How does the LIS2DH accelerometer generate its clock, and what could be causing the sampling frequency discrepancy in its interrupts?

[ADelb.1]

I'm working with the LIS2DH accelerometer and I'm trying to obtain acceleration data at a rate of 100 Hz. However, I've noticed that the accelerometer interrupts have a frequency of 99 Hz. Also this frequency changes if I use another accelerometer of the same model.

I'm curious to know what kind of clock the accelerometer is using and what error is causing this discrepancy in the sampling frequency. What percentage of error in frequency is expected?

Any help or insights would be greatly appreciated. Thank you!

[Federica Bossi · Accepted solution]

Hi @ADelb.1​ ,

Data from characterization show that the ODR accuracy is usually below 5%, however these data are not guaranteed in production because a limited samples of sensors were tested.

Consider that there is a piece to piece variability and so it is possible to have different frequencies for different accelerometers of the same model.

I suggest you to always set the BDU bit of CTRL_REG4 (23h) register, to avoid any dataout shift.

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[ADelb.1]

Thanks for your anwser Federica.

Sorry, in the previous message I confused the model of the accelerometer, it is the lis2dh12 not the lis2dh. Does this one have the same accuracy?

[Federica Bossi]

Hi @ADelb.1​ ,

Yes it has.

If my previous reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster ;)