MMA8451 Interrupt config question

[jesperwe]

Hello. I am looking for help on how to achieve the following using an MMA8451 Accelerometer sensor:

The device is to remain in WAKE mode as long as it is in motion, and goes to SLEEP if it is still (not in motion) for 30 seconds.

It should only go back to WAKE after a double tap pulse is detected.

I want the INT1 pin to indicate that the device has gone to sleep (ASLP interrupt) and the INT2 pin to indicate that a double tap pulse interrupt has occurred.

I do specifically NOT want the FF/Motion interrupt to cause any change on INT1 or INT2, it should only keep the device from falling asleep.

After going back and forth in the spec and app notes I can't understand how to activate FF/Motion without having it affect the INT1 or INT2 pins.

Is it possible to do what I am looking for?

/j

[TomasVaverka]

Hi Jesper,

Unfortunately the internal logic does not allow to achieve exactly what you want. To use the FF/Motion function to keep the device from falling asleep, both the WAKE_FF_MT and INT_EN_FF_MT bits need to be set and thus routed to the INT1 or INT2 pin.

Let me know if you have any other questions.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.