diff --git a/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c b/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c
index 934088a94b..4d6a10d6f5 100644
--- a/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c
+++ b/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/us_ticker.c
@@ -100,7 +100,7 @@ static void rtc1_start(uint32_t prescaler)
 
 /**@brief Function for stopping the RTC1 timer. We don't expect to call this.
  */
-static void rtc1_stop(void)
+void rtc1_stop(void)
 {
     if (!m_rtc1_running) {
         return;