LSM6DSTTR datasheet(22/180 Pages) STMICROELECTRONICS

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Embedded low-power features

LSM6DST

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DocID033525 Rev 2

2.1

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 ultra-low 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 phone is in a front pants pocket and the user goes from sitting to

standing or standing to sitting;

Doesn’t trigger when phone is in a front pants pocket and the user is walking,

running or going upstairs.

2.2

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 LSM6DST 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.

2.3

Finite State Machine

The LSM6DST can be configured to generate interrupt signals activated by user-defined

motion patterns. To do this, up to 16 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. Figure 1: Generic

state machine shows a generic state machine.

LSM6DSTTR Datasheet(PDF) 22 Page - STMicroelectronics