[SOLVED] arduino save int variable value on SD



  • Hi, how can I save an int variable value on m5stack? (like eeprom)
    is it possible to save it on sd card?

    tnks


  • M5Stack

    I'm not sure I quite understand your question. Do you want to log the output of a variable to a text file on the SD?



  • on esp8266, to save/read a value in to eeprom, I do:

    #include <EEPROM.h>
    int address = 0;
    
     EEPROM.begin(512);
      
    byte x = sonar.convert_cm(echoTime);
      delay(1000);
      EEPROM.write(address, x);
      delay(1000);
      EEPROM.commit();
      delay(1000);
    
      x = EEPROM.read(address);
      delay (500);
    

    how can I do to save/read x variable on sd with m5?

    tnks a lot



  • M5Stack has the same "EEPROM" (Which is really a simulation that simply uses a small partition in the flash memory.) If I am not mistaken the code you quote should work still on the ESP32 (and thus on the M5Stack).

    ESP32's have something called NVM, which stores key-value pairs in another partition of the same flash. In the Arduino world, "Preferences.h" provides a wrapper to use these functions. Have a look here for an example that stores a value (the number of times the ESP was booted) in flash.



  • How many cycle before dead of flash partition?



  • I would like to save some variables, like I did with EEPROM on esp8266, but on M5Stack sd.. (to kill sd card instead of esp32 memory)

    I'm trying this sketch:

    // http://forum.m5stack.com/topic/184/problems-writing-to-sd-card
    #include <M5Stack.h>
    
    //Micro SD / TF Card Test
    
    
    String cal;
    String lum;
    String unit;
    
    bool brght = 0;
    bool ftmt = 1;
    
    int x = 1680;
    
    void listDir(fs::FS &fs, const char * dirname, uint8_t levels) {
    
      // Print blank line on screen
      M5.Lcd.printf(" \n  ");
      M5.Lcd.printf(" \n  ");
    
      Serial.printf("Listing directory: %s\n", dirname);
      M5.Lcd.printf("Listing directory: %s\n", dirname);
    
      File root = fs.open(dirname);
      if (!root) {
        Serial.println("Failed to open directory");
        M5.Lcd.println("Failed to open directory");
        return;
      }
      if (!root.isDirectory()) {
        Serial.println("Not a directory");
        M5.Lcd.println("Not a directory");
        return;
      }
    
      File file = root.openNextFile();
      while (file) {
        if (file.isDirectory()) {
          Serial.print("  DIR : ");
          M5.Lcd.print("  DIR : ");
          Serial.println(file.name());
          M5.Lcd.println(file.name());
          if (levels) {
            listDir(fs, file.name(), levels - 1);
          }
        } else {
          Serial.print("  FILE: ");
          M5.Lcd.print("  FILE: ");
          Serial.print(file.name());
          M5.Lcd.print(file.name());
          Serial.print("  SIZE: ");
          M5.Lcd.print("  SIZE: ");
          Serial.println(file.size());
          M5.Lcd.println(file.size());
        }
        file = root.openNextFile();
      }
    }
    
    void readFile(fs::FS &fs, const char * path) {
      Serial.printf("Reading file: %s\n", path);
      M5.Lcd.printf("Reading file: %s\n", path);
    
      File file = fs.open(path);
      if (!file) {
        Serial.println("Failed to open file for reading");
        M5.Lcd.println("Failed to open file for reading");
        return;
      }
    
      Serial.print("Read from file: ");
      M5.Lcd.print("Read from file: ");
      while (file.available()) {
        int ch = file.read();
        Serial.write(ch);
        M5.Lcd.write(ch);
      }
    }
    
    void writeFile(fs::FS &fs, const char * path, const char * message) {
      Serial.printf("Writing file: %s\n", path);
      M5.Lcd.printf("Writing file: %s\n", path);
    
      File file = fs.open(path, FILE_WRITE);
      if (!file) {
        Serial.println("Failed to open file for writing");
        M5.Lcd.println("Failed to open file for writing");
        return;
      }
      if (file.print(message)) {
        Serial.println("File written");
        M5.Lcd.println("File written");
      } else {
        Serial.println("Write failed");
        M5.Lcd.println("Write failed");
      }
    }
    
    void setup() {
    
      M5.begin();
      Wire.begin();
    
      Serial.begin(115200);
    
      // Lcd display
      M5.Lcd.setBrightness(100);
      M5.Lcd.fillScreen(BLACK);
      M5.Lcd.setCursor(0, 10);
      M5.Lcd.setTextColor(WHITE);
      M5.Lcd.setTextSize(2);
    
      // Page Header
      M5.Lcd.fillScreen(BLACK);
      M5.Lcd.setCursor(0, 05);
      M5.Lcd.printf("Testing SD Card Functions:\r\n");
    
      /////////////////////////////////////////////////////////////////////////
      cal = String("cal = ") + String(x) + "\r\n";
      lum = String("lum = ") + String(brght) + "\r\n";
      unit = String("unit = ") + String(ftmt) + "\r\n";
    
      writeFile(SD, "/cal.txt", cal.c_str()); // questa funziona!!!!
      writeFile(SD, "/lum.txt", lum.c_str()); // questa funziona!!!!
      writeFile(SD, "/unit.txt", unit.c_str()); // questa funziona!!!!
      /////////////////////////////////////////////////////////////////////////
    
      M5.Lcd.printf("");
      // Print blank line on screen
      M5.Lcd.printf(" \n  ");
      // Print blank line on screen
      M5.Lcd.printf(" \n  ");
    
      readFile(SD, "/cal.txt");
      readFile(SD, "/lum.txt");
      readFile(SD, "/unit.txt");
    
    }
    
    void loop() {
    
      // put your main code here, to run repeatedly:
    
      M5.update();
    }
    

    but I can't understand how to read from sd and use the variables in the sketch..
    I need to read and write two boolean state and one int variables ..
    I'm a newbi and all the sketch I found on line that use sd.h library doesn't work on M5Stack

    if I upload read/write arduino sd example, this is the serial monitor output:

    error opening test.txt

    please help

    thanks a lot



  • @yellowelise said in arduino save int variable value:

    How many cycle before dead of flash partition?

    I'm interested too



  • @cepics
    Have you tried playing with the sd read and write examples?



  • @ajb2k3 said in arduino save int variable value:

    @cepics
    Have you tried playing with the sd read and write examples?

    yes this one

    /*
      SD card read/write
    
     This example shows how to read and write data to and from an SD card file
     The circuit:
     * SD card attached to SPI bus as follows:
     ** MOSI - pin 11
     ** MISO - pin 12
     ** CLK - pin 13
     ** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN)
    
     created   Nov 2010
     by David A. Mellis
     modified 9 Apr 2012
     by Tom Igoe
    
     This example code is in the public domain.
    
     */
    
    #include <SPI.h>
    #include <SD.h>
    
    File myFile;
    
    void setup() {
      // Open serial communications and wait for port to open:
      Serial.begin(9600);
      while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only
      }
    
    
      Serial.print("Initializing SD card...");
    
      if (!SD.begin(4)) {
        Serial.println("initialization failed!");
        while (1);
      }
      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
    }
    
    
    

    it compile but the serial monitor say:
    error opening test.txt

    right now, with an example from here, I can write an int variable in a file on sd

    
    #include <M5Stack.h>
    int cal = 2000;
    
    
    void setup() {
    
      M5.begin();
      Wire.begin();
    
      Serial.begin(115200);
    
      File file = SD.open("/cal.txt", FILE_WRITE);
      if (!file) {
        Serial.println("Failed to open file for writing");
        return;
      }
      if (file.print(cal)) {
        Serial.println("File written");
      } else {
        Serial.println("Write failed");
      }
    
    }
    
    void loop() {
      // put your main code here, to run repeatedly:
    
    }
    

    and I can read the file with

    
    #include <M5Stack.h>
    int ch;
    
    void setup() {
    
      M5.begin();
      Wire.begin();
    
      Serial.begin(115200);
    
      File file = SD.open("/cal.txt");
      if (!file) {
        Serial.println("Failed to open file for reading");
        return;
      }
    
      Serial.print("Read from file: ");
      M5.Lcd.print("Read from file: ");
      while (file.available()) {
        ch = file.read();
        Serial.write(ch);
        M5.Lcd.write(ch);
      }
    }
    
    
    void loop() {
      // put your main code here, to run repeatedly:
    
    }
    

    but I can't use the "ch" variable ..

    if I add, on the "read" sketch

    int y = ch + 2000;
    Serial.print(y);
    

    in the serial monitor I have:

    M5Stack initializing...O�������
    Read from file: 2000
    2048
    

    2048 instead of 4000

    now I'm searching how to convert ASCII to binary

    thanks for interest..



  • Hello,if you want use eeprom, suggest try this example in arduino ide:

    file->Examples->Preferences
    

    https://github.com/espressif/arduino-esp32/blob/master/libraries/Preferences/examples/StartCounter/StartCounter.ino



  • the solution:

    file.parseInt();

    thanks a lot !!!


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