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H3LIS331DL interrupt threshold

Pradeep Hegde
Associate
Posted on February 16, 2017 at 23:37

hello,

we are using H3LIS331DL to record shock on our instrument.

we have setup INT1 to interrupt when acceleration>threshold.

when the interrupt occurs we read out values and store it.

we have observed that sometimes we read out acceleration that is less than threshold.

why is this happening

Pradeep

#authentix #h3lis331dl
2 REPLIES 2
Miroslav BATEK
ST Employee
Posted on February 17, 2017 at 11:04

I suppose it is caused by a delay between the time when interrupt occurs and the time you read the value from output registers. In case of very short peek which exceed the threshold, you can read subsequent value which is already lower then the threshold. You can try to decrease the sensor ODR and/or optimize code for your MCU, which reads the value if interrupt occurs.

Pradeep Hegde
Associate
Posted on February 17, 2017 at 16:19

Miroslav, thanks for responding.

ODR = 1KHz.  this means we have 1ms between updates of internal registers.

Once the interrupt occurs, we read out all 6 values within 750 micro seconds, so the chances of us missing any value is very small.

'You can try to decrease the sensor ODR' -- how will this help us read the values of a very short peak?

Pradeep