fix msc external flash example issue if flash is not formatted

examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino

Author: hathach

examples/MassStorage/msc_external_flash/msc_external_flash.ino

@@ -77,6 +77,9 @@ FatFile file;
 // USB Mass Storage object
 Adafruit_USBD_MSC usb_msc;
 
+// Check if flash is formatted
+bool fs_formatted;
+
 // Set to true when PC write to flash
 bool fs_changed;
 
@@ -98,15 +101,20 @@ void setup()
 
   // MSC is ready for read/write
   usb_msc.setUnitReady(true);
-  
+
   usb_msc.begin();
 
   // Init file system on the flash
-  fatfs.begin(&flash);
+  fs_formatted = fatfs.begin(&flash);
 
   Serial.begin(115200);
   //while ( !Serial ) delay(10);   // wait for native usb
 
+  if ( !fs_formatted )
+  {
+    Serial.println("Failed to init files system, flash may not be formatted");
+  }
+
   Serial.println("Adafruit TinyUSB Mass Storage External Flash example");
   Serial.print("JEDEC ID: 0x"); Serial.println(flash.getJEDECID(), HEX);
   Serial.print("Flash size: "); Serial.print(flash.size() / 1024); Serial.println(" KB");
@@ -119,7 +127,18 @@ void loop()
   if ( fs_changed )
   {
     fs_changed = false;
-    
+
+    // check if host formatted disk
+    if (!fs_formatted)
+    {
+      fs_formatted = fatfs.begin(&flash);
+    }
+
+    // skip if still not formatted
+    if (!fs_formatted) return;
+
+    Serial.println("Opening root");
+
     if ( !root.open("/") )
     {
       Serial.println("open root failed");

examples/MassStorage/msc_external_flash_sdcard/msc_external_flash_sdcard.ino

@@ -94,13 +94,14 @@ Adafruit_USBD_MSC usb_msc;
 // Set to true when PC write to flash
 bool sd_changed = false;
 bool sd_inited = false;
+
+bool flash_formatted = false;
 bool flash_changed = false;
 
 // the setup function runs once when you press reset or power the board
 void setup()
 {
   pinMode(LED_BUILTIN, OUTPUT);
-
   Serial.begin(115200);
 
   // MSC with 2 Logical Units: LUN0: External Flash, LUN1: SDCard
@@ -117,7 +118,7 @@ void setup()
 
   //------------- Lun 0 for external flash -------------//
   flash.begin();
-  fatfs.begin(&flash);
+  flash_formatted = fatfs.begin(&flash);
 
   usb_msc.setCapacity(0, flash.size()/512, 512);
   usb_msc.setReadWriteCallback(0, external_flash_read_cb, external_flash_write_cb, external_flash_flush_cb);
@@ -193,14 +194,23 @@ void loop()
 {
   if ( flash_changed )
   {
-    File root;
-    root = fatfs.open("/");
+    if (!flash_formatted)
+    {
+      flash_formatted = fatfs.begin(&flash);
+    }
 
-    Serial.println("Flash contents:");
-    print_rootdir(&root);
-    Serial.println();
+    // skip if still not formatted
+    if (flash_formatted)
+    {
+      File root;
+      root = fatfs.open("/");
 
-    root.close();
+      Serial.println("Flash contents:");
+      print_rootdir(&root);
+      Serial.println();
+
+      root.close();
+    }
 
     flash_changed = false;
   }

src/arduino/Adafruit_USBD_CDC.h

@@ -50,6 +50,8 @@ class Adafruit_USBD_CDC : public Stream, public Adafruit_USBD_Interface {
   void begin(uint32_t baud, uint8_t config);
   void end(void);
 
+  void setDebugOutput(bool en) {}
+
   // return line coding set by host
   uint32_t baud(void);
   uint8_t stopbits(void);