Implemented on-demand PLL clock generation for the U4, U6 and U7 series USB AVRs...
[pub/USBasp.git] / Bootloaders / CDC / BootloaderCDC.c
index 0add977..99e0ccb 100644 (file)
-/*\r
-             LUFA Library\r
-     Copyright (C) Dean Camera, 2009.\r
-              \r
-  dean [at] fourwalledcubicle [dot] com\r
-      www.fourwalledcubicle.com\r
-*/\r
-\r
-/*\r
-  Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)\r
-\r
-  Permission to use, copy, modify, and distribute this software\r
-  and its documentation for any purpose and without fee is hereby\r
-  granted, provided that the above copyright notice appear in all\r
-  copies and that both that the copyright notice and this\r
-  permission notice and warranty disclaimer appear in supporting\r
-  documentation, and that the name of the author not be used in\r
-  advertising or publicity pertaining to distribution of the\r
-  software without specific, written prior permission.\r
-\r
-  The author disclaim all warranties with regard to this\r
-  software, including all implied warranties of merchantability\r
-  and fitness.  In no event shall the author be liable for any\r
-  special, indirect or consequential damages or any damages\r
-  whatsoever resulting from loss of use, data or profits, whether\r
-  in an action of contract, negligence or other tortious action,\r
-  arising out of or in connection with the use or performance of\r
-  this software.\r
-*/\r
-\r
-/** \file\r
- *\r
- *  Main source file for the CDC class bootloader. This file contains the complete bootloader logic.\r
- */\r
\r
-#define  INCLUDE_FROM_BOOTLOADERCDC_C\r
-#include "BootloaderCDC.h"\r
-\r
-/* Globals: */\r
-/** Line coding options for the virtual serial port. Although the virtual serial port data is never\r
- *  sent through a physical serial port, the line encoding data must still be read and preserved from\r
- *  the host, or the host will detect a problem and fail to open the port. This structure contains the\r
- *  current encoding options, including baud rate, character format, parity mode and total number of \r
- *  bits in each data chunk.\r
- */\r
-CDC_Line_Coding_t LineCoding = { BaudRateBPS: 9600,\r
-                                 CharFormat:  OneStopBit,\r
-                                 ParityType:  Parity_None,\r
-                                 DataBits:    8            };\r
-\r
-/** Current address counter. This stores the current address of the FLASH or EEPROM as set by the host,\r
- *  and is used when reading or writing to the AVRs memory (either FLASH or EEPROM depending on the issued\r
- *  command.)\r
- */\r
-uint16_t CurrAddress;\r
-\r
-/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run\r
- *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application\r
- *  jumped to via an indirect jump to location 0x0000.\r
- */\r
-bool RunBootloader = true;\r
-\r
-\r
-/** Main program entry point. This routine configures the hardware required by the bootloader, then continuously \r
- *  runs the bootloader processing routine until instructed to soft-exit, or hard-reset via the watchdog to start\r
- *  the loaded application code.\r
- */\r
-int main(void)\r
-{\r
-       /* Disable watchdog if enabled by bootloader/fuses */\r
-       MCUSR &= ~(1 << WDRF);\r
-       wdt_disable();\r
-\r
-       /* Disable clock division */\r
-       clock_prescale_set(clock_div_1);\r
-       \r
-       /* Relocate the interrupt vector table to the bootloader section */\r
-       MCUCR = (1 << IVCE);\r
-       MCUCR = (1 << IVSEL);\r
-       \r
-       /* Initialize USB Subsystem */\r
-       USB_Init();\r
-\r
-       while (RunBootloader)\r
-       {\r
-               USB_USBTask();\r
-               CDC_Task();\r
-       }\r
-       \r
-       Endpoint_SelectEndpoint(CDC_TX_EPNUM);\r
-\r
-       /* Wait until any pending transmissions have completed before shutting down */\r
-       while (!(Endpoint_ReadWriteAllowed()));\r
-       \r
-       /* Shut down the USB subsystem */\r
-       USB_ShutDown();\r
-       \r
-       /* Relocate the interrupt vector table back to the application section */\r
-       MCUCR = (1 << IVCE);\r
-       MCUCR = 0;\r
-\r
-       /* Reset any used hardware ports back to their defaults */\r
-       PORTD = 0;\r
-       DDRD  = 0;\r
-       \r
-       #if defined(PORTE)\r
-       PORTE = 0;\r
-       DDRE  = 0;\r
-       #endif\r
-       \r
-       /* Re-enable RWW section */\r
-       boot_rww_enable();\r
-\r
-       /* Start the user application */\r
-       AppPtr_t AppStartPtr = (AppPtr_t)0x0000;\r
-       AppStartPtr();  \r
-}\r
-\r
-/** Event handler for the USB_Disconnect event. This indicates that the bootloader should exit and the user\r
- *  application started.\r
- */\r
-EVENT_HANDLER(USB_Disconnect)\r
-{\r
-       /* Upon disconnection, run user application */\r
-       RunBootloader = false;\r
-}\r
-\r
-/** Event handler for the USB_ConfigurationChanged event. This configures the device's endpoints ready\r
- *  to relay data to and from the attached USB host.\r
- */\r
-EVENT_HANDLER(USB_ConfigurationChanged)\r
-{\r
-       /* Setup CDC Notification, Rx and Tx Endpoints */\r
-       Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,\r
-                                      ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,\r
-                                  ENDPOINT_BANK_SINGLE);\r
-\r
-       Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,\r
-                                      ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,\r
-                                  ENDPOINT_BANK_SINGLE);\r
-\r
-       Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,\r
-                                      ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,\r
-                                  ENDPOINT_BANK_SINGLE);\r
-}\r
-\r
-/** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific\r
- *  control requests that are not handled internally by the USB library, so that they can be handled appropriately\r
- *  for the application.\r
- */\r
-EVENT_HANDLER(USB_UnhandledControlPacket)\r
-{\r
-       uint8_t* LineCodingData = (uint8_t*)&LineCoding;\r
-\r
-       Endpoint_Discard_Word();\r
-\r
-       /* Process CDC specific control requests */\r
-       switch (bRequest)\r
-       {\r
-               case REQ_GetLineEncoding:\r
-                       if (bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))\r
-                       {\r
-                               Endpoint_ClearSetupReceived();\r
-\r
-                               for (uint8_t i = 0; i < sizeof(LineCoding); i++)\r
-                                 Endpoint_Write_Byte(*(LineCodingData++));     \r
-                               \r
-                               Endpoint_ClearSetupIN();\r
-                               \r
-                               /* Acknowledge status stage */\r
-                               while (!(Endpoint_IsSetupOUTReceived()));\r
-                               Endpoint_ClearSetupOUT();\r
-                       }\r
-                       \r
-                       break;\r
-               case REQ_SetLineEncoding:\r
-                       if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))\r
-                       {\r
-                               Endpoint_ClearSetupReceived();\r
-\r
-                               while (!(Endpoint_IsSetupOUTReceived()));\r
-\r
-                               for (uint8_t i = 0; i < sizeof(LineCoding); i++)\r
-                                 *(LineCodingData++) = Endpoint_Read_Byte();\r
-\r
-                               Endpoint_ClearSetupOUT();\r
-\r
-                               /* Acknowledge status stage */\r
-                               while (!(Endpoint_IsSetupINReady()));\r
-                               Endpoint_ClearSetupIN();\r
-                       }\r
-       \r
-                       break;\r
-               case REQ_SetControlLineState:\r
-                       if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))\r
-                       {\r
-                               Endpoint_ClearSetupReceived();\r
-                               \r
-                               /* Acknowledge status stage */\r
-                               while (!(Endpoint_IsSetupINReady()));\r
-                               Endpoint_ClearSetupIN();\r
-                       }\r
-       \r
-                       break;\r
-       }\r
-}\r
-\r
-/** Reads or writes a block of EEPROM or FLASH memory to or from the appropriate CDC data endpoint, depending\r
- *  on the AVR910 protocol command issued.\r
- *\r
- *  \param Command  Single character AVR910 protocol command indicating what memory operation to perform\r
- */\r
-static void ReadWriteMemoryBlock(const uint8_t Command)\r
-{\r
-       uint16_t BlockSize;\r
-       char     MemoryType;\r
-       \r
-       bool     HighByte = false;\r
-       uint8_t  LowByte  = 0;\r
-       \r
-       BlockSize  = (FetchNextCommandByte() << 8);\r
-       BlockSize |=  FetchNextCommandByte();\r
-       \r
-       MemoryType =  FetchNextCommandByte();\r
-\r
-       if ((MemoryType == 'E') || (MemoryType == 'F'))\r
-       {\r
-               /* Check if command is to read memory */\r
-               if (Command == 'g')\r
-               {\r
-                       /* Re-enable RWW section */\r
-                       boot_rww_enable();\r
-\r
-                       while (BlockSize--)\r
-                       {\r
-                               if (MemoryType == 'E')\r
-                               {\r
-                                       /* Read the next EEPROM byte into the endpoint */\r
-                                       WriteNextResponseByte(eeprom_read_byte((uint8_t*)CurrAddress));\r
-\r
-                                       /* Increment the address counter after use */\r
-                                       CurrAddress++;\r
-                               }\r
-                               else\r
-                               {\r
-                                       /* Read the next FLASH byte from the current FLASH page */\r
-                                       #if defined(RAMPZ)\r
-                                       WriteNextResponseByte(pgm_read_byte_far(((uint32_t)CurrAddress << 1) + HighByte));\r
-                                       #else\r
-                                       WriteNextResponseByte(pgm_read_byte((CurrAddress << 1) + HighByte));                                    \r
-                                       #endif\r
-                                       \r
-                                       /* If both bytes in current word have been read, increment the address counter */\r
-                                       if (HighByte)\r
-                                         CurrAddress++;\r
-                                       \r
-                                       HighByte ^= 1;\r
-                               }\r
-                       }\r
-               }\r
-               else\r
-               {\r
-                       uint32_t PageStartAddress = ((uint32_t)CurrAddress << 1);\r
-       \r
-                       if (MemoryType == 'F')\r
-                       {\r
-                               boot_page_erase(PageStartAddress);\r
-                               boot_spm_busy_wait();\r
-                       }\r
-                       \r
-                       while (BlockSize--)\r
-                       {\r
-                               if (MemoryType == 'E')\r
-                               {\r
-                                       /* Write the next EEPROM byte from the endpoint */\r
-                                       eeprom_write_byte((uint8_t*)CurrAddress, FetchNextCommandByte());                                       \r
-\r
-                                       /* Increment the address counter after use */\r
-                                       CurrAddress++;\r
-                               }\r
-                               else\r
-                               {       \r
-                                       /* If both bytes in current word have been written, increment the address counter */\r
-                                       if (HighByte)\r
-                                       {\r
-                                               /* Write the next FLASH word to the current FLASH page */\r
-                                               boot_page_fill(((uint32_t)CurrAddress << 1), ((FetchNextCommandByte() << 8) | LowByte));\r
-\r
-                                               HighByte = false;\r
-                                               \r
-                                               /* Increment the address counter after use */\r
-                                               CurrAddress++;\r
-                                       }\r
-                                       else\r
-                                       {\r
-                                               LowByte = FetchNextCommandByte();\r
-                                       \r
-                                               HighByte = true;\r
-                                       }\r
-                               }\r
-                       }\r
-\r
-                       /* If in FLASH programming mode, commit the page after writing */\r
-                       if (MemoryType == 'F')\r
-                       {\r
-                               /* Commit the flash page to memory */\r
-                               boot_page_write(PageStartAddress);\r
-                               \r
-                               /* Wait until write operation has completed */\r
-                               boot_spm_busy_wait();\r
-                       }\r
-               \r
-                       /* Send response byte back to the host */\r
-                       WriteNextResponseByte('\r');            \r
-               }\r
-       }\r
-       else\r
-       {\r
-               /* Send error byte back to the host */\r
-               WriteNextResponseByte('?');\r
-       }\r
-}\r
-\r
-/** Retrieves the next byte from the host in the CDC data OUT endpoint, and clears the endpoint bank if needed\r
- *  to allow reception of the next data packet from the host.\r
- *\r
- *  \return Next received byte from the host in the CDC data OUT endpoint\r
- */\r
-static uint8_t FetchNextCommandByte(void)\r
-{\r
-       /* Select the OUT endpoint so that the next data byte can be read */\r
-       Endpoint_SelectEndpoint(CDC_RX_EPNUM);\r
-       \r
-       /* If OUT endpoint empty, clear it and wait for the next packet from the host */\r
-       if (!(Endpoint_ReadWriteAllowed()))\r
-       {\r
-               Endpoint_ClearCurrentBank();\r
-               while (!(Endpoint_ReadWriteAllowed()));\r
-       }\r
-       \r
-       /* Fetch the next byte from the OUT endpoint */\r
-       return Endpoint_Read_Byte();\r
-}\r
-\r
-/** Writes the next response byte to the CDC data IN endpoint, and sends the endpoint back if needed to free up the\r
- *  bank when full ready for the next byte in the packet to the host.\r
- *\r
- *  \param Response  Next response byte to send to the host\r
- */\r
-static void WriteNextResponseByte(const uint8_t Response)\r
-{\r
-       /* Select the IN endpoint so that the next data byte can be written */\r
-       Endpoint_SelectEndpoint(CDC_TX_EPNUM);\r
-       \r
-       /* If OUT endpoint empty, clear it and wait for the next packet from the host */\r
-       if (!(Endpoint_ReadWriteAllowed()))\r
-       {\r
-               Endpoint_ClearCurrentBank();\r
-               while (!(Endpoint_ReadWriteAllowed()));\r
-       }\r
-       \r
-       /* Write the next byte to the OUT endpoint */\r
-       Endpoint_Write_Byte(Response);\r
-}\r
-\r
-/** Task to read in AVR910 commands from the CDC data OUT endpoint, process them, perform the required actions\r
- *  and send the appropriate response back to the host.\r
- */\r
-TASK(CDC_Task)\r
-{\r
-       /* Select the OUT endpoint */\r
-       Endpoint_SelectEndpoint(CDC_RX_EPNUM);\r
-       \r
-       /* Check if endpoint has a command in it sent from the host */\r
-       if (Endpoint_ReadWriteAllowed())\r
-       {\r
-               /* Read in the bootloader command (first byte sent from host) */\r
-               uint8_t Command = FetchNextCommandByte();\r
-\r
-               if ((Command == 'L') || (Command == 'P') || (Command == 'T') || (Command == 'E'))\r
-               {\r
-                       if (Command == 'E')\r
-                         RunBootloader = false;\r
-                       if (Command == 'T')\r
-                         FetchNextCommandByte();\r
-\r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');                    \r
-               }\r
-               else if (Command == 't')\r
-               {\r
-                       /* Return ATMEGA128 part code - this is only to allow AVRProg to use the bootloader */\r
-                       WriteNextResponseByte(0x44);\r
-\r
-                       WriteNextResponseByte(0x00);\r
-               }\r
-               else if (Command == 'a')\r
-               {\r
-                       /* Indicate auto-address increment is supported */\r
-                       WriteNextResponseByte('Y');\r
-               }\r
-               else if (Command == 'A')\r
-               {\r
-                       /* Set the current address to that given by the host */\r
-                       CurrAddress  = (FetchNextCommandByte() << 8);\r
-                       CurrAddress |=  FetchNextCommandByte();\r
-\r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');\r
-               }\r
-               else if (Command == 'p')\r
-               {\r
-                       /* Indicate serial programmer back to the host */\r
-                       WriteNextResponseByte('S');              \r
-               }\r
-               else if (Command == 'S')\r
-               {\r
-                       /* Write the 7-byte software identifier to the endpoint */\r
-                       for (uint8_t CurrByte = 0; CurrByte < 7; CurrByte++)\r
-                         WriteNextResponseByte(SOFTWARE_IDENTIFIER[CurrByte]);         \r
-               }\r
-               else if (Command == 'V')\r
-               {\r
-                       WriteNextResponseByte('0' + BOOTLOADER_VERSION_MAJOR);\r
-                       WriteNextResponseByte('0' + BOOTLOADER_VERSION_MINOR);\r
-               }\r
-               else if (Command == 's')\r
-               {\r
-                       WriteNextResponseByte(boot_signature_byte_get(4));\r
-                       WriteNextResponseByte(boot_signature_byte_get(2));\r
-                       WriteNextResponseByte(boot_signature_byte_get(0));              \r
-               }\r
-               else if (Command == 'b')\r
-               {\r
-                       WriteNextResponseByte('Y');\r
-                               \r
-                       /* Send block size to the host */\r
-                       WriteNextResponseByte(SPM_PAGESIZE >> 8);\r
-                       WriteNextResponseByte(SPM_PAGESIZE & 0xFF);             \r
-               }\r
-               else if (Command == 'e')\r
-               {\r
-                       /* Clear the application section of flash */\r
-                       for (uint32_t CurrFlashAddress = 0; CurrFlashAddress < BOOT_START_ADDR; CurrFlashAddress++)\r
-                       {\r
-                               boot_page_erase(CurrFlashAddress);\r
-                               boot_spm_busy_wait();\r
-                               boot_page_write(CurrFlashAddress);\r
-                               boot_spm_busy_wait();\r
-\r
-                               CurrFlashAddress += SPM_PAGESIZE;\r
-                       }\r
-                       \r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');            \r
-               }\r
-               else if (Command == 'l')\r
-               {\r
-                       /* Set the lock bits to those given by the host */\r
-                       boot_lock_bits_set(FetchNextCommandByte());\r
-\r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');\r
-               }\r
-               else if (Command == 'r')\r
-               {\r
-                       WriteNextResponseByte(boot_lock_fuse_bits_get(GET_LOCK_BITS));          \r
-               }\r
-               else if (Command == 'F')\r
-               {\r
-                       WriteNextResponseByte(boot_lock_fuse_bits_get(GET_LOW_FUSE_BITS));\r
-               }\r
-               else if (Command == 'N')\r
-               {\r
-                       WriteNextResponseByte(boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS));             \r
-               }\r
-               else if (Command == 'Q')\r
-               {\r
-                       WriteNextResponseByte(boot_lock_fuse_bits_get(GET_EXTENDED_FUSE_BITS));         \r
-               }\r
-               else if ((Command == 'C') || (Command == 'c'))\r
-               {\r
-                       if (Command == 'c')\r
-                       {\r
-                               /* Increment the address if the second byte is being written */\r
-                               CurrAddress++;\r
-                       }\r
-                       \r
-                       /* Write the high byte to the current flash page */\r
-                       boot_page_fill(((uint32_t)CurrAddress << 1), FetchNextCommandByte());\r
-                       \r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');            \r
-               }\r
-               else if (Command == 'm')\r
-               {\r
-                       /* Commit the flash page to memory */\r
-                       boot_page_write((uint32_t)CurrAddress << 1);\r
-                       \r
-                       /* Wait until write operation has completed */\r
-                       boot_spm_busy_wait();\r
-\r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');            \r
-               }\r
-               else if ((Command == 'B') || (Command == 'g'))\r
-               {\r
-                       /* Delegate the block write/read to a seperate function for clarity */\r
-                       ReadWriteMemoryBlock(Command);\r
-               }\r
-               else if (Command == 'R')\r
-               {\r
-                       #if defined(RAMPZ)\r
-                       uint16_t ProgramWord = pgm_read_word_far(((uint32_t)CurrAddress << 1));\r
-                       #else\r
-                       uint16_t ProgramWord = pgm_read_word(CurrAddress << 1);                 \r
-                       #endif\r
-                       \r
-                       WriteNextResponseByte(ProgramWord >> 8);\r
-                       WriteNextResponseByte(ProgramWord & 0xFF);\r
-               }\r
-               else if (Command == 'D')\r
-               {\r
-                       /* Read the byte from the endpoint and write it to the EEPROM */\r
-                       eeprom_write_byte((uint8_t*)CurrAddress, FetchNextCommandByte());\r
-                       \r
-                       /* Increment the address after use */                   \r
-                       CurrAddress++;\r
-       \r
-                       /* Send confirmation byte back to the host */\r
-                       WriteNextResponseByte('\r');            \r
-               }\r
-               else if (Command == 'd')\r
-               {\r
-                       /* Read the EEPROM byte and write it to the endpoint */\r
-                       WriteNextResponseByte(eeprom_read_byte((uint8_t*)CurrAddress));\r
-\r
-                       /* Increment the address after use */\r
-                       CurrAddress++;\r
-               }\r
-               else if (Command == 27)\r
-               {\r
-                       /* Escape is sync, ignore */\r
-               }\r
-               else\r
-               {\r
-                       /* Unknown command, return fail code */\r
-                       WriteNextResponseByte('?');\r
-               }\r
-\r
-               /* Select the IN endpoint */\r
-               Endpoint_SelectEndpoint(CDC_TX_EPNUM);\r
-\r
-               /* Remember if the endpoint is completely full before clearing it */\r
-               bool IsEndpointFull = !(Endpoint_ReadWriteAllowed());\r
-\r
-               /* Send the endpoint data to the host */\r
-               Endpoint_ClearCurrentBank();\r
-               \r
-               /* If a full endpoint's worth of data was sent, we need to send an empty packet afterwards to signal end of transfer */\r
-               if (IsEndpointFull)\r
-               {\r
-                       while (!(Endpoint_ReadWriteAllowed()));\r
-                       Endpoint_ClearCurrentBank();\r
-               }\r
-               \r
-               /* Select the OUT endpoint */\r
-               Endpoint_SelectEndpoint(CDC_RX_EPNUM);\r
-\r
-               /* Acknowledge the command from the host */\r
-               Endpoint_ClearCurrentBank();\r
-       }\r
-}\r
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2011.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+
+  Permission to use, copy, modify, distribute, and sell this
+  software and its documentation for any purpose is hereby granted
+  without fee, provided that the above copyright notice appear in
+  all copies and that both that the copyright notice and this
+  permission notice and warranty disclaimer appear in supporting
+  documentation, and that the name of the author not be used in
+  advertising or publicity pertaining to distribution of the
+  software without specific, written prior permission.
+
+  The author disclaim all warranties with regard to this
+  software, including all implied warranties of merchantability
+  and fitness.  In no event shall the author be liable for any
+  special, indirect or consequential damages or any damages
+  whatsoever resulting from loss of use, data or profits, whether
+  in an action of contract, negligence or other tortious action,
+  arising out of or in connection with the use or performance of
+  this software.
+*/
+
+/** \file
+ *
+ *  Main source file for the CDC class bootloader. This file contains the complete bootloader logic.
+ */
+
+#define  INCLUDE_FROM_BOOTLOADERCDC_C
+#include "BootloaderCDC.h"
+
+/** Contains the current baud rate and other settings of the first virtual serial port. This must be retained as some
+ *  operating systems will not open the port unless the settings can be set successfully.
+ */
+static CDC_LineEncoding_t LineEncoding = { .BaudRateBPS = 0,
+                                           .CharFormat  = CDC_LINEENCODING_OneStopBit,
+                                           .ParityType  = CDC_PARITY_None,
+                                           .DataBits    = 8                            };
+
+/** Current address counter. This stores the current address of the FLASH or EEPROM as set by the host,
+ *  and is used when reading or writing to the AVRs memory (either FLASH or EEPROM depending on the issued
+ *  command.)
+ */
+static uint32_t CurrAddress;
+
+/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
+ *  via a watchdog reset. When cleared the bootloader will exit, starting the watchdog and entering an infinite
+ *  loop until the AVR restarts and the application runs.
+ */
+static bool RunBootloader = true;
+
+
+/** Main program entry point. This routine configures the hardware required by the bootloader, then continuously
+ *  runs the bootloader processing routine until instructed to soft-exit, or hard-reset via the watchdog to start
+ *  the loaded application code.
+ */
+int main(void)
+{
+       /* Setup hardware required for the bootloader */
+       SetupHardware();
+
+       /* Enable global interrupts so that the USB stack can function */
+       sei();
+
+       while (RunBootloader)
+       {
+               CDC_Task();
+               USB_USBTask();
+       }
+
+       /* Disconnect from the host - USB interface will be reset later along with the AVR */
+       USB_Detach();
+
+       /* Enable the watchdog and force a timeout to reset the AVR */
+       wdt_enable(WDTO_250MS);
+
+       for (;;);
+}
+
+/** Configures all hardware required for the bootloader. */
+void SetupHardware(void)
+{
+       /* Disable watchdog if enabled by bootloader/fuses */
+       MCUSR &= ~(1 << WDRF);
+       wdt_disable();
+
+       /* Disable clock division */
+       clock_prescale_set(clock_div_1);
+
+       /* Relocate the interrupt vector table to the bootloader section */
+       MCUCR = (1 << IVCE);
+       MCUCR = (1 << IVSEL);
+
+       /* Initialize USB Subsystem */
+       USB_Init();
+}
+
+/** Event handler for the USB_ConfigurationChanged event. This configures the device's endpoints ready
+ *  to relay data to and from the attached USB host.
+ */
+void EVENT_USB_Device_ConfigurationChanged(void)
+{
+       /* Setup CDC Notification, Rx and Tx Endpoints */
+       Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
+                                  ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
+                                  ENDPOINT_BANK_SINGLE);
+
+       Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
+                                  ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
+                                  ENDPOINT_BANK_SINGLE);
+
+       Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
+                                  ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
+                                  ENDPOINT_BANK_SINGLE);
+}
+
+/** Event handler for the USB_ControlRequest event. This is used to catch and process control requests sent to
+ *  the device from the USB host before passing along unhandled control requests to the library for processing
+ *  internally.
+ */
+void EVENT_USB_Device_ControlRequest(void)
+{
+       /* Ignore any requests that aren't directed to the CDC interface */
+       if ((USB_ControlRequest.bmRequestType & (CONTROL_REQTYPE_TYPE | CONTROL_REQTYPE_RECIPIENT)) !=
+           (REQTYPE_CLASS | REQREC_INTERFACE))
+       {
+               return;
+       }
+
+       /* Process CDC specific control requests */
+       switch (USB_ControlRequest.bRequest)
+       {
+               case CDC_REQ_GetLineEncoding:
+                       if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
+                       {
+                               Endpoint_ClearSETUP();
+
+                               /* Write the line coding data to the control endpoint */
+                               Endpoint_Write_Control_Stream_LE(&LineEncoding, sizeof(CDC_LineEncoding_t));
+                               Endpoint_ClearOUT();
+                       }
+
+                       break;
+               case CDC_REQ_SetLineEncoding:
+                       if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
+                       {
+                               Endpoint_ClearSETUP();
+
+                               /* Read the line coding data in from the host into the global struct */
+                               Endpoint_Read_Control_Stream_LE(&LineEncoding, sizeof(CDC_LineEncoding_t));
+                               Endpoint_ClearIN();
+                       }
+
+                       break;
+       }
+}
+
+#if !defined(NO_BLOCK_SUPPORT)
+/** Reads or writes a block of EEPROM or FLASH memory to or from the appropriate CDC data endpoint, depending
+ *  on the AVR910 protocol command issued.
+ *
+ *  \param[in] Command  Single character AVR910 protocol command indicating what memory operation to perform
+ */
+static void ReadWriteMemoryBlock(const uint8_t Command)
+{
+       uint16_t BlockSize;
+       char     MemoryType;
+
+       bool     HighByte = false;
+       uint8_t  LowByte  = 0;
+
+       BlockSize  = (FetchNextCommandByte() << 8);
+       BlockSize |=  FetchNextCommandByte();
+
+       MemoryType =  FetchNextCommandByte();
+
+       if ((MemoryType != 'E') && (MemoryType != 'F'))
+       {
+               /* Send error byte back to the host */
+               WriteNextResponseByte('?');
+
+               return;
+       }
+
+       /* Check if command is to read memory */
+       if (Command == 'g')
+       {
+               /* Re-enable RWW section */
+               boot_rww_enable();
+
+               while (BlockSize--)
+               {
+                       if (MemoryType == 'F')
+                       {
+                               /* Read the next FLASH byte from the current FLASH page */
+                               #if (FLASHEND > 0xFFFF)
+                               WriteNextResponseByte(pgm_read_byte_far(CurrAddress | HighByte));
+                               #else
+                               WriteNextResponseByte(pgm_read_byte(CurrAddress | HighByte));
+                               #endif
+
+                               /* If both bytes in current word have been read, increment the address counter */
+                               if (HighByte)
+                                 CurrAddress += 2;
+
+                               HighByte = !HighByte;
+                       }
+                       else
+                       {
+                               /* Read the next EEPROM byte into the endpoint */
+                               WriteNextResponseByte(eeprom_read_byte((uint8_t*)(intptr_t)(CurrAddress >> 1)));
+
+                               /* Increment the address counter after use */
+                               CurrAddress += 2;
+                       }
+               }
+       }
+       else
+       {
+               uint32_t PageStartAddress = CurrAddress;
+
+               if (MemoryType == 'F')
+               {
+                       boot_page_erase(PageStartAddress);
+                       boot_spm_busy_wait();
+               }
+
+               while (BlockSize--)
+               {
+                       if (MemoryType == 'F')
+                       {
+                               /* If both bytes in current word have been written, increment the address counter */
+                               if (HighByte)
+                               {
+                                       /* Write the next FLASH word to the current FLASH page */
+                                       boot_page_fill(CurrAddress, ((FetchNextCommandByte() << 8) | LowByte));
+
+                                       /* Increment the address counter after use */
+                                       CurrAddress += 2;
+                               }
+                               else
+                               {
+                                       LowByte = FetchNextCommandByte();
+                               }
+                               
+                               HighByte = !HighByte;
+                       }
+                       else
+                       {
+                               /* Write the next EEPROM byte from the endpoint */
+                               eeprom_write_byte((uint8_t*)((intptr_t)(CurrAddress >> 1)), FetchNextCommandByte());
+
+                               /* Increment the address counter after use */
+                               CurrAddress += 2;
+                       }
+               }
+
+               /* If in FLASH programming mode, commit the page after writing */
+               if (MemoryType == 'F')
+               {
+                       /* Commit the flash page to memory */
+                       boot_page_write(PageStartAddress);
+
+                       /* Wait until write operation has completed */
+                       boot_spm_busy_wait();
+               }
+
+               /* Send response byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+}
+#endif
+
+/** Retrieves the next byte from the host in the CDC data OUT endpoint, and clears the endpoint bank if needed
+ *  to allow reception of the next data packet from the host.
+ *
+ *  \return Next received byte from the host in the CDC data OUT endpoint
+ */
+static uint8_t FetchNextCommandByte(void)
+{
+       /* Select the OUT endpoint so that the next data byte can be read */
+       Endpoint_SelectEndpoint(CDC_RX_EPNUM);
+
+       /* If OUT endpoint empty, clear it and wait for the next packet from the host */
+       while (!(Endpoint_IsReadWriteAllowed()))
+       {
+               Endpoint_ClearOUT();
+
+               while (!(Endpoint_IsOUTReceived()))
+               {
+                       if (USB_DeviceState == DEVICE_STATE_Unattached)
+                         return 0;
+               }
+       }
+
+       /* Fetch the next byte from the OUT endpoint */
+       return Endpoint_Read_Byte();
+}
+
+/** Writes the next response byte to the CDC data IN endpoint, and sends the endpoint back if needed to free up the
+ *  bank when full ready for the next byte in the packet to the host.
+ *
+ *  \param[in] Response  Next response byte to send to the host
+ */
+static void WriteNextResponseByte(const uint8_t Response)
+{
+       /* Select the IN endpoint so that the next data byte can be written */
+       Endpoint_SelectEndpoint(CDC_TX_EPNUM);
+
+       /* If IN endpoint full, clear it and wait until ready for the next packet to the host */
+       if (!(Endpoint_IsReadWriteAllowed()))
+       {
+               Endpoint_ClearIN();
+
+               while (!(Endpoint_IsINReady()))
+               {
+                       if (USB_DeviceState == DEVICE_STATE_Unattached)
+                         return;
+               }
+       }
+
+       /* Write the next byte to the IN endpoint */
+       Endpoint_Write_Byte(Response);
+}
+
+/** Task to read in AVR910 commands from the CDC data OUT endpoint, process them, perform the required actions
+ *  and send the appropriate response back to the host.
+ */
+void CDC_Task(void)
+{
+       /* Select the OUT endpoint */
+       Endpoint_SelectEndpoint(CDC_RX_EPNUM);
+
+       /* Check if endpoint has a command in it sent from the host */
+       if (!(Endpoint_IsOUTReceived()))
+         return;
+
+       /* Read in the bootloader command (first byte sent from host) */
+       uint8_t Command = FetchNextCommandByte();
+
+       if (Command == 'E')
+       {
+               RunBootloader = false;
+       
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'T')
+       {
+               FetchNextCommandByte();
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if ((Command == 'L') || (Command == 'P'))
+       {
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 't')
+       {
+               /* Return ATMEGA128 part code - this is only to allow AVRProg to use the bootloader */
+               WriteNextResponseByte(0x44);
+               WriteNextResponseByte(0x00);
+       }
+       else if (Command == 'a')
+       {
+               /* Indicate auto-address increment is supported */
+               WriteNextResponseByte('Y');
+       }
+       else if (Command == 'A')
+       {
+               /* Set the current address to that given by the host */
+               CurrAddress   = (FetchNextCommandByte() << 9);
+               CurrAddress  |= (FetchNextCommandByte() << 1);
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'p')
+       {
+               /* Indicate serial programmer back to the host */
+               WriteNextResponseByte('S');
+       }
+       else if (Command == 'S')
+       {
+               /* Write the 7-byte software identifier to the endpoint */
+               for (uint8_t CurrByte = 0; CurrByte < 7; CurrByte++)
+                 WriteNextResponseByte(SOFTWARE_IDENTIFIER[CurrByte]);
+       }
+       else if (Command == 'V')
+       {
+               WriteNextResponseByte('0' + BOOTLOADER_VERSION_MAJOR);
+               WriteNextResponseByte('0' + BOOTLOADER_VERSION_MINOR);
+       }
+       else if (Command == 's')
+       {
+               WriteNextResponseByte(AVR_SIGNATURE_3);
+               WriteNextResponseByte(AVR_SIGNATURE_2);
+               WriteNextResponseByte(AVR_SIGNATURE_1);
+       }
+       else if (Command == 'e')
+       {
+               /* Clear the application section of flash */
+               for (uint32_t CurrFlashAddress = 0; CurrFlashAddress < BOOT_START_ADDR; CurrFlashAddress += SPM_PAGESIZE)
+               {
+                       boot_page_erase(CurrFlashAddress);
+                       boot_spm_busy_wait();
+                       boot_page_write(CurrFlashAddress);
+                       boot_spm_busy_wait();
+               }
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       #if !defined(NO_LOCK_BYTE_WRITE_SUPPORT)
+       else if (Command == 'l')
+       {
+               /* Set the lock bits to those given by the host */
+               boot_lock_bits_set(FetchNextCommandByte());
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       #endif
+       else if (Command == 'r')
+       {
+               WriteNextResponseByte(boot_lock_fuse_bits_get(GET_LOCK_BITS));
+       }
+       else if (Command == 'F')
+       {
+               WriteNextResponseByte(boot_lock_fuse_bits_get(GET_LOW_FUSE_BITS));
+       }
+       else if (Command == 'N')
+       {
+               WriteNextResponseByte(boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS));
+       }
+       else if (Command == 'Q')
+       {
+               WriteNextResponseByte(boot_lock_fuse_bits_get(GET_EXTENDED_FUSE_BITS));
+       }
+       #if !defined(NO_BLOCK_SUPPORT)
+       else if (Command == 'b')
+       {
+               WriteNextResponseByte('Y');
+
+               /* Send block size to the host */
+               WriteNextResponseByte(SPM_PAGESIZE >> 8);
+               WriteNextResponseByte(SPM_PAGESIZE & 0xFF);
+       }
+       else if ((Command == 'B') || (Command == 'g'))
+       {
+               /* Delegate the block write/read to a separate function for clarity */
+               ReadWriteMemoryBlock(Command);
+       }
+       #endif
+       #if !defined(NO_FLASH_BYTE_SUPPORT)
+       else if (Command == 'C')
+       {
+               /* Write the high byte to the current flash page */
+               boot_page_fill(CurrAddress, FetchNextCommandByte());
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'c')
+       {
+               /* Write the low byte to the current flash page */
+               boot_page_fill(CurrAddress | 0x01, FetchNextCommandByte());
+
+               /* Increment the address */
+               CurrAddress += 2;
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'm')
+       {
+               /* Commit the flash page to memory */
+               boot_page_write(CurrAddress);
+
+               /* Wait until write operation has completed */
+               boot_spm_busy_wait();
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'R')
+       {
+               #if (FLASHEND > 0xFFFF)
+               uint16_t ProgramWord = pgm_read_word_far(CurrAddress);
+               #else
+               uint16_t ProgramWord = pgm_read_word(CurrAddress);
+               #endif
+
+               WriteNextResponseByte(ProgramWord >> 8);
+               WriteNextResponseByte(ProgramWord & 0xFF);
+       }
+       #endif
+       #if !defined(NO_EEPROM_BYTE_SUPPORT)
+       else if (Command == 'D')
+       {
+               /* Read the byte from the endpoint and write it to the EEPROM */
+               eeprom_write_byte((uint8_t*)((intptr_t)(CurrAddress >> 1)), FetchNextCommandByte());
+
+               /* Increment the address after use */
+               CurrAddress += 2;
+
+               /* Send confirmation byte back to the host */
+               WriteNextResponseByte('\r');
+       }
+       else if (Command == 'd')
+       {
+               /* Read the EEPROM byte and write it to the endpoint */
+               WriteNextResponseByte(eeprom_read_byte((uint8_t*)((intptr_t)(CurrAddress >> 1))));
+
+               /* Increment the address after use */
+               CurrAddress += 2;
+       }
+       #endif
+       else if (Command != 27)
+       {
+               /* Unknown (non-sync) command, return fail code */
+               WriteNextResponseByte('?');
+       }
+
+       /* Select the IN endpoint */
+       Endpoint_SelectEndpoint(CDC_TX_EPNUM);
+
+       /* Remember if the endpoint is completely full before clearing it */
+       bool IsEndpointFull = !(Endpoint_IsReadWriteAllowed());
+
+       /* Send the endpoint data to the host */
+       Endpoint_ClearIN();
+
+       /* If a full endpoint's worth of data was sent, we need to send an empty packet afterwards to signal end of transfer */
+       if (IsEndpointFull)
+       {
+               while (!(Endpoint_IsINReady()))
+               {
+                       if (USB_DeviceState == DEVICE_STATE_Unattached)
+                         return;
+               }
+
+               Endpoint_ClearIN();
+       }
+
+       /* Wait until the data has been sent to the host */
+       while (!(Endpoint_IsINReady()))
+       {
+               if (USB_DeviceState == DEVICE_STATE_Unattached)
+                 return;
+       }
+
+       /* Select the OUT endpoint */
+       Endpoint_SelectEndpoint(CDC_RX_EPNUM);
+
+       /* Acknowledge the command from the host */
+       Endpoint_ClearOUT();
+}
+