https://devzone.nordicsemi.com/f/nordic-q-a/35805/use-of-timer-in-beacon-exampleI am using SDK15 , nRF52832 custom board , keil uVISION 5 , ble_app_beacon example. I am adding timer to the example. In below code, when I comment out update_vbatt() &amp; advertising_init() LED toggles perfectly means timer is working. but with thoseen-USTelligent Community 13Fri, 29 Jun 2018 12:05:29 GMThttps://devzone.nordicsemi.com/thread/138272?ContentTypeID=1Fri, 29 Jun 2018 12:05:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:478d9d1b-6caf-4acd-8dd9-718777fc3d84Susheel Nuguru<p>Hi,</p> <p>1) You can know what peripherals softdevice is reserving <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s132.sds%2Fdita%2Fsoftdevices%2Fs130%2Fsd_resource_reqs%2Fhw_block_interrupt_vector.html&amp;cp=2_3_1_0_6_0">here</a>. You can see that softdevice is using Timer0 and&nbsp; hence applications does not have access to this when softdevice is enabled.</p> <p>2) Softdevice also uses RTC0, and app_timer library (which is application code) uses RTC1</p> <p>2) Normally timers_start in examples initializes application timers RTC1 and TIMER1 (in some cases) based on the use case. Please read the documentation on this in <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v15.0.0%2Flib_timer.html&amp;cp=4_0_0_3_48">infocenter</a>, I think this topic is very well covered here in the forum also.</p> <p>About your problem having issues with timer after using&nbsp;update_vbatt() function.&nbsp;Either it is touching the app_timer registers (RTC1) or disabling its interrupt or maybe there is a hardfault or system reset in this function. I think you should be able to debug this once your run your code in debug mode and stepping through&nbsp;update_vbatt function.</p><div style="clear:both;"></div>