Interrupt generation

AN2847

20/31

Doc ID 15136 Rev 2

5

Interrupt generation

The LIS331DLH can provide two interrupt signals and offers several possibilities for

personalizing these signals. The registers involved in the interrupt generation behavior are

CTRL_REG3, INT1_CFG, INT2_CFG, INT1_THS, INT2_THS, INT1_DURATION, and

INT2_DURATION.

The LIS331DLH interrupt signal can behave as Free-Fall, Wake-Up or 6D orientation

detection.

Whenever an interrupt condition is verified, the interrupt signal is generated and by reading

the INT1_SRC and INT2_SRC registers it is possible to detect which condition has

occurred.

5.1

Duration

The content of the duration registers set the minimum duration of the interrupt event to be

recognized. Duration steps and maximum values depend on the ODR chosen.

When in Normal mode, duration time is measured in N/ODR, where N is the content of the

duration register and ODR is 50, 100, 400, 1000 Hz.

Table 15.

Interrupt mode configuration

AOI

6D

Interrupt mode

0

0

OR combination of interrupt events

0

1

6 direction movement recognition

1

0

AND combination of interrupt events

1

1

6 direction position recognition

Table 16.

Duration LSB value in normal mode

ODR (Hz)

Duration LSB value (ms)

50

20

100

10

400

2.5

1000

1