https://devzone.nordicsemi.com/f/nordic-q-a/16027/is-it-possible-to-decrease-the-softdevice-start-timeHello, I&#39;m currently working on profiling an embedded application on an nRF52 using the S132 SoftDevice. I&#39;ve found that the svcall sd_softdevice_enable takes approximately 250ms to return control to the calling thread. This increases our startupen-USTelligent Community 13Wed, 07 Sep 2016 11:07:28 GMThttps://devzone.nordicsemi.com/thread/61114?ContentTypeID=1Wed, 07 Sep 2016 11:07:28 GMT137ad170-7792-4731-bb38-c0d22fbe4515:cf0c3c06-273f-47d6-b86f-bc405404af94bjj<p>Indeed we are using the system OFF low power mode. I will look into whether we can use the RC oscillator instead.</p> <p>Many thanks for your help.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/61113?ContentTypeID=1Mon, 29 Aug 2016 11:08:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fecf7156-f3e6-444b-aa2a-a9bc9306229dEinar Thorsrud<p>The <code>sd_softdevice_enable()</code> does not return until the 32 kHz clock is started, and the startup time for the 32 kHz <em>crystal</em> oscillator is 0.25 s (see <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/clock.html?cp=2_2_0_18_3_3#unique_2071721038">spec</a>). If startup time is important, you could consider using the 32 kHz <em>RC</em> oscillator instead, which has a startup time of only 600 µs (see <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/clock.html?cp=2_2_0_18_3_2#unique_1650707097">spec</a>). In that case the total time spend in <code>sd_softdevice_enable()</code> is approximately 1.1 ms.</p> <p>Note that in general the start-up time is not very important as the SoftDevice is started once, and the LF clock is always running. The exception is if you use system OFF low power mode, where 32 kHz clock is not running, and the SoftDevice must be re-initialized after wakeup.</p><div style="clear:both;"></div>