diff --git a/libpsx/include/memcard.h b/libpsx/include/memcard.h
index 11b443f..4ca965a 100644
--- a/libpsx/include/memcard.h
+++ b/libpsx/include/memcard.h
@@ -4,6 +4,8 @@
 /*Card connection related*/
 enum memcard_status
 {
+	/** Memory card state unknown */
+	MEMCARD_STATUS_UNKNOWN = 0,
 	/** Memory card is connected */
 	MEMCARD_CONNECTED = 1,
 	/** Memory card is formatted */