diff --git a/arch/arm/src/sam3u/sam3u_allocateheap.c b/arch/arm/src/sam3u/sam3u_allocateheap.c
index b27f28564e..1d94c1e488 100755
--- a/arch/arm/src/sam3u/sam3u_allocateheap.c
+++ b/arch/arm/src/sam3u/sam3u_allocateheap.c
@@ -113,7 +113,7 @@ void up_allocate_heap(FAR void **heap_start, size_t *heap_size)
 
   /* Allow access to the heap memory */
 
-   sam3u_mpuheap((uintptr_)g_heapbase, size);
+   sam3u_mpuheap((uintptr_t)g_heapbase, size);
 }
 
 /************************************************************************