LIS2DUXS12 datasheet(24/104 Pages) STMICROELECTRONICS

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5.4

Tilt detection

The tilt function helps to detect activity change and has been implemented in hardware using only the

accelerometer to achieve targets of both ultralow power consumption and robustness during the short duration of

dynamic accelerations.

The tilt function is based on a trigger of an event each time the device's tilt changes and can be used with

different scenarios, for example:

•

Triggers when the phone is in a front pants pocket and the user goes from sitting to standing or standing to

sitting

•

Does not trigger when the phone is in a front pants pocket and the user is walking, running, or going

upstairs

5.5

Significant motion detection

The significant motion detection (SMD) function generates an interrupt when a ‘significant motion’, that could be

due to a change in user location, is detected. In the LIS2DUXS12 device this function has been implemented in

hardware using only the accelerometer.

SMD functionality can be used in location-based applications in order to receive a notification indicating when the

user is changing location.

5.6

Finite state machine

The LIS2DUXS12 can be configured to generate interrupt signals activated by user-defined motion patterns. To

do this, up to 8 embedded finite state machines can be programmed independently for motion detection such as

glance gestures, absolute wrist tilt, shake and double-shake detection.

Definition of finite state machine

A state machine is a mathematical abstraction used to design logic connections. It is a behavioral model

composed of a finite number of states and transitions between states, similar to a flow chart in which one can

inspect the way logic runs when certain conditions are met. The state machine begins with a start state, goes to

different states through transitions dependent on the inputs, and can finally end in a specific state (called stop

state). The current state is determined by the past states of the system. The following figure shows a generic

state machine.

Figure 10. Generic state machine

LIS2DUXS12

Tilt detection

DS14035 - Rev 2

page 24/104

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