Set all CDC and MassStorage device mode demos (LowLevel and ClassDriver) to use the USE_INTERNAL_SERIAL feature, add compile time warnings for devices which do not have an internal serial.

Demos/Device/ClassDriver/CDC/Descriptors.h

@@ -42,6 +42,10 @@
 		#include <LUFA/Drivers/USB/USB.h>
 		#include <LUFA/Drivers/USB/Class/CDC.h>
 		
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+
 	/* Macros: */
 		/** Endpoint number of the CDC device-to-host notification IN endpoint. */
 		#define CDC_NOTIFICATION_EPNUM         2

Demos/Device/ClassDriver/DualCDC/Descriptors.h

@@ -42,6 +42,10 @@
 		#include <LUFA/Drivers/USB/USB.h>
 		#include <LUFA/Drivers/USB/Class/CDC.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+
 	/* Macros: */
 		/** Endpoint number of the first CDC interface's device-to-host notification IN endpoint. */
 		#define CDC1_NOTIFICATION_EPNUM        3

Demos/Device/ClassDriver/MassStorage/Descriptors.h

@@ -37,10 +37,15 @@
 #define _DESCRIPTORS_H_
 
 	/* Includes: */
-		#include <LUFA/Drivers/USB/USB.h>
-
 		#include <avr/pgmspace.h>
 
+		#include <LUFA/Drivers/USB/USB.h>
+		#include <LUFA/Drivers/USB/Class/MassStorage.h>
+
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+
 	/* Macros: */
 		/** Endpoint number of the Mass Storage device-to-host data IN endpoint. */
 		#define MASS_STORAGE_IN_EPNUM          3	

Demos/Device/ClassDriver/USBtoSerial/Descriptors.h

@@ -42,6 +42,10 @@
 		#include <LUFA/Drivers/USB/USB.h>
 		#include <LUFA/Drivers/USB/Class/CDC.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+
 	/* Macros: */
 		/** Endpoint number of the CDC device-to-host notification IN endpoint. */
 		#define CDC_NOTIFICATION_EPNUM         2

Demos/Device/LowLevel/CDC/Descriptors.c

@@ -59,7 +59,7 @@ USB_Descriptor_Device_t PROGMEM DeviceDescriptor =
 		
 	.ManufacturerStrIndex   = 0x01,
 	.ProductStrIndex        = 0x02,
-	.SerialNumStrIndex      = NO_DESCRIPTOR,
+	.SerialNumStrIndex      = USE_INTERNAL_SERIAL,
 		
 	.NumberOfConfigurations = 1
 };

Demos/Device/LowLevel/CDC/Descriptors.h

@@ -41,6 +41,10 @@
 
 		#include <avr/pgmspace.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+		
 	/* Macros: */
 		/** Macro to define a CDC class-specific functional descriptor. CDC functional descriptors have a
 		 *  uniform structure but variable sized data payloads, thus cannot be represented accurately by

Demos/Device/LowLevel/DualCDC/Descriptors.c

@@ -59,7 +59,7 @@ USB_Descriptor_Device_t PROGMEM DeviceDescriptor =
 		
 	.ManufacturerStrIndex   = 0x01,
 	.ProductStrIndex        = 0x02,
-	.SerialNumStrIndex      = NO_DESCRIPTOR,
+	.SerialNumStrIndex      = USE_INTERNAL_SERIAL,
 		
 	.NumberOfConfigurations = 1
 };

Demos/Device/LowLevel/DualCDC/Descriptors.h

@@ -41,6 +41,10 @@
 
 		#include <avr/pgmspace.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+		
 	/* Macros: */
 		/** Macro to define a CDC class-specific functional descriptor. CDC functional descriptors have a
 		 *  uniform structure but variable sized data payloads, thus cannot be represented accurately by

Demos/Device/LowLevel/MassStorage/Descriptors.c

@@ -59,7 +59,7 @@ USB_Descriptor_Device_t PROGMEM DeviceDescriptor =
 		
 	.ManufacturerStrIndex   = 0x01,
 	.ProductStrIndex        = 0x02,
-	.SerialNumStrIndex      = 0x03,
+	.SerialNumStrIndex      = USE_INTERNAL_SERIAL,
 		
 	.NumberOfConfigurations = 1
 };
@@ -156,20 +156,6 @@ USB_Descriptor_String_t PROGMEM ProductString =
 	.UnicodeString          = L"LUFA Mass Storage Demo"
 };
 
-/** Serial number descriptor string. This is a Unicode string containing a string of HEX characters at least 12
- *  digits in length to uniquely identify a device when concatenated with the device's Vendor and Product IDs. By
- *  using the unique serial number string to identify a device, the device drivers do not need to be reinstalled
- *  each time the device is inserted into a different USB port on the same system. <b>This should be unique between
- *  devices, or conflicts will occur if two devices sharing the same serial number are inserted into the same system
- *  at the same time.</b>
- */
-USB_Descriptor_String_t PROGMEM SerialNumberString =
-{
-	.Header                 = {.Size = USB_STRING_LEN(12), .Type = DTYPE_String},
-		
-	.UnicodeString          = L"000000000000"
-};
-
 /** This function is called by the library when in device mode, and must be overridden (see library "USB Descriptors"
  *  documentation) by the application code so that the address and size of a requested descriptor can be given
  *  to the USB library. When the device receives a Get Descriptor request on the control endpoint, this function
@@ -209,10 +195,6 @@ uint16_t CALLBACK_USB_GetDescriptor(const uint16_t wValue, const uint8_t wIndex,
 					Address = (void*)&ProductString;
 					Size    = pgm_read_byte(&ProductString.Header.Size);
 					break;
-				case 0x03: 
-					Address = (void*)&SerialNumberString;
-					Size    = pgm_read_byte(&SerialNumberString.Header.Size);
-					break;
 			}
 			
 			break;

Demos/Device/LowLevel/MassStorage/Descriptors.h

@@ -41,6 +41,10 @@
 
 		#include <avr/pgmspace.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+
 	/* Macros: */
 		/** Endpoint number of the Mass Storage device-to-host data IN endpoint. */
 		#define MASS_STORAGE_IN_EPNUM          3	

Demos/Device/LowLevel/USBtoSerial/Descriptors.c

@@ -59,7 +59,7 @@ USB_Descriptor_Device_t PROGMEM DeviceDescriptor =
 		
 	.ManufacturerStrIndex   = 0x01,
 	.ProductStrIndex        = 0x02,
-	.SerialNumStrIndex      = NO_DESCRIPTOR,
+	.SerialNumStrIndex      = USE_INTERNAL_SERIAL,
 		
 	.NumberOfConfigurations = 1
 };

Demos/Device/LowLevel/USBtoSerial/Descriptors.h

@@ -41,6 +41,10 @@
 
 		#include <avr/pgmspace.h>
 
+		#if (USE_INTERNAL_SERIAL == NO_DESCRIPTOR)
+			#warning USE_INTERNAL_SERIAL is not available on this AVR - please manually construct a device serial descriptor.
+		#endif
+		
 	/* Macros: */
 		/** Macro to define a CDC class-specific functional descriptor. CDC functional descriptors have a
 		 *  uniform structure but variable sized data payloads, thus cannot be represented accurately by