https://devzone.nordicsemi.com/f/nordic-q-a/81416/zephyr-rtt-log-output-stops-with-shell-is-enabledHello, I had RTT configured as the logging backend and it was working fine. When I enabled the SHELL on RTT, the log output stopped. Maybe more specifically, printk() output stopped. It looks like this should be the default operation but it isn&#39;ten-USTelligent Community 13Mon, 15 Nov 2021 23:49:54 GMThttps://devzone.nordicsemi.com/thread/339105?ContentTypeID=1Mon, 15 Nov 2021 23:49:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2fba5899-5a41-4024-8f7f-fecb47f1f506Allen<p>Put these options in &quot;prj.conf&quot; to enable Shell and Log output via RTT. This will also enable printk() RTT output.</p> <div style="background-color:#1e1e1e;color:#d4d4d4;font-family:Menlo, Monaco, &#39;Courier New&#39;, monospace;font-size:10.5px;font-weight:normal;line-height:16px;white-space:pre;"> <div><span style="color:#569cd6;">CONFIG_NCS_SAMPLES_DEFAULTS</span><span style="color:#d4d4d4;">=n</span></div> <div> <div style="background-color:#1e1e1e;color:#d4d4d4;font-family:Menlo, Monaco, &#39;Courier New&#39;, monospace;font-size:10.5px;font-weight:normal;line-height:16px;white-space:pre;"> <div><span style="color:#569cd6;">CONFIG_SHELL</span><span style="color:#d4d4d4;">=y</span></div> <div><span style="color:#569cd6;">CONFIG_SHELL_STACK_SIZE</span><span style="color:#d4d4d4;">=1024</span></div> <div><span style="color:#569cd6;">CONFIG_SHELL_BACKEND_SERIAL</span><span style="color:#d4d4d4;">=n</span></div> <div><span style="color:#569cd6;">CONFIG_SHELL_BACKEND_RTT</span><span style="color:#d4d4d4;">=y</span></div> <br /> <div><span style="color:#569cd6;">CONFIG_LOG</span><span style="color:#d4d4d4;">=y</span></div> <div><span style="color:#569cd6;">CONFIG_LOG_PRINTK</span><span style="color:#d4d4d4;">=y</span></div> <div><span style="color:#569cd6;">CONFIG_LOG_BACKEND_UART</span><span style="color:#d4d4d4;">=n</span></div> <div><span style="color:#569cd6;">CONFIG_SHELL_LOG_BACKEND</span><span style="color:#d4d4d4;">=y</span></div> </div> </div> </div><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/339104?ContentTypeID=1Mon, 15 Nov 2021 23:27:17 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4d957c9e-a2ed-49fc-be68-0202de91dd3aAllen<p>Ok, here is some more info.</p> <p>CONFIG_SHELL_LOG_BACKEND=y</p> <p>This option can only be enabled if CONFIG_LOG_MINIMAL=n</p> <p>CONFIG_LOG_MINIMAL can not be set to &#39;n&#39; when CONFIG_NCS_SAMPLES_DEFAULTS=y</p> <p>However setting CONFIG_NCS_SAMPLES_DEFAULTS=n sees to have its own set of problems.</p> <p></p> <p>I am still unable to get printk() output when the CONFIG_SHELL=y</p><div style="clear:both;"></div>