diff --git a/fsm.h b/fsm.h
index 4e6941e..3851344 100644
--- a/fsm.h
+++ b/fsm.h
@@ -3,8 +3,36 @@
 //
 #ifndef QF_FSM_FSM_H
 #define QF_FSM_FSM_H
-
-struct qf_fsm
+#include <stdint.h>
+typedef enum
 {
+    FSM_OK,
+    FSM_FAIL
+} fsm_result_e;
+
+typedef fsm_result_e (*fsm_cb)(void *userdata);
+typedef struct qf_fsm_state
+{
+    uint16_t state;
+    fsm_cb   on_exit;
+    fsm_cb   on_entry;
+    void    *user_data;
+} fsm_state_t;
+typedef struct qf_fsm_transition
+{
+    uint16_t state;
+    uint16_t event;
+    fsm_cb   on_action;
+} fsm_transition_t;
+struct qf_fsm_event
+{
+    uint16_t event;
+    void    *user_data;
 };
+typedef struct qf_fsm
+{
+    uint16_t     current_state;
+    fsm_state_t *p_state_list;
+    
+} fsm_handle_t;
 #endif // QF_FSM_FSM_H