ADXL372 invalid triplets for XYZ configuration

Hello,

I am using ADXL372 in stream mode to collect sample sets of concurrent 3-axis data using FIFO.

Configuration :
HPF on with filter Settling Time of 370ms
Full-Bandwidth mode

SPI is used with 6MHz CLK using DMA download on a TI CC2640R2F micro-controller and with the TI SimpleLink SDK.


FIFO format :

  • XYZ (3-Axis) in stream mode for ODR's from 400 to 3200 Hz
    • Watermark Level =  501 (167 XYZ triplets).
  • Z (single axis) in stream mode for 6400 Hz ODR
    • Watermark Level =  500 (500 Z axis samples).

For 6400Hz, the series start indicator is present in all the downloaded Z-axis samples, when FIFO Full interrupt occurs.

Problem Scenario:

Upon FIFO FULL interrupt , the data is downloaded and validated to find available number of valid samples.

Sometimes the series start indicator is missing for 2-3 triplets and thus exactly 167 triplets(watermark level) is not available.

Could this situation be avoided by a specific configuration?

Any clue regarding this will be of great help.

Thanks in advance.

Regards,

Shanmathi P