diff --git a/README.md b/README.md
index 97ff9282..9c73ad70 100644
--- a/README.md
+++ b/README.md
@@ -125,6 +125,7 @@ pre_build/latest/nodemcu_512k_latest.bin is removed. use pre_build/latest/nodemc
 #define LUA_USE_MODULES_UART
 #define LUA_USE_MODULES_OW
 #define LUA_USE_MODULES_BIT
+#define LUA_USE_MODULES_WS2812
 #endif /* LUA_USE_MODULES */
 ...
 // LUA_NUMBER_INTEGRAL
@@ -381,3 +382,14 @@ They'll be available as `u8g.<font_name>` in Lua.
   - [ ] setPrintPos()
   - [ ] setHardwareBackup()
   - [ ] setRGB()
+
+
+####Control a WS2812 based light strip
+```lua
+	-- set the color of one LED on GPIO 2 to red
+	ws2812.write(4, string.char(0, 255, 0)) 
+	-- set the color of 10 LEDs on GPIO 0 to blue
+	ws2812.write(3, string.char(0, 0, 255):rep(10))
+	-- first LED green, second LED white
+	ws2812.write(4, string.char(255, 0, 0, 255, 255, 255))
+```
diff --git a/app/include/driver/uart.h b/app/include/driver/uart.h
index bc175ee8..b4f4acfb 100644
--- a/app/include/driver/uart.h
+++ b/app/include/driver/uart.h
@@ -33,18 +33,23 @@ typedef enum {
 } UartExistParity;
 
 typedef enum {
-    BIT_RATE_1200     = 1200,
-    BIT_RATE_2400     = 2400,
-    BIT_RATE_4800     = 4800,  
-    BIT_RATE_9600     = 9600,
+    BIT_RATE_300     = 300,
+    BIT_RATE_600     = 600,
+    BIT_RATE_1200    = 1200,
+    BIT_RATE_2400    = 2400,
+    BIT_RATE_4800    = 4800,
+    BIT_RATE_9600    = 9600,
     BIT_RATE_19200   = 19200,
     BIT_RATE_38400   = 38400,
     BIT_RATE_57600   = 57600,
     BIT_RATE_74880   = 74880,
-    BIT_RATE_115200 = 115200,
-    BIT_RATE_230400 = 230400,
-    BIT_RATE_460800 = 460800,
-    BIT_RATE_921600 = 921600
+    BIT_RATE_115200  = 115200,
+    BIT_RATE_230400  = 230400,
+    BIT_RATE_256000  = 256000,
+    BIT_RATE_460800  = 460800,
+    BIT_RATE_921600  = 921600,
+    BIT_RATE_1843200 = 1843200,
+    BIT_RATE_3686400 = 3686400,
 } UartBautRate;
 
 typedef enum {
diff --git a/app/include/lwip/app/espconn.h b/app/include/lwip/app/espconn.h
index e6e60fd1..6eda9e3a 100644
--- a/app/include/lwip/app/espconn.h
+++ b/app/include/lwip/app/espconn.h
@@ -394,5 +394,21 @@ extern sint8 espconn_igmp_join(ip_addr_t *host_ip, ip_addr_t *multicast_ip);
 *******************************************************************************/
 extern sint8 espconn_igmp_leave(ip_addr_t *host_ip, ip_addr_t *multicast_ip);
 
+/******************************************************************************
+ * FunctionName : espconn_recv_hold
+ * Description  : hold tcp receive
+ * Parameters   : espconn -- espconn to hold
+ * Returns      : none
+*******************************************************************************/
+extern sint8 espconn_recv_hold(struct espconn *pespconn);
+
+/******************************************************************************
+ * FunctionName : espconn_recv_unhold
+ * Description  : unhold tcp receive
+ * Parameters   : espconn -- espconn to unhold
+ * Returns      : none
+*******************************************************************************/
+extern sint8 espconn_recv_unhold(struct espconn *pespconn);
+
 #endif
 
diff --git a/app/include/lwip/tcp.h b/app/include/lwip/tcp.h
index 909ff9b7..7856a92d 100644
--- a/app/include/lwip/tcp.h
+++ b/app/include/lwip/tcp.h
@@ -277,6 +277,8 @@ struct tcp_pcb {
 
   /* KEEPALIVE counter */
   u8_t keep_cnt_sent;
+
+  u8_t hold;
 };
 
 struct tcp_pcb_listen {  
diff --git a/app/include/user_config.h b/app/include/user_config.h
index 97972c0c..66cf8a15 100644
--- a/app/include/user_config.h
+++ b/app/include/user_config.h
@@ -40,7 +40,6 @@
 #define ICACHE_STORE_TYPEDEF_ATTR __attribute__((aligned(4),packed))
 #define ICACHE_STORE_ATTR __attribute__((aligned(4)))
 #define ICACHE_RAM_ATTR __attribute__((section(".iram0.text")))
-// #define ICACHE_RODATA_ATTR __attribute__((section(".rodata2.text")))
 
 #define CLIENT_SSL_ENABLE
 #define GPIO_INTERRUPT_ENABLE
@@ -63,8 +62,9 @@
 #define LUA_USE_MODULES_UART
 #define LUA_USE_MODULES_OW
 #define LUA_USE_MODULES_BIT
-#define LUA_USE_MODULES_MQTT
 #define LUA_USE_MODULES_U8G
+#define LUA_USE_MODULES_MQTT
+#define LUA_USE_MODULES_WS2812
 #endif /* LUA_USE_MODULES */
 
 // #define LUA_NUMBER_INTEGRAL
diff --git a/app/libc/c_math.c b/app/libc/c_math.c
index 859b143b..1433b1b2 100644
--- a/app/libc/c_math.c
+++ b/app/libc/c_math.c
@@ -1,60 +1,62 @@
 #include "c_math.h"
 #include "c_types.h"
+#include "user_config.h"
 
 double floor(double x)
 {
     return (double) (x < 0.f ? (((int) x) - 1) : ((int) x));
 }
 
-double pow(double x, double y)
-{
 #define MAXEXP 2031     /* (MAX_EXP * 16) - 1           */
 #define MINEXP -2047        /* (MIN_EXP * 16) - 1           */
 #define HUGE MAXFLOAT
-    double a1[] =
-    {
-        1.0,
-        0.95760328069857365,
-        0.91700404320467123,
-        0.87812608018664974,
-        0.84089641525371454,
-        0.80524516597462716,
-        0.77110541270397041,
-        0.73841307296974966,
-        0.70710678118654752,
-        0.67712777346844637,
-        0.64841977732550483,
-        0.62092890603674203,
-        0.59460355750136054,
-        0.56939431737834583,
-        0.54525386633262883,
-        0.52213689121370692,
-        0.50000000000000000
-    };
-    double a2[] =
-    {
-        0.24114209503420288E-17,
-        0.92291566937243079E-18,
-        -0.15241915231122319E-17,
-        -0.35421849765286817E-17,
-        -0.31286215245415074E-17,
-        -0.44654376565694490E-17,
-        0.29306999570789681E-17,
-        0.11260851040933474E-17
-    };
-    double p1 = 0.833333333333332114e-1;
-    double p2 = 0.125000000005037992e-1;
-    double p3 = 0.223214212859242590e-2;
-    double p4 = 0.434457756721631196e-3;
-    double q1 = 0.693147180559945296e0;
-    double q2 = 0.240226506959095371e0;
-    double q3 = 0.555041086640855953e-1;
-    double q4 = 0.961812905951724170e-2;
-    double q5 = 0.133335413135857847e-2;
-    double q6 = 0.154002904409897646e-3;
-    double q7 = 0.149288526805956082e-4;
-    double k = 0.442695040888963407;
 
+double a1[] ICACHE_STORE_ATTR ICACHE_RODATA_ATTR =
+{
+    1.0,
+    0.95760328069857365,
+    0.91700404320467123,
+    0.87812608018664974,
+    0.84089641525371454,
+    0.80524516597462716,
+    0.77110541270397041,
+    0.73841307296974966,
+    0.70710678118654752,
+    0.67712777346844637,
+    0.64841977732550483,
+    0.62092890603674203,
+    0.59460355750136054,
+    0.56939431737834583,
+    0.54525386633262883,
+    0.52213689121370692,
+    0.50000000000000000
+};
+double a2[] ICACHE_STORE_ATTR ICACHE_RODATA_ATTR =
+{
+    0.24114209503420288E-17,
+    0.92291566937243079E-18,
+    -0.15241915231122319E-17,
+    -0.35421849765286817E-17,
+    -0.31286215245415074E-17,
+    -0.44654376565694490E-17,
+    0.29306999570789681E-17,
+    0.11260851040933474E-17
+};
+double p1 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.833333333333332114e-1;
+double p2 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.125000000005037992e-1;
+double p3 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.223214212859242590e-2;
+double p4 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.434457756721631196e-3;
+double q1 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.693147180559945296e0;
+double q2 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.240226506959095371e0;
+double q3 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.555041086640855953e-1;
+double q4 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.961812905951724170e-2;
+double q5 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.133335413135857847e-2;
+double q6 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.154002904409897646e-3;
+double q7 ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.149288526805956082e-4;
+double k ICACHE_STORE_ATTR ICACHE_RODATA_ATTR = 0.442695040888963407;
+
+double pow(double x, double y)
+{
     double frexp(), g, ldexp(), r, u1, u2, v, w, w1, w2, y1, y2, z;
     int iw1, m, p;
 
diff --git a/app/lwip/app/espconn.c b/app/lwip/app/espconn.c
index bd81e4d6..114f1b59 100644
--- a/app/lwip/app/espconn.c
+++ b/app/lwip/app/espconn.c
@@ -718,3 +718,32 @@ espconn_gethostbyname(struct espconn *pespconn, const char *hostname, ip_addr_t
     return dns_gethostbyname(hostname, addr, found, pespconn);
 }
 
+sint8 espconn_recv_hold(struct espconn *pespconn) {
+  espconn_msg *pnode = NULL;
+
+  if (pespconn == NULL) {
+    return ESPCONN_ARG;
+  }
+  pespconn->state = ESPCONN_WRITE;
+  if (!espconn_find_connection(pespconn, &pnode)) {
+      return ESPCONN_ARG;
+  }
+
+  espconn_tcp_hold(pnode);
+  return ESPCONN_OK;
+}
+
+sint8 espconn_recv_unhold(struct espconn *pespconn) {
+  espconn_msg *pnode = NULL;
+
+  if (pespconn == NULL) {
+    return ESPCONN_ARG;
+  }
+  pespconn->state = ESPCONN_WRITE;
+  if (!espconn_find_connection(pespconn, &pnode)) {
+      return ESPCONN_ARG;
+  }
+
+  espconn_tcp_unhold(pnode);
+  return ESPCONN_OK;
+}
diff --git a/app/lwip/app/espconn_tcp.c b/app/lwip/app/espconn_tcp.c
index 91843887..da5c441a 100644
--- a/app/lwip/app/espconn_tcp.c
+++ b/app/lwip/app/espconn_tcp.c
@@ -948,3 +948,19 @@ sint8 ICACHE_FLASH_ATTR espconn_tcp_delete(struct espconn *pdeletecon)
 			return ESPCONN_ARG;
 	}
 }
+
+void espconn_tcp_hold(void *arg) {
+    espconn_msg *ptcp_sent = arg;
+    struct tcp_pcb *pcb = NULL;
+    pcb = ptcp_sent->pcommon.pcb;
+
+    pcb->hold = 1;
+}
+
+void espconn_tcp_unhold(void *arg) {
+    espconn_msg *ptcp_sent = arg;
+    struct tcp_pcb *pcb = NULL;
+    pcb = ptcp_sent->pcommon.pcb;
+
+    pcb->hold = 0;
+}
diff --git a/app/lwip/core/tcp.c b/app/lwip/core/tcp.c
index e3193cc7..fe0bb913 100644
--- a/app/lwip/core/tcp.c
+++ b/app/lwip/core/tcp.c
@@ -1259,6 +1259,7 @@ tcp_alloc(u8_t prio)
 #endif /* LWIP_TCP_KEEPALIVE */
 
     pcb->keep_cnt_sent = 0;									//���ķ��ʹ���
+    pcb->hold = 0;
   }
   return pcb;
 }
diff --git a/app/lwip/core/tcp_in.c b/app/lwip/core/tcp_in.c
index 2f4a1c42..2aca07d4 100644
--- a/app/lwip/core/tcp_in.c
+++ b/app/lwip/core/tcp_in.c
@@ -1137,7 +1137,7 @@ tcp_receive(struct tcp_pcb *pcb)
 
   /* If the incoming segment contains data, we must process it
      further. */
-  if (tcplen > 0) {
+  if ((tcplen > 0) && (!pcb->hold)) {
     /* This code basically does three things:
 
     +) If the incoming segment contains data that is the next
diff --git a/app/modules/modules.h b/app/modules/modules.h
index c37b5091..03396249 100644
--- a/app/modules/modules.h
+++ b/app/modules/modules.h
@@ -125,6 +125,15 @@
 #define ROM_MODULES_BIT
 #endif
 
+#if defined(LUA_USE_MODULES_WS2812)
+#define MODULES_WS2812 "ws2812"
+#define ROM_MODULES_WS2812 \
+		_ROM(MODULES_WS2812, luaopen_ws2812, ws2812_map)
+#else
+#define ROM_MODULES_WS2812
+#endif
+
+
 #define LUA_MODULES_ROM      \
         ROM_MODULES_GPIO    \
         ROM_MODULES_PWM		\
@@ -140,7 +149,8 @@
         ROM_MODULES_ADC     \
         ROM_MODULES_UART    \
         ROM_MODULES_OW      \
-        ROM_MODULES_BIT
+        ROM_MODULES_BIT		\
+		ROM_MODULES_WS2812
 
 #endif
 
diff --git a/app/modules/mqtt.c b/app/modules/mqtt.c
index a37974ec..13b182bc 100644
--- a/app/modules/mqtt.c
+++ b/app/modules/mqtt.c
@@ -725,8 +725,15 @@ static int mqtt_socket_connect( lua_State* L )
   if(mud == NULL)
     return 0;
 
-  if(mud->pesp_conn)
-    	c_free(mud->pesp_conn);
+  if(mud->pesp_conn){   //TODO: should I free tcp struct directly or ask user to call close()???
+    mud->pesp_conn->reverse = NULL;
+    if(mud->pesp_conn->proto.tcp)
+      c_free(mud->pesp_conn->proto.tcp);
+    mud->pesp_conn->proto.tcp = NULL;
+    c_free(mud->pesp_conn);
+    mud->pesp_conn = NULL;
+  }
+
   struct espconn *pesp_conn = NULL;
 	pesp_conn = mud->pesp_conn = (struct espconn *)c_zalloc(sizeof(struct espconn));
 	if(!pesp_conn)
diff --git a/app/modules/net.c b/app/modules/net.c
index 92514c9b..51639b54 100644
--- a/app/modules/net.c
+++ b/app/modules/net.c
@@ -665,6 +665,10 @@ static int net_start( lua_State* L, const char* mt )
   	return 0;
   }
 
+  if(nud->pesp_conn == NULL){
+    NODE_DBG("nud->pesp_conn is NULL.\n");
+    return 0;
+  }
   pesp_conn = nud->pesp_conn;
   port = luaL_checkinteger( L, stack );
   stack++;
@@ -1074,6 +1078,10 @@ static int net_dns( lua_State* L, const char* mt )
     return 0;
   }
 
+  if(nud->pesp_conn == NULL){
+    NODE_DBG("nud->pesp_conn is NULL.\n");
+    return 0;
+  }
   pesp_conn = nud->pesp_conn;
 
   if(!isserver || pesp_conn->type == ESPCONN_UDP){    // self_ref is only needed by socket userdata, or udp server
@@ -1185,6 +1193,54 @@ static int net_socket_send( lua_State* L )
   return net_send(L, mt);
 }
 
+static int net_socket_hold( lua_State* L )
+{
+  const char *mt = "net.socket";
+  struct espconn *pesp_conn = NULL;
+  lnet_userdata *nud;
+  size_t l;
+
+  nud = (lnet_userdata *)luaL_checkudata(L, 1, mt);
+  luaL_argcheck(L, nud, 1, "Server/Socket expected");
+  if(nud==NULL){
+    NODE_DBG("userdata is nil.\n");
+    return 0;
+  }
+
+  if(nud->pesp_conn == NULL){
+    NODE_DBG("nud->pesp_conn is NULL.\n");
+    return 0;
+  }
+  pesp_conn = nud->pesp_conn;
+  espconn_recv_hold(pesp_conn);
+
+  return 0;
+}
+
+static int net_socket_unhold( lua_State* L )
+{
+  const char *mt = "net.socket";
+  struct espconn *pesp_conn = NULL;
+  lnet_userdata *nud;
+  size_t l;
+
+  nud = (lnet_userdata *)luaL_checkudata(L, 1, mt);
+  luaL_argcheck(L, nud, 1, "Server/Socket expected");
+  if(nud==NULL){
+    NODE_DBG("userdata is nil.\n");
+    return 0;
+  }
+
+  if(nud->pesp_conn == NULL){
+    NODE_DBG("nud->pesp_conn is NULL.\n");
+    return 0;
+  }
+  pesp_conn = nud->pesp_conn;
+  espconn_recv_unhold(pesp_conn);
+
+  return 0;
+}
+
 // Lua: socket:dns( string, function(ip) )
 static int net_socket_dns( lua_State* L )
 {
@@ -1243,6 +1299,8 @@ static const LUA_REG_TYPE net_socket_map[] =
   { LSTRKEY( "close" ), LFUNCVAL ( net_socket_close ) },
   { LSTRKEY( "on" ), LFUNCVAL ( net_socket_on ) },
   { LSTRKEY( "send" ), LFUNCVAL ( net_socket_send ) },
+  { LSTRKEY( "hold" ), LFUNCVAL ( net_socket_hold ) },
+  { LSTRKEY( "unhold" ), LFUNCVAL ( net_socket_unhold ) },
   { LSTRKEY( "dns" ), LFUNCVAL ( net_socket_dns ) },
   // { LSTRKEY( "delete" ), LFUNCVAL ( net_socket_delete ) },
   { LSTRKEY( "__gc" ), LFUNCVAL ( net_socket_delete ) },
diff --git a/app/modules/ws2812.c b/app/modules/ws2812.c
new file mode 100644
index 00000000..aab28e92
--- /dev/null
+++ b/app/modules/ws2812.c
@@ -0,0 +1,82 @@
+#include "lualib.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "auxmods.h"
+#include "lrotable.h"
+/**
+ * All this code is mostly from http://www.esp8266.com/viewtopic.php?f=21&t=1143&sid=a620a377672cfe9f666d672398415fcb
+ * from user Markus Gritsch.
+ * I just put this code into its own module and pushed into a forked repo,
+ * to easily create a pull request. Thanks to Markus Gritsch for the code.
+ *
+ */
+
+// ----------------------------------------------------------------------------
+// -- This WS2812 code must be compiled with -O2 to get the timing right.
+// -- http://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/
+// The ICACHE_FLASH_ATTR is there to trick the compiler and get the very first pulse width correct.
+static void ICACHE_FLASH_ATTR send_ws_0(uint8_t gpio) {
+  uint8_t i;
+  i = 4;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << gpio);
+  i = 9;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << gpio);
+}
+
+static void ICACHE_FLASH_ATTR send_ws_1(uint8_t gpio) {
+  uint8_t i;
+  i = 8;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << gpio);
+  i = 6;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << gpio);
+}
+
+// Lua: ws2812.write(pin, "string")
+// Byte triples in the string are interpreted as G R B values.
+// ws2812.write(4, string.char(0, 255, 0)) uses GPIO2 and sets the first LED red.
+// ws2812.write(3, string.char(0, 0, 255):rep(10)) uses GPIO0 and sets ten LEDs blue.
+// ws2812.write(4, string.char(255, 0, 0, 255, 255, 255)) first LED green, second LED white.
+static int ICACHE_FLASH_ATTR ws2812_write(lua_State* L) {
+  const uint8_t pin = luaL_checkinteger(L, 1);
+  size_t length;
+  const char *buffer = luaL_checklstring(L, 2, &length);
+
+  platform_gpio_mode(pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT);
+  platform_gpio_write(pin, 0);
+  os_delay_us(10);
+
+  os_intr_lock();
+  const char * const end = buffer + length;
+  while (buffer != end) {
+    uint8_t mask = 0x80;
+    while (mask) {
+      (*buffer & mask) ? send_ws_1(pin_num[pin]) : send_ws_0(pin_num[pin]);
+      mask >>= 1;
+    }
+    ++buffer;
+  }
+  os_intr_unlock();
+
+  return 0;
+}
+
+#define MIN_OPT_LEVEL 2
+#include "lrodefs.h"
+const LUA_REG_TYPE ws2812_map[] =
+{
+  { LSTRKEY( "write" ), LFUNCVAL( ws2812_write )},
+  { LNILKEY, LNILVAL}
+};
+
+LUALIB_API int luaopen_ws2812(lua_State *L) {
+  // TODO: Make sure that the GPIO system is initialized
+  LREGISTER(L, "ws2812", ws2812_map);
+  return 1;
+}
+
+// ----------------------------------------------------------------------------
+
diff --git a/examples/telnet.lua b/examples/telnet.lua
index 482fcb41..f8ed7340 100644
--- a/examples/telnet.lua
+++ b/examples/telnet.lua
@@ -31,7 +31,7 @@ function startServer()
    print("===Now,Using xcon_tcp logon and input LUA.====")
 end
 
-tmr.alarm(1000, 1, function() 
+tmr.alarm(0, 1000, 1, function() 
    if wifi.sta.getip()=="0.0.0.0" then
       print("Connect AP, Waiting...") 
    else
diff --git a/ld/eagle.app.v6.ld b/ld/eagle.app.v6.ld
index e0bff22b..2de963dc 100644
--- a/ld/eagle.app.v6.ld
+++ b/ld/eagle.app.v6.ld
@@ -5,7 +5,7 @@ MEMORY
   dport0_0_seg :                      	org = 0x3FF00000, len = 0x10
   dram0_0_seg :                       	org = 0x3FFE8000, len = 0x14000
   iram1_0_seg :                       	org = 0x40100000, len = 0x8000
-  irom0_0_seg :                       	org = 0x40210000, len = 0x53000
+  irom0_0_seg :                       	org = 0x40210000, len = 0x54000
 }
 
 PHDRS
diff --git a/tools/esptool.py b/tools/esptool.py
index c6027eb7..130e80f0 100755
--- a/tools/esptool.py
+++ b/tools/esptool.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python
 #
 # ESP8266 ROM Bootloader Utility
 # https://github.com/themadinventor/esptool