Is softdevice doing anything when ADV is disabled?

[Al Bundy]

I perform some time critical task in my application and sometimes this task fails. Before executing the task I make sure that my device in not in BLE connection and ADV is disabled.

Is there any chance that softdevice (I use s110 sdk v.8.0.0) will preempt my code when advertising is disabled however softdevice is enabled?

If yes, is there any timing information of such scenarios?

I know that I can disable softdevice to be sure but after reenabling it needs full reinitialization.

[Hung Bui]

As far as I know, if you are not in a connection, not doing any advertising, then the only possible activity of the softdevice is to calibrate the 32kHz RC. If you don't use RC but using crystal, I think you are safe.

 

Some alternatives are to use timeslot API, or to temporarily disable the softdevice and then enable it again. 

 

[Al Bundy]

Yes, I use crystal.

[Hung Bui]

You can test if the softdevice preempt your application by simply flipping a GPIO pin in your task routine or in main loop. Then can use a logic analyzer to check if there is any period that the pin flipping get preempted (flat).  Make sure you don't have interrupts from other peripherals.