https://devzone.nordicsemi.com/f/nordic-q-a/43012/how-to-turn-off-12-leds-together-after-a-certain-interval-of-time-the-leds-are-connected-using-shift-register-hc595-and-bluetooth-module-nrf51822-is-the-main-moduleThere are 12 LEDs which are connected using shift register HC595 ,the module used is nrf51822(bluetooth module). I want the LEDs to go off after 3 seconds interval. My code is as follows- #include &quot;main.h&quot; #include &quot;uart.h&quot; #include &quot;nrf_delay.h&quot; #includeen-USTelligent Community 13Fri, 25 Jan 2019 10:37:08 GMThttps://devzone.nordicsemi.com/thread/167866?ContentTypeID=1Fri, 25 Jan 2019 10:37:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:17025b17-fa26-4ee8-92b4-e6bdb80732c6awneil[quote userid="76799" url="~/f/nordic-q-a/43012/how-to-turn-off-12-leds-together-after-a-certain-interval-of-time-the-leds-are-connected-using-shift-register-hc595-and-bluetooth-module-nrf51822-is-the-main-module"]code doesn&#39;t seem to work[/quote] <p>is uninformative</p> <p><a href="http://www.catb.org/esr/faqs/smart-questions.html#code">www.catb.org/.../smart-questions.html</a></p> <p>So:</p> <ol> <li>what did you <em>expect</em> it to do?</li> <li>what is it <em>actually</em> doing?</li> <li>what debugging have <em><strong>you</strong> </em>done to find what&#39;s going on?</li> </ol> <p>Before adding the complication of&nbsp; the shift register, Does your code work for just blinking a simple, single LED on the Nordic Dev Kit?</p> <p>Does your LED control code work on its own?</p> <p>How To Debug:&nbsp;<a href="https://www.avrfreaks.net/comment/2418156#comment-2418156">www.avrfreaks.net/.../2418156</a></p> <p>How to properly post source code:</p> <p><img alt=" " src="https://devzone.nordicsemi.com/resized-image/__size/320x240/__key/communityserver-discussions-components-files/4/3835._5F00_Insert-Code-_2D00_-Nordic.png" /></p><div style="clear:both;"></div>