Arduino ESP32 第三方库读取SD卡信息

Posted 2021-12-24 perseverance52

Arduino ESP32 第三方库读取SD卡信息（三）

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相关篇《Arduino ESP32 第三方库读取SD卡信息（一）》
《Arduino ESP32 第三方库读取SD卡信息（二）》

• 所需库github地址：https://github.com/nhatuan84/esp32-micro-sdcard

如果网页无法加载，将域名改为镜像地址的例如：https://hub.fastgit.org/nhatuan84/esp32-micro-sdcard

• 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接口就这样初始化：

  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

实例代码三（文件读写测试）

和固件自带的示例差不多。

#include <SPI.h>
#include <mySD.h>

File myFile;

// change this to match your SD shield or module;
//     Arduino Ethernet shield: pin 4
//     Adafruit SD shields and modules: pin 10
//     Sparkfun SD shield: pin 8
//const int chipSelect = 4;

void setup()

 // Open serial communications and wait for port to open:
  Serial.begin(115200);
   while (!Serial) 
    ; // wait for serial port to connect. Needed for Leonardo only
  


  Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin 
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output 
  // or the SD library functions will not work. 
  // pinMode(SS, OUTPUT);
   
  if (!SD.begin(26, 14, 13, 27)) 
    Serial.println("initialization failed!");
    return;
  
  Serial.println("initialization done.");
  
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  myFile = SD.open("test.txt", FILE_WRITE);
  
  // if the file opened okay, write to it:
  if (myFile) 
    Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
	// close the file:
    myFile.close();
    Serial.println("done.");
   else 
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  
  
  // re-open the file for reading:
  myFile = SD.open("test.txt");
  if (myFile) 
    Serial.println("test.txt:");
    
    // read from the file until there's nothing else in it:
    while (myFile.available()) 
    	Serial.write(myFile.read());
    
    // close the file:
    myFile.close();
   else 
  	// if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  


void loop()

	// nothing happens after setup

• 编译信息

使用 1.0  版本的库 SPI 在文件夹： C:\\Users\\Administrator\\AppData\\Local\\Arduino15\\packages\\esp32\\hardware\\esp32\\1.0.6\\libraries\\SPI 
使用库 esp32-micro-sdcard-master 在文件夹： C:\\Program Files (x86)\\Arduino\\libraries\\esp32-micro-sdcard-master (legacy)
"C:\\\\Users\\\\Administrator\\\\AppData\\\\Local\\\\Arduino15\\\\packages\\\\esp32\\\\tools\\\\xtensa-esp32-elf-gcc\\\\1.22.0-97-gc752ad5-5.2.0/bin/xtensa-esp32-elf-size" -A "d:\\\\arduino\\\\MyHexDir/nanosdcard2.ino.elf"
项目使用了 215894 字节，占用了 (16%) 程序存储空间。最大为 1310720 字节。
全局变量使用了14224字节，(4%)的动态内存，余留313456字节局部变量。最大为327680字节。

• 串口打印信息
  

示例2

#include <mySD.h>

File root;

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)) 
    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 there's 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('\\t');   // we'll 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("\\t\\t");
       Serial.println(entry.size());
     
     entry.close();