diff --git a/arch/arm/src/samv7/sam_mcan.c b/arch/arm/src/samv7/sam_mcan.c
index 230e6e22e8f..4c56cc9d839 100755
--- a/arch/arm/src/samv7/sam_mcan.c
+++ b/arch/arm/src/samv7/sam_mcan.c
@@ -124,7 +124,7 @@
 #  define MCAN_ALIGN_UP(n)  (((n) + MCAN_ALIGN_MASK) & ~MCAN_ALIGN_MASK)
 
 #  ifndef CONFIG_ARMV7M_DCACHE_WRITETHROUGH
-#    warning !!! This driver will not workCONFIG_ARMV7M_DCACHE_WRITETHROUGH=y!!!
+#    warning !!! This driver will not work without CONFIG_ARMV7M_DCACHE_WRITETHROUGH=y!!!
 #  endif
 #endif