Data Sheet

BNO055
Data sheet
Page 40
BST-BNO055-DS000-14 | Revision 1.4 | June 2016 Bosch Sensortec
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on
to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
slope_th
INT
slope
acceleration
acc(t
0
)
acc(t
0
−1/(2*bw))
slope(t
0
)=acc(t
0
)−acc(t
0
−1/(2*bw))
time
time
time
slope_dur
slope_dur
Axis selection
X-axis
[ACC_INT_Settings]: xxxxx1xxb
Y-axis
[ACC_INT_Settings]: xxxx1xxxb
Z-axis
[ACC_INT_Settings]: xxx1xxxxb
3.8.2.2 Accelerometer Any Motion Interrupt
The any-motion interrupt uses the slope between successive acceleration signals to detect
changes in motion. An interrupt is generated when the slope (absolute value of acceleration
difference) exceeds a preset threshold. It is cleared as soon as the slope falls below the
threshold. The principle is made clear in Figure 2: Principle of any-motion detection.
Figure 2: Principle of any-motion detection
The threshold is defined through register ACC_AM_THRES. In terms of scaling 1 LSB of
ACC_AM_THRES corresponds to 3.91 mg in 2g-range (7.81 mg in 4g-range, 15.6 mg in 8g-
range and 31.3 mg in 16g-range). Therefore the maximum value is 996 mg in 2g-range
(1.99g in 4g-range, 3.98g in 8g-range and 7.97g in 16g-range).
The time difference between the successive acceleration signals depends on the selected
bandwidth and equates to 1/(2*bandwidth) (t=1/(2*bw)). In order to suppress false triggers,
the interrupt is only generated (cleared) if a certain number N of consecutive slope data
points is larger (smaller) than the slope threshold given by ACC_AM_THRES. This number is
set by the AM_DUR bits. It is N = AM_DUR + 1.