RE: SoftDevice Timers - Real-life Requirement(s) vs SoftDevice Spec

snoopy20 — Fri, 08 May 2020 09:50:45 GMT

So to confirm, the softdevice (s112) consumes one RTC and one TIMER internally (from datasheet) and the ble library blocks off another RTC for scheduling?

My app requirements are currently one RTC and two timers for-

RTC1 = 0.5s tasker runner
TIMERB = ADC @ ~500Hz
TIMERC = falling edge counter.

RTC1 and TIMERC start at the same time and TIMERC stops counting by PPI event when RTC1 reaches it's compare point, so a fairly accurate frequency is determined (measuring upto 255Hz so pretty low).

If the BLE is also taking up RTC1 then I'll have to look again at how do do it. I can see the scheduler library is being used, perhaps I should use that to start the ADC instead (accuracy isn't needed).

RE: SoftDevice Timers - Real-life Requirement(s) vs SoftDevice Spec

Turbo J — Thu, 07 May 2020 14:25:37 GMT

The app_timer library actually only uses one RTC hardware timer. it is intended for use cases with timeouts in seconds or minutes.

In your example the conn params are checked (and negotiated) and if that fails it causes a disconnect after some time. This allows somewhat faster conn pars during connection setup (key exchange, discovery) and then you switch to low power (=long interval) after 30 sec or a minute.