如何使用Arduino ESP32将数据存储到MicroSD(软SPI和硬SPI)

如何使用Arduino ESP32将数据存储到MicroSD(软SPI和硬SPI)

主要针对使用这个库：github地址：

如果网页无法加载，将域名改为镜像地址的例如：

该库支持软SPI接口和硬SPI接口.如果使用硬SPI接口直接定义：

if (!SD.begin()) {
          
    
    Serial.println("initialization failed!");
    return;
  }

如果是软SPI接口就：

if (!SD.begin(26, 14, 13, 27)) {
          
   
    Serial.println("initialization failed!");
    return;
  }

接线说明

软SPI接口接线方式：

Soft SPI 
[ESP32 IO26 – CS MICRO SD]
[ESP32 IO14 – MOSI MICRO SD]
[ESP32 IO13 – MISO MICRO SD]
[ESP32 IO27 – SCK MICRO SD]
[ESP32 GND – GND MICRO SD]
[VIN – VCC MICRO SD]

硬SPI接口接线方式：

Hard SPI
 * MICROSD CS    -    ESP32 IO5
  MICROSD SCK   -     ESP32 IO18
  MICROSD MOSI  -    ESP32 IO23
  MICROSD MISO   -   ESP32 IO19
  MICROSD Vcc   -      ESP32 VIN
  MICROSD GND   -    ESP32 GND

实例代码

#include <mySD.h>

File root;
void printDirectory(File dir, int numTabs);

void setup()
{
          
   
  Serial.begin(115200);

  Serial.print("Initializing SD card...");
  /* initialize SD library with Soft SPI pins, if using Hard SPI replace with this SD.begin()*/
//  if (!SD.begin(26, 14, 13, 27)) {//采用软SPI接口
  if (!SD.begin()) {
          
    采用硬SPI接口
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
  /* Begin at the root "/" */
  root = SD.open("/");
  if (root) {
          
       
    printDirectory(root, 0);
    root.close();
  } else {
          
   
    Serial.println("error opening test.txt");
  }
  /* open "test.txt" for writing */
  root = SD.open("test.txt", FILE_WRITE);
  /* if open succesfully -> root != NULL 
    then write string "Hello world!" to it
  */
  if (root) {
          
   
    root.println("Hello world!");
    root.flush();
   /* close the file */
    root.close();
  } else {
          
   
    /* if the file open error, print an error */
    Serial.println("error opening test.txt");
  }
  delay(1000);
  /* after writing then reopen the file and read it */
  root = SD.open("test.txt");
  if (root) {
          
       
    /* read from the file until theres nothing else in it */
    while (root.available()) {
          
   
      /* read the file and print to Terminal */
      Serial.write(root.read());
    }
    root.close();
  } else {
          
   
    Serial.println("error opening test.txt");
  }
  
  Serial.println("done!");
}

void loop()
{
          
   
}

void printDirectory(File dir, int numTabs) {
          
   
  
  while(true) {
          
   
     File entry =  dir.openNextFile();
     if (! entry) {
          
   
       break;
     }
     for (uint8_t i=0; i<numTabs; i++) {
          
   
       Serial.print(	);   // well have a nice indentation
     }
     // Print the name
     Serial.print(entry.name());
     /* Recurse for directories, otherwise print the file size */
     if (entry.isDirectory()) {
          
   
       Serial.println("/");
       printDirectory(entry, numTabs+1);
     } else {
          
   
       /* files have sizes, directories do not */
       Serial.print("		");
       Serial.println(entry.size());
     }
     entry.close();
   }
}

相关接口函数

Class SD:

-SD.begin(uint8_t cs , int8_t mosi , int8_t miso , int8_t sck): 使用SPI引脚初始化库 SD.open(filename, FILE_WRITE): 打开文件进行写入 SD.open(filename): 打开文件进行读取 SD.open("/"): 打开sdcard at root“/”

Class File:

openNextFile(): 检查条目是否为目录 name(): get the name of file or directory isDirectory(): check if entry is directory size(): 获取文件大小 println(text): 将文本写入打开的文件 available(): 检查可用的数据reading read(): 如果数据可用则读取数据 close(): 关闭打开的文件