Datasheet

BMI160
Data sheet
Page 36
BST-BMI160-DS000-07 | Revision 0.8 | February 2015 Bosch Sensortec
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Note: Specifications within this document are preliminary and subject to change without notice.
Before the interrupt is actually fired, the device must remain flat for a certain period (e.g.
int_flat_hold_time = 1s).
Note:
Rotation of the Reference Coordinate System is possible for the Flat interrupt, see chapter
2.6.5.3.
2.6.7 Low-g / free-fall Detection (Accel)
For freefall detection, the absolute values of the acceleration data of all axes are observed
(global criteria). There are two modes of this interrupt – single and sum. The mode is selected
by the register int_low_mode (‘1’ means sum mode). In the single mode, absolute value of the
acceleration of each axis is compared with the threshold int_low_th. In the sum mode, a sum of
the absolute values of all accelerations |acc_x| + |acc_y| + |acc_z| is compared with the
threshold. The int_low_mode bit is only enabled when int_low_mode_en is set. If
int_low_mode_en is ‘0’ then sum mode is enabled and the int_low_mode bit has no function.
The int_low_mode_en bit is NVM backed in an extended page.
The interrupt will be generated if the threshold is exceeded and the measured acceleration
stays below the hysteresis level int_low_th+int_low_hy for some minimum number of
samples(int_low_dur).
time
time
time
low_th + low_hy
low_th
low_dur
INT
non-latched
latched
counter
value
Figure 14: Free-fall detection
acceleration