概述：
1.wifi连接，扫描WiFi连接json序列化，http.get和http.post。
2.数据的存储和全局常量的flash定义。
3.文件的存储读写。
4.板子外设资源的访问：Libraries - Arduino Reference
注意：开发板未nodeMCU1.0(esp-12e)(esp8266-01s上调试的。)
1.添加arduino提供的库
代码：
#include <ESP8266WiFi.h>//默认，加载WIFI头文件#include <Arduino_JSON.h> //加载解析文件库#include <ArduinoHttpClient.h> //加载http客户端库WiFiClient espClient;const char * ssid="wifi_name";//wifi名称const chat * pwd="wifi_password";//WiFi 密码HttpClient http = HttpClient(espClient,"www.baidu.com",80);//定义一个http客户端String mes;
void setup(){WiFi.begin(ssid.pwd);//连接wifiif(WiFi.state()==3)printf("连接成功");delay(500);int n=WiFi.scanNetworks();//扫描附近wifimes=JsonSerialization(n); //将扫描出的WiFi信息json序列化printf(mes);//打印出扫描到的附近wifidelay(100);
}void loop（）{String contentType="application/json"; //请求内容格式String url=""; //数据路径httpm.get(url);//发送get请求，所有的东西都在url中int mhttpCode = http.responseStatusCode();//阻塞响应，就是等待响应，一般10s超时跳过String mresponse = http.responseBody(); //获得响应数据JSONVar mtemp=JSON.parse(mresponse);//将字符串转成json格式if (JSON.typeof(mtemp) == "undefined") {Serial.println("Parsing input failed!");return;}delay(1000);String contentType="application/json";String url="";http.post(url, contentType, message); //可以发现post和get还是比较像的，数据和url不在一起int httpCode = http.responseStatusCode();String response = http.responseBody(); printf(response);delay(1000);}总结：
非常简单，基本上全部封装到位，只需要简单的调用填参数就行。http中的get和post本质没有区别，只不过在封装的时候考虑了标志，数据的位置，服务器的解析。
2.数据的动态存储和读写
#include <se_eeprom.h> //这个库包含了arduino.h和eeprom.h//可以读取1字节到32字节的数据
void setup(){SE_EEPROM my_eeprom;//建立对象unsigned short eeprom_size=256;//flash存储区大小my_eeprom.SetEEPROMSize(256);//申请一个256字节的flash存储区my_eeprom.WriteEEPROMByte(1, ver);//写1到数据区索引1ver=my_eeprom.ReadEEPROMByte(1)；//在数据区索引1读取数据my_eeprom.WriteEEPROMStr32(64, "Hello World!!!");//写字符串到数据区索引64Serial.println(my_eeprom.ReadEEPROMStr32(64));//从数据区索引64读取字符串
}
//这个库是毛子写的，可以发现这个库非常好用
//直接搜就可以在ide上搜到
void loop(){}6.全局常量定义在flash节省ram空间
//字节和整数
// 保存无符号整型
const PROGMEM uint16_t charSet[] = { 65000, 32796, 16843, 10, 11234};// 保存字符
const char signMessage[] PROGMEM = {"I AM PREDATOR, UNSEEN COMBATANT. CREATED BY THE UNITED STATES DEPART"};unsigned int displayInt;
char myChar;void setup() {Serial.begin(9600);while (!Serial); // wait for serial port to connect. Needed for native USB// put your setup code here, to run once:// 读回一个2字节长整型for (byte k = 0; k < 5; k++) {displayInt = pgm_read_word_near(charSet + k);Serial.println(displayInt);}Serial.println();// 读回一个字符int signMessageLength = strlen_P(signMessage);for (byte k = 0; k < signMessageLength; k++) {myChar = pgm_read_byte_near(signMessage + k);Serial.print(myChar);}Serial.println();
}void loop() {// put your main code here, to run repeatedly:
}//存储字符串
/*PROGMEM string demoHow to store a table of strings in program memory (flash),and retrieve them.Information summarized from:http://www.nongnu.org/avr-libc/user-manual/pgmspace.htmlSetting up a table (array) of strings in program memory is slightly complicated, buthere is a good template to follow.Setting up the strings is a two-step process. First, define the strings.
*/#include <avr/pgmspace.h>
const char string_0[] PROGMEM = "String 0"; // "String 0" 等将以表格式存储
const char string_1[] PROGMEM = "String 1";
const char string_2[] PROGMEM = "String 2";
const char string_3[] PROGMEM = "String 3";
const char string_4[] PROGMEM = "String 4";
const char string_5[] PROGMEM = "String 5";
//字符串// 把字符串放到表中.const char *const string_table[] PROGMEM = {string_0, string_1, string_2, string_3, string_4, string_5};char buffer[30]; // 确认能够存储字符串的最大长度void setup() {Serial.begin(9600);while (!Serial); // wait for serial port to connect. Needed for native USBSerial.println("OK");
}void loop() {/* Using the string table in program memory requires the use of special functions to retrieve the data.The strcpy_P function copies a string from program space to a string in RAM ("buffer").Make sure your receiving string in RAM is large enough to hold whateveryou are retrieving from program space. *//*这段话的意思是使用字符串表编程到内存，需要特殊的函数复原数据，而strcpy_P就是把数据从内存拷贝到ram区域，保证ram区有足够的空间。*/for (int i = 0; i < 6; i++) {strcpy_P(buffer, (char *)pgm_read_ptr(&(string_table[i]))); // 必要的格式转换和定义Serial.println(buffer);delay(500);}
}/*ram是程序运行区，flash也就是eeprom就是程序存储区*/
/*大部分程序都是三级流水线*///取指：把数据从存储区取出来放到缓存区//译码：把缓存区的数据解析，它们该去哪？有的去寄存器，有的去堆栈，有的去外设//执行：把数据放到它应该去的地方，然后晶振一动，数据就被运行，然后pc+1代码是官网上抄的，官网全英文，不想区去官网看英文的可以看这个。
官网地址：PROGMEM - Arduino Reference
3.文件的操作（有的开发板不支持，差一些开发板的资料）
esp32和esp8266架构支持。毛子的话看不懂，但是代码很清晰简单。
#include <Arduino.h>
#include <FileData.h>
#include <LittleFS.h>struct Data {uint8_t val8;uint16_t val16;uint32_t val32 = 12345;char str[20];
};
Data mydata;FileData data(&LittleFS, "/data.dat", 'B', &mydata, sizeof(mydata));void setup() {Serial.begin(115200);delay(1000);Serial.println();LittleFS.begin();// прочитать данные из файла в переменную// при первом запуске в файл запишутся данные из структурыFDstat_t stat = data.read();switch (stat) {case FD_FS_ERR: Serial.println("FS Error");break;case FD_FILE_ERR: Serial.println("Error");break;case FD_WRITE: Serial.println("Data Write");break;case FD_ADD: Serial.println("Data Add");break;case FD_READ: Serial.println("Data Read");break;default:break;}Serial.println("Data read:");Serial.println(mydata.val8);Serial.println(mydata.val16);Serial.println(mydata.val32);Serial.println(mydata.str);
}void loop() {// data.tick(); // вызывать тикер в loop// можно отловить момент записиif (data.tick() == FD_WRITE) Serial.println("Data updated!");// запишем в данные строку из монитора порта// а также присвоим остальным переменным случайные значенияif (Serial.available()) {int len = Serial.readBytes(mydata.str, 20);mydata.str[len] = '\0';mydata.val8 = random(255);mydata.val16 = random(65000);Serial.println("Update");// отложить обновлениеdata.update();}
}代码地址：GitHub - GyverLibs/FileData: Замена EEPROM для ESP8266/32 для хранения любых данных в файлах
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