Changes to blocking interrupts, etc for PR change

1 files changed, 617 insertions, 0 deletions

diff --git a/ISPProtocol.c b/ISPProtocol.c
new file mode 100644
index 000000000..ffe2c56db
--- /dev/null
+++ b/ISPProtocol.c
@@ -0,0 +1,617 @@
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2018.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2018  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+  
+  Function ISPProtocol_Calibrate() copyright 2018 Jacob September
+
+  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
+ *
+ *  ISP Protocol handler, to process V2 Protocol wrapped ISP commands used in Atmel programmer devices.
+ */
+
+#include "ISPProtocol.h"
+#include <util/atomic.h>
+
+#if defined(ENABLE_ISP_PROTOCOL) || defined(__DOXYGEN__)
+
+/** Handler for the CMD_ENTER_PROGMODE_ISP command, which attempts to enter programming mode on
+ *  the attached device, returning success or failure back to the host.
+ */
+void ISPProtocol_EnterISPMode(void)
+{
+	struct
+	{
+		uint8_t TimeoutMS;
+		uint8_t PinStabDelayMS;
+		uint8_t ExecutionDelayMS;
+		uint8_t SynchLoops;
+		uint8_t ByteDelay;
+		uint8_t PollValue;
+		uint8_t PollIndex;
+		uint8_t EnterProgBytes[4];
+	} Enter_ISP_Params;
+
+	Endpoint_Read_Stream_LE(&Enter_ISP_Params, sizeof(Enter_ISP_Params), NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	uint8_t ResponseStatus = STATUS_CMD_FAILED;
+
+	CurrentAddress = 0;
+
+	/* Perform execution delay, initialize SPI bus */
+	ISPProtocol_DelayMS(Enter_ISP_Params.ExecutionDelayMS);
+	ISPTarget_EnableTargetISP();
+
+	ISPTarget_ChangeTargetResetLine(true);
+	ISPProtocol_DelayMS(Enter_ISP_Params.PinStabDelayMS);
+
+	/* Continuously attempt to synchronize with the target until either the number of attempts specified
+	 * by the host has exceeded, or the the device sends back the expected response values */
+	while (Enter_ISP_Params.SynchLoops-- && TimeoutTicksRemaining)
+	{
+		uint8_t ResponseBytes[4];
+
+		for (uint8_t RByte = 0; RByte < sizeof(ResponseBytes); RByte++)
+		{
+			ISPProtocol_DelayMS(Enter_ISP_Params.ByteDelay);
+			ResponseBytes[RByte] = ISPTarget_TransferByte(Enter_ISP_Params.EnterProgBytes[RByte]);
+		}
+
+		/* Check if polling disabled, or if the polled value matches the expected value */
+		if (!(Enter_ISP_Params.PollIndex) || (ResponseBytes[Enter_ISP_Params.PollIndex - 1] == Enter_ISP_Params.PollValue))
+		{
+			ResponseStatus = STATUS_CMD_OK;
+			break;
+		}
+		else
+		{
+			ISPTarget_ChangeTargetResetLine(false);
+			ISPProtocol_DelayMS(Enter_ISP_Params.PinStabDelayMS);
+			ISPTarget_ChangeTargetResetLine(true);
+			ISPProtocol_DelayMS(Enter_ISP_Params.PinStabDelayMS);
+		}
+	}
+
+	Endpoint_Write_8(CMD_ENTER_PROGMODE_ISP);
+	Endpoint_Write_8(ResponseStatus);
+	Endpoint_ClearIN();
+}
+
+/** Handler for the CMD_LEAVE_ISP command, which releases the target from programming mode. */
+void ISPProtocol_LeaveISPMode(void)
+{
+	struct
+	{
+		uint8_t PreDelayMS;
+		uint8_t PostDelayMS;
+	} Leave_ISP_Params;
+
+	Endpoint_Read_Stream_LE(&Leave_ISP_Params, sizeof(Leave_ISP_Params), NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	/* Perform pre-exit delay, release the target /RESET, disable the SPI bus and perform the post-exit delay */
+	ISPProtocol_DelayMS(Leave_ISP_Params.PreDelayMS);
+	ISPTarget_ChangeTargetResetLine(false);
+	ISPTarget_DisableTargetISP();
+	ISPProtocol_DelayMS(Leave_ISP_Params.PostDelayMS);
+
+	Endpoint_Write_8(CMD_LEAVE_PROGMODE_ISP);
+	Endpoint_Write_8(STATUS_CMD_OK);
+	Endpoint_ClearIN();
+}
+
+/** Handler for the CMD_PROGRAM_FLASH_ISP and CMD_PROGRAM_EEPROM_ISP commands, writing out bytes,
+ *  words or pages of data to the attached device.
+ *
+ *  \param[in] V2Command  Issued V2 Protocol command byte from the host
+ */
+void ISPProtocol_ProgramMemory(uint8_t V2Command)
+{
+	struct
+	{
+		uint16_t BytesToWrite;
+		uint8_t  ProgrammingMode;
+		uint8_t  DelayMS;
+		uint8_t  ProgrammingCommands[3];
+		uint8_t  PollValue1;
+		uint8_t  PollValue2;
+		uint8_t  ProgData[256]; // Note, the Jungo driver has a very short ACK timeout period, need to buffer the
+	} Write_Memory_Params;      // whole page and ACK the packet as fast as possible to prevent it from aborting
+
+	Endpoint_Read_Stream_LE(&Write_Memory_Params, (sizeof(Write_Memory_Params) -
+	                                               sizeof(Write_Memory_Params.ProgData)), NULL);
+	Write_Memory_Params.BytesToWrite = SwapEndian_16(Write_Memory_Params.BytesToWrite);
+
+	if (Write_Memory_Params.BytesToWrite > sizeof(Write_Memory_Params.ProgData))
+	{
+		Endpoint_ClearOUT();
+		Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+		Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+		Endpoint_Write_8(V2Command);
+		Endpoint_Write_8(STATUS_CMD_FAILED);
+		Endpoint_ClearIN();
+		return;
+	}
+
+	Endpoint_Read_Stream_LE(&Write_Memory_Params.ProgData, Write_Memory_Params.BytesToWrite, NULL);
+
+	// The driver will terminate transfers that are a round multiple of the endpoint bank in size with a ZLP, need
+	// to catch this and discard it before continuing on with packet processing to prevent communication issues
+	if (((sizeof(uint8_t) + sizeof(Write_Memory_Params) - sizeof(Write_Memory_Params.ProgData)) +
+	    Write_Memory_Params.BytesToWrite) % AVRISP_DATA_EPSIZE == 0)
+	{
+		Endpoint_ClearOUT();
+		Endpoint_WaitUntilReady();
+	}
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	uint8_t  ProgrammingStatus = STATUS_CMD_OK;
+	uint8_t  PollValue         = (V2Command == CMD_PROGRAM_FLASH_ISP) ? Write_Memory_Params.PollValue1 :
+	                                                                    Write_Memory_Params.PollValue2;
+	uint16_t PollAddress       = 0;
+	uint8_t* NextWriteByte     = Write_Memory_Params.ProgData;
+	uint16_t PageStartAddress  = (CurrentAddress & 0xFFFF);
+
+	for (uint16_t CurrentByte = 0; CurrentByte < Write_Memory_Params.BytesToWrite; CurrentByte++)
+	{
+		uint8_t ByteToWrite     = *(NextWriteByte++);
+		uint8_t ProgrammingMode = Write_Memory_Params.ProgrammingMode;
+
+		/* Check to see if we need to send a LOAD EXTENDED ADDRESS command to the target */
+		if (MustLoadExtendedAddress)
+		{
+			ISPTarget_LoadExtendedAddress();
+			MustLoadExtendedAddress = false;
+		}
+
+		ISPTarget_SendByte(Write_Memory_Params.ProgrammingCommands[0]);
+		ISPTarget_SendByte(CurrentAddress >> 8);
+		ISPTarget_SendByte(CurrentAddress & 0xFF);
+		ISPTarget_SendByte(ByteToWrite);
+
+		/* AVR FLASH addressing requires us to modify the write command based on if we are writing a high
+		 * or low byte at the current word address */
+		if (V2Command == CMD_PROGRAM_FLASH_ISP)
+		  Write_Memory_Params.ProgrammingCommands[0] ^= READ_WRITE_HIGH_BYTE_MASK;
+
+		/* Check to see if we have a valid polling address */
+		if (!(PollAddress) && (ByteToWrite != PollValue))
+		{
+			if ((CurrentByte & 0x01) && (V2Command == CMD_PROGRAM_FLASH_ISP))
+			  Write_Memory_Params.ProgrammingCommands[2] |=  READ_WRITE_HIGH_BYTE_MASK;
+			else
+			  Write_Memory_Params.ProgrammingCommands[2] &= ~READ_WRITE_HIGH_BYTE_MASK;
+
+			PollAddress = (CurrentAddress & 0xFFFF);
+		}
+
+		/* If in word programming mode, commit the byte to the target's memory */
+		if (!(ProgrammingMode & PROG_MODE_PAGED_WRITES_MASK))
+		{
+			/* If the current polling address is invalid, switch to timed delay write completion mode */
+			if (!(PollAddress) && !(ProgrammingMode & PROG_MODE_WORD_READYBUSY_MASK))
+			  ProgrammingMode = (ProgrammingMode & ~PROG_MODE_WORD_VALUE_MASK) | PROG_MODE_WORD_TIMEDELAY_MASK;
+
+			ProgrammingStatus = ISPTarget_WaitForProgComplete(ProgrammingMode, PollAddress, PollValue,
+			                                                  Write_Memory_Params.DelayMS,
+			                                                  Write_Memory_Params.ProgrammingCommands[2]);
+
+			/* Abort the programming loop early if the byte/word programming failed */
+			if (ProgrammingStatus != STATUS_CMD_OK)
+			  break;
+
+			/* Must reset the polling address afterwards, so it is not erroneously used for the next byte */
+			PollAddress = 0;
+		}
+
+		/* EEPROM just increments the address each byte, flash needs to increment on each word and
+		 * also check to ensure that a LOAD EXTENDED ADDRESS command is issued each time the extended
+		 * address boundary has been crossed during FLASH memory programming */
+		if ((CurrentByte & 0x01) || (V2Command == CMD_PROGRAM_EEPROM_ISP))
+		{
+			CurrentAddress++;
+
+			if ((V2Command == CMD_PROGRAM_FLASH_ISP) && !(CurrentAddress & 0xFFFF))
+			  MustLoadExtendedAddress = true;
+		}
+	}
+
+	/* If the current page must be committed, send the PROGRAM PAGE command to the target */
+	if (Write_Memory_Params.ProgrammingMode & PROG_MODE_COMMIT_PAGE_MASK)
+	{
+		ISPTarget_SendByte(Write_Memory_Params.ProgrammingCommands[1]);
+		ISPTarget_SendByte(PageStartAddress >> 8);
+		ISPTarget_SendByte(PageStartAddress & 0xFF);
+		ISPTarget_SendByte(0x00);
+
+		/* Check if polling is enabled and possible, if not switch to timed delay mode */
+		if ((Write_Memory_Params.ProgrammingMode & PROG_MODE_PAGED_VALUE_MASK) && !(PollAddress))
+		{
+			Write_Memory_Params.ProgrammingMode = (Write_Memory_Params.ProgrammingMode & ~PROG_MODE_PAGED_VALUE_MASK) |
+												   PROG_MODE_PAGED_TIMEDELAY_MASK;
+		}
+
+		ProgrammingStatus = ISPTarget_WaitForProgComplete(Write_Memory_Params.ProgrammingMode, PollAddress, PollValue,
+		                                                  Write_Memory_Params.DelayMS,
+		                                                  Write_Memory_Params.ProgrammingCommands[2]);
+
+		/* Check to see if the FLASH address has crossed the extended address boundary */
+		if ((V2Command == CMD_PROGRAM_FLASH_ISP) && !(CurrentAddress & 0xFFFF))
+		  MustLoadExtendedAddress = true;
+	}
+
+	Endpoint_Write_8(V2Command);
+	Endpoint_Write_8(ProgrammingStatus);
+	Endpoint_ClearIN();
+}
+
+/** Handler for the CMD_READ_FLASH_ISP and CMD_READ_EEPROM_ISP commands, reading in bytes,
+ *  words or pages of data from the attached device.
+ *
+ *  \param[in] V2Command  Issued V2 Protocol command byte from the host
+ */
+void ISPProtocol_ReadMemory(uint8_t V2Command)
+{
+	struct
+	{
+		uint16_t BytesToRead;
+		uint8_t  ReadMemoryCommand;
+	} Read_Memory_Params;
+
+	Endpoint_Read_Stream_LE(&Read_Memory_Params, sizeof(Read_Memory_Params), NULL);
+	Read_Memory_Params.BytesToRead = SwapEndian_16(Read_Memory_Params.BytesToRead);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	Endpoint_Write_8(V2Command);
+	Endpoint_Write_8(STATUS_CMD_OK);
+
+	/* Read each byte from the device and write them to the packet for the host */
+	for (uint16_t CurrentByte = 0; CurrentByte < Read_Memory_Params.BytesToRead; CurrentByte++)
+	{
+		/* Check to see if we need to send a LOAD EXTENDED ADDRESS command to the target */
+		if (MustLoadExtendedAddress)
+		{
+			ISPTarget_LoadExtendedAddress();
+			MustLoadExtendedAddress = false;
+		}
+
+		/* Read the next byte from the desired memory space in the device */
+		ISPTarget_SendByte(Read_Memory_Params.ReadMemoryCommand);
+		ISPTarget_SendByte(CurrentAddress >> 8);
+		ISPTarget_SendByte(CurrentAddress & 0xFF);
+		Endpoint_Write_8(ISPTarget_ReceiveByte());
+
+		/* Check if the endpoint bank is currently full, if so send the packet */
+		if (!(Endpoint_IsReadWriteAllowed()))
+		{
+			Endpoint_ClearIN();
+			Endpoint_WaitUntilReady();
+		}
+
+		/* AVR FLASH addressing requires us to modify the read command based on if we are reading a high
+		 * or low byte at the current word address */
+		if (V2Command == CMD_READ_FLASH_ISP)
+		  Read_Memory_Params.ReadMemoryCommand ^= READ_WRITE_HIGH_BYTE_MASK;
+
+		/* EEPROM just increments the address each byte, flash needs to increment on each word and
+		 * also check to ensure that a LOAD EXTENDED ADDRESS command is issued each time the extended
+		 * address boundary has been crossed */
+		if ((CurrentByte & 0x01) || (V2Command == CMD_READ_EEPROM_ISP))
+		{
+			CurrentAddress++;
+
+			if ((V2Command != CMD_READ_EEPROM_ISP) && !(CurrentAddress & 0xFFFF))
+			  MustLoadExtendedAddress = true;
+		}
+	}
+
+	Endpoint_Write_8(STATUS_CMD_OK);
+
+	bool IsEndpointFull = !(Endpoint_IsReadWriteAllowed());
+	Endpoint_ClearIN();
+
+	/* Ensure last packet is a short packet to terminate the transfer */
+	if (IsEndpointFull)
+	{
+		Endpoint_WaitUntilReady();
+		Endpoint_ClearIN();
+		Endpoint_WaitUntilReady();
+	}
+}
+
+/** Handler for the CMD_CHI_ERASE_ISP command, clearing the target's FLASH memory. */
+void ISPProtocol_ChipErase(void)
+{
+	struct
+	{
+		uint8_t EraseDelayMS;
+		uint8_t PollMethod;
+		uint8_t EraseCommandBytes[4];
+	} Erase_Chip_Params;
+
+	Endpoint_Read_Stream_LE(&Erase_Chip_Params, sizeof(Erase_Chip_Params), NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	uint8_t ResponseStatus = STATUS_CMD_OK;
+
+	/* Send the chip erase commands as given by the host to the device */
+	for (uint8_t SByte = 0; SByte < sizeof(Erase_Chip_Params.EraseCommandBytes); SByte++)
+	  ISPTarget_SendByte(Erase_Chip_Params.EraseCommandBytes[SByte]);
+
+	/* Use appropriate command completion check as given by the host (delay or busy polling) */
+	if (!(Erase_Chip_Params.PollMethod))
+	  ISPProtocol_DelayMS(Erase_Chip_Params.EraseDelayMS);
+	else
+	  ResponseStatus = ISPTarget_WaitWhileTargetBusy();
+
+	Endpoint_Write_8(CMD_CHIP_ERASE_ISP);
+	Endpoint_Write_8(ResponseStatus);
+	Endpoint_ClearIN();
+}
+
+/** Global volatile variables used in ISRs relating to ISPProtocol_Calibrate() */
+volatile uint16_t HalfCyclesRemaining;
+volatile uint8_t  ResponseTogglesRemaining;
+
+/** ISR to toggle MOSI pin when TIMER1 overflows */
+ISR(TIMER1_OVF_vect, ISR_BLOCK)
+{
+	PINB |= (1 << PB2);	// toggle PB2 (MOSI) by writing 1 to its bit in PINB
+	HalfCyclesRemaining--;
+}
+
+/** ISR to listen for toggles on MISO pin */
+ISR(PCINT0_vect, ISR_BLOCK)
+{
+	ResponseTogglesRemaining--;
+}
+
+/** Handler for the CMD_OSCCAL command, entering RC-calibration mode as specified in AVR053 */
+void ISPProtocol_Calibrate(void)
+{
+	#define CALIB_CLOCK			32768
+		// CALIB_TICKS uses 2x frequency because we toggle twice per cycle
+		//  and adds 1/2 denom. to nom. to ensure rounding instead of flooring of integer division
+	#define CALIB_TICKS			( (F_CPU+CALIB_CLOCK) / (2*CALIB_CLOCK) )
+		// Per AVR053, calibration guaranteed to take 1024 cycles (2048 half-cycles) or fewer;
+		//  add some cycles for response delay (5-10 after success) and response itself
+	#define HALF_CYCLE_LIMIT	(2*1024 + 50)
+	#define SUCCESS_TOGGLE_NUM	8
+	
+	uint8_t ResponseStatus = STATUS_CMD_OK;
+	
+	/* Don't entirely know why this is needed, something to do with the USB communication back to PC */
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+	
+	/* Enable pullup on MISO and release ~RESET */
+	DDRB	=  ~(1 << PB3);					// explicitly set all PORTB to outputs except PB3 (MISO)
+	PORTB  |= ( (1 << PB4) | (1 << PB3) );	// set PB4 (TARG_RST) high (i.e. not reset) and enable pullup on PB3 (MISO)
+	
+	/* Set up MISO pin (PCINT3) to listen for toggles */
+	PCMSK0	= (1 << PCINT3);	// set mask to enable PCINT on only Pin 3 (MISO)
+	
+	/* Set up timer that fires at a rate of 65536 Hz - this will drive the MOSI toggle */
+	OCR1A	= CALIB_TICKS - 1;		// zero-indexed counter; for 16MHz system clock, this becomes 243
+	TCCR1A	= ( (1 << WGM11) | (1 << WGM10) );					// set for fast PWM, TOP = OCR1A
+	TCCR1B	= ( (1 << WGM13) | (1 << WGM12) | (1 << CS10) );	//  ... and no clock prescaling
+	TCNT1	= 0;												// reset counter
+
+	/* Initialize counter variables */
+	HalfCyclesRemaining			= HALF_CYCLE_LIMIT;
+	ResponseTogglesRemaining	= SUCCESS_TOGGLE_NUM;
+
+	/* Turn on interrupts */
+	PCICR  |= (1 << PCIE0);	// enable interrupts for PCINT7:0 (don't touch setting for PCINT12:8)
+	TIMSK1	= (1 << TOIE1);	// enable T1 OVF interrupt (and no other T1 interrupts)
+	
+	/* Turn on global interrupts for the following block, restoring current state at end */
+	NONATOMIC_BLOCK(NONATOMIC_RESTORESTATE)
+	{
+		/* Let device do its calibration, wait for reponse on MISO */
+		while ( HalfCyclesRemaining && ResponseTogglesRemaining )
+		{
+			// do nothing...
+		}
+		
+		/* Disable interrupts */
+		PCICR  &= ~(1 << PCIE0);
+		TIMSK1	= 0;
+	}
+	
+	/* Check if device responded with a success message or if we timed out */
+	if (ResponseTogglesRemaining)
+	{
+		ResponseStatus = STATUS_CMD_TOUT;
+	}
+
+	/* Report back to PC via USB */
+	Endpoint_Write_8(CMD_OSCCAL);
+	Endpoint_Write_8(ResponseStatus);
+	Endpoint_ClearIN();
+	
+} // void ISPProtocol_Calibrate(void)
+
+/** Handler for the CMD_READ_FUSE_ISP, CMD_READ_LOCK_ISP, CMD_READ_SIGNATURE_ISP and CMD_READ_OSCCAL commands,
+ *  reading the requested configuration byte from the device.
+ *
+ *  \param[in] V2Command  Issued V2 Protocol command byte from the host
+ */
+void ISPProtocol_ReadFuseLockSigOSCCAL(uint8_t V2Command)
+{
+	struct
+	{
+		uint8_t RetByte;
+		uint8_t ReadCommandBytes[4];
+	} Read_FuseLockSigOSCCAL_Params;
+
+	Endpoint_Read_Stream_LE(&Read_FuseLockSigOSCCAL_Params, sizeof(Read_FuseLockSigOSCCAL_Params), NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	uint8_t ResponseBytes[4];
+
+	/* Send the Fuse or Lock byte read commands as given by the host to the device, store response */
+	for (uint8_t RByte = 0; RByte < sizeof(ResponseBytes); RByte++)
+	  ResponseBytes[RByte] = ISPTarget_TransferByte(Read_FuseLockSigOSCCAL_Params.ReadCommandBytes[RByte]);
+
+	Endpoint_Write_8(V2Command);
+	Endpoint_Write_8(STATUS_CMD_OK);
+	Endpoint_Write_8(ResponseBytes[Read_FuseLockSigOSCCAL_Params.RetByte - 1]);
+	Endpoint_Write_8(STATUS_CMD_OK);
+	Endpoint_ClearIN();
+}
+
+/** Handler for the CMD_WRITE_FUSE_ISP and CMD_WRITE_LOCK_ISP commands, writing the requested configuration
+ *  byte to the device.
+ *
+ *  \param[in] V2Command  Issued V2 Protocol command byte from the host
+ */
+void ISPProtocol_WriteFuseLock(uint8_t V2Command)
+{
+	struct
+	{
+		uint8_t WriteCommandBytes[4];
+	} Write_FuseLockSig_Params;
+
+	Endpoint_Read_Stream_LE(&Write_FuseLockSig_Params, sizeof(Write_FuseLockSig_Params), NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	/* Send the Fuse or Lock byte program commands as given by the host to the device */
+	for (uint8_t SByte = 0; SByte < sizeof(Write_FuseLockSig_Params.WriteCommandBytes); SByte++)
+	  ISPTarget_SendByte(Write_FuseLockSig_Params.WriteCommandBytes[SByte]);
+
+	Endpoint_Write_8(V2Command);
+	Endpoint_Write_8(STATUS_CMD_OK);
+	Endpoint_Write_8(STATUS_CMD_OK);
+	Endpoint_ClearIN();
+}
+
+/** Handler for the CMD_SPI_MULTI command, writing and reading arbitrary SPI data to and from the attached device. */
+void ISPProtocol_SPIMulti(void)
+{
+	struct
+	{
+		uint8_t TxBytes;
+		uint8_t RxBytes;
+		uint8_t RxStartAddr;
+		uint8_t TxData[255];
+	} SPI_Multi_Params;
+
+	Endpoint_Read_Stream_LE(&SPI_Multi_Params, (sizeof(SPI_Multi_Params) - sizeof(SPI_Multi_Params.TxData)), NULL);
+	Endpoint_Read_Stream_LE(&SPI_Multi_Params.TxData, SPI_Multi_Params.TxBytes, NULL);
+
+	Endpoint_ClearOUT();
+	Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+	Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
+
+	Endpoint_Write_8(CMD_SPI_MULTI);
+	Endpoint_Write_8(STATUS_CMD_OK);
+
+	uint8_t CurrTxPos = 0;
+	uint8_t CurrRxPos = 0;
+
+	/* Write out bytes to transmit until the start of the bytes to receive is met */
+	while (CurrTxPos < SPI_Multi_Params.RxStartAddr)
+	{
+		if (CurrTxPos < SPI_Multi_Params.TxBytes)
+		  ISPTarget_SendByte(SPI_Multi_Params.TxData[CurrTxPos]);
+		else
+		  ISPTarget_SendByte(0);
+
+		CurrTxPos++;
+	}
+
+	/* Transmit remaining bytes with padding as needed, read in response bytes */
+	while (CurrRxPos < SPI_Multi_Params.RxBytes)
+	{
+		if (CurrTxPos < SPI_Multi_Params.TxBytes)
+		  Endpoint_Write_8(ISPTarget_TransferByte(SPI_Multi_Params.TxData[CurrTxPos++]));
+		else
+		  Endpoint_Write_8(ISPTarget_ReceiveByte());
+
+		/* Check to see if we have filled the endpoint bank and need to send the packet */
+		if (!(Endpoint_IsReadWriteAllowed()))
+		{
+			Endpoint_ClearIN();
+			Endpoint_WaitUntilReady();
+		}
+
+		CurrRxPos++;
+	}
+
+	Endpoint_Write_8(STATUS_CMD_OK);
+
+	bool IsEndpointFull = !(Endpoint_IsReadWriteAllowed());
+	Endpoint_ClearIN();
+
+	/* Ensure last packet is a short packet to terminate the transfer */
+	if (IsEndpointFull)
+	{
+		Endpoint_WaitUntilReady();
+		Endpoint_ClearIN();
+		Endpoint_WaitUntilReady();
+	}
+}
+
+/** Blocking delay for a given number of milliseconds. This provides a simple wrapper around
+ *  the avr-libc provided delay function, so that the delay function can be called with a
+ *  constant value (to prevent run-time floating point operations being required).
+ *
+ *  \param[in] DelayMS  Number of milliseconds to delay for
+ */
+void ISPProtocol_DelayMS(uint8_t DelayMS)
+{
+	while (DelayMS-- && TimeoutTicksRemaining)
+	  Delay_MS(1);
+}
+
+#endif