Hi,
BMA253 low power mode 2 (LPM2) automatically switches between normal mode and standby mode based on sleeptime. Every time when BMA253 wakes up from standby mode to normal mode, it will take a measurement and place the data sample in FIFO if it is enabled. Then BMA253 goes to standby mode. When the sleeptime expires, it wakes up and takes a measurement again.
However, if high-g interrupt is enabled, then every time when BMA253 wakes up from standby mode to normal mode, it will take more measurements based on high-g duration to see if high-g interrupt event is valid or not and place the first data sample in FIFO if it is enabled. Then BMA253 goes to standby mode. When the sleeptime expires, it wakes up and takes a few measurements again.
This means that in LPM2 mode if FIFO is enabled you will not be able to see data samples that are beyond high-g threshold, because high-g interrupt event always happens after FIFO data sample is filled in.
Please see the attached two screenshots for more informaiton. BMA253 is set to 2000Hz ODR, +/-2g full scale range, LPM2 with equidistant sampling time-based, high-g threshold 1.4g and high-g duration 2ms.
In order to see FIFO data beyond high-g threshold you have to always use normal mode.
Thanks.
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