--- /dev/null
+/*****************************************************************
+ * unexpected interrupt vector handler
+ * can be overwriten by user function with the same name:
+ * interrupt(NOVECTOR) _unexpected_()
+ * {
+ *
+ * }
+ *
+ *****************************************************************/
+
+ .weak _unexpected_
+
+ .text
+ .p2align 1,0
+
+_unexpected_:
+ reti