Squashed 'lib/lufa/' content from commit 385d40300

git-subtree-dir: lib/lufa
git-subtree-split: 385d4030035dbaf41591309dbde47653bd03841b

1 files changed, 891 insertions, 0 deletions

diff --git a/Bootloaders/DFU/BootloaderDFU.c b/Bootloaders/DFU/BootloaderDFU.c
new file mode 100644
index 000000000..928cf6fe3
--- /dev/null
+++ b/Bootloaders/DFU/BootloaderDFU.c
@@ -0,0 +1,891 @@
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2017.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2017  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 disclaims 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 DFU class bootloader. This file contains the complete bootloader logic.
+ */
+
+#define  INCLUDE_FROM_BOOTLOADER_C
+#include "BootloaderDFU.h"
+
+/** Flag to indicate if the bootloader is currently running in secure mode, disallowing memory operations
+ *  other than erase. This is initially set to the value set by SECURE_MODE, and cleared by the bootloader
+ *  once a memory erase has completed in a bootloader session.
+ */
+static bool IsSecure = SECURE_MODE;
+
+/** Flag to indicate if the bootloader should be running, or should exit and allow the application code to run
+ *  via a soft reset. When cleared, the bootloader will abort, the USB interface will shut down and the application
+ *  jumped to via an indirect jump to location 0x0000 (or other location specified by the host).
+ */
+static bool RunBootloader = true;
+
+/** Flag to indicate if the bootloader is waiting to exit. When the host requests the bootloader to exit and
+ *  jump to the application address it specifies, it sends two sequential commands which must be properly
+ *  acknowledged. Upon reception of the first the RunBootloader flag is cleared and the WaitForExit flag is set,
+ *  causing the bootloader to wait for the final exit command before shutting down.
+ */
+static bool WaitForExit = false;
+
+/** Current DFU state machine state, one of the values in the DFU_State_t enum. */
+static uint8_t DFU_State = dfuIDLE;
+
+/** Status code of the last executed DFU command. This is set to one of the values in the DFU_Status_t enum after
+ *  each operation, and returned to the host when a Get Status DFU request is issued.
+ */
+static uint8_t DFU_Status = OK;
+
+/** Data containing the DFU command sent from the host. */
+static DFU_Command_t SentCommand;
+
+/** Response to the last issued Read Data DFU command. Unlike other DFU commands, the read command
+ *  requires a single byte response from the bootloader containing the read data when the next DFU_UPLOAD command
+ *  is issued by the host.
+ */
+static uint8_t ResponseByte;
+
+/** Pointer to the start of the user application. By default this is 0x0000 (the reset vector), however the host
+ *  may specify an alternate address when issuing the application soft-start command.
+ */
+static AppPtr_t AppStartPtr = (AppPtr_t)0x0000;
+
+/** 64-bit flash page number. This is concatenated with the current 16-bit address on USB AVRs containing more than
+ *  64KB of flash memory.
+ */
+static uint8_t Flash64KBPage = 0;
+
+/** Memory start address, indicating the current address in the memory being addressed (either FLASH or EEPROM
+ *  depending on the issued command from the host).
+ */
+static uint16_t StartAddr = 0x0000;
+
+/** Memory end address, indicating the end address to read from/write to in the memory being addressed (either FLASH
+ *  of EEPROM depending on the issued command from the host).
+ */
+static uint16_t EndAddr = 0x0000;
+
+/** Magic lock for forced application start. If the HWBE fuse is programmed and BOOTRST is unprogrammed, the bootloader
+ *  will start if the /HWB line of the AVR is held low and the system is reset. However, if the /HWB line is still held
+ *  low when the application attempts to start via a watchdog reset, the bootloader will re-start. If set to the value
+ *  \ref MAGIC_BOOT_KEY the special init function \ref Application_Jump_Check() will force the application to start.
+ */
+uint16_t MagicBootKey ATTR_NO_INIT;
+
+
+/** Special startup routine to check if the bootloader was started via a watchdog reset, and if the magic application
+ *  start key has been loaded into \ref MagicBootKey. If the bootloader started via the watchdog and the key is valid,
+ *  this will force the user application to start via a software jump.
+ */
+void Application_Jump_Check(void)
+{
+	bool JumpToApplication = false;
+
+	#if (BOARD == BOARD_LEONARDO)
+		/* Enable pull-up on the IO13 pin so we can use it to select the mode */
+		PORTC |= (1 << 7);
+		Delay_MS(10);
+
+		/* If IO13 is not jumpered to ground, start the user application instead */
+		JumpToApplication = ((PINC & (1 << 7)) != 0);
+
+		/* Disable pull-up after the check has completed */
+		PORTC &= ~(1 << 7);
+	#elif ((BOARD == BOARD_XPLAIN) || (BOARD == BOARD_XPLAIN_REV1))
+		/* Disable JTAG debugging */
+		JTAG_DISABLE();
+
+		/* Enable pull-up on the JTAG TCK pin so we can use it to select the mode */
+		PORTF |= (1 << 4);
+		Delay_MS(10);
+
+		/* If the TCK pin is not jumpered to ground, start the user application instead */
+		JumpToApplication = ((PINF & (1 << 4)) != 0);
+
+		/* Re-enable JTAG debugging */
+		JTAG_ENABLE();
+	#else
+		/* Check if the device's BOOTRST fuse is set */
+		if (boot_lock_fuse_bits_get(GET_HIGH_FUSE_BITS) & FUSE_BOOTRST)
+		{
+			/* If the reset source was not an external reset or the key is correct, clear it and jump to the application */
+			//if (!(MCUSR & (1 << EXTRF)) || (MagicBootKey == MAGIC_BOOT_KEY))
+			//  JumpToApplication = true;
+
+			/* Clear reset source */
+			MCUSR &= ~(1 << EXTRF);
+		}
+		else
+		{
+			/* If the reset source was the bootloader and the key is correct, clear it and jump to the application;
+			 * this can happen in the HWBE fuse is set, and the HBE pin is low during the watchdog reset */
+			//if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
+			//	JumpToApplication = true;
+
+			/* Clear reset source */
+			MCUSR &= ~(1 << WDRF);
+		}
+	#endif
+
+	/* Don't run the user application if the reset vector is blank (no app loaded) */
+	bool ApplicationValid = (pgm_read_word_near(0) != 0xFFFF);
+
+	/* If a request has been made to jump to the user application, honor it */
+	if (JumpToApplication && ApplicationValid)
+	{
+		/* Turn off the watchdog */
+		MCUSR &= ~(1 << WDRF);
+		wdt_disable();
+
+		/* Clear the boot key and jump to the user application */
+		MagicBootKey = 0;
+
+		// cppcheck-suppress constStatement
+		((void (*)(void))0x0000)();
+	}
+}
+
+/** 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)
+{
+	/* Configure hardware required by the bootloader */
+	SetupHardware();
+
+	/* Turn on first LED on the board to indicate that the bootloader has started */
+	LEDs_SetAllLEDs(LEDS_LED1 | LEDS_LED2);
+
+	/* Enable global interrupts so that the USB stack can function */
+	GlobalInterruptEnable();
+
+
+	#if (BOARD == BOARD_QMK)
+		uint16_t keypress = 0;
+	#endif
+
+	/* Run the USB management task while the bootloader is supposed to be running */
+	while (RunBootloader || WaitForExit) {
+	  USB_USBTask();
+	  #if (BOARD == BOARD_QMK)
+	  	bool pressed = (PIN(QMK_ESC_ROW) & NUM(QMK_ESC_ROW));
+		if ((DFU_State == dfuIDLE) && (keypress > 5000) && pressed) {
+			break;
+		}
+		if (pressed) {
+		  	keypress++;
+		} else {
+		  	keypress = 0;
+		}
+
+	  #endif
+	}
+
+	/* Reset configured hardware back to their original states for the user application */
+	ResetHardware();
+
+	/* Start the user application */
+	AppStartPtr();
+}
+
+/** Configures all hardware required for the bootloader. */
+static 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);
+
+	#if (BOARD == BOARD_QMK)
+		// column setup
+		DDR(QMK_ESC_COL) |= NUM(QMK_ESC_COL);
+		PORT(QMK_ESC_COL) |= NUM(QMK_ESC_COL);
+
+		// row setup
+		DDR(QMK_ESC_ROW) |= NUM(QMK_ESC_ROW);
+	#endif
+
+	/* Initialize the USB and other board hardware drivers */
+	USB_Init();
+	LEDs_Init();
+
+	/* Bootloader active LED toggle timer initialization */
+	TIMSK1 = (1 << TOIE1);
+	TCCR1B = ((1 << CS11) | (1 << CS10));
+
+}	
+
+/** Resets all configured hardware required for the bootloader back to their original states. */
+static void ResetHardware(void)
+{
+	/* Shut down the USB and other board hardware drivers */
+	USB_Disable();
+	LEDs_Disable();
+
+	/* Disable Bootloader active LED toggle timer */
+	TIMSK1 = 0;
+	TCCR1B = 0;
+
+	/* Relocate the interrupt vector table back to the application section */
+	MCUCR = (1 << IVCE);
+	MCUCR = 0;
+
+	#if (BOARD == BOARD_QMK)
+		DDR(QMK_ESC_COL) = PORT(QMK_ESC_COL) = DDR(QMK_ESC_ROW) = PORT(QMK_ESC_ROW) = 0;
+	#endif
+}
+
+/** ISR to periodically toggle the LEDs on the board to indicate that the bootloader is active. */
+ISR(TIMER1_OVF_vect, ISR_BLOCK)
+{
+	LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);
+}
+
+/** 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 DFU interface */
+	if ((USB_ControlRequest.bmRequestType & (CONTROL_REQTYPE_TYPE | CONTROL_REQTYPE_RECIPIENT)) !=
+	    (REQTYPE_CLASS | REQREC_INTERFACE))
+	{
+		return;
+	}
+
+	/* Activity - toggle indicator LEDs */
+	LEDs_ToggleLEDs(LEDS_LED1 | LEDS_LED2);
+
+	/* Get the size of the command and data from the wLength value */
+	SentCommand.DataSize = USB_ControlRequest.wLength;
+
+	switch (USB_ControlRequest.bRequest)
+	{
+		case DFU_REQ_DNLOAD:
+			Endpoint_ClearSETUP();
+
+			/* Check if bootloader is waiting to terminate */
+			if (WaitForExit)
+			{
+				/* Bootloader is terminating - process last received command */
+				ProcessBootloaderCommand();
+
+				/* Indicate that the last command has now been processed - free to exit bootloader */
+				WaitForExit = false;
+			}
+
+			/* If the request has a data stage, load it into the command struct */
+			if (SentCommand.DataSize)
+			{
+				while (!(Endpoint_IsOUTReceived()))
+				{
+					if (USB_DeviceState == DEVICE_STATE_Unattached)
+					  return;
+				}
+
+				/* First byte of the data stage is the DNLOAD request's command */
+				SentCommand.Command = Endpoint_Read_8();
+
+				/* One byte of the data stage is the command, so subtract it from the total data bytes */
+				SentCommand.DataSize--;
+
+				/* Load in the rest of the data stage as command parameters */
+				for (uint8_t DataByte = 0; (DataByte < sizeof(SentCommand.Data)) &&
+				     Endpoint_BytesInEndpoint(); DataByte++)
+				{
+					SentCommand.Data[DataByte] = Endpoint_Read_8();
+					SentCommand.DataSize--;
+				}
+
+				/* Process the command */
+				ProcessBootloaderCommand();
+			}
+
+			/* Check if currently downloading firmware */
+			if (DFU_State == dfuDNLOAD_IDLE)
+			{
+				if (!(SentCommand.DataSize))
+				{
+					DFU_State = dfuIDLE;
+				}
+				else
+				{
+					/* Throw away the filler bytes before the start of the firmware */
+					DiscardFillerBytes(DFU_FILLER_BYTES_SIZE);
+
+					/* Throw away the packet alignment filler bytes before the start of the firmware */
+					DiscardFillerBytes(StartAddr % FIXED_CONTROL_ENDPOINT_SIZE);
+
+					/* Calculate the number of bytes remaining to be written */
+					uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);
+
+					if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))        // Write flash
+					{
+						/* Calculate the number of words to be written from the number of bytes to be written */
+						uint16_t WordsRemaining = (BytesRemaining >> 1);
+
+						union
+						{
+							uint16_t Words[2];
+							uint32_t Long;
+						} CurrFlashAddress                 = {.Words = {StartAddr, Flash64KBPage}};
+
+						uint32_t CurrFlashPageStartAddress = CurrFlashAddress.Long;
+						uint8_t  WordsInFlashPage          = 0;
+
+						while (WordsRemaining--)
+						{
+							/* Check if endpoint is empty - if so clear it and wait until ready for next packet */
+							if (!(Endpoint_BytesInEndpoint()))
+							{
+								Endpoint_ClearOUT();
+
+								while (!(Endpoint_IsOUTReceived()))
+								{
+									if (USB_DeviceState == DEVICE_STATE_Unattached)
+									  return;
+								}
+							}
+
+							/* Write the next word into the current flash page */
+							boot_page_fill(CurrFlashAddress.Long, Endpoint_Read_16_LE());
+
+							/* Adjust counters */
+							WordsInFlashPage      += 1;
+							CurrFlashAddress.Long += 2;
+
+							/* See if an entire page has been written to the flash page buffer */
+							if ((WordsInFlashPage == (SPM_PAGESIZE >> 1)) || !(WordsRemaining))
+							{
+								/* Commit the flash page to memory */
+								boot_page_write(CurrFlashPageStartAddress);
+								boot_spm_busy_wait();
+
+								/* Check if programming incomplete */
+								if (WordsRemaining)
+								{
+									CurrFlashPageStartAddress = CurrFlashAddress.Long;
+									WordsInFlashPage          = 0;
+
+									/* Erase next page's temp buffer */
+									boot_page_erase(CurrFlashAddress.Long);
+									boot_spm_busy_wait();
+								}
+							}
+						}
+
+						/* Once programming complete, start address equals the end address */
+						StartAddr = EndAddr;
+
+						/* Re-enable the RWW section of flash */
+						boot_rww_enable();
+					}
+					else                                                   // Write EEPROM
+					{
+						while (BytesRemaining--)
+						{
+							/* Check if endpoint is empty - if so clear it and wait until ready for next packet */
+							if (!(Endpoint_BytesInEndpoint()))
+							{
+								Endpoint_ClearOUT();
+
+								while (!(Endpoint_IsOUTReceived()))
+								{
+									if (USB_DeviceState == DEVICE_STATE_Unattached)
+									  return;
+								}
+							}
+
+							/* Read the byte from the USB interface and write to to the EEPROM */
+							eeprom_update_byte((uint8_t*)StartAddr, Endpoint_Read_8());
+
+							/* Adjust counters */
+							StartAddr++;
+						}
+					}
+
+					/* Throw away the currently unused DFU file suffix */
+					DiscardFillerBytes(DFU_FILE_SUFFIX_SIZE);
+				}
+			}
+
+			Endpoint_ClearOUT();
+
+			Endpoint_ClearStatusStage();
+
+			break;
+		case DFU_REQ_UPLOAD:
+			Endpoint_ClearSETUP();
+
+			while (!(Endpoint_IsINReady()))
+			{
+				if (USB_DeviceState == DEVICE_STATE_Unattached)
+				  return;
+			}
+
+			if (DFU_State != dfuUPLOAD_IDLE)
+			{
+				if ((DFU_State == dfuERROR) && IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))       // Blank Check
+				{
+					/* Blank checking is performed in the DFU_DNLOAD request - if we get here we've told the host
+					   that the memory isn't blank, and the host is requesting the first non-blank address */
+					Endpoint_Write_16_LE(StartAddr);
+				}
+				else
+				{
+					/* Idle state upload - send response to last issued command */
+					Endpoint_Write_8(ResponseByte);
+				}
+			}
+			else
+			{
+				/* Determine the number of bytes remaining in the current block */
+				uint16_t BytesRemaining = ((EndAddr - StartAddr) + 1);
+
+				if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))            // Read FLASH
+				{
+					/* Calculate the number of words to be written from the number of bytes to be written */
+					uint16_t WordsRemaining = (BytesRemaining >> 1);
+
+					union
+					{
+						uint16_t Words[2];
+						uint32_t Long;
+					} CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};
+
+					while (WordsRemaining--)
+					{
+						/* Check if endpoint is full - if so clear it and wait until ready for next packet */
+						if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
+						{
+							Endpoint_ClearIN();
+
+							while (!(Endpoint_IsINReady()))
+							{
+								if (USB_DeviceState == DEVICE_STATE_Unattached)
+								  return;
+							}
+						}
+
+						/* Read the flash word and send it via USB to the host */
+						#if (FLASHEND > 0xFFFF)
+							Endpoint_Write_16_LE(pgm_read_word_far(CurrFlashAddress.Long));
+						#else
+							Endpoint_Write_16_LE(pgm_read_word(CurrFlashAddress.Long));
+						#endif
+
+						/* Adjust counters */
+						CurrFlashAddress.Long += 2;
+					}
+
+					/* Once reading is complete, start address equals the end address */
+					StartAddr = EndAddr;
+				}
+				else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))       // Read EEPROM
+				{
+					while (BytesRemaining--)
+					{
+						/* Check if endpoint is full - if so clear it and wait until ready for next packet */
+						if (Endpoint_BytesInEndpoint() == FIXED_CONTROL_ENDPOINT_SIZE)
+						{
+							Endpoint_ClearIN();
+
+							while (!(Endpoint_IsINReady()))
+							{
+								if (USB_DeviceState == DEVICE_STATE_Unattached)
+								  return;
+							}
+						}
+
+						/* Read the EEPROM byte and send it via USB to the host */
+						Endpoint_Write_8(eeprom_read_byte((uint8_t*)StartAddr));
+
+						/* Adjust counters */
+						StartAddr++;
+					}
+				}
+
+				/* Return to idle state */
+				DFU_State = dfuIDLE;
+			}
+
+			Endpoint_ClearIN();
+
+			Endpoint_ClearStatusStage();
+			break;
+		case DFU_REQ_GETSTATUS:
+			Endpoint_ClearSETUP();
+
+			while (!(Endpoint_IsINReady()))
+			{
+				if (USB_DeviceState == DEVICE_STATE_Unattached)
+				  return;
+			}
+
+			/* Write 8-bit status value */
+			Endpoint_Write_8(DFU_Status);
+
+			/* Write 24-bit poll timeout value */
+			Endpoint_Write_8(0);
+			Endpoint_Write_16_LE(0);
+
+			/* Write 8-bit state value */
+			Endpoint_Write_8(DFU_State);
+
+			/* Write 8-bit state string ID number */
+			Endpoint_Write_8(0);
+
+			Endpoint_ClearIN();
+
+			Endpoint_ClearStatusStage();
+			break;
+		case DFU_REQ_CLRSTATUS:
+			Endpoint_ClearSETUP();
+
+			/* Reset the status value variable to the default OK status */
+			DFU_Status = OK;
+
+			Endpoint_ClearStatusStage();
+			break;
+		case DFU_REQ_GETSTATE:
+			Endpoint_ClearSETUP();
+
+			while (!(Endpoint_IsINReady()))
+			{
+				if (USB_DeviceState == DEVICE_STATE_Unattached)
+				  return;
+			}
+
+			/* Write the current device state to the endpoint */
+			Endpoint_Write_8(DFU_State);
+
+			Endpoint_ClearIN();
+
+			Endpoint_ClearStatusStage();
+			break;
+		case DFU_REQ_ABORT:
+			Endpoint_ClearSETUP();
+
+			/* Reset the current state variable to the default idle state */
+			DFU_State = dfuIDLE;
+
+			Endpoint_ClearStatusStage();
+			break;
+	}
+}
+
+/** Routine to discard the specified number of bytes from the control endpoint stream. This is used to
+ *  discard unused bytes in the stream from the host, including the memory program block suffix.
+ *
+ *  \param[in] NumberOfBytes  Number of bytes to discard from the host from the control endpoint
+ */
+static void DiscardFillerBytes(uint8_t NumberOfBytes)
+{
+	while (NumberOfBytes--)
+	{
+		if (!(Endpoint_BytesInEndpoint()))
+		{
+			Endpoint_ClearOUT();
+
+			/* Wait until next data packet received */
+			while (!(Endpoint_IsOUTReceived()))
+			{
+				if (USB_DeviceState == DEVICE_STATE_Unattached)
+				  return;
+			}
+		}
+		else
+		{
+			Endpoint_Discard_8();
+		}
+	}
+}
+
+/** Routine to process an issued command from the host, via a DFU_DNLOAD request wrapper. This routine ensures
+ *  that the command is allowed based on the current secure mode flag value, and passes the command off to the
+ *  appropriate handler function.
+ */
+static void ProcessBootloaderCommand(void)
+{
+	/* Check if device is in secure mode */
+	if (IsSecure)
+	{
+		/* Don't process command unless it is a READ or chip erase command */
+		if (!(((SentCommand.Command == COMMAND_WRITE)             &&
+		        IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF)) ||
+			   (SentCommand.Command == COMMAND_READ)))
+		{
+			/* Set the state and status variables to indicate the error */
+			DFU_State  = dfuERROR;
+			DFU_Status = errWRITE;
+
+			/* Stall command */
+			Endpoint_StallTransaction();
+
+			/* Don't process the command */
+			return;
+		}
+	}
+
+	/* Dispatch the required command processing routine based on the command type */
+	switch (SentCommand.Command)
+	{
+		case COMMAND_PROG_START:
+			ProcessMemProgCommand();
+			break;
+		case COMMAND_DISP_DATA:
+			ProcessMemReadCommand();
+			break;
+		case COMMAND_WRITE:
+			ProcessWriteCommand();
+			break;
+		case COMMAND_READ:
+			ProcessReadCommand();
+			break;
+		case COMMAND_CHANGE_BASE_ADDR:
+			if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x03, 0x00))              // Set 64KB flash page command
+			  Flash64KBPage = SentCommand.Data[2];
+
+			break;
+	}
+}
+
+/** Routine to concatenate the given pair of 16-bit memory start and end addresses from the host, and store them
+ *  in the StartAddr and EndAddr global variables.
+ */
+static void LoadStartEndAddresses(void)
+{
+	union
+	{
+		uint8_t  Bytes[2];
+		uint16_t Word;
+	} Address[2] = {{.Bytes = {SentCommand.Data[2], SentCommand.Data[1]}},
+	                {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}}};
+
+	/* Load in the start and ending read addresses from the sent data packet */
+	StartAddr = Address[0].Word;
+	EndAddr   = Address[1].Word;
+}
+
+/** Handler for a Memory Program command issued by the host. This routine handles the preparations needed
+ *  to write subsequent data from the host into the specified memory.
+ */
+static void ProcessMemProgCommand(void)
+{
+	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Write FLASH command
+	    IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                            // Write EEPROM command
+	{
+		/* Load in the start and ending read addresses */
+		LoadStartEndAddresses();
+
+		/* If FLASH is being written to, we need to pre-erase the first page to write to */
+		if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))
+		{
+			union
+			{
+				uint16_t Words[2];
+				uint32_t Long;
+			} CurrFlashAddress = {.Words = {StartAddr, Flash64KBPage}};
+
+			/* Erase the current page's temp buffer */
+			boot_page_erase(CurrFlashAddress.Long);
+			boot_spm_busy_wait();
+		}
+
+		/* Set the state so that the next DNLOAD requests reads in the firmware */
+		DFU_State = dfuDNLOAD_IDLE;
+	}
+}
+
+/** Handler for a Memory Read command issued by the host. This routine handles the preparations needed
+ *  to read subsequent data from the specified memory out to the host, as well as implementing the memory
+ *  blank check command.
+ */
+static void ProcessMemReadCommand(void)
+{
+	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00) ||                          // Read FLASH command
+        IS_ONEBYTE_COMMAND(SentCommand.Data, 0x02))                            // Read EEPROM command
+	{
+		/* Load in the start and ending read addresses */
+		LoadStartEndAddresses();
+
+		/* Set the state so that the next UPLOAD requests read out the firmware */
+		DFU_State = dfuUPLOAD_IDLE;
+	}
+	else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                       // Blank check FLASH command
+	{
+		uint32_t CurrFlashAddress = 0;
+
+		while (CurrFlashAddress < (uint32_t)BOOT_START_ADDR)
+		{
+			/* Check if the current byte is not blank */
+			#if (FLASHEND > 0xFFFF)
+			if (pgm_read_byte_far(CurrFlashAddress) != 0xFF)
+			#else
+			if (pgm_read_byte(CurrFlashAddress) != 0xFF)
+			#endif
+			{
+				/* Save the location of the first non-blank byte for response back to the host */
+				Flash64KBPage = (CurrFlashAddress >> 16);
+				StartAddr     = CurrFlashAddress;
+
+				/* Set state and status variables to the appropriate error values */
+				DFU_State  = dfuERROR;
+				DFU_Status = errCHECK_ERASED;
+
+				break;
+			}
+
+			CurrFlashAddress++;
+		}
+	}
+}
+
+/** Handler for a Data Write command issued by the host. This routine handles non-programming commands such as
+ *  bootloader exit (both via software jumps and hardware watchdog resets) and flash memory erasure.
+ */
+static void ProcessWriteCommand(void)
+{
+	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x03))                            // Start application
+	{
+		/* Indicate that the bootloader is terminating */
+		WaitForExit = true;
+
+		/* Check if data supplied for the Start Program command - no data executes the program */
+		if (SentCommand.DataSize)
+		{
+			if (SentCommand.Data[1] == 0x01)                                   // Start via jump
+			{
+				union
+				{
+					uint8_t  Bytes[2];
+					AppPtr_t FuncPtr;
+				} Address = {.Bytes = {SentCommand.Data[4], SentCommand.Data[3]}};
+
+				/* Load in the jump address into the application start address pointer */
+				AppStartPtr = Address.FuncPtr;
+			}
+		}
+		else
+		{
+			if (SentCommand.Data[1] == 0x00)                                   // Start via watchdog
+			{
+				/* Unlock the forced application start mode of the bootloader if it is restarted */
+				MagicBootKey = MAGIC_BOOT_KEY;
+
+				/* Start the watchdog to reset the AVR once the communications are finalized */
+				wdt_enable(WDTO_250MS);
+			}
+			else                                                               // Start via jump
+			{
+				/* Set the flag to terminate the bootloader at next opportunity if a valid application has been loaded */
+				if (pgm_read_word_near(0) == 0xFFFF)
+				  RunBootloader = false;
+			}
+		}
+	}
+	else if (IS_TWOBYTE_COMMAND(SentCommand.Data, 0x00, 0xFF))                 // Erase flash
+	{
+		uint32_t CurrFlashAddress = 0;
+
+		/* Clear the application section of flash */
+		while (CurrFlashAddress < (uint32_t)BOOT_START_ADDR)
+		{
+			boot_page_erase(CurrFlashAddress);
+			boot_spm_busy_wait();
+			boot_page_write(CurrFlashAddress);
+			boot_spm_busy_wait();
+
+			CurrFlashAddress += SPM_PAGESIZE;
+		}
+
+		/* Re-enable the RWW section of flash as writing to the flash locks it out */
+		boot_rww_enable();
+
+		/* Memory has been erased, reset the security bit so that programming/reading is allowed */
+		IsSecure = false;
+	}
+}
+
+/** Handler for a Data Read command issued by the host. This routine handles bootloader information retrieval
+ *  commands such as device signature and bootloader version retrieval.
+ */
+static void ProcessReadCommand(void)
+{
+	const uint8_t BootloaderInfo[3] = {BOOTLOADER_VERSION, BOOTLOADER_ID_BYTE1, BOOTLOADER_ID_BYTE2};
+	const uint8_t SignatureInfo[4]  = {0x58, AVR_SIGNATURE_1, AVR_SIGNATURE_2, AVR_SIGNATURE_3};
+
+	uint8_t DataIndexToRead    = SentCommand.Data[1];
+	bool    ReadAddressInvalid = false;
+
+	if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x00))                        // Read bootloader info
+	{
+		if (DataIndexToRead < 3)
+		  ResponseByte = BootloaderInfo[DataIndexToRead];
+		else
+		  ReadAddressInvalid = true;
+	}
+	else if (IS_ONEBYTE_COMMAND(SentCommand.Data, 0x01))                    // Read signature byte
+	{
+		switch (DataIndexToRead)
+		{
+			case 0x30:
+				ResponseByte = SignatureInfo[0];
+				break;
+			case 0x31:
+				ResponseByte = SignatureInfo[1];
+				break;
+			case 0x60:
+				ResponseByte = SignatureInfo[2];
+				break;
+			case 0x61:
+				ResponseByte = SignatureInfo[3];
+				break;
+			default:
+				ReadAddressInvalid = true;
+				break;
+		}
+	}
+
+	if (ReadAddressInvalid)
+	{
+		/* Set the state and status variables to indicate the error */
+		DFU_State  = dfuERROR;
+		DFU_Status = errADDRESS;
+	}
+}