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arduino-libraries / Arduino_UnifiedStorage

Read and write files to flash, USB mass storage and SD cards in a unified way.
GNU Lesser General Public License v2.1
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USB storage initialization fails if performed inside connection callback #40

Open haveyouseenf opened 5 months ago

haveyouseenf commented 5 months ago

I wrote a simple sketch for the Opta that creates a new file in the root folder of a connected USB device and then writes inside it.

I planned to use the connection callback to immediately initialize the USB storage, but unfortunately it did not work. In fact the following sketch cannot create a new file:

Click to expand ```cpp #include USBStorage usbStorage; volatile bool usbAvailable = false; void setup() { // Disable debugging of storage operations. Arduino_UnifiedStorage::debuggingModeEnabled = false; // Init USBStorage object. usbStorage = USBStorage(); // Register connect callback. usbStorage.onConnect(connectionCallback); usbStorage.onDisconnect(disconnectionCallback); } void loop() { while (!usbAvailable) { digitalWrite(LED_USER, HIGH); delay(200); digitalWrite(LED_USER, LOW); delay(200); } digitalWrite(LED_USER, LOW); Folder root = usbStorage.getRootFolder(); UFile outFile = root.createFile("test.txt", FileMode::APPEND); outFile.write("Hello, World!"); outFile.close(); usbStorage.unmount(); digitalWrite(LED_USER, HIGH); while (1) { } } void connectionCallback() { usbAvailable = true; usbStorage.removeOnConnectCallback(); // This does not work! if (!usbStorage.isMounted()) { usbStorage.begin(); } } void disconnectionCallback() { usbAvailable = false; usbStorage.onConnect(connectionCallback); } ```

Furthemore, I suspect the storage might not be initialized at all when using the above code, as a simple call to root.exists() in the loop would halt the execution causing a board reset.

If I instead move the storage initialization code in the loop() function, the sketch works as expected. I will attach the functioning sketch below for completeness:

Click to expand ```cpp #include USBStorage usbStorage; volatile bool usbAvailable = false; void setup() { // Disable debugging of storage operations. Arduino_UnifiedStorage::debuggingModeEnabled = false; // Init USBStorage object. usbStorage = USBStorage(); // Register connect callback. usbStorage.onConnect(connectionCallback); usbStorage.onDisconnect(disconnectionCallback); } void loop() { while (!usbAvailable) { digitalWrite(LED_USER, HIGH); delay(200); digitalWrite(LED_USER, LOW); delay(200); } digitalWrite(LED_USER, LOW); // This works! if (!usbStorage.isMounted()) { usbStorage.begin(); } Folder root = usbStorage.getRootFolder(); UFile outFile = root.createFile("test.txt", FileMode::APPEND); outFile.write("Hello, World!"); outFile.close(); usbStorage.unmount(); digitalWrite(LED_USER, HIGH); while (1) { } } void connectionCallback() { usbAvailable = true; usbStorage.removeOnConnectCallback(); } void disconnectionCallback() { usbAvailable = false; usbStorage.onConnect(connectionCallback); } ```

I did not find any mention of this behavior in the docs. If I can provide further details or assistance ping me!