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Can ADXL375 trigger shocks and high g data not present in the FIFO register?

Question asked by mmehta on Dec 14, 2015
Latest reply on Apr 27, 2016 by AustinR

I am doing development on the ADXL375 for a future product.

 

I have set with the following parameters

 

Data format control - 0x0B - LSB

Data rate and power mode control - 0x0F - 3200 Hz sample rate

FIFO control - 0xDF - Trigger mode with 32 samples

Shock threshold - 0x0C - (780 mg * 12 = 9360 mg)

Shock Duration -  0xFF - (625 us * 255 = 159375 us)

Axis control for single shock/double shock - 0x07 (shock detection enabled on all axis)

Interrupt enable control - 0x40 (single shock)

 

Also, doing a multiple-byte read when reading the data and multiplying by 0.049 to convert into g's.

 

When i get a shock event on the device, i read all the 32 samples (on all axis) from the FIFO register. This data shows the variation in the g values indicating a shock happened but the highest g value only ends up around 6 or 7 g's but not 9.36 as set using the threshold register.

 

Can ADXL375 trigger shocks and high g data will not be present in the FIFO register even when using 3200 Hz sample rate? Please advice.

 

Thanks,

Mayank

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