AN2960 datasheet(28/41 Pages) STMICROELECTRONICS

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Free-fall and wake-up registers

AN2960

28/41

Doc ID 15557 Rev 1

Figure 12.

DCRM bit function

8.5

FF_WU_DURATION_1 (33h)

Set the minimum duration of the free-fall, wake-up event that must be recognized by the

LIS331DL.

D7, D0 define the minimum duration of the programmed inertial event such as free-fall and

wake-up that must be recognized by the device. Duration increments and maximum value

depend on the ODR chosen. For an output data rate of 400 Hz, the register allows setting a

duration spanning from 0 to 637.5 ms in increments of 2.5 ms. Conversely, when the output

data rate is set to 100 Hz, it is possible to define an event duration spanning from 0 to 2.55

seconds in increments of 10 ms. The counter used to implement the duration function is

blocked when the LIR bit in the configuration register is set to one and the interrupt event

has occurred.

Free-fall event

Counter value

Duration THS

Free-fall interrupt

Free-fall event

Counter value

Duration THS

Free-fall interrupt

Free-fall event

Counter value

Duration THS

Free-fall interrupt

Duration

D7, D0

Duration value. Default value: 0000 0000

AN2960 Datasheet(PDF) 28 Page - STMicroelectronics