app_timer stops when BLE advertising times out

RE: app_timer stops when BLE advertising times out

masterLee — Tue, 28 May 2019 12:10:47 GMT

Ok I will follow your notes.

Thank you for your support!

RE: app_timer stops when BLE advertising times out

Jørgen Holmefjord — Tue, 28 May 2019 11:25:56 GMT

The app_timer library should not be affected by disabling or enabling the softdevice, but I would recommend that you use the clock driver in the SDK (nrf_drv_clock) to request LFCLK. This driver will make sure that the LFCLK should stay enabled it the softdevice state change.

RE: app_timer stops when BLE advertising times out

masterLee — Tue, 28 May 2019 10:55:47 GMT

Ok now I get it.

Possible Scenario: Assume that I have the softdevice disabled and I create an app timer instance in my code and enable it (with clock driver for example), the RTC will start counting.

What would happen if at some point I decide to enable the softdevice (i.e with button press) while the app timer instance is running? What will happen to the app_timer instance? Will it reset its counting, stop, or something else?

Will the softdevice start normally or not?

Is there something else that I have to be aware of?

Thank you for your help

RE: app_timer stops when BLE advertising times out

Jørgen Holmefjord — Mon, 27 May 2019 14:37:38 GMT

No, it is not possible to run the softdevice off another clock source, there is only one LFCLK in the chip. Just avoid entering system OFF mode, and make sure that you have a app_timer running to not stop the RTC. LFCLK is always running when softdevice is enabled, but if you disable it in your application at anytime, will have to request the LFCLK from clock driver or directly in the CLOCK peripheral.

RE: app_timer stops when BLE advertising times out

masterLee — Mon, 27 May 2019 14:14:02 GMT

Hi,

Is it possible to isolate the app_timer functionality from the advertising process?

I want the app_timer to be independent of the softdevice . Is it possible to run the softdevice on another clock source and leave the LFCLK for the RTC only?

I want to use the app_timer as real time counter that never stops in order to create timestamps for my sensor samples.

RE: app_timer stops when BLE advertising times out

Jørgen Holmefjord — Mon, 27 May 2019 11:09:49 GMT

Hi,

The default behavior in many of the SDK examples is to go to System OFF sleep mode when advertising enters idle state. See function sleep_mode_enter() and BLE_ADV_EVT_IDLE in on_adv_evt().

In System OFF mode, all clock sources will be stopped and the chip can only wake up by these sources. Wake up from System OFF mode will trigger a chip reset.

Best regards,
Jørgen