diff --git a/radio/src/targets/simu/simpgmspace.cpp b/radio/src/targets/simu/simpgmspace.cpp
index 282644bc2..44e249e15 100644
--- a/radio/src/targets/simu/simpgmspace.cpp
+++ b/radio/src/targets/simu/simpgmspace.cpp
@@ -95,6 +95,18 @@ uint16_t getTmr2MHz()
 #endif
 }
 
+U64 CoGetOSTime(void)
+{
+  // one tick is 2ms
+#if defined(_MSC_VER)
+  return GetTickCount()/2;
+#else
+  struct timespec ts;
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  return ((U64)ts.tv_sec * 1000 + ts.tv_nsec / 1000000) /2;
+#endif
+}
+
 void simuInit()
 {
 #if defined(STM32)
diff --git a/radio/src/targets/simu/simpgmspace.h b/radio/src/targets/simu/simpgmspace.h
index e2853d112..317505c93 100644
--- a/radio/src/targets/simu/simpgmspace.h
+++ b/radio/src/targets/simu/simpgmspace.h
@@ -429,7 +429,7 @@ OS_TID CoCreateTask(FUNCPtr task, void *argv, uint32_t parameter, void * stk, ui
 #define CoWaitForSingleFlag(...)       0
 #define CoTickDelay(x)                 sleep(2*(x))
 #define CoCreateFlag(...)              0
-#define CoGetOSTime(...)               0
+U64 CoGetOSTime(void);
 #define UART_Stop(...)
 #define UART3_Stop(...)
 #define USART_GetITStatus(...)         0