Intermittent functioning of SD card module on ESP32

I have two different models of ESP32 boards to which I have each connected an SD card module. I am trying to read and write to the SD card and am currently using a slightly modified version of the SD_test code.

On Board-A everything functions as desired. The test code executes perfectly and the serial monitor displays the desired results.

On Board-B however, the SD card functionality only works intermittently. Sometimes it reads and writes the the SD card just fine, and other times I get errors. Each time I press the reset button on the board, it's a roll of the dice whether the SD card read/write, etc works or not. I can't figure out why this functions correctly so inconsistently.

The Board-B is the one I am looking to use for my project but because lots of the pins aren't exposed, I have had to define other GPIO pins as SPI pins and connect the SD card to these. I don't know whether this is where the issue is coming from?

Below is the code I'm using.

/*
  Rui Santos
  Complete project details at https://RandomNerdTutorials.com/esp32-microsd-card-arduino/
  
  This sketch was modified from: Examples > SD(esp32) > SD_Test
*/

#include "FS.h"
#include "SD.h"
#include "SPI.h"

/* Board-A
#define SCK  15
#define MISO  27
#define MOSI  4
#define CS  14
*/

/* Board-B*/
#define SCK  22
#define MISO  5
#define MOSI  4
#define CS  0


SPIClass spi = SPIClass(VSPI);

void listDir(fs::FS &fs, const char * dirname, uint8_t levels){
  Serial.printf("Listing directory: %s\n", dirname);

  File root = fs.open(dirname);
  if(!root){
    Serial.println("Failed to open directory");
    return;
  }
  if(!root.isDirectory()){
    Serial.println("Not a directory");
    return;
  }

  File file = root.openNextFile();
  while(file){
    if(file.isDirectory()){
      Serial.print("  DIR : ");
      Serial.println(file.name());
      if(levels){
        listDir(fs, file.name(), levels -1);
      }
    } else {
      Serial.print("  FILE: ");
      Serial.print(file.name());
      Serial.print("  SIZE: ");
      Serial.println(file.size());
    }
    file = root.openNextFile();
  }
}

void createDir(fs::FS &fs, const char * path){
  Serial.printf("Creating Dir: %s\n", path);
  if(fs.mkdir(path)){
    Serial.println("Dir created");
  } else {
    Serial.println("mkdir failed");
  }
}

void removeDir(fs::FS &fs, const char * path){
  Serial.printf("Removing Dir: %s\n", path);
  if(fs.rmdir(path)){
    Serial.println("Dir removed");
  } else {
    Serial.println("rmdir failed");
  }
}

void readFile(fs::FS &fs, const char * path){
  Serial.printf("Reading file: %s\n", path);

  File file = fs.open(path);
  if(!file){
    Serial.println("Failed to open file for reading");
    return;
  }

  Serial.print("Read from file: ");
  while(file.available()){
    Serial.write(file.read());
  }
  file.close();
}

void writeFile(fs::FS &fs, const char * path, const char * message){
  Serial.printf("Writing file: %s\n", path);

  File file = fs.open(path, FILE_WRITE);
  if(!file){
    Serial.println("Failed to open file for writing");
    return;
  }
  if(file.print(message)){
    Serial.println("File written");
  } else {
    Serial.println("Write failed");
  }
  file.close();
}

void appendFile(fs::FS &fs, const char * path, const char * message){
  Serial.printf("Appending to file: %s\n", path);

  File file = fs.open(path, FILE_APPEND);
  if(!file){
    Serial.println("Failed to open file for appending");
    return;
  }
  if(file.print(message)){
    Serial.println("Message appended");
  } else {
    Serial.println("Append failed");
  }
  file.close();
}

void renameFile(fs::FS &fs, const char * path1, const char * path2){
  Serial.printf("Renaming file %s to %s\n", path1, path2);
  if (fs.rename(path1, path2)) {
    Serial.println("File renamed");
  } else {
    Serial.println("Rename failed");
  }
}

void deleteFile(fs::FS &fs, const char * path){
  Serial.printf("Deleting file: %s\n", path);
  if(fs.remove(path)){
    Serial.println("File deleted");
  } else {
    Serial.println("Delete failed");
  }
}

void testFileIO(fs::FS &fs, const char * path){
  File file = fs.open(path);
  static uint8_t buf[512];
  size_t len = 0;
  uint32_t start = millis();
  uint32_t end = start;
  if(file){
    len = file.size();
    size_t flen = len;
    start = millis();
    while(len){
      size_t toRead = len;
      if(toRead > 512){
        toRead = 512;
      }
      file.read(buf, toRead);
      len -= toRead;
    }
    end = millis() - start;
    Serial.printf("%u bytes read for %u ms\n", flen, end);
    file.close();
  } else {
    Serial.println("Failed to open file for reading");
  }


  file = fs.open(path, FILE_WRITE);
  if(!file){
    Serial.println("Failed to open file for writing");
    return;
  }

  size_t i;
  start = millis();
  for(i=0; i<2048; i++){
    file.write(buf, 512);
  }
  end = millis() - start;
  Serial.printf("%u bytes written for %u ms\n", 2048 * 512, end);
  file.close();
}

void setup(){
  Serial.begin(115200);
  spi.begin(SCK, MISO, MOSI, CS);

  if (!SD.begin(CS,spi,80000000)) {
    Serial.println("Card Mount Failed");
    return;
  }
  uint8_t cardType = SD.cardType();

  if(cardType == CARD_NONE){
    Serial.println("No SD card attached");
    return;
  }

  Serial.print("SD Card Type: ");
  if(cardType == CARD_MMC){
    Serial.println("MMC");
  } else if(cardType == CARD_SD){
    Serial.println("SDSC");
  } else if(cardType == CARD_SDHC){
    Serial.println("SDHC");
  } else {
    Serial.println("UNKNOWN");
  }

  uint64_t cardSize = SD.cardSize() / (1024 * 1024);
  Serial.printf("SD Card Size: %lluMB\n", cardSize);

  listDir(SD, "/", 0);
  createDir(SD, "/mydir");
  listDir(SD, "/", 0);
  removeDir(SD, "/mydir");
  listDir(SD, "/", 2);
  writeFile(SD, "/hello.txt", "Hello ");
  appendFile(SD, "/hello.txt", "World2!\n");
  readFile(SD, "/hello.txt");
  deleteFile(SD, "/foo.txt");
  renameFile(SD, "/hello.txt", "/foo.txt");
  readFile(SD, "/foo.txt");
  testFileIO(SD, "/test.txt");
  Serial.printf("Total space: %lluMB\n", SD.totalBytes() / (1024 * 1024));
  Serial.printf("Used space: %lluMB\n", SD.usedBytes() / (1024 * 1024));
}

void loop(){

}

A year ago or so, someone had an SD card unit with improperly soldered connections. Perhaps you have another one?

1 Like

It sounds like an intermittent connections, be sure they are all good. Try putting pressure on each wire and see if it solves or causes the problem. If so you found the problem.

Thank you @Paul_KD7HB and @gilshultz very much for the assistance! I made sure all the jumper wires were properly connected and everything seems to be working smoothly now!

Could be a power problem. I assume you steal power for the SD card from the 3.3volt pin of the ESP. (they are falsely advertised as 5volt modules). The regulators on the ESP modules are different, and one also has to power a display. The USB cables must also be short/fat for stable power.

Better SD card modules have their own built-in voltage regulator, so you can power them from the 5volt pin of the ESP.
Leo..

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