save some variables into sd card



  • Hi,
    I would like to save three variables value on the sd.
    boolean brgt
    boolean unit
    int x
    and, on setup() read that values...
    I'm trying with String, and I can save a string of my value in a file on sd..
    but I don't know how to read the separate value to use it in the sketch

    // http://forum.m5stack.com/topic/184/problems-writing-to-sd-card
    #include <M5Stack.h>

    //Micro SD / TF Card Test

    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");
    }
    }

    //////////////////////////////////////////////////////////////////////////////////////
    bool suca = 1;
    bool assai = 0;
    int x = 1680;
    //////////////////////////////////////////////////////////////////////////////////////

    // the setup routine runs once when M5Stack starts up

    void setup() {

    // initialize the M5Stack object
    M5.begin();

    // M5.startupLogo();
    Wire.begin();

    // 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");

    //////////////////////////////////////////////////////////////////////////////////////

    store = String(brgt) + "," + String(unit) + "," + String(x) + "\r\n";

    //////////////////////////////////////////////////////////////////////////////////////
    // writeFile(SD, "/hello.txt", "Hello world from M5Stack !!");
    writeFile(SD, "/hello.txt", store.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, "/hello.txt");
    // store2[3] = (readFile(SD, "/hello.txt"));
    }

    void loop() {

    // put your main code here, to run repeatedly:

    M5.update();
    }

    is it correct to use String?
    is it the best way to save/read my variables?

    in the past, with esp8266, I saved my three variables on EEPROM but since M5Stack have sd card I would like to have infinite cycle of read/write


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