Added compile time error to the AVRISP-MKII project when built for the U4 chips, as the default VTARGET detection ADC channel does not exist on these chips (thanks to Marco).

LUFA/Drivers/USB/LowLevel/Endpoint.c

@@ -87,6 +87,8 @@ bool Endpoint_ConfigureEndpoint_Prv(const uint8_t Number,
 
 void Endpoint_ClearEndpoints(void)
 {
+	UEINT = 0;
+
 	for (uint8_t EPNum = 0; EPNum < ENDPOINT_TOTAL_ENDPOINTS; EPNum++)
 	{
 		Endpoint_SelectEndpoint(EPNum);	

LUFA/ManPages/ChangeLog.txt

@@ -18,6 +18,8 @@
   *  - Changed over all device demos to use a clearer algorithm for the configuring of the application's endpoints
   *  - Added missing DataflashManager_CheckDataflashOperation() function to the MassStorageKeyboard demo, removed redundant
   *    SCSI_Codes.h file as these values are part of the MassStorage Class Driver
+  *  - Added compile time error to the AVRISP-MKII project when built for the U4 chips, as the default VTARGET detection ADC channel
+  *    does not exist on these chips (thanks to Marco)
   *
   *  <b>Fixed:</b>
   *  - Fixed USB_GetHIDReportItemInfo() function modifying the given report item's data when the report item does not exist

Projects/AVRISP-MKII/Lib/V2Protocol.h

@@ -53,6 +53,10 @@
 				#define ENABLE_XPROG_PROTOCOL
 			#endif
 		#endif
+		
+		#if defined(USB_SERIES_4_AVR) && ((VTARGET_ADC_CHANNEL == 2) || (VTARGET_ADC_CHANNEL == 3))
+			#error The U4 AVR chips do not contain ADC channels 2 or 3. Please change VTARGET_ADC_CHANNEL or define NO_VTARGET_DETECT in the makefile.
+		#endif
 
 	/* Macros: */
 		#if !defined(__DOXYGEN__)