Hi,
When BMA280 is working in low power mode 1 (LPM1), it switches between suspend mode and normal mode automatically based on the preselected sleep time. This is so called duty cycling to save current consumption. However, when an interrupt is enabled, every time when BMA280 wakes up from suspend mode and enters normal mode, it will take one measurement and then spend the amount of duration time of the interrupt to take more measurements to see if the interrupt condition is met or not. If yes, BMA280 will generate an interrupt signal. If the interrupt condition is always met, then BMA280 will not go to suspend mode. Instead, it will remain in normal mode to keep checking if the interrupt condition is still valid or not. If not, then it will enter suspend mode and wake up again once the sleep time expires.
This means that if you only use BMA280 no-motion interrupt in LPM1, when BMA280 is stationary, then BMA280 will always stay in normal mode that consumes 130uA all the time.
So my suggestion to you is that whenever you see no-motion interrupt, you disable it and enable Slope (also called any-motion) interrupt. Whenever you see any-motion interrupt, you disable it and then enable no-motion interrupt. Therefore, you will save current consumption in all situation.
Thanks.
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