A third, newly ordered sd card works now. 👍It is a Verbatin 16Gb Premium microSDHC. The m5stack seems to be pretty picky?!

I like it!👍

I tried it on my M5Stack Core with a SanDisk 32GB Fat32 and a Noname 4GB Fat32. Even repeated formatting did not lead to success. Do you have another tip for me?

@jj said in Problems writing to SD Card:

@vsthose Hi Vsthose,

The following code should work provided you use a Micro SD / TF card that only has a few files on it.... too many and the display will run off the screen and you won't see the write to card and read back.

#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");
    }
}

// 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(1);

    // Page Header
    M5.Lcd.fillScreen(BLACK);
    M5.Lcd.setCursor(0, 05);
    M5.Lcd.printf("           Testing Micro SD Card Functions:\r\n");
    // digitalWrite(TFT_CS, 1);
 
    // Print blank line on screen
    M5.Lcd.printf(" \n    ");
    M5.Lcd.printf(" \n    ");
    
    listDir(SD, "/", 0);
    M5.Lcd.printf("");
    M5.Lcd.printf("");

    // Print blank line on screen
    M5.Lcd.printf(" \n  ");
    M5.Lcd.printf(" \n  ");
    
    writeFile(SD, "/hello.txt", "Hello world from M5Stack !!");
    M5.Lcd.printf("");
    M5.Lcd.printf("");

    // Print blank line on screen
    M5.Lcd.printf(" \n  ");
    M5.Lcd.printf(" \n  ");

    // Print blank line on screen
    M5.Lcd.printf(" \n  ");
    M5.Lcd.printf(" \n  ");
    
    readFile(SD, "/hello.txt");
}

void loop() {

  // put your main code here, to run repeatedly:
   
    M5.update();
}

I tested the example. unfortunately it doesn't work for me. there are no folders or many other files on the card. what am I doing wrong?

rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:1344
load:0x40078000,len:13516
load:0x40080400,len:3604
entry 0x400805f0
M5Stack initializing...OK
Listing directory: /
Failed to open directory
Writing file: /hello.txt
Failed to open file for writing
Reading file: /hello.txt
Failed to open file for reading

I just want to update a single value in the display. Is this possible without first deleting the entire display?

Unfortunately, a restart doesn't help either. maybe it's because of my older router.

Unfortunately this doesn't work for me. I am doing something wrong?

......
String hostname = "newName";
......

void initWiFi() {
WiFi.mode(WIFI_STA);
//WiFi.disconnect(); //Turn off all wifi connections.
//delay(100);
WiFi.config(INADDR_NONE, INADDR_NONE, INADDR_NONE, INADDR_NONE);
WiFi.setHostname(hostname.c_str()); //define hostname (wifi.config muss davor stehen
WiFi.begin(ssid, password);
M5.Lcd.print("Call to " + String(ssid));
while (WiFi.status() != WL_CONNECTED) {
M5.Lcd.print('.');
delay(1000);
}
M5.Lcd.println(" ");
M5.Lcd.println(WiFi.localIP());
M5.Lcd.print("Signalstearke: ");
M5.Lcd.println(WiFi.RSSI());
server.begin();
delay(4000);
M5.Lcd.clear();
}

I don't get an error message from the compiler, but the new name doesn't appear in the router

WiFi.mode(WIFI_STA);
WiFi.disconnect(); //Turn off all wifi connections.
delay(100);
WiFi.setHostname("M5StackCoreZaehler");
WiFi.begin(ssid, password);
M5.Lcd.print("Call to " + String(ssid));
while (WiFi.status() != WL_CONNECTED) {
M5.Lcd.print('.');
delay(1000);
}
M5.Lcd.println(" ");
M5.Lcd.println(WiFi.localIP());
M5.Lcd.print("Signalstearke: ");
M5.Lcd.println(WiFi.RSSI());
server.begin();
delay(4000);
M5.Lcd.clear();

Yes, it works! Thanks!

The standard font is very small. If i use "M5.Lcd.setFreeFont(FSS9)" within the code, how do I get back to the small standard font? I need smaller then 9pt.