.. _onidatasheet_bno055:

BNO055
###########################################
:Authors: Jonathan P. Newman
:Version: 1
:IO: Frame Source, Register Access
:ONIX ID: 9
:ONIX Hubs: :ref:`headstage_64`, :ref:`headstage_neuropix1`

Description
*******************************************
The **BNO055** is a 9-axis inertial measurement unit (IMU) that provides
orientation and acceleration information. At is core, this device corresponds
to a single chip:

- `BNO055 <https://www.bosch-sensortec.com/products/smart-sensors/bno055/>`__
  9-Axis IMU

This device implementation has hard-coded all of the configuration required to
operate the BNO055 with the following properties:

- 100 Hz update rate
- Full on-chip sensor fusion ("NDOF" mode)
- Hardcoded axis map (orientation depends on the headstage)

.. _onidatasheet_bno055_reg:

Register Programming
*******************************************

.. list-table::
    :widths: auto
    :header-rows: 1

    * - Address
      - Name
      - Access
      - Time of Effect
      - POR Value
      - Reset Action
      - Description

    * - 0x00
      - ENABLE
      - R/W
      - On Reset
      - Implementation dependent, see hub documentation
      - None
      - The LSB is used to enable or disable the device data stream:

        * 0x0: data output disabled
        * 0x1: data output enabled

.. _onidatasheet_bno055_d2h:

Device To Host Data Frames
******************************************
Each frame transmitted to the host is structured as follows:

.. wavedrom::

    {
        reg: [
          {bits: 64, name: "Acquisition Clock Counter", type: 0},
          {bits: 32, name: "Device Address", type: 0},
          {bits: 32, name: "Data Size", type: 0, attr: 36},

          {bits: 64, name: "Hub Clock Counter", type: 3},

          {bits: 16, name: "Euler Angle Yaw", type: 4},
          {bits: 16, name: "Euler Angle Roll", type: 4},
          {bits: 16, name: "Euler Angle Pitch", type: 4},

          {bits: 16, name: "Quaternion W", type: 5},
          {bits: 16, name: "Quaternion X", type: 5},
          {bits: 16, name: "Quaternion Y", type: 5},
          {bits: 16, name: "Quaternion Z", type: 5},

          {bits: 16, name: "Linear Acceleration X", type: 6},
          {bits: 16, name: "Linear Acceleration Y", type: 6},
          {bits: 16, name: "Linear Acceleration Z", type: 6},

          {bits: 16, name: "Gravity Vector X", type: 7},
          {bits: 16, name: "Gravity Vector Y", type: 7},
          {bits: 16, name: "Gravity Vector Z", type: 7},

          {bits: 8, name: "Temperature", type: 2},

          {bits: 2, name: "Sys. Cal.", type: 2},
          {bits: 2, name: "Gyro. Cal.", type: 2},
          {bits: 2, name: "Accel. Cal.", type: 2},
          {bits: 2, name: "Mag. Cal.", type: 2}
        ],
        config: {bits: 416, lanes: 13, vflip: true, hflip: true, fontsize: 11}
    }

All IMU data is signed with the exception of the calibration status bits (last
byte in the frame). The unit conversions for each of these measurements are as
follows:

- Euler angle (Tait-Bryan formalism)

  - Yaw: 0 to 360 degrees
  - Roll: -180 to 180 degrees
  - Pitch: -90 to 90 degrees

.. math::

    1^{\circ} = 16\ LSB

- Quaternion

.. math::

    1 = 2^{14}\  LSB

- Acceleration & Gravity Vector

.. math::

    1\ m/s^2 = 100\ LSB

- Temperature

.. math::

    1^{\circ}C = 1\ LSB

- Calibration Status

  - 0: not calibrated
  - 3: fully calibrated

Host To Device Data Frames
******************************************
This device does not accept input frames. All write attempts will fail with an
error.