NodeMCU

NodeMCU是一個開源^[4]的物聯網平台。 它使用Lua手稿語言編程^[4]。該平台基於eLua ^[5]開源專案,底層使用ESP8266 sdk 0.9.5版本。該平台使用了很多開源專案, 例如 lua-cjson^[6], spiffs^[7]. NodeMCU包含了可以執行在 esp8266 Wi-Fi SoC晶片之上的韌體,以及基於ESP-12模組的硬體。

已隱藏部分未翻譯內容，歡迎參與翻譯。

History

NodeMCU is started after ESP8266 come out. In December 30, 2013, Espressif systems begin production of ESP8266.^[8] ESP8266 is an Wi-Fi SoC and integrated with LX106 core, widely used in IoT applications(See related projects^[9][10][11]). In 13 Oct 2014, Hong committed first file of nodemcu-firmware to github,^[12] NodeMCU project started. And then more and more developers from ESP8266 opensource community join in NodeMCU developer team. On 1 Dec 2014, Huang R commit the gerber file of an ESP8266 board, then NodeMCU project have the first open-hardware which named devkit 1.0,^[13] thus NodeMCU is not only a firmware, it becomes a platform. In 31 Dec 2014, Tuan PM port MQTT client library from Contiki to ESP8266 SoC platform,^[14] and commit to NodeMCU project, then NodeMCU can support MQTT IoT protocol, using Lua access MQTT broker, it is an important update of firmware. Another important update is in 30 Jan 2015, Devsaurus port u8glib^[15] to NodeMCU project,^[16] and NodeMCU can drive LCD, Screen, OLED, even VGA display module easily.

NodeMCU

NodeMCU DEVKIT 1.0 BETA
研發商	ESP8266開源社群
類型	片上系統
作業系統	XTOS
電源	USB
中央處理器	ESP8266[1](LX106[2])
記憶體	20kBytes
硬碟儲存空間	4MBytes[3]
網站	http://www.nodemcu.com

NodeMCU DEVKIT 1.0 BETA 背面

Pins腳

NodeMCU 提供對 GPIO（通用輸入/輸出）的存取控制，並且引腳對映表是 API 檔案的一部分。 ^[17]

I/O index	ESP8266 pin
0 [*]	GPIO16
1	GPIO5
2	GPIO4
3	GPIO0
4	GPIO2
5	GPIO14
6	GPIO12
7	GPIO13
8	GPIO15
9	GPIO3
10	GPIO1
11	GPIO9
12	GPIO10

[*] D0 (GPIO16) 只能用於GPIO讀/寫。它不支援open-drain/interrupt/PWM/I²C 或 1-Wire。

硬體連接

如果使用 NodeMCU devkit, 只需要安裝 CH340G 驅動程式^[18], 並且將開發模組使用micro-usb 線連接到電腦。 然後，將波特率設為9600, 並打開序列埠。若使用普通的esp8266模組, 則必須準備usb-ttl 轉接器。

韌體燒寫

nodemcu_latest.bin: 0x00000
對於大多數 esp8266 模組, 直接拉低 GPIO0 引腳的電平，並且重新上電或重新啟動。
可以使用 nodemcu-flasher（頁面存檔備份，存於網際網路檔案館） 燒寫韌體^[18]。

特別的，如果你想編譯/構建自己的韌體，需要注意以下燒寫位址：
0x00000.bin: 0x00000
0x10000.bin: 0x10000

注意，在燒寫之後，最好執行 file.format()

程式舉例

連接Wi-Fi熱點

    ip = wifi.sta.getip()
    print(ip)
    --nil
    wifi.setmode(wifi.STATION)
    wifi.sta.config("SSID","password")
    ip = wifi.sta.getip()
    print(ip)
    --192.168.18.110

如同arduino般操作硬體

    pin = 1
    gpio.mode(pin,gpio.OUTPUT)
    gpio.write(pin,gpio.HIGH)
    print(gpio.read(pin))

使用 nodejs 風格網路編程

    -- A simple http client
    conn=net.createConnection(net.TCP, 0)
    conn:on("receive", function(conn, payload) print(payload) end )
    conn:connect(80,"115.239.210.27")
    conn:send("GET / HTTP/1.1\r\nHost: www.baidu.com\r\n"
        .."Connection: keep-alive\r\nAccept: */*\r\n\r\n")

簡易的HTTP伺服器

    -- A simple http server
    srv=net.createServer(net.TCP)
    srv:listen(80,function(conn)
      conn:on("receive",function(conn,payload)
        print(payload)
        conn:send("<h1> Hello, NodeMcu.</h1>")
      end)
      conn:on("sent",function(conn) conn:close() end)
    end)

連接 MQTT Broker

-- init mqtt client with keepalive timer 120sec
m = mqtt.Client("clientid", 120, "user", "password")

-- setup Last Will and Testament (optional)
-- Broker will publish a message with qos = 0, retain = 0, data = "offline"
-- to topic "/lwt" if client don't send keepalive packet
m:lwt("/lwt", "offline", 0, 0)

m:on("connect", function(con) print ("connected") end)
m:on("offline", function(con) print ("offline") end)

-- on publish message receive event
m:on("message", function(conn, topic, data)
  print(topic .. ":" )
  if data ~= nil then
    print(data)
  end
end)

-- for secure: m:connect("192.168.11.118", 1880, 1)
m:connect("192.168.11.118", 1880, 0, function(conn) print("connected") end)

-- subscribe topic with qos = 0
m:subscribe("/topic",0, function(conn) print("subscribe success") end)
-- or subscribe multiple topic (topic/0, qos = 0; topic/1, qos = 1; topic2 , qos = 2)
-- m:subscribe({["topic/0"]=0,["topic/1"]=1,topic2=2}, function(conn) print("subscribe success") end)
-- publish a message with data = hello, QoS = 0, retain = 0
m:publish("/topic","hello",0,0, function(conn) print("sent") end)

m:close();
-- you can call m:connect again

UDP 客戶端與伺服器

-- a udp server
s=net.createServer(net.UDP)
s:on("receive",function(s,c) print(c) end)
s:listen(5683)

-- a udp client
cu=net.createConnection(net.UDP)
cu:on("receive",function(cu,c) print(c) end)
cu:connect(5683,"192.168.18.101")
cu:send("hello")