diff --git a/src/app/definition.h b/src/app/definition.h
index 821f006..6791b66 100644
--- a/src/app/definition.h
+++ b/src/app/definition.h
@@ -39,6 +39,10 @@ typedef enum {  GPIO_0 = 0,
 #define BATT_DIFF 95
 #define USB_THRESHOLD 600
 
+//SD card file structure :
+#define AP_CFG_FILE "/CONFIG/AP.CFG"
+#define STA_CFG_FILE "/CONFIG/STA.CFG"
+
 typedef enum { OR_0 = 2, OR_90 = 3, OR_180 = 0, OR_270 = 1 } Orientation;
 
 typedef enum { BIT = 0, BYTE, KBIT, KBYTE, MBIT, MBYTE, GBIT, GBYTE } SizeUnit;