基于Arduino IDE 野火ESP8266模块WIiFi开发

一、函数介绍

头文件

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>

ESP8266WiFi.h库主要用于连接单个WiFi网络。如果需要连接到多个WiFi网络，例如在需要切换不同网络或者备用网络时，可以使用ESP8266WiFiMulti.h头文件，它是ESP8266WiFi.h的扩展
ESP8266WiFi.h头文件的内容如下：

/*ESP8266WiFi.h - esp8266 Wifi support.Based on WiFi.h from Arduino WiFi shield library.Copyright (c) 2011-2014 Arduino.  All right reserved.Modified by Ivan Grokhotkov, December 2014This library is free software; you can redistribute it and/ormodify it under the terms of the GNU Lesser General PublicLicense as published by the Free Software Foundation; eitherversion 2.1 of the License, or (at your option) any later version.This library is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNULesser General Public License for more details.You should have received a copy of the GNU Lesser General PublicLicense along with this library; if not, write to the Free SoftwareFoundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA*/#ifndef WiFi_h
#define WiFi_h#include <stdint.h>extern "C" {
#include <wl_definitions.h>
}#include "IPAddress.h"#include "ESP8266WiFiType.h"
#include "ESP8266WiFiSTA.h"
#include "ESP8266WiFiAP.h"
#include "ESP8266WiFiScan.h"
#include "ESP8266WiFiGeneric.h"#include "WiFiClient.h"
#include "WiFiServer.h"
#include "WiFiServerSecure.h"
#include "WiFiClientSecure.h"
#include "BearSSLHelpers.h"
#include "CertStoreBearSSL.h"#ifdef DEBUG_ESP_WIFI
#ifdef DEBUG_ESP_PORT
#define DEBUG_WIFI(fmt, ...) DEBUG_ESP_PORT.printf_P( (PGM_P)PSTR(fmt), ##__VA_ARGS__ )
#endif
#endif#ifndef DEBUG_WIFI
#define DEBUG_WIFI(...) do { (void)0; } while (0)
#endifextern "C" void enableWiFiAtBootTime (void) __attribute__((noinline));class ESP8266WiFiClass : public ESP8266WiFiGenericClass, public ESP8266WiFiSTAClass, public ESP8266WiFiScanClass, public ESP8266WiFiAPClass {public:// workaround same function name with different signatureusing ESP8266WiFiGenericClass::channel;using ESP8266WiFiSTAClass::SSID;using ESP8266WiFiSTAClass::RSSI;using ESP8266WiFiSTAClass::BSSID;using ESP8266WiFiSTAClass::BSSIDstr;using ESP8266WiFiScanClass::SSID;using ESP8266WiFiScanClass::encryptionType;using ESP8266WiFiScanClass::RSSI;using ESP8266WiFiScanClass::BSSID;using ESP8266WiFiScanClass::BSSIDstr;using ESP8266WiFiScanClass::channel;using ESP8266WiFiScanClass::isHidden;// ----------------------------------------------------------------------------------------------// ------------------------------------------- Debug --------------------------------------------// ----------------------------------------------------------------------------------------------public:void printDiag(Print& dest);friend class WiFiClient;friend class WiFiServer;};extern ESP8266WiFiClass WiFi;#endif

ESP8266 Wi-Fi库是基于ESP8266 SDK开发的。
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WiFi.mode函数

WiFi.mode()//设置模式

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WiFi.begin函数

WiFi.begin("network-name", "pass-to-network");

WiFi.status函数

WiFi.status()//获取连接是否已经完成，连接过程可能需要几秒钟

WiFi.localIP函数

WiFi.localIP()//获取DHCP分配给ESP模块的IP地址

根据以上一个函数，可以编写一个测试代码，来进行esp8266的联网功能测试。

二、测试例程

测试代码如下：

#include <ESP8266WiFi.h>void setup()
{Serial.begin(115200);Serial.println();WiFi.begin("network-name", "pass-to-network");Serial.print("Connecting");while (WiFi.status() != WL_CONNECTED){delay(500);Serial.print(".");}Serial.println();Serial.print("Connected, IP address: ");Serial.println(WiFi.localIP());
}void loop() {}

如果串口输出只有越来越多的点… ,原因可能是输入的Wi-Fi网络的名称或密码就不正确。可通过PC或手机从头连接到该Wi-Fi网络，验证名称和密码。
注意:如果建立了连接，然后由于某种原因失去了连接，ESP将自动重新连接到上次使用的接入点，一旦它再次联机。这将由Wi-Fi库自动完成，无需任何用户干预。

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编写复杂点的功能，连接tcp服务器，并进行通信，代码示例如下：

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>#ifndef STASSID
#define STASSID "your-ssid"
#define STAPSK "your-password"
#endifconst char* ssid = STASSID;
const char* password = STAPSK;const char* host = "djxmmx.net";
const uint16_t port = 3000;ESP8266WiFiMulti WiFiMulti;void setup() {Serial.begin(115200);// We start by connecting to a WiFi networkWiFi.mode(WIFI_STA);WiFiMulti.addAP(ssid, password);Serial.println();Serial.println();Serial.print("Wait for WiFi... ");while (WiFiMulti.run() != WL_CONNECTED) {Serial.print(".");delay(500);}Serial.println("");Serial.println("WiFi connected");Serial.println("IP address: ");Serial.println(WiFi.localIP());delay(500);
}void loop() {Serial.print("connecting to ");Serial.print(host);Serial.print(':');Serial.println(port);// Use WiFiClient class to create TCP connectionsWiFiClient client;if (!client.connect(host, port)) {Serial.println("connection failed");Serial.println("wait 5 sec...");delay(5000);return;}// This will send the request to the serverclient.println("hello from ESP8266");while(client.status() == ESTABLISHED){// read back one line from serverSerial.println("receiving from remote server");String line = client.readStringUntil('\r');if(!line.isEmpty()){Serial.println(line);client.println(line);}delay(3000);}// not testing 'client.connected()' since we do not need to send data here//while (client.available()) {char ch = static_cast<char>(client.read());Serial.print(ch);//String line = client.readStringUntil('\r');//Serial.println(line);// }Serial.println("closing connection");client.stop();Serial.println("wait 5 sec...");delay(5000);
}

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