diff --git a/firmware/export/s5l8700.h b/firmware/export/s5l8700.h
index 94b0c4e703..ff8daf044a 100644
--- a/firmware/export/s5l8700.h
+++ b/firmware/export/s5l8700.h
@@ -312,7 +312,7 @@
 #define TDCNT                   (*(REG32_PTR_T)(0x3C700074))     /* Counter register */
 #define FIVE_USEC_TIMER         (((uint64_t)(*(REG32_PTR_T)(0x3C700080)) << 32) \
                                 | (*(REG32_PTR_T)(0x3C700084)))  /* 64bit 5usec timer */
-#define USEC_TIMER              FIVE_USEC_TIMER * 5 /* usecs */
+#define USEC_TIMER              (FIVE_USEC_TIMER * 5) /* usecs */
 
 /* 12. NAND FLASH CONTROLER */
 #if CONFIG_CPU==S5L8701