_t acc_y, int16_t acc_z, int16_t mag_x, int16_t mag_y, int16_t mag_z, int16_t ang_x, int16_t ang_y, int16_t ang_z, int16_t temperature, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_all_data_period`. The parameters are the acceleration,
 the magnetic field and the angular velocity for the x, y and z axis as
 well as the temperature of the IMU Brick.
 
.. c:var:: IMU_CALLBACK_ORIENTATION

 .. code-block:: c

  void callback(int16_t roll, int16_t pitch, int16_t yaw, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_orientation_period`. The parameters are the orientation
 (roll, pitch and yaw) of the IMU Brick in Euler angles. See
 :c:func:`imu_get_orientation` for details.
 
.. c:var:: IMU_CALLBACK_QUATERNION

 .. code-block:: c

  void callback(float x, float y, float z, float w, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`imu_set_quaternion_period`. The parameters are the orientation
 (x, y, z, w) of the IMU Brick in quaternions. See :c:func:`imu_get_quaternion`
 for details.
 


.. _imu_brick_c_constants:

Constants
^^^^^^^^^

.. c:var:: IMU_DEVICE_IDENTIFIER

 This constant is used to identify a IMU Brick.

 The :c:func:`imu_get_identity` function and the :c:data:`IPCON_CALLBACK_ENUMERATE`
 callback of the IP Connection have a ``device_identifier`` parameter to specify
 the Brick's or Bricklet's type.

