https://devzone.nordicsemi.com/f/nordic-q-a/25909/eclipse-environment-and-rtt-viewerI made eclipse environment and get rtt log with JLinkGDBServerCL.exe (set in eclipse environment) J-Link RTT Client so I start &quot;Debug&quot; in eclipse, and start &quot;J-Link RTT Client&quot; then I can see to RTT log. My Question. thisen-USTelligent Community 13Fri, 13 Oct 2017 09:50:37 GMThttps://devzone.nordicsemi.com/thread/102047?ContentTypeID=1Fri, 13 Oct 2017 09:50:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f52c33d1-36dc-4376-a77c-8ae3837e2402Jeong Hyun Seok<p>I found answer.</p> <p>it&#39;s just matter of optimization parameter issue in Makefile I just change O1 to O0, then it works. :-)</p> <blockquote> </blockquote> <p>CFLAGS = -DNRF_LOG_USES_RTT=1 -DNRF_LOG_USES_COLORS=0 -DDEBUGGING_MODE=1 -Wall -Werror <strong>-O0</strong> -g3</p><div style="clear:both;"></div>