https://devzone.nordicsemi.com/f/nordic-q-a/13940/rtt-viewer---j-link-plus-won-t-debugI&#39;m using a nRF51 with 32K RAM and SD120. When I started using RTT Viewer I could send data to the terminal, and debug my code. Recently my J-Link plus won&#39;t allow me to debug. In Keil debug mode, I click the run button, and my application starts, buten-USTelligent Community 13Fri, 20 May 2016 12:43:53 GMThttps://devzone.nordicsemi.com/thread/53272?ContentTypeID=1Fri, 20 May 2016 12:43:53 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5e6a77dd-c05a-4ede-8524-8c7134d1673fSusheel Nuguru<p>seems like the battery was just enough to run your application but was not enough to for the debugger to detect the chip. Thanks for the update and please keep us posted if you see this issue again.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/53271?ContentTypeID=1Fri, 20 May 2016 12:41:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3c087830-e80c-43c9-9133-2bbbd60266f9c cook<p>Keil Version 5.18a and JLink dll V5.12f</p> <p>I think the issue was a low battery. I&#39;m using custom hardware, which runs on a small coin cell. I noticed the battery was getting low and replaced it. Since then I haven&#39;t had the issue.</p> <p>It still seems a bit strange that the RTT Viewer was still receiving data from my Jlink, and I could load my code, reset and start my application with the debugger. Just not actually debug. If the issue proves not to be battery related, I&#39;ll repost the question.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/53270?ContentTypeID=1Fri, 20 May 2016 10:15:22 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8a375639-0f83-4013-b77e-bb15e9b1736eSusheel Nuguru<p>haven&#39;t seen it myself. is it related to updated jlink drivers? which version of Keil are you using?</p><div style="clear:both;"></div>