H3LIS331DL output seems not correct

[EYuen]

Hi, i'm testing H3LIS331DL and the configuration is as below:

Normal mode, 1000Hz sampling, +/-400g

Sensor data is read by MCU under 1ms timer. If sensor is placed upside or downside, the output value of is verified to be normal (+1/-1g value).

However if apply a small click on the PCB, the output value can be over 100g. Refer to attached figure which captured by logic analyser, the output value for x/y/z axis are 0xFEC0, 0xF1E0, 0x7FF0 (decimal value would be -320, -3616, 32752). The resolution is 12.208mg. Hence the acceleration are -3.9g, -44.1g, 399.8g. I think 399.8g would be too high... I've tested some samples but same result. What's the possible cause? Thanks.

[Eleon BORLINI]

​Hi, which kind of "click" do you apply to the board? A mechanical pulse? Or something electrical or acoustical? And does the detected acceleration remains high also after the stimulus? In case of a mechanical pulse, please consider that the narrower the pulse, the higher the peak intensity (not 100g but high...)

Could you also share the Vdd / VddIO configuration?

[EYuen]

Hi, please see below video that device is free falling from 3cm height. The measured peak impact can be 108g, 374g... Those value seems to be not true in my opinion. (SPI reading is verified to be correct by logic analyser as mention above), Vdd & VddIO are connected to same level. Battery (CR2032 typical 3.0V) and power supply (3.0V) are tested, but same result.

https://youtu.be/7DMpWE8bE1w

[NLieb]

Make sure you shift the incoming values by 4 bits to the left. Althoug the datasheet claims 16 bit values you can see at the end of the pages that's actually 12 bit.