https://devzone.nordicsemi.com/f/nordic-q-a/26784/no-rtt-viewer-output-if-no-call-to-nrf_pwr_mgmt_runHi! I&#39;ve based a new project for the nRF52840/S140/Preview-DK on ble_central/ble_app_uart_c . I use the NRF_LOG_XXXX macros for debug and they print fine in RTT Viewer. However, I do not need any powersave in my app but when I remove the callen-USTelligent Community 13Fri, 10 Nov 2017 09:21:23 GMThttps://devzone.nordicsemi.com/thread/105286?ContentTypeID=1Fri, 10 Nov 2017 09:21:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d9eebf54-2995-42e3-a165-75be62a9fd07Lars<p>Thanks! That seem to do the trick and I could keep NRF_LOG_DEFERRED enabled :)</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/105285?ContentTypeID=1Fri, 10 Nov 2017 08:48:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7b909cdf-4488-4f34-b2b6-91ded95532c7J&#248;rgen Holmefjord<p>Glad to hear that you got it working. You can also use <code>NRF_LOG_PROCESS()</code>/<code>NRF_LOG_FLUSH()</code> to process the log queue when the CPU have nothing else to do. Heavy logging inside functions can slow down the application. Please refer the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v14.1.0/nrf_log.html?cp=4_0_0_3_25_3#nrf_log_performance"><em>&quot;Preformance&quot;-section</em></a> in the library documentation.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/105287?ContentTypeID=1Fri, 10 Nov 2017 08:41:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:abd3527b-ced3-4f9c-af86-37bf5ccf38c1Lars<p>I can answer this myself after checking the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v14.1.0/nrf_log.html?cp=4_0_0_3_25">InfoCenter</a> a little better.</p> <p>NRF_LOG_DEFERRED was enabled. Quote: <em>&quot;NRF_LOG_DEFERRED - If enabled, then the logs are not processed directly where they are called but deferred to idle state. &quot;</em></p> <p>If I disable this in <em>sdk_config.h</em>, everything seems to work fine!</p><div style="clear:both;"></div>