https://devzone.nordicsemi.com/f/nordic-q-a/17335/how-many-rtc-use-inside-ble_uart-example-of-sdk-12i m using gcc toochain setup in windows for pca10028 devlopment kit... and load BLE_UART code inside it... and now i m add onother rtc code inside it.. but it&#39;s not work... so, may i know that how many rtc use inside ble_uart code.. like rtc1 use foren-USTelligent Community 13Wed, 26 Oct 2016 07:09:03 GMThttps://devzone.nordicsemi.com/thread/66611?ContentTypeID=1Wed, 26 Oct 2016 07:09:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:93e590df-0fff-470c-b46b-011754acd5b9J&#248;rgen Holmefjord<p>The nRF51422, which is found on nRF51-DK (PCA10028) board, has only 2 RTCs. See chapter 4.3 of the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf51/dita/nrf51/pdflinks/51422_ps.html?cp=3_4_0">nRF51422 Product Specification v3.2</a> about Real Time Conter (RTC). When using a softdevice, access to <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s130.sds/dita/softdevices/s130/sd_resource_reqs/hw_block_interrupt_vector.html?cp=3_6_2_0_6_0">RTC0 is blocked</a>. RTC1 is, like you mention, used by the timer library (app_timer), and you will have to use this library to use RTC1 in your application. What are you trying to accomplish?</p><div style="clear:both;"></div>