Datasheet

Data Sheet
BMA456
Page 41
BST-BMA456-DS000-01 | Version 1.1 | October 2017 Bosch Sensortec
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Note: Specifications within this document are subject to change without notice.
Any Motion / No motion detection
Any Motion Detection:
The any-motion detection uses the slope between two acceleration signals to detect changes in motion.
The interrupt is configured by setting at least one of the following flags:
FEATURES_IN.any_motion.settings_2.en_x, FEATURES_IN.any_motion.settings_2.en_y and
FEATURES_IN.any_motion.settings_2.en_z, respectively for each axis.
It generates an interrupt when the absolute value of the slope (the difference between two
accelerations) exceeds the preset FEATURES_IN.any_motion.settings_1.threshold for a certain
number, FEATURES_IN.any_motion.settings_2.duration, of consecutive data points.
The slope (difference) is being computed between the current acceleration sample and the reference
sample. The reference sample is updated while the Anymotion is detected; basically this means the
reference is the last state when sensor detected Anymotion.
If the same number of data points falls below the FEATURES_IN.any_motion.settings_1.threshold,
the interrupt is reset.
anym_th
INT
slope
acc(t
0
+dt)
acc(t
0
)
slope(t
0
+dt)= acc(t
0
+dt) - acc(t
0
)
time
time
anym_du
r
anym_dur
latched
Any-motion (slope) interrupt detection