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jgaldana
Visitor II
November 29, 2016
Question

Free-fall and motion detection simultaneously on LIS3DH

  • November 29, 2016
  • 1 reply
  • 796 views
Posted on November 29, 2016 at 23:46

Hi support,

We wonder if there is any register configuration that allow us to route the motion detection to the INT1 pin and the free-fall detection to the INT2 pin and both working at the same time? Both pins are routed/connected to our uP and we need to have these two features enabled and working at the same time.

Thanks in advance
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    1 reply

    M
    Miroslav BATEK
    ST Employee
    December 6, 2016
    Posted on December 06, 2016 at 11:48

    Yes, this configuration is possible.

    You should enable interrupt generator (AOI1) on interrupt pin INT1 (CTRL_REG3 0x22h) and interrupt generator (AOI2) on interrupt pit INT2 (CTRL_REG6 0x25h).

    Then configure interrupt generator according to you needs. Configuration of INT1 is described in the datasheet, check registers INT1_CFG, INT1_SRC, INT1_THS, INT1_DURATION. Below is the list of registers for INT2 which are not in the current version of the datasheet but will be published soon.

    Please also check application note

    http://www.st.com/resource/en/application_note/cd00290365.pdf

    for details about free fall and wake-up interrupt configuration.

    INT2_CFG (34h)

    AOI -> AND/OR combination of interrupt events. Default value: 0

    6D -> 6-direction detection function enabled. Default value: 0.

    ZHIE ->Enable interrupt generation on Z high event. Default value: 0

    ZLIE ->Enable interrupt generation on Z low event. Default value: 0

    YHIE ->Enable interrupt generation on Y high event. Default value: 0

    YLIE ->Enable interrupt generation on Y low event. Default value: 0

    XHIE ->Enable interrupt generation on X high event. Default value: 0

    XLIE ->Enable interrupt generation on X low event. Default value: 0

    INT2_SRC (35h)

    0-> do not change

    IA->Interrupt active.

    ZH->Z high. Default value: 0

    ZL->Z low. Default value: 0

    YH->Y high. Default value: 0

    YL->Y low. Default value: 0

    XH->X high. Default value: 0

    XL->X low. Default value: 0

    INT2_THS (36h)

    THS[6:0] ->

    1 LSb = 16 mg @ FS = 2 g

    1 LSb = 32 mg @ FS = 4 g

    1 LSb = 62 mg @ FS = 8 g

    1 LSb = 186 mg @ FS = 16 g

    INT2_DURATION (37h)

    D[6:0] 1 LSb = 1/ODR (Duration time is measured in N/ODR, where N is the content of the duration register.)

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