https://devzone.nordicsemi.com/f/nordic-q-a/8863/bug-in-bsp-hHi Nordic, Where is a bug in bsp.h nRF51 SDK 9.0.0 and I think it was were before as well: LEDS_NUMBER equal 0 causing a compilation error. In Line 59: #if (LEDS_NUMBER &gt; 0) &amp;&amp; !defined(BSP_SIMPLE) #define BSP_LED_APP_TIMERS_NUMBER 2 #elseen-USTelligent Community 13Mon, 24 Aug 2015 13:25:19 GMThttps://devzone.nordicsemi.com/thread/32594?ContentTypeID=1Mon, 24 Aug 2015 13:25:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:aa5c57e3-bb5f-4046-97db-fa87f7001fe3MartinBL<p>You are right. It was there previously as well. At least in <a href="https://devzone.nordicsemi.com/question/41676/use-of-bsp_simple-causing-build-failure-in-bsp-version-811/">SDK 8.1.1</a>. It was supposed to be fixed, but apparently there has been a mistake. The SDK team is notified. Thank you for bringing it to our attention.</p><div style="clear:both;"></div>