diff --git a/README.md b/README.md
index 13a817da..1e71a8fe 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,12 @@ Tencent QQ group: 309957875<br />
 - cross compiler (done)
 
 # Change log
+2015-03-31<br />
+polish mqtt module, add queue for mqtt module.<br />
+add reconnect option to mqtt.connect api, :connect( host, port, secure, auto_reconnect, function(client) )<br />
+move node.readvdd33 to adc.readvdd33.<br />
+tools/esptool.py supported NodeMCU devkit automatic flash.
+
 2015-03-18<br />
 update u8glib.<br />
 merge everything to master.
diff --git a/app/modules/mqtt.c b/app/modules/mqtt.c
index 2cc3ad6d..d64a831b 100644
--- a/app/modules/mqtt.c
+++ b/app/modules/mqtt.c
@@ -231,7 +231,7 @@ READPACKET:
       msg_qos = mqtt_get_qos(mud->mqtt_state.in_buffer);
       msg_id = mqtt_get_id(mud->mqtt_state.in_buffer, mud->mqtt_state.in_buffer_length);
 
-      msg_queue_t *pending_msg = mud->mqtt_state.pending_msg_q;
+      msg_queue_t *pending_msg = msg_peek(&(mud->mqtt_state.pending_msg_q));
 
       NODE_DBG("MQTT_DATA: type: %d, qos: %d, msg_id: %d, pending_id: %d\r\n",
             msg_type,
@@ -263,12 +263,12 @@ READPACKET:
           if(msg_qos == 1){
             mud->mqtt_state.outbound_message = mqtt_msg_puback(&mud->mqtt_state.mqtt_connection, msg_id);
             node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
-                      msg_id, MQTT_MSG_TYPE_PUBACK, (int)msg_qos );
+                      msg_id, MQTT_MSG_TYPE_PUBACK, 0 );
           }
           else if(msg_qos == 2){
             mud->mqtt_state.outbound_message = mqtt_msg_pubrec(&mud->mqtt_state.mqtt_connection, msg_id);
             node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
-                      msg_id, MQTT_MSG_TYPE_PUBREC, (int)msg_qos );
+                      msg_id, MQTT_MSG_TYPE_PUBREC, 0 );
           }
           if(msg_qos == 1 || msg_qos == 2){
             NODE_DBG("MQTT: Queue response QoS: %d\r\n", msg_qos);
@@ -290,19 +290,27 @@ READPACKET:
 
           break;
         case MQTT_MSG_TYPE_PUBREC:
+          if(pending_msg && pending_msg->msg_type == MQTT_MSG_TYPE_PUBLISH && pending_msg->msg_id == msg_id){
+            NODE_DBG("MQTT: Publish  with QoS = 2 Received PUBREC\r\n"); 
+            // Note: actrually, should not destroy the msg until PUBCOMP is received.
+            msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
             mud->mqtt_state.outbound_message = mqtt_msg_pubrel(&mud->mqtt_state.mqtt_connection, msg_id);
             node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
-                      msg_id, MQTT_MSG_TYPE_PUBREL, (int)msg_qos );
+                      msg_id, MQTT_MSG_TYPE_PUBREL, 1 );
             NODE_DBG("MQTT: Response PUBREL\r\n");
+          }
           break;
         case MQTT_MSG_TYPE_PUBREL:
+          if(pending_msg && pending_msg->msg_type == MQTT_MSG_TYPE_PUBREC && pending_msg->msg_id == msg_id){
+            msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
             mud->mqtt_state.outbound_message = mqtt_msg_pubcomp(&mud->mqtt_state.mqtt_connection, msg_id);
             node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
-                      msg_id, MQTT_MSG_TYPE_PUBCOMP, (int)msg_qos );
+                      msg_id, MQTT_MSG_TYPE_PUBCOMP, 0 );
             NODE_DBG("MQTT: Response PUBCOMP\r\n");
+          }
           break;
         case MQTT_MSG_TYPE_PUBCOMP:
-          if(pending_msg && pending_msg->msg_type == MQTT_MSG_TYPE_PUBLISH && pending_msg->msg_id == msg_id){
+          if(pending_msg && pending_msg->msg_type == MQTT_MSG_TYPE_PUBREL && pending_msg->msg_id == msg_id){
             NODE_DBG("MQTT: Publish  with QoS = 2 successful\r\n");
             msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
             if(mud->cb_puback_ref == LUA_NOREF)
@@ -317,7 +325,7 @@ READPACKET:
         case MQTT_MSG_TYPE_PINGREQ:
             mud->mqtt_state.outbound_message = mqtt_msg_pingresp(&mud->mqtt_state.mqtt_connection);
             node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
-                      msg_id, MQTT_MSG_TYPE_PINGRESP, (int)msg_qos );
+                      msg_id, MQTT_MSG_TYPE_PINGRESP, 1 );
             NODE_DBG("MQTT: Response PINGRESP\r\n");
           break;
         case MQTT_MSG_TYPE_PINGRESP:
@@ -345,7 +353,7 @@ READPACKET:
       break;
   }
 
-  if(node && (mud->mqtt_state.pending_msg_q->next == NULL) && mud->event_timeout == 0){
+  if(node && (1==msg_size(&(mud->mqtt_state.pending_msg_q))) && mud->event_timeout == 0){
     mud->event_timeout = MQTT_SEND_TIMEOUT;
     NODE_DBG("Sent: %d\n", node->msg.length);
     if( mud->secure )
@@ -355,6 +363,7 @@ READPACKET:
     mud->keep_alive_tick = 0;
     mud->mqtt_state.outbound_message = NULL;
   }
+  NODE_DBG("receive, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   NODE_DBG("leave mqtt_socket_received.\n");
   return;
 }
@@ -376,9 +385,9 @@ static void mqtt_socket_sent(void *arg)
 
   // call mqtt_sent()
   mud->event_timeout = 0;
-
+  NODE_DBG("sent1, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   // qos = 0, publish and forgot.
-  msg_queue_t *node = mud->mqtt_state.pending_msg_q;
+  msg_queue_t *node = msg_peek(&(mud->mqtt_state.pending_msg_q));
   if(node && node->msg_type == MQTT_MSG_TYPE_PUBLISH && node->publish_qos == 0) {
     msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
   	if(mud->cb_puback_ref == LUA_NOREF)
@@ -388,7 +397,14 @@ static void mqtt_socket_sent(void *arg)
 		lua_rawgeti(gL, LUA_REGISTRYINDEX, mud->cb_puback_ref);
 		lua_rawgeti(gL, LUA_REGISTRYINDEX, mud->self_ref);  // pass the userdata to callback func in lua
 		lua_call(gL, 1, 0);
+  } else if(node && node->msg_type == MQTT_MSG_TYPE_PUBACK && node->publish_qos == 1) {
+    msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
+  } else if(node && node->msg_type == MQTT_MSG_TYPE_PUBCOMP) {
+    msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
+  } else if(node && node->msg_type == MQTT_MSG_TYPE_PINGRESP) {
+    msg_destroy(msg_dequeue(&(mud->mqtt_state.pending_msg_q)));
   }
+  NODE_DBG("sent2, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   NODE_DBG("leave mqtt_socket_sent.\n");
 }
 
@@ -423,16 +439,21 @@ static void mqtt_socket_connected(void *arg)
 
 void mqtt_socket_timer(void *arg)
 {
-  // NODE_DBG("enter mqtt_socket_timer.\n");
+  NODE_DBG("enter mqtt_socket_timer.\n");
   lmqtt_userdata *mud = (lmqtt_userdata*) arg;
 
   if(mud == NULL)
     return;
+  NODE_DBG("timer, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   if(mud->event_timeout > 0){
     NODE_DBG("event_timeout: %d.\n", mud->event_timeout);
   	mud->event_timeout --;
     if(mud->event_timeout > 0){
       return;
+    } else {
+      NODE_DBG("event timeout. \n");    
+      // should remove the head of the queue and re-send with DUP = 1
+      // Not implemented yet.
     }
   }
 
@@ -453,7 +474,7 @@ void mqtt_socket_timer(void *arg)
   } else if(mud->connState == MQTT_CONNECT_SENT){ // wait for CONACK time out.
     NODE_DBG("MQTT_CONNECT failed.\n");
   } else if(mud->connState == MQTT_DATA){
-    msg_queue_t *pending_msg = mud->mqtt_state.pending_msg_q;
+    msg_queue_t *pending_msg = msg_peek(&(mud->mqtt_state.pending_msg_q));
     if(pending_msg){
       mud->event_timeout = MQTT_SEND_TIMEOUT;
       if(mud->secure)
@@ -477,7 +498,7 @@ void mqtt_socket_timer(void *arg)
       }
     }
   }
-  // NODE_DBG("leave mqtt_socket_timer.\n");
+  NODE_DBG("leave mqtt_socket_timer.\n");
 }
 
 // Lua: mqtt.Client(clientid, keepalive, user, pass)
@@ -1057,7 +1078,7 @@ static int mqtt_socket_subscribe( lua_State* L ) {
 
   NODE_DBG("topic: %s - id: %d - qos: %d, length: %d\n", topic, node->msg_id, node->publish_qos, node->msg.length);
 
-  if(node && (mud->mqtt_state.pending_msg_q->next == NULL) && mud->event_timeout == 0){
+  if(node && (1==msg_size(&(mud->mqtt_state.pending_msg_q))) && mud->event_timeout == 0){
   	mud->event_timeout = MQTT_SEND_TIMEOUT;
   	NODE_DBG("Sent: %d\n", node->msg.length);
   	if( mud->secure )
@@ -1073,6 +1094,7 @@ static int mqtt_socket_subscribe( lua_State* L ) {
     lua_pushboolean(L, 1);  // enqueued succeed.
   }
   mud->mqtt_state.outbound_message = NULL;
+  NODE_DBG("subscribe, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   NODE_DBG("leave mqtt_socket_subscribe.\n");
 	return 1;
 }
@@ -1133,7 +1155,7 @@ static int mqtt_socket_publish( lua_State* L )
   msg_queue_t *node = msg_enqueue(&(mud->mqtt_state.pending_msg_q), mud->mqtt_state.outbound_message, 
                       msg_id, MQTT_MSG_TYPE_PUBLISH, (int)qos );
 
-  if(node && (mud->mqtt_state.pending_msg_q->next == NULL) && mud->event_timeout == 0){
+  if(node && (1==msg_size(&(mud->mqtt_state.pending_msg_q))) && mud->event_timeout == 0){
     mud->event_timeout = MQTT_SEND_TIMEOUT;
     NODE_DBG("Sent: %d\n", node->msg.length);
     if( mud->secure )
@@ -1149,6 +1171,7 @@ static int mqtt_socket_publish( lua_State* L )
     lua_pushboolean(L, 1);  // enqueued succeed.
   }
   mud->mqtt_state.outbound_message = NULL;
+  NODE_DBG("publish, queue size: %d\n", msg_size(&(mud->mqtt_state.pending_msg_q)));
   NODE_DBG("leave mqtt_socket_publish.\n");
   return 1;
 }
diff --git a/app/mqtt/msg_queue.c b/app/mqtt/msg_queue.c
index afa98d41..1258ad6e 100644
--- a/app/mqtt/msg_queue.c
+++ b/app/mqtt/msg_queue.c
@@ -58,3 +58,25 @@ msg_queue_t * msg_dequeue(msg_queue_t **head){
   node->next = NULL;
   return node;
 }
+
+msg_queue_t * msg_peek(msg_queue_t **head){
+  if(!head || !*head){
+    return NULL;
+  }
+  return *head;  // fetch head.
+}
+
+int msg_size(msg_queue_t **head){
+  if(!head || !*head){
+    return 0;
+  }
+  int i = 1;
+  msg_queue_t *tail = *head;
+  if(tail){
+    while(tail->next!=NULL){
+      tail = tail->next;
+      i++;
+    }
+  }
+  return i;
+}
diff --git a/app/mqtt/msg_queue.h b/app/mqtt/msg_queue.h
index 9da3f6bc..05b910ae 100644
--- a/app/mqtt/msg_queue.h
+++ b/app/mqtt/msg_queue.h
@@ -18,6 +18,8 @@ typedef struct msg_queue_t {
 msg_queue_t * msg_enqueue(msg_queue_t **head, mqtt_message_t *msg, uint16_t msg_id, int msg_type, int publish_qos);
 void msg_destroy(msg_queue_t *node);
 msg_queue_t * msg_dequeue(msg_queue_t **head);
+msg_queue_t * msg_peek(msg_queue_t **head);
+int msg_size(msg_queue_t **head);
 
 #ifdef __cplusplus
 }
diff --git a/examples/fragment.lua b/examples/fragment.lua
index fb938191..2e2e752a 100644
--- a/examples/fragment.lua
+++ b/examples/fragment.lua
@@ -418,7 +418,7 @@ m:publish("/topic1","hello",0,0)
 m:publish("/topic3","hello",0,0) m:publish("/topic4","hello",0,0)
 m:publish("/topic1","hello1",0,0) m:publish("/topic2","hello2",0,0)
 m:publish("/topic1","hello",1,0)
-m:subscribe("/topic3",2,function(m) print("sub done") end)
+m:subscribe("/topic3",0,function(m) print("sub done") end)
 m:publish("/topic3","hello3",2,0)
 
 m=mqtt.Client()
@@ -450,3 +450,13 @@ end)
 m:connect("192.168.18.88",1883)
 
 m:close()
+
+m=mqtt.Client()
+m:connect("192.168.18.88",1883)
+m:on("message",function(m,t,pl) print(t..":") if pl~=nil then print(pl) end end )
+m:subscribe("/topic1",0,function(m) print("sub done") end)
+m:publish("/topic1","hello3",2,0) m:publish("/topic1","hello2",2,0)
+m:publish("/topic1","hello3",0,0) m:publish("/topic1","hello2",2,0)
+
+m:subscribe("/topic2",2,function(m) print("sub done") end)
+m:publish("/topic2","hello3",0,0) m:publish("/topic2","hello2",2,0)