AN2989

Interrupt generation

Doc ID 15761 Rev 1

19/28

5

Interrupt generation

The LIS331DLM can provide two interrupt signals and offers several possibilities to

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

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

INT2_DURATION.

The LIS331DLM interrupt signal can behave as free-fall, wakeup 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 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 of LSB value in normal mode

ODR (Hz)

Duration of LSB value (ms)

50

20

100

10

400

2.5

Table 17.

Duration of LSB value in low-power mode

ODR (Hz)

Duration of LSB value (s)

0.5

2

11

20.5