diff --git a/libraries/DataFlash/DataFlash_APM2.cpp b/libraries/DataFlash/DataFlash_APM2.cpp
index f9cba3a067..d38f2cdba0 100644
--- a/libraries/DataFlash/DataFlash_APM2.cpp
+++ b/libraries/DataFlash/DataFlash_APM2.cpp
@@ -97,8 +97,8 @@ unsigned char DataFlash_APM2::SPI_transfer(unsigned char data)
 
     // get spi3 semaphore if required.  if failed to get semaphore then
     // just quietly fail
-    if ( _semaphore != NULL) {
-        if( !_semaphore->get(this) ) {
+    if ( _spi3_semaphore != NULL) {
+        if( !_spi3_semaphore->get(this) ) {
             return 0;
         }
     }
@@ -113,8 +113,8 @@ unsigned char DataFlash_APM2::SPI_transfer(unsigned char data)
     retval = UDR3;
 
     // release spi3 semaphore
-    if ( _semaphore != NULL) {
-        _semaphore->release(this);
+    if ( _spi3_semaphore != NULL) {
+        _spi3_semaphore->release(this);
     }
 
     return retval;
diff --git a/libraries/DataFlash/DataFlash_APM2.h b/libraries/DataFlash/DataFlash_APM2.h
index 43ee446c24..37efe0178e 100644
--- a/libraries/DataFlash/DataFlash_APM2.h
+++ b/libraries/DataFlash/DataFlash_APM2.h
@@ -27,9 +27,9 @@ private:
     void                    BlockErase (uint16_t BlockAdr);
     void                    ChipErase(void (*delay_cb)(unsigned long));
 
-    AP_Semaphore* _semaphore;
+    AP_Semaphore*           _spi3_semaphore;
 public:
-    DataFlash_APM2(AP_Semaphore* semaphore = NULL) : _semaphore(semaphore) {}
+    DataFlash_APM2(AP_Semaphore* spi3_semaphore = NULL) : _spi3_semaphore(spi3_semaphore) {}
 
     void        Init();
     void        ReadManufacturerID();