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    BMA280 slope detection interrupt in temporary latched mode switches to off periodically

    BMA280 slope detection interrupt in temporary latched mode switches to off periodically

    Christof
    New Poster

    Hi,

    i have a strange beahaviour after configuring the BMA280 slope detection. I am using INT1 as the associated interrupt and after configuring it in temporary latched mode (e.g. 500ms) the pin switches to low periodically for a short amount of time even if the condition for the slope detection is met permanently. The time between these periodically peaks is the configured latch-time ( i tested it with several configurations).

    I hope someone can help.

    Regards,

    Christof

    3 REPLIES 3

    Jet
    Occasional Contributor

    Hi Sir:

    Do you mean that you use 4.7.5 Slope / any-motion detection?

    I verified this feature, and maybe found the same phenomenon you said.

    I think it is normal, because in the temporary mode an asserted interrupt and selected pin are cleared after a defined period
    of time if you don't read int_status registers, you can browse BMA280 datasheet to know it more.

    Please see the 4.7.1 General features and Figure 6 in the datasheet.

    If you don't want the pin switches to low , you should choose latch mode.

    Hi,

    "Do you mean that you use 4.7.5 Slope / any-motion detection?"

    Yes, thats the one I used

    "I think it is normal, because in the temporary mode an asserted interrupt and selected pin are cleared after a defined period
    of time if you don't read int_status registers, you can browse BMA280 datasheet to know it more.

    Please see the 4.7.1 General features and Figure 6 in the datasheet."

    Looks like i missed this sentence in the Datasheet but in figure 6 it looks like the latch time is triggered after the internal signal from interrupt engine switches to low. Therefore I would expect the interrupt pin to stay high as long as the internal signal never turns low and to trigger the latch-time afterwards.

    Nonetheless, as you can verify this behaviour i expect it to be normal for latched interrupts.

     

    Jet
    Occasional Contributor

    If you don't read int_status register, the interrupt pin keep high in latch mode after slope interrupt occur.

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