Free fall detection in LSM6DSO not working.

[DDuc .1]

Hello everyone!

I got LSM6DSO on my custom board with stm32l4 MCU, I only use I2C interface (that i don't use interrupt). I'm using LSM6DSO free fall example code in STMems standard C drivers, I can get the id of LSM6DSO so i think the I2C interface is working fine, I have tried doing some free fall test (drop it from my hand) but the FF_IA in WAKE_UP_SRC kept staying 0) so the free fall can't be detected.

Can anyone help me?

[niccolò]

Hi @DDuc .1​ ,

did you configure the wake-up interrupt?

I ask this, because the register you are reading is for the wake-up

you should check the FF_IA bit in register ALL_INT_SRC (1Ah)

also can you confirm that you set the INTERRUPTS_ ENABLE bit in register TAP_CFG2 (58h)?

even if you do not route the interrupts on INT1 or INT2, you have to set it to let the free-fall trigger

I hope this helps

Niccolò

[DDuc .1]

Hi @niccolo.ruffini​ 

Your configuring the wake-up interrupt suggestion really help me a lot, I have configured wake-up interrupt and it worked! The FF_IO in WAKE_UP_SRC turn to 1 as my expectation.

Beside, I have checked the FF_IO from ALL_INT_SRC instead of WAKE_UP_SRC bit it didn't go to 1 when I tested free-fall (even I routed the interrupt). Do you know why ?

Thanks for your big help!

[niccolò]

Hi @DDuc .1​ ,

you are welcome, I'm glad to hear it worked =)

regarding the ALL_INT_SRC it can depend on how you configured other registers.

depending on your configuration I figured one of the two suggestion was right.

if you want we can dig deep into it.

Niccolò

p.s. if the problem is solved, you can select a best answer to help other members of the community with similar problems