Configuration

The settings a BNO08x needs: which reports at which rates, the pins sampled at reset, and the limits of the hub.

Every snippet here is compiled from tests/docs/configuration.cpp. The driver has no configuration struct: the hub is configured per report with EnableSensor(), and the board with straps.

Report rates

bool configure_reports(BNO085<MyI2c>& imu) {
  // interval_ms: period between reports. The hub picks a rate between 0.9x and 2.1x the request.
  // sensitivity: for on-change reports, the change that triggers a report; 0 disables the filter.
  return imu.EnableSensor(BNO085Sensor::RotationVector, 10)         // 100 Hz, 9-axis
         && imu.EnableSensor(BNO085Sensor::GyroIntegratedRV, 2)     // 500 Hz, up to 1 kHz
         && imu.EnableSensor(BNO085Sensor::Accelerometer, 4)        // 250 Hz, up to 500 Hz
         && imu.EnableSensor(BNO085Sensor::Magnetometer, 20)        // 50 Hz, up to 100 Hz
         && imu.EnableSensor(BNO085Sensor::StabilityClassifier, 0); // on change
}

Argument	Meaning
interval_ms	Report period. The driver sends interval_ms × 1000 µs; the hub runs between 0.9 and 2.1 times the requested rate
sensitivity	For on-change reports, the change that triggers a report, rounded to an integer and clamped to 0 ... 65535; 0 turns the filter off

The driver does not expose batching or the sensor-specific configuration word: it sends a batch interval of 0 and sensorSpecific = 0. Use the SH-2 library's sh2_setSensorConfig() directly if you need them.

Maximum rates

From the datasheet (figure 6-16). Each report can run at its maximum on its own; all of them at once cannot, so balance high and low rates against the bus bandwidth and the hub's processing.

Report	Maximum (Hz)
GyroIntegratedRV	1000
Accelerometer	500
RotationVector, GameRotationVector (and the AR/VR stabilised versions)	400
Gravity, LinearAcceleration, Gyroscope	400
Magnetometer	100
GeomagneticRotationVector	90

The SH-2 firmware sets the accelerometer to ±8 g and the gyroscope to ±2000 °/s.

Report types

BNO085Sensor holds the 40 SH-2 report IDs the driver decodes; the values are the SH-2 sensor IDs.

Group	Reports
Orientation	RotationVector (9-axis), GameRotationVector (no magnetometer, no heading drift correction), GeomagneticRotationVector (accelerometer + magnetometer, low power), ARVRStabilizedRV, ARVRStabilizedGameRV, GyroIntegratedRV
Motion	Accelerometer, LinearAcceleration, Gravity, Gyroscope, Magnetometer
Uncalibrated and raw	GyroUncalibrated, MagneticFieldUncalibrated, RawAccelerometer, RawGyroscope, RawMagnetometer
Environmental (external sensors on ENV_SCL / ENV_SDA)	Pressure, AmbientLight, Humidity, Proximity, Temperature
Activity and gestures	StepCounter, StepDetector, TapDetector, ShakeDetector, FlipDetector, PickupDetector, TiltDetector, PocketDetector, CircleDetector, SignificantMotion, SleepDetector
Classifiers	StabilityClassifier, StabilityDetector, PersonalActivityClassifier
Other	HeartRateMonitor, IZroMotionRequest, RawOpticalFlow, DeadReckoningPose, WheelEncoder

Which reports a part supports depends on its firmware. The SH-2 reference manual defines each report.

Pins sampled at reset

void select_interface_and_reset(BNO085<MyI2c>& imu) {
  imu.SetBootPin(false); // BOOTN high: boot the application, not the bootloader
  imu.HardwareReset(10); // NRST low 10 ms; PS0, PS1, BOOTN and SA0 are sampled now
}

Pin	Selects	Typical strap
PS0, PS1	Host interface (Hardware)	Both to GND for I2C
SA0	I2C address bit 0: 0x4A or 0x4B	GND or VDDIO
BOOTN	Application or bootloader	10 kΩ to VDDIO; a GPIO for firmware updates
CLKSEL0, CLKSEL1	Internal oscillator, external crystal or external clock	Board-specific; UART modes need the crystal or clock

Accuracy

Rotation vectors and calibrated vectors carry an accuracy from 0 to 3: unreliable, low, medium, high. The hub calibrates continuously; heading (RotationVector) needs the magnetometer calibrated, which takes a few movements through different orientations. Use GameRotationVector when heading does not matter and magnetic disturbances do.

Where the values come from

The report IDs and units are in inc/bno08x.hpp and the API reference; the rates and ranges in the datasheet, sections 6.6 and 6.9.