Data Sheet

October 2017 BNO080 Datasheet 1000-3927

The highlighted row is also shown pictorially in Figure 4-2. For rotations that are not a multiple of 90 degree

rotations the appropriate angular rotations should be applied.

4.1.1 Tare

The outputs generated by BNO080 can also be oriented under user control by a tare function. Taring allows a

user to mount the BNO080 in an arbitrary manner and by invoking the tare command the SH-2 software will

determine the orientation that needs to be applied to the outputs to align with an Up, North, East frame of

reference. This orientation will then be applied to all motion outputs.

If the Rotation Vector or Geomagnetic Rotation Vector is necessary for the application, the BNO080 must have

resolved magnetic North before applying the tare function. Otherwise when the magnetometer calibrates the

heading will change.

4.1.1.1 Types of Tare

There are two types of tare defined, tare around all axes and tare around the Z-axis. A tare around all axes solves

for tilt and heading. A tare around the Z-axis only solves for the heading. In an HMD application, the all-axis tare

is useful for initial adjustment, further adjustments are likely for heading reasons and then the tare-Z may be more

applicable.

The result of a tare function is applied wherever power is applied to the device. To ensure the reorientation is

permanent there is a Persist Tare function to allow storage of the orientation configuration. Note that if tare-Z is

used for the Game Rotation Vector, then the BNO080 must be reset. At startup, the BNO080 will apply the new

orientation to the Game Rotation Vector. Persist tare does not apply to the Game Rotation Vector.

Refer to the BNO080 Tare Function Usage Guide application note [8] for more information on how to use tare.