AVRISP-MKII Clone: Clean up ISP driver code, namespace module variables.
[pub/USBasp.git] / Projects / AVRISP-MKII / Lib / ISP / ISPProtocol.c
index 133c451..5fc321e 100644 (file)
@@ -8,7 +8,7 @@
 
 /*
   Copyright 2018  Dean Camera (dean [at] fourwalledcubicle [dot] com)
-  
+
   Copyright 2019 Jacob September (jacobseptember [at] gmail [dot] com)
 
   Permission to use, copy, modify, distribute, and sell this
  */
 
 #include "ISPProtocol.h"
-#include <util/atomic.h>
 
 #if defined(ENABLE_ISP_PROTOCOL) || defined(__DOXYGEN__)
 
+/* Half cycles of the OSCCAL calibration period remaining */
+static volatile uint16_t ISPProtocol_HalfCyclesRemaining;
+
+/** Target device response I/O pin toggles remaining for successful OSCCAL calibration */
+static volatile uint8_t  ISPProtocol_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
+    ISPProtocol_HalfCyclesRemaining--;
+}
+
+/** ISR to listen for toggles on MISO pin */
+ISR(PCINT0_vect, ISR_BLOCK)
+{
+    ISPProtocol_ResponseTogglesRemaining--;
+}
+
 /** 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();
+    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();
+    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,
@@ -139,146 +158,146 @@ void ISPProtocol_LeaveISPMode(void)
  */
 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();
+    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,
@@ -288,192 +307,160 @@ void ISPProtocol_ProgramMemory(uint8_t V2Command)
  */
 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();
-       }
+    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--;
+    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();
 }
 
 /** 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)
+    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 pull-up on MISO and release ~RESET */
+    DDRB    =  ~(1 << PB3);
+    PORTB  |= ( (1 << PB4) | (1 << PB3) );
+
+    /* Set up MISO pin (PCINT3) to listen for toggles */
+    PCMSK0  = (1 << PCINT3);
+
+    /* Set up timer that fires at a rate of 65536 Hz - this will drive the MOSI toggle */
+    OCR1A  = ISPPROTOCOL_CALIB_TICKS - 1;
+    TCCR1A = ( (1 << WGM11) | (1 << WGM10) );               // set for fast PWM, TOP = OCR1A
+    TCCR1B = ( (1 << WGM13) | (1 << WGM12) | (1 << CS10) ); //  ... and no clock prescaling
+    TCNT1  = 0;
+
+    /* Initialize counter variables */
+    ISPProtocol_HalfCyclesRemaining      = ISPPROTOCOL_CALIB_HALF_CYCLE_LIMIT;
+    ISPProtocol_ResponseTogglesRemaining = ISPPROTOCOL_CALIB_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 response on MISO */
+        while (ISPProtocol_HalfCyclesRemaining && ISPProtocol_ResponseTogglesRemaining);
+
+        /* Disable timer and pin change interrupts */
+        PCICR  &= ~(1 << PCIE0);
+        TIMSK1  = 0;
+    }
+
+    /* Check if device responded with a success message or if we timed out */
+    if (ISPProtocol_ResponseTogglesRemaining)
+      ResponseStatus = STATUS_CMD_TOUT;
+
+    /* Report back to PC via USB */
+    Endpoint_Write_8(CMD_OSCCAL);
+    Endpoint_Write_8(ResponseStatus);
+    Endpoint_ClearIN();
+}
 
 /** 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.
@@ -482,29 +469,29 @@ void ISPProtocol_Calibrate(void)
  */
 void ISPProtocol_ReadFuseLockSigOSCCAL(uint8_t V2Command)
 {
-       struct
-       {
-               uint8_t RetByte;
-               uint8_t ReadCommandBytes[4];
-       } Read_FuseLockSigOSCCAL_Params;
+    struct
+    {
+        uint8_t RetByte;
+        uint8_t ReadCommandBytes[4];
+    } Read_FuseLockSigOSCCAL_Params;
 
-       Endpoint_Read_Stream_LE(&Read_FuseLockSigOSCCAL_Params, sizeof(Read_FuseLockSigOSCCAL_Params), NULL);
+    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);
+    Endpoint_ClearOUT();
+    Endpoint_SelectEndpoint(AVRISP_DATA_IN_EPADDR);
+    Endpoint_SetEndpointDirection(ENDPOINT_DIR_IN);
 
-       uint8_t ResponseBytes[4];
+    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]);
+    /* 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();
+    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
@@ -514,92 +501,92 @@ void ISPProtocol_ReadFuseLockSigOSCCAL(uint8_t V2Command)
  */
 void ISPProtocol_WriteFuseLock(uint8_t V2Command)
 {
-       struct
-       {
-               uint8_t WriteCommandBytes[4];
-       } Write_FuseLockSig_Params;
+    struct
+    {
+        uint8_t WriteCommandBytes[4];
+    } Write_FuseLockSig_Params;
 
-       Endpoint_Read_Stream_LE(&Write_FuseLockSig_Params, sizeof(Write_FuseLockSig_Params), NULL);
+    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);
+    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]);
+    /* 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();
+    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();
-       }
+    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
@@ -610,8 +597,8 @@ void ISPProtocol_SPIMulti(void)
  */
 void ISPProtocol_DelayMS(uint8_t DelayMS)
 {
-       while (DelayMS-- && TimeoutTicksRemaining)
-         Delay_MS(1);
+    while (DelayMS-- && TimeoutTicksRemaining)
+      Delay_MS(1);
 }
 
 #endif