diff --git a/libraries/mbed/common/error.c b/libraries/mbed/common/error.c
index 7c6a556c03..0af7fd1caf 100644
--- a/libraries/mbed/common/error.c
+++ b/libraries/mbed/common/error.c
@@ -21,6 +21,10 @@
 #include <stdio.h>
 #endif
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+    
 WEAK void error(const char* format, ...);
 WEAK void error(const char* format, ...) {
 #if DEVICE_STDIO_MESSAGES
@@ -31,3 +35,7 @@ WEAK void error(const char* format, ...) {
 #endif
     exit(1);
 }
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_NRF51822/us_ticker.c b/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_NRF51822/us_ticker.c
index b6b2551753..b650d52e0e 100644
--- a/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_NRF51822/us_ticker.c
+++ b/libraries/mbed/targets/hal/TARGET_NORDIC/TARGET_NRF51822/us_ticker.c
@@ -62,7 +62,7 @@ void TIMER1_IRQHandler(void){
 }
 #endif 
 void us_ticker_init(void){
-    if (us_ticker_inited){
+    if (us_ticker_inited && US_TICKER_TIMER->POWER){
         return;
     }
     
@@ -75,18 +75,18 @@ void us_ticker_init(void){
     
     US_TICKER_TIMER->PRESCALER = 4;
     US_TICKER_TIMER->BITMODE = TIMER_BITMODE_BITMODE_16Bit; 
-	US_TICKER_TIMER->TASKS_CLEAR =1;
-	US_TICKER_TIMER->CC[1] = 0xFFFF;
-	US_TICKER_TIMER->INTENSET = TIMER_INTENSET_COMPARE1_Set << TIMER_INTENSET_COMPARE1_Pos;
+    US_TICKER_TIMER->TASKS_CLEAR =1;
+    US_TICKER_TIMER->CC[1] = 0xFFFF;
+    US_TICKER_TIMER->INTENSET = TIMER_INTENSET_COMPARE1_Set << TIMER_INTENSET_COMPARE1_Pos;
 	
-	NVIC_SetPriority(US_TICKER_TIMER_IRQn, 3);
+    NVIC_SetPriority(US_TICKER_TIMER_IRQn, 3);
     NVIC_EnableIRQ(US_TICKER_TIMER_IRQn);
     
     US_TICKER_TIMER->TASKS_START = 0x01;
 }
 
 uint32_t us_ticker_read(){
-    if (!us_ticker_inited){
+    if (!us_ticker_inited || US_TICKER_TIMER->POWER==0){
         us_ticker_init();
     }
     
@@ -101,7 +101,7 @@ uint32_t us_ticker_read(){
 }
 
 void us_ticker_set_interrupt(unsigned int timestamp){
-    if (!us_ticker_inited)
+    if (!us_ticker_inited || US_TICKER_TIMER->POWER==0)
     {
         us_ticker_init();
     }