Arduino Giga R1 WIFI - USB File Write only works when connected to PC

Official Hardware Mega GIGA R1 WiFi
1

Hey guys,

I have a problem with the Arduino Giga using an USB stick to write the measured values into a file. It all works when connected to the PC. But it doesn't update the file when i power the board with a powerbank. I have formatted the USB Drive to FAT32 and MBR, but it still does not work.

Here is my code:

#include <Arduino_USBHostMbed5.h>
#include <DigitalOut.h>
#include <FATFileSystem.h>
#include <Wire.h>
#include <SparkFun_u-blox_GNSS_Arduino_Library.h>
#include <LiquidCrystal_I2C.h>

SFE_UBLOX_GNSS myGNSS;

long lastTime = 0;

USBHostMSD msd;
mbed::FATFileSystem usb("VOLUME");

void setup() {
  Serial.begin(115200);
  pinMode(PA_15, OUTPUT);
  digitalWrite(PA_15, HIGH);
  while (!Serial);
  
  while (!msd.connect()) {
    delay(1000);
  }

  Wire.begin();

  if (myGNSS.begin() == false) {
    Serial.println(F("u-blox GNSS not detected at default I2C address. Please check wiring. Freezing."));
    while (1);
  }
 
  Serial.println("Mounting USB device...");

  int err = usb.mount(&msd); // Mount USB device
  if (err) {
    Serial.print("Error mounting USB device ");
    Serial.println(err);
    while (1);
  }
  Serial.println("USB device mounted.");
}

void loop() {
  if (!msd.connected()) {
    msd.connect(); // Reconnect USB device if disconnected
  }

  if (millis() - lastTime > 1000) {
    lastTime = millis();

    byte fixType = myGNSS.getFixType();
    Serial.print(F(" Fix: "));
    if(fixType == 0) Serial.print(F("No fix"));
    else if(fixType == 1) Serial.print(F("Dead reckoning"));
    else if(fixType == 2) Serial.print(F("2D"));
    else if(fixType == 3) Serial.print(F("3D"));
    else if(fixType == 4) Serial.print(F("GNSS + Dead reckoning"));
    else if(fixType == 5) Serial.print(F("Time only"));

    long latitude = myGNSS.getLatitude();
    long longitude = myGNSS.getLongitude();

    Serial.print("Latitude: ");
    Serial.println(latitude);
    Serial.print("Longitude: ");
    Serial.println(longitude);

    long speed = myGNSS.getGroundSpeed();
    long altitude = myGNSS.getAltitude();
    long altitudeMSL = myGNSS.getAltitudeMSL();
    long heading = myGNSS.getHeading();
    
    
    // Open file on USB stick
    FILE *f = fopen("/VOLUME/gps_data.txt", "a"); // Open file in append mode
    if (f == NULL) {
      Serial.println("Error opening file!");
    } else {
      // Write all GPS data to file
      fprintf(f, "Latitude: %ld, Longitude: %ld, Speed: %ld, Altitude: %ld, AltitudeMSL: %ld, Heading: %ld\n",
              latitude, longitude, speed, altitude, altitudeMSL, heading);
      fclose(f); // Close the file
      Serial.println("Data written to USB stick.");
    }
  }
}
2

Your code will hang here until it sees a Serial port (i.e USB).

I typically do something similar, but with a timeout, like:
while (!Serial && millis() < 5000) {}
Which will wait for up to 5 seconds for it connects up to something like a Serial monitor.

3

I‘ve already figured that out recently, but thank you, I‘ll try that out.