https://devzone.nordicsemi.com/f/nordic-q-a/7714/code-runs-in-debugger-but-not-on-power-upI have an app built in IAR using S110, SDK 7 on PCA10028 DK board that runs fine with the debugger, but if I stop the debugger and unplug and plug back in the USB cable, it does not run. This used to work, but has recently stopped. The only thing Ien-USTelligent Community 13Mon, 22 Jun 2015 19:24:55 GMThttps://devzone.nordicsemi.com/thread/27485?ContentTypeID=1Mon, 22 Jun 2015 19:24:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8a1d9b4a-0201-4fcd-a7ed-235574dd8635Jeff Wormsley<p>And I found the answer.</p> <p>I had ENABLE_DEBUG_LOG_SUPPORT enabled, and this requires an implementation of printf. When running in the IAR debugger, there is a mechanism for &quot;semi-hosting&quot; that redirects printf and scanf and the like for stdio to the debugger. Running without the debugger, nowhere for that stuff to go and it hangs. Removing ENABLE_DEBUG_LOG_SUPPORT from my compile options allows the code to work from a power up without the debugger.</p> <p>Jeff.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/27484?ContentTypeID=1Mon, 22 Jun 2015 18:42:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:0e817490-5bbb-4524-b660-957aab6a2d06Jeff Wormsley<p>By using the LEDs and putting in rather large delays, I&#39;ve found that the place the code hangs is in dm_init(). Not sure why it hangs there running outside the debugger, and not when running inside the debugger, but at least I can see where it is hanging.</p> <p>The dm_init() routine is fairly large, so it will take some time to figure out where it is in there that is causing the issue.</p><div style="clear:both;"></div>