diff --git a/targets/TARGET_NUVOTON/TARGET_M480/pinmap.c b/targets/TARGET_NUVOTON/TARGET_M480/pinmap.c
index ced36f0f2eb3..2a6c43cb3fd0 100644
--- a/targets/TARGET_NUVOTON/TARGET_M480/pinmap.c
+++ b/targets/TARGET_NUVOTON/TARGET_M480/pinmap.c
@@ -82,6 +82,22 @@ void pin_mode(PinName pin, PinMode mode)
      */
 }
 
+/* List of pins excluded from testing */
+const PinList *pinmap_restricted_pins()
+{
+    static const PinName pins[] = {
+        USBTX, USBRX,   // Dedicated to USB VCOM
+#if defined(TARGET_NUMAKER_IOT_M487)
+        A2, A3,         // Dedicated to on-board ESP8266 WiFi module RTS/CTS
+#endif
+    };
+    static const PinList pin_list = {
+        sizeof(pins) / sizeof(pins[0]),
+        pins
+    };
+    return &pin_list;
+}
+
 /* List of peripherals excluded from testing */
 const PeripheralList *pinmap_restricted_peripherals()
 {