前言

esp8266文件服务器 esp8266作为服务器_ci

随着现在物联网设备的而越来越多，现在市场上出现越来越多的物联网设备，其中 ESP8266 是最受欢迎、价格便宜且易于使用的模块，它可以将您的硬件连接到互联网。

今天我们就以ESP8266和STM32来实现一台网络服务器，我们使用 ESP8266 将 STM32F103C8 连接到互联网。 ESP8266 Wi-Fi 模块与 STM32F103C8 板接口，并将数据发送到 ESP8266 网络服务器上托管的网页。

所需硬件

  • STM32F103C8板
  • ESP8266 无线无线模块
  • 笔记本电脑和无线网络热点

ESP8266 模块

大多数人将 ESP8266 称为 WIFI 模块，但它实际上是一个微控制器。ESP8266 是乐鑫公司（一家总部位于上海的公司）开发的微控制器的名称。该微控制器具有执行WIFI相关活动的能力，因此被广泛用作WIFI模块。

esp8266文件服务器 esp8266作为服务器_IP_02

esp8266文件服务器 esp8266作为服务器_ci_03

引脚说明

  • GND：接地
  • TX：发射传输数据位
  • GPIO2：通用输入/输出 2
  • CH_PD：使能
  • GPIO0：通用输入/输出0
  • RST：复位
  • RX：接收数据位
  • VCC：+3.3 V

常用AT指令

AT 命令用于与 ESP8266 通信。下表显示了一些常用的 AT 命令

esp8266文件服务器 esp8266作为服务器_单片机_04

电路图和连接

下图显示了STM32和ESP8266无线模块之间的连接。

esp8266文件服务器 esp8266作为服务器_单片机_05

esp8266文件服务器 esp8266作为服务器_ci_06

SMT32F103C8具有三套UART串行通信。在下图中，您可以看到相同的以下引脚：

esp8266文件服务器 esp8266作为服务器_ci_07

ESP8266 使用串行通信与STM32进行通讯。所以这里 ESP8266 的 TX 和 RX 都与 STM32 板的串行 2 端口 （PA2 和 PA3） 连接。

代码解释

ESP8266 与 STM32 的接口工作非常简单。您可以在本教程末尾的代码中找到完整的工作。

首先，我们需要按照电路图中所示进行电路连接。上传代码后，打开串行监视器（工具>>串行监视器）以查看发生的情况。您将在串行监视器上看到IP地址，从串行监视器复制IP地址并将其粘贴到浏览器中，然后单击Enter以查看我们的网页。请记住将计算机和 ESP8266 模块连接到同一 Wi-Fi 网络上。

完整的代码在最后给出，并通过注释很好地解释了，在这里我们解释了其中的几个重要部分。

首先，我们使用以下两个语句开始串行监视器和 ESP8266 的串行通信：

Serial.println(cmd);
Serial2.println(cmd);

注意： 我使用过STM32串行2端口的引脚（PA2，PA3），因为它可以承受3.3V。

然后，我们需要让 ESP8266 准备就绪，方法是通过重置任何旧的已连接的 AP 并将其设置为 AP 和 STA 来退出任何旧的 AP

connect_wifi("AT",100);  //Sends AT command with time(Command for Acknowledgement)
connect_wifi("AT+CWMODE=3",100);   //Sends AT command with time (For setting mode of Wi-Fi)
connect_wifi("AT+CWQAP",100);  //Sends AT command with time (for Quit AP)
connect_wifi("AT+RST",5000);   //Sends AT command with time (For RESETTING WIFI)

然后将 ESP8266 与无线网络连接。您必须填写您的Wi-Fi详细信息，如下面的代码所示：

connect_wifi("AT+CWJAP=\"Pramo\",\"pokemon08\"",7000);  //provide your WiFi username and password here

然后我们获取 ESP8266 模块的 IP 地址，并使用下面的代码将其显示在串行监视器上

Serial2.println("AT+CIFSR");           //GET IP AT COMMAND
if(Serial2.find("STAIP,"))                 //This finds the STAIP that is the STATIC IP ADDRESS of ESP8266
Serial.print(IP);                                //prints IP address in Serial monitor

接下来，我们将为网页编写 HTML 代码。要将HTML代码转换为Arduino代码，您可以使用此链接。

HTML在线转Arduino代码

webpage = "<h1>Welcome to Circuit Digest</h1><body bgcolor=f0f0f0>"; //This is the heading line with black font colour
String name="<p>Circuit Digest</p><p>A community of electrical and electronics students, engineers and makers</p>";
String data="<p>Data Received Successfully.....</p>";     //These two lines are of two paragraph
webpage = "<a href=\"http://circuitdigest.com/\"";
webpage+="\">Click Here to get into circuitdigest.com</a>"; //At last we insert the hyperlink to link the website address

接下来在void send() 函数中，我们使用发送网络数据函数打印了HTML，并使用AT + CIPCLOSE = 0关闭了服务器连接

完成所有工作后，您可以通过在任何 Web 浏览器中打开 ESP8266 的 IP 并单击网页上显示的链接来测试工作，单击此处进入 circuitdigest.com，如下所示

esp8266文件服务器 esp8266作为服务器_stm32_08

单击链接后，您会在网页上看到一条文本，上面写着Data Received Successfully.....

完整代码

//Interfacing ESP8266 Wi-Fi with STM32F103C8

//CIRCUIT DIGEST

//NOTE: Serial is serial monitor with baud rate(9600)

//NOTE: Serial2 (TX2, RX2)is connected with ESP8266(RX,TX)respectively with baud rate (9600)


String webpage = ""; //String variable to store characters

int i = 0, k = 0, x = 0; //integer variables

String readString; //using readString feature to read characters                       


boolean No_IP = false; //boolean variables 

String IP = ""; //String variable to store data

char temp1 = '0'; //character variable


String name = "<p>Circuit Digest</p><p>A community of electrical and electronics students, engineers and makers</p>"; //String with html notations

String data = "<p>Data Received Successfully.....</p>"; //String with html 



void check4IP(int t1) //A function to check ip of ESP8266 

{

    int t2 = millis();

    while (t2 + t1 > millis())

    {

        while (Serial2.available() > 0)

        {

            if (Serial2.find("WIFI GOT IP"))

            {

                No_IP = true;

            }

        }

    }

}


void get_ip() //After cheacking ip ,this is a function to get IP address

{

    IP = "";

    char ch = 0;

    while (1)

    {

        Serial2.println("AT+CIFSR"); //GET IP AT COMMAND

        while (Serial2.available() > 0)

        {

            if (Serial2.find("STAIP,")) //This finds the STAIP that is the STATIC IP ADDRESS of ESP8266

            {

                delay(1000);

                Serial.print("IP Address:");

                while (Serial2.available() > 0)

                {

                    ch = Serial2.read(); //Serial2 reads from ESP8266

                    if (ch == '+')

                        break;

                    IP += ch;

                }

            }

            if (ch == '+')

                break;

        }

        if (ch == '+')

            break;

        delay(1000);

    }

    Serial.print(IP); //prints IP address in Serial monitor

    Serial.print("Port:");

    Serial.println(80);

}


void connect_wifi(String cmd, int t) //This function is for connecting ESP8266 with wifi network by using AT commands

{

    int temp = 0, i = 0;

    while (1)

    {

        Serial.println(cmd); //Sends to serial monitor

        Serial2.println(cmd); //sends to ESP8266 via serial communication

        while (Serial2.available())

        {

            if (Serial2.find("OK"))

                i = 8;

        }

        delay(t);

        if (i > 5)

            break;

        i++;

    }

    if (i == 8)

        Serial.println("OK");

    else

        Serial.println("Error");

}


void wifi_init() //This function contains AT commands that passes to connect_wifi()

{

    connect_wifi("AT", 100); //Sends AT command with time(Command for Achknowledgement)

    connect_wifi("AT+CWMODE=3", 100); //Sends AT command with time (For setting mode of Wifi)

    connect_wifi("AT+CWQAP", 100); //Sends AT command with time (for Quit AP)

    connect_wifi("AT+RST", 5000); //Sends AT command with time (For RESETTING WIFI)

    check4IP(5000);

    if (!No_IP)

    {



        Serial.println("Connecting Wifi....");

        connect_wifi("AT+CWJAP=\"Pramo\",\"pokemon08\"", 7000); //provide your WiFi username and password here



    } else

    {

    }

    Serial.println("Wifi Connected");

    get_ip();



    connect_wifi("AT+CIPMUX=1", 100); //Sends AT command with time (For creating multiple connections)

    connect_wifi("AT+CIPSERVER=1,80", 100); //Sends AT command with time (For setting up server with port 80)

}


void sendwebdata(String webPage) //This function is used to send webpage datas to the localserver

{

    int ii = 0;

    while (1)

    {

        unsigned int l = webPage.length();

        Serial.print("AT+CIPSEND=0,");

        Serial2.print("AT+CIPSEND=0,");

        Serial.println(l + 2);

        Serial2.println(l + 2);

        delay(100);

        Serial.println(webPage); //sends webpage data to serial monitor

        Serial2.println(webPage); //sends webpage data to serial2 ESP8266

        while (Serial2.available())

        {



            if (Serial2.find("OK"))

            {

                ii = 11;

                break;

            }

        }

        if (ii == 11)

            break;

        delay(100);

    }

}


void setup()

{

    Serial.begin(9600); //begins serial monitor with baud rate 9600

    Serial2.begin(9600); //begins serial communication with esp8266 with baud rate 9600 (Change according to your esp8266 module)

    wifi_init();

    Serial.println("System Ready..");

}


void loop()

{

    k = 0;

    Serial.println("Please Refresh your Page");

    while (k < 1000)

    {

        k++;

        while (Serial2.available())

        {

            if (Serial2.find("0,CONNECT"))

            {

                Serial.println("Start Printing");

                Send();

                Serial.println("Done Printing");

                delay(1000);

            }

        }

        delay(1);

    }

}


void Send() //This function contains data to be sent to local server

{

    webpage = "<h1>Welcome to Circuit Digest</h1><body bgcolor=f0f0f0>";

    sendwebdata(webpage);

    webpage = name;

    sendwebdata(webpage);

    delay(1000);

    webpage = "<a href=\"http://circuitdigest.com/\"";

    webpage += "\">Click Here to get into circuitdigest.com</a>";

    webpage += data;

    sendwebdata(webpage);

    Serial2.println("AT+CIPCLOSE=0"); //Closes the server connection

}

结语

看到这里相信你已经知道了使用共ESP266与STM32通讯的整个思路和流程了