SD BLE Event priority and task management

[Dave_couling]

Currently I have a few characteristics which are Authorized Read and Writes. Upon detected of the Authorization from the Central I trigger a few events such as:

1. Measure Temp
2. Measure Battery
3. Start/Stop app_timers
4. Blink LED
5. Start PWM
6. Start Timer and GPIOTE sd_nvic_SetPriority(TIMER2_IRQn, NRF_APP_PRIORITY_LOW);
7. sd_ble_gap_rssi_start()
8. sd_ble_gatts_value_set()
9. Save to Flash

...etc

In cases like reading Temp or Battery, these call sd_ functions. So my question is, does this violate the proper IRQ Priority sequencing? Since I initialize the SOFTDEVICE_HANDLER_INIT with scheduler param = true I always assumed this meant BLE events are now moved automatically to scheduler context and thus I didn't have an issue called any sd_ functions from these events. Could someone provide some clarity on this please? Thank you

I ask because in the field some testers have seen their device basically brick. Power Reset's do not bring it back to life. They have to physically trigger the Reset pin in order to get the Device working again.

-DC

[RK]

That question doesn't make sense, are you asking about BLE event handlers or app_timers, which are two entirely different things. And app_timer_start() is a function you call, not a function you write which calls other things.

Either way the answer continues to be the same, if you are running in any context less than the priority of the SVC handler, you can call sd_ functions. If you are running at or above that priority, you cannot. You don't need to enumerate every possible scenario, that's the entire rule, there is no more to it than that.

[Dave_couling]

I apologize for the lack of clarity. I mean any potential issue with functions called from within on_ble_evt(ble_evt_t * p_ble_evt)

[RichieJH]

I do calls all the time there without an issue.

[RK]

Indeed. And the reason there is no issue is because, and this is the last time I'm writing this, on_ble_evt() runs in a context lower than the SVC interrupt priority so you can call as many sd_ functions from it as you like.

[RichieJH]

Although make sure you don't call in such a way that prevents it from doing its other tasks, that could be bad. But if you are always returning in short order its hard to see how you could. Oh, and I wouldn't try to do something funky that might get in the way of those other calls. They are housekeeping and without them occurring you might face issues.