diff --git a/libraries/AP_Semaphore/AP_Semaphore.cpp b/libraries/AP_Semaphore/AP_Semaphore.cpp
index 69a1f22036..05ac5fbc6a 100644
--- a/libraries/AP_Semaphore/AP_Semaphore.cpp
+++ b/libraries/AP_Semaphore/AP_Semaphore.cpp
@@ -13,9 +13,6 @@ extern "C" {
  #include "WConstants.h"
 #endif
 
-// include some global constants
-AP_Semaphore AP_Semaphore_spi3;
-
 // Constructor
 AP_Semaphore::AP_Semaphore()
 {
@@ -78,4 +75,4 @@ bool AP_Semaphore::call_on_release(void* caller, ap_semaphore_callback callback_
     }
     sei();
     return result;
-}
\ No newline at end of file
+}
diff --git a/libraries/AP_Semaphore/AP_Semaphore.h b/libraries/AP_Semaphore/AP_Semaphore.h
index e7ee8cc99d..d11f595b42 100644
--- a/libraries/AP_Semaphore/AP_Semaphore.h
+++ b/libraries/AP_Semaphore/AP_Semaphore.h
@@ -36,7 +36,4 @@ protected:
     ap_semaphore_callback     _waiting_callback;       // call back procedure of process waiting for sempahore
 };
 
-// some global semaphores
-extern AP_Semaphore AP_Semaphore_spi3;
-
-#endif  // AP_SEMAPHORE
\ No newline at end of file
+#endif  // AP_SEMAPHORE