NuMaker tickless example

Revision:
21:5424989f037f
Parent:
13:c1c711d573f2
--- a/main.cpp	Tue Feb 25 17:34:02 2020 +0800
+++ b/main.cpp	Thu Feb 25 15:25:00 2021 +0800
@@ -13,7 +13,9 @@
 EventFlags wakeup_eventflags;
 
 int main() {
-
+#ifdef MBED_MAJOR_VERSION
+    printf("Mbed OS version %d.%d.%d\r\n\n", MBED_MAJOR_VERSION, MBED_MINOR_VERSION, MBED_PATCH_VERSION);
+#endif
     config_pwrctl();
     config_button_wakeup();
     config_wdt_wakeup();