don't override CFG_TUSB_OS in cdc_dual_ports example
#error "Incorrect RHPort configuration"
#endif
-// This example doesn't use an RTOS
+#ifndef CFG_TUSB_OS
#define CFG_TUSB_OS OPT_OS_NONE
+#endif
// CFG_TUSB_DEBUG is defined by compiler in DEBUG build
// #define CFG_TUSB_DEBUG 0
