Disable DEBUGPRINTF I/O when FUNCONF_USE_DEBUGPRINTF = 0

ch32v003fun/ch32v003fun.c

@@ -1003,6 +1003,19 @@ void WaitForDebuggerToAttach()
 
 #endif
 
+#if defined( FUNCONF_USE_DEBUGPRINTF ) && !FUNCONF_USE_DEBUGPRINTF
+int _write(int fd, const char *buf, int size)
+{
+	return size;
+}
+
+// single to debug intf
+int putchar(int c)
+{
+	return 1;
+}
+#endif
+
 void DelaySysTick( uint32_t n )
 {
 	uint32_t targend = SysTick->CNT + n;