diff --git a/include/stack_macros.h b/include/stack_macros.h
index f53afb2cd..bd9ec2770 100644
--- a/include/stack_macros.h
+++ b/include/stack_macros.h
@@ -91,7 +91,7 @@
     #define taskCHECK_FOR_STACK_OVERFLOW()                                                      \
     do {                                                                                        \
         const uint32_t * const pulStack = ( uint32_t * ) pxCurrentTCB->pxStack;                 \
-        const uint32_t ulCheckValue = ( uint32_t ) 0xa5a5a5a5;                                  \
+        const uint32_t ulCheckValue = ( uint32_t ) 0xa5a5a5a5U;                                 \
                                                                                                 \
         if( ( pulStack[ 0 ] != ulCheckValue ) ||                                                \
             ( pulStack[ 1 ] != ulCheckValue ) ||                                                \