diff --git a/src/app/definition.h b/src/app/definition.h
index 7148e3a..6d783fe 100644
--- a/src/app/definition.h
+++ b/src/app/definition.h
@@ -22,6 +22,7 @@ typedef enum {  GPIO_0 = 0,
 #define RTC_BEGIN_ERR   B00000001
 #define DISP_BEGIN_ERR  B00000010
 #define SDCARD_INIT_ERR B00000100
+#define IO_INIT_ERR     B00001000
 
 #define MALLOC_ERR   B00000001