BMA400 Entering Sleep Mode Unintended

[Boondocks9918]

Hi everyone, 

For an asset tracker application, we use the BMA400 to wake-up the device on activity. 

Now for some reason the BMA400 sometimes goes into sleep mode, not low-power mode. Which, as I understand it, prevents the wake-up trigger to be fired and will never wake-up our device on movement.

I verified this by checking the BMA400 power mode - using bma400_get_power_mode - when waking up by a heartbeat trigger.
I also verified that after configuring the BMA400 that the power mode is BMA400_NORMAL_MODE. 

• Is there a way that the BMA400 goes to sleep mode on its own? 
  
  • From the documentation I gather that this should only be at power cycle, reset or setting the power mode manually?
• Any ideas what the issue could be?

Any thoughts/ideas are highly appreceated.

[BSTRobin]

Hi Boondocks9918,

You can refer to the knowledge base in community https://community.bosch-sensortec.com/t5/Knowledge-base/Introduction-about-BMA400-Auto-Wakeup-and-Au...

[Boondocks9918]

Hi BSTRobin,

Thank you for your reply.
I've consulted the knowledge base, and the interrupts are working well. There are just some cases where the BMA400 goes into sleep mode without the firmware telling it so (this functionality is nowhere in our codebase), at which point the interrupts ofc stop working.

So I wonder what it could be that would put the BMA400 into sleep mode, any idea? 

PS: Out application corresponds to Auto wakeup and auto low power by activity, but I left out the configuration of GEN2 as it is not used (also not in the example) and just set it to BMA400_INACTIVE (as in the example).

Thanks!

[Boondocks9918]

Any more ideas @BSTRobin ?

Thanks!

[BSTRobin]

Hi Boondocks9918,

BMA400 power mode only supports automatic switching between normal mode and low power mode.
If the power mode is switched from other modes to sleep mode, it may be because the sensor has received a command to enter sleep mode.