diff --git a/targets/TARGET_NUVOTON/TARGET_M480/sleep.c b/targets/TARGET_NUVOTON/TARGET_M480/sleep.c
index 49ff02008a..ab1b9daa37 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/sleep.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/sleep.c
@@ -36,7 +36,7 @@ int pwmout_allow_powerdown(void);
 /**
  * Enter Idle mode.
  */
-void sleep(void)
+void hal_sleep(void)
 {
     struct sleep_s sleep_obj;
     sleep_obj.powerdown = 0;
@@ -47,7 +47,7 @@ void sleep(void)
 /**
  * Enter Power-down mode while no peripheral is active; otherwise, enter Idle mode.
  */
-void deepsleep(void)
+void hal_deepsleep(void)
 {
     struct sleep_s sleep_obj;
     sleep_obj.powerdown = 1;