diff --git a/targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c b/targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c
index 6e07e785fa1..033b9e5898a 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/lp_ticker.c
@@ -103,8 +103,6 @@ void lp_ticker_init(void)
 
     // Schedule wakeup to match semantics of lp_ticker_get_compare_match()
     lp_ticker_set_interrupt(wakeup_tick);
-
-
 }
 
 timestamp_t lp_ticker_read()
@@ -144,21 +142,13 @@ timestamp_t lp_ticker_read()
 
 void lp_ticker_set_interrupt(timestamp_t timestamp)
 {
-    uint32_t now = lp_ticker_read();
+    uint32_t delta = timestamp - lp_ticker_read();
     wakeup_tick = timestamp;
 
     TIMER_Stop((TIMER_T *) NU_MODBASE(timer3_modinit.modname));
 
-    int delta = (int) (timestamp - now);
-    if (delta > 0) {
-        cd_major_minor_clks = (uint64_t) delta * US_PER_TICK * TMR3_CLK_PER_SEC / US_PER_SEC;
-        lp_ticker_arm_cd();
-    } else {
-        // NOTE: With lp_ticker_fire_interrupt() introduced, upper layer would handle past event case.
-        //       This code fragment gets redundant, but it is still kept here for backward-compatible.
-        void lp_ticker_fire_interrupt(void);
-        lp_ticker_fire_interrupt();
-    }
+    cd_major_minor_clks = (uint64_t) delta * US_PER_TICK * TMR3_CLK_PER_SEC / US_PER_SEC;
+    lp_ticker_arm_cd();
 }
 
 void lp_ticker_fire_interrupt(void)
diff --git a/targets/TARGET_NUVOTON/TARGET_M480/us_ticker.c b/targets/TARGET_NUVOTON/TARGET_M480/us_ticker.c
index 6665c3cfa46..cae36145014 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/us_ticker.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/us_ticker.c
@@ -147,16 +147,9 @@ void us_ticker_set_interrupt(timestamp_t timestamp)
 {
     TIMER_Stop((TIMER_T *) NU_MODBASE(timer1hires_modinit.modname));
 
-    int delta = (int) (timestamp - us_ticker_read());
-    if (delta > 0) {
-        cd_major_minor_us = delta * US_PER_TICK;
-        us_ticker_arm_cd();
-    } else {
-        // NOTE: With us_ticker_fire_interrupt() introduced, upper layer would handle past event case.
-        //       This code fragment gets redundant, but it is still kept here for backward-compatible.
-        void us_ticker_fire_interrupt(void);
-        us_ticker_fire_interrupt();
-    }
+    uint32_t delta = timestamp - us_ticker_read();
+    cd_major_minor_us = delta * US_PER_TICK;
+    us_ticker_arm_cd();
 }
 
 void us_ticker_fire_interrupt(void)