MC3253 Datasheet, PDF (32/72 Pages) List of Unclassifed Manufacturers – Axis Accelerometer

MC3253 3-Axis Accelerometer
Preliminary Datasheet
9.5 DROP DETECTION
Drop detection is defined as a low-g acceleration applied to all axes. Two modes of drop
detection are supported:
Mode A: Drop detection is a summation of all 3 axes:
Drop is detected when:
Sum( mag(X) + mag(Y) + mag(Z) ) < 0.5g ± DROP_TH Threshold
else Drop not detected;
Mode B: Drop detection is the logical AND of three comparisons:
Drop is detected when:
mag(X) < 0.5g ± DROP_TH Threshold and
mag(Y) < 0.5g ± DROP_TH Threshold and
mag(Z) < 0.5g ± DROP_TH Threshold
else Drop not detected.
The typical drop threshold value is on the order of < 0.5g for all axes. The drop detection range
is from 0.125g to 0.872g. The drop debounce value (bit-field DDB in the DROP: Drop Event
Control Register) can filter from 1 to 8 consecutive events before setting the drop interrupt.
Event
X Axis
Y Axis
Z Axis
Drop Mode
A
Sum (|X|
+
|Y|
+
|Z|) < 0.5g ±
DROP_TH
Drop Mode
B
|X| < 0.5g ±
DROP_TH
and
|Y| < 0.5g ±
DROP_TH
and
|Z| < 0.5g ±
DROP_TH
Table 21. Drop Event Evaluation
mCube Proprietary.
APS-048-0026v1.2
© 2014 mCube Inc. All rights reserved.
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