I have used the LIS3DH for movement and angle detection for about 18 months. I now wish to use it for fall detection. Previously I ued another brand where you setup a register and get an interrupt when a zero G occurs in all axes for a certain time. I can see no way to do this with the LIS3DH but it advertises that it can be done. I can do it ''manually'' by continually reading each axis and setting a timer to record when it is continuously like this for, say 100mS. Is there an easier way that uses less power?
May be ''Application Note'' AN3308 is help you?CD00290365.pdf: AN3308, 6.3 Free-fall and wake-up interrupts:The LIS3DH interrupts signal can behave as free-fall and wake-up. (and so on...)
It appears that some of the registers in the attached image from Thiago Reis (e.g. INT2_CFG, INT2_THS) are not defined in the datasheet. Also, I'm not able to see an interrupt when executing the sequence in paragh. 6.3.3 of AN3308 (Wakeup with HPF). I was not able to find the address of the register HP_FILTER_RESET mentioned in step # 8, since this register is also missing from the datasheet. Could there be an updated version of the datasheet that I may have missed? It would be great if someone at ST could send a working sequence for the wake-up usecase with HPF turned on.
