TMS320F28377D: USB Bulk Transfer Max Rate

//*****************************************************************************
//
// usb_bulk_example.c - A very simple command line application that attempts
//      to open the Luminary Micro Generic Bulk USB device and exchange data
//      with it.
//
// Copyright (c) 2008-2009 Luminary Micro, Inc.  All rights reserved.
// Software License Agreement
// 
// Luminary Micro, Inc. (LMI) is supplying this software for use solely and
// exclusively on LMI's microcontroller products.
// 
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws.  All rights are reserved.  You may not combine
// this software with "viral" open-source software in order to form a larger
// program.  Any use in violation of the foregoing restrictions may subject
// the user to criminal sanctions under applicable laws, as well as to civil
// liability for the breach of the terms and conditions of this license.
// 
// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 4674 of the Stellaris Firmware Development Package.
//
//*****************************************************************************

//****************************************************************************
//
// If the device is successfully opened, the user is prompted for a string
// which is then sent to the device. The device toggles the case of any
// alphabet characters in the the data and sends it back. We receive this
// and print out the result.
//
// Communication with the device is carried out via a simple DLL, lmusbdll,
// which is responsible for opening and closing the device and for
// sending and receiving blocks of data.  This structure allows the
// application code to be kept independent of the underlying USB driver
// in use.  In this implementation, Microsoft's WinUSB interface is used
// but a switch to another stack, for example the open source libusb-win32
// interface could be made merely be replacing the lmusbdll.dll with
// another version writing to the different USB stack.
//
// One downside to using WinUSB is that it requires you to have the Windows
// Device Driver Kit (DDK) installed to build applications which use the
// interface. This is a very large download making it awkward for people
// with slow internet connections. The use of lmusbdll.dll also offers
// the advantage that applications using it can still be modified and
// rebuilt even without the DDK installed on the development system.  To
// update and rebuild lmusbdll itself, however, the DDK is still required.
//
//****************************************************************************
#include <windows.h>
#include <strsafe.h>
#include <initguid.h>
#include "tiusbdll.h"
#include "ti_guids.h"

//****************************************************************************
//
// Buffer size definitions.
//
//****************************************************************************
#define MAX_STRING_LEN 65536
#define MAX_ENTRY_LEN 65536

//****************************************************************************
//
// The build version number
//
//****************************************************************************
#define BLDVER "4674"

//****************************************************************************
//
// The number of bytes we read and write per transaction if in echo mode.
//
//****************************************************************************
#define ECHO_PACKET_SIZE 65535

//****************************************************************************
//
// Buffer into which error messages are written.
//
//****************************************************************************
TCHAR g_pcErrorString[MAX_STRING_LEN];

//****************************************************************************
//
// The number of bytes transfered in the last measurement interval.
//
//****************************************************************************
ULONG g_ulByteCount = 0;

//****************************************************************************
//
// The total number of packets transfered.
//
//****************************************************************************
ULONG g_ulPacketCount = 0;

//****************************************************************************
//
// Return a string describing the supplied system error code.
//
// \param dwError is a Windows system error code.
//
// This function returns a pointer to a string describing the error code
// passed in the dwError parameter. If no description string can be found
// the string "Unknown" is returned.
//
// \return Returns a pointer to a string describing the error.
//
//****************************************************************************
LPTSTR GetSystemErrorString(DWORD dwError)
{
    DWORD dwRetcode;

    //
    // Ask Windows for the error message description.
    //
    dwRetcode = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, "%0", dwError, 0,
                              g_pcErrorString, MAX_STRING_LEN, NULL);

    if(dwRetcode == 0)
    {
        return((LPTSTR)L"Unknown");
    }
    else
    {
        //
        // Remove the trailing "\n\r" if present.
        //
        if(dwRetcode >= 2)
        {
            if(g_pcErrorString[dwRetcode - 2] == '\r')
            {
                g_pcErrorString[dwRetcode - 2] = '\0';
            }
        }

        return(g_pcErrorString);
    }
}

//****************************************************************************
//
// Print the throughput in terms of Kbps once per second.
//
//****************************************************************************
void UpdateThroughput(void)
{
    static ULONG ulStartTime = 0;
    static ULONG ulLast = 0;
    ULONG ulNow;
    ULONG ulElapsed;
    SYSTEMTIME sSysTime;

    //
    // Get the current system time.
    //
    GetSystemTime(&sSysTime);
    ulNow = (((((sSysTime.wHour * 60) +
               sSysTime.wMinute) * 60) +
              sSysTime.wSecond) * 1000) + sSysTime.wMilliseconds;

    //
    // If this is the first call, set the start time.
    //
    if(ulStartTime == 0)
    {
        ulStartTime = ulNow;
        ulLast = ulNow;
        return;
    }

    //
    // How much time has elapsed since the last measurement?
    //
    ulElapsed = (ulNow > ulStartTime) ? (ulNow - ulStartTime) : (ulStartTime - ulNow);

    //
    // We dump a new measurement every second.
    //
    if(ulElapsed > 1000)
    {

        printf("\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b");
        printf("%6dKbps Packets: %10d ", ((g_ulByteCount * 8) / ulElapsed), g_ulPacketCount);
        g_ulByteCount = 0;
        ulStartTime = ulNow;
    }
}

//****************************************************************************
//
// The main application entry function.
//
// \param None.
//
// This function forms the main entry point of the example application. It
// initializes the USB bulk device, prompts the user for an ASCII string,
// sends this string to the device, reads the response from the device (which
// will be the same string with the character order reversed if using the
// sample device provided by Luminary Micro) and displays the returned
// string.
//
// \return Set the exit code to 0 of no errors cause the application to end
// or a non-zero value otherwise.
//
//****************************************************************************
int main(int argc, char *argv[])
{
    BOOL bResult;
    BOOL bDriverInstalled;
    BOOL bEcho;
    char szBuffer[MAX_ENTRY_LEN];
    ULONG ulWritten;
    ULONG ulRead;
    ULONG ulLength;
    DWORD dwError;
	TIUSB_HANDLE hUSB;

    //
    // Are we operating in echo mode or not? The "-e" parameter tells the
    // app to echo everything it receives back to the device unchanged.
    //
    bEcho = ((argc > 1) && (argv[1][1] == 'e')) ? TRUE : FALSE;

    //
    // Print a cheerful welcome.
    //
    printf("\nLuminary Micro Bulk USB Device Example\n");
    printf("--------------------------------------\n\n");
    printf("Version %s\n\n", BLDVER);
    if(!bEcho)
    {
        printf("This is a partner application to the usb_dev_bulk example\n");
        printf("shipped with StellarisWare software releases for USB-enabled\n");
        printf("boards. Strings entered here are sent to the board which\n");
        printf("inverts the case of the characters in the string and returns\n");
        printf("them to the host.\n\n");
    }
    else
    {
        printf("If run with the \"-e\" command line switch, this application\n");
        printf("echoes all data received on the bulk IN endpoint to the bulk\n");
        printf("OUT endpoint.  This feature may be helpful during development\n");
        printf("and debug of your own USB devices.  Note that this will not\n");
        printf("do anything exciting if run with the usb_dev_bulk example\n");
        printf("device attached since it expects the host to initiate transfers.\n\n");
    }

    //
    // Find our USB device and prepare it for communication.
    //
    hUSB = InitializeDevice(BULK_VID, BULK_PID,
                            (LPGUID)&(GUID_DEVINTERFACE_LUMINARY_BULK),
                            &bDriverInstalled);

    if(hUSB)
    {
        //
        // Are we operating in echo mode or not? The "-e" parameter tells the
        // app to echo everything it receives back to the device unchanged.
        //
        if(bEcho)
        {
            //
            // Yes - we are in echo mode.
            //
            printf("Running in echo mode. Press Ctrl+C to exit.\n\n"
                "Throughput:      0Kbps Packets:           0");

            while(1)
            {
                //
                // Read a packet of data from the device.
                //
                dwError = ReadUSBPacket(hUSB, szBuffer, ECHO_PACKET_SIZE, &ulRead,
                                        INFINITE, NULL);

                if(dwError != ERROR_SUCCESS)
                {
                    //
                    // We failed to read from the device.
                    //
                    printf("\n\nError %d (%S) reading from bulk IN pipe.\n", dwError,
                           GetSystemErrorString(dwError));
                    break;
                }
                else
                {
                    //
                    // Update our byte and packet counters.
                    //
                    g_ulByteCount += ulRead;
                    g_ulPacketCount++;
					szBuffer[ulRead] = '\0';

                    //printf("\nReturned string: \"%s\"\n", szBuffer);
                    //
                    // Write the data back out to the device.
                    //

					//COMMENTED OUT FOR DEVICE TO HOST THROUGHPUT TEST!  NO ECHO BACK TO DEVICE!!
                    /*
					bResult = WriteUSBPacket(hUSB, szBuffer, ulRead, &ulWritten);
                    if(!bResult)
                    {
                        //
                        // We failed to write the data for some reason.
                        //
                        dwError = GetLastError();
                        printf("\n\nError %d (%S) writing to bulk OUT pipe.\n", dwError,
                               GetSystemErrorString(dwError));
                        break;
                    }
					*/
					//COMMENTED OUT FOR DEVICE TO HOST THROUGHPUT TEST!  NO ECHO BACK TO DEVICE!!

                    //
                    // Display the throughput.
                    //
                    UpdateThroughput();
                }
            }
        }
        else
        {
            //
            // We are running in normal mode.  Keep sending and receiving
            // strings until the user indicates that it is time to exit.
            //
            while(1)
            {

                //
                // The device was found and successfully configured. Now get a string from
                // the user...
                //
                do
                {
                    printf("\nEnter a string (EXIT to exit): ");
                    fgets(szBuffer, MAX_ENTRY_LEN, stdin);
                    printf("\n");

                    //
                    // How many characters were entered (including the trailing '\n')?
                    //
                    ulLength = (ULONG)strlen(szBuffer);

                    if(ulLength <= 1)
                    {
                        //
                        // The string is either nothing at all or a single '\n' so reprompt the user.
                        //
                        printf("\nPlease enter some text.\n");
                        ulLength = 0;
                    }
                    else
                    {
                        //
                        // Get rid of the trailing '\n' if there is one there.
                        //
                        if(szBuffer[ulLength - 1] == '\n')
                        {
                            szBuffer[ulLength - 1] = '\0';
                            ulLength--;
                        }
                    }
                }
                while(ulLength == 0);

                //
                // Are we being asked to exit the application?
                //
                if(!(strcmp("EXIT", szBuffer)))
                {
                    //
                    // Yes - drop out and exit.
                    //
                    printf("Exiting on user request.\n");
                    break;
                }

                //
                // Write the user's string to the device.
                //
                bResult = WriteUSBPacket(hUSB, szBuffer, ulLength, &ulWritten);
                if(!bResult)
                {
                    //
                    // We failed to write the data for some reason.
                    //
                    dwError = GetLastError();
                    printf("Error %d (%S) writing to bulk OUT pipe.\n", dwError,
                           GetSystemErrorString(dwError));
                }
                else
                {
                    //
                    // We wrote data successfully so now read it back.
                    //
                    printf("Wrote %d bytes to the device. Expected %d\n",
                           ulWritten, ulLength);

                    //
                    // We expect the same number of bytes as we just sent.
                    //
                    dwError = ReadUSBPacket(hUSB, szBuffer, ulWritten, &ulRead,
                                            INFINITE, NULL);

                    if(dwError != ERROR_SUCCESS)
                    {
                        //
                        // We failed to read from the device.
                        //
                        printf("Error %d (%S) reading from bulk IN pipe.\n", dwError,
                               GetSystemErrorString(dwError));
                    }
                    else
                    {
                        //
                        // Add a string terminator to the returned data (this
                        // should already be there but, just in case...)
                        //
                        szBuffer[ulRead] = '\0';

                        printf("Read %d bytes from device. Expected %d\n",
                               ulRead, ulWritten);
                        printf("\nReturned string: \"%s\"\n", szBuffer);
                    }
                }
            }
        }
    }
    else
    {
        //
        // An error was reported while trying to connect to the device.
        //
        dwError = GetLastError();

        printf("\nUnable to initialize the Luminary Bulk USB Device.\n");
        printf("Error code is %d (%S)\n\n", dwError, GetSystemErrorString(dwError));
        printf("Please make sure you have a Luminary Stellaris USB-enabled\n");
        printf("evaluation or development kit running the usb_dev_bulk example\n");
        printf("application connected to this system via the \"USB OTG\" or\n");
        printf("\"USB DEVICE\" connectors. Once the device is connected, run\n");
        printf("this application again.\n\n");

        printf("\nPress \"Enter\" to exit: ");
        fgets(szBuffer, MAX_STRING_LEN, stdin);
        printf("\n");
        return(2);
    }

    TerminateDevice(hUSB);

    return(0);
}

//###########################################################################
// FILE:   usb_dev_bulk.c
// TITLE:  Main routines for the generic bulk device example.
//###########################################################################
// $TI Release: F28M3Xx Support Library v110 $
// $Release Date: December 12, 2011 $
//###########################################################################

#include "F28x_Project.h"
#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/systick.h"
#include "driverlib/uart.h"
#include "driverlib/usb.h"
#include "driverlib/usb_hal.h"
#include "driverlib/rom.h"
#include "usblib/usblib.h"
#include "usblib/usb-ids.h"
#include "usblib/device/usbdevice.h"
#include "usblib/device/usbdbulk.h"
#include "utils/uartstdio.h"
#include "usb_bulk_structs.h"


//*****************************************************************************
//! \addtogroup cpu01_example_list
//! <h1>USB Generic Bulk Device (usb_dev_bulk)</h1>
//!
//! This example provides a generic USB device offering simple bulk data
//! transfer to and from the host.  The device uses a vendor-specific class ID
//! and supports a single bulk IN endpoint and a single bulk OUT endpoint.
//! Data received from the host is assumed to be ASCII text and it is
//! echoed back with the case of all alphabetic characters swapped.
//!
//! UART0, connected to the FTDI virtual COM port and running at 115,200,
//! 8-N-1, is used to display messages from this application.
//!
//! A Windows INF file for the device is provided in ControlSUITE.  This
//! INF contains information required to install the WinUSB subsystem on
//! WindowsXP and Windows 7.  WinUSB is a Windows subsystem allowing user mode
//! applications to access the USB device without the need for a
//! vendor-specific kernel mode driver.
//!
//! A sample Windows command-line application, usb_bulk_example, illustrating
//! how to connect to and communicate with the bulk device is also provided.
//! Project files are included to allow the examples to be built using Microsoft
//! VisualStudio.  Source code for this application can be found in directory
//! F28X7x_common/tools/usb_bulk_example/Release.
//*****************************************************************************

//*****************************************************************************
//
// The system tick rate expressed both as ticks per second and a millisecond
// period.
//
//*****************************************************************************
#define SYSTICKS_PER_SECOND     100
#define SYSTICK_PERIOD_MS       (1000 / SYSTICKS_PER_SECOND)

//*****************************************************************************
//
// The global system tick counter.
//
//*****************************************************************************
volatile uint32_t g_ui32SysTickCount = 0;

//*****************************************************************************
//
// Variables tracking transmit and receive counts.
//
//*****************************************************************************
volatile uint32_t g_ui32TxCount = 0;
volatile uint32_t g_ui32RxCount = 0;
#ifdef DEBUG
uint32_t g_ui32UARTRxErrors = 0;
#endif

//*****************************************************************************
//
// The current USB operating mode - Host, Device or unknown.
//
//*****************************************************************************
tUSBMode g_eCurrentUSBMode;

//*****************************************************************************
//
// Debug-related definitions and declarations.
//
// Debug output is available via UART0 if DEBUG is defined during build.
//
//*****************************************************************************
#ifdef DEBUG
//*****************************************************************************
//
// Map all debug print calls to UARTprintf in debug builds.
//
//*****************************************************************************
#define DEBUG_PRINT UARTprintf

#else

//*****************************************************************************
//
// Compile out all debug print calls in release builds.
//
//*****************************************************************************
#define DEBUG_PRINT while(0) ((int32_t (*)(char *, ...))0)
#endif

//*****************************************************************************
//
// Flags used to pass commands from interrupt context to the main loop.
//
//*****************************************************************************
#define COMMAND_PACKET_RECEIVED 0x00000001
#define COMMAND_STATUS_UPDATE   0x00000002

volatile uint32_t g_ui32Flags = 0;
char *g_pcStatus;
unsigned char g_bConnected = 0;

//*****************************************************************************
//
// Global flag indicating that a USB configuration has been set.
//
//*****************************************************************************
static volatile bool g_bUSBConfigured = false;

unsigned char buffer[256];

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
    UARTprintf("Error at line %d of %s\n", ui32Line, pcFilename);
    while(1)
    {
    }
}

#endif

//*****************************************************************************
//
// Interrupt handler for the system tick counter.
//
//*****************************************************************************
__interrupt void
SysTickIntHandler(void)
{
    //
    // Update our system tick counter.
    //
    g_ui32SysTickCount++;
    PieCtrlRegs.PIEACK.all |= 1;
}

//*****************************************************************************
//
// Receive new data and echo it back to the host.
//
// \param psDevice points to the instance data for the device whose data is to
// be processed.
// \param pi8Data points to the newly received data in the USB receive buffer.
// \param ui32NumBytes is the number of bytes of data available to be processed.
//
// This function is called whenever we receive a notification that data is
// available from the host. We read the data, byte-by-byte and swap the case
// of any alphabetical characters found then write it back out to be
// transmitted back to the host.
//
// \return Returns the number of bytes of data processed.
//
//*****************************************************************************
static uint32_t
EchoNewDataToHost(tUSBDBulkDevice *psDevice, uint8_t *pi8Data,
                  uint_fast32_t ui32NumBytes)
{
    uint_fast32_t ui32Loop, ui32Space, ui32Count;
    uint_fast32_t ui32ReadIndex;
    uint_fast32_t ui32WriteIndex;
    tUSBRingBufObject sTxRing;

    //
    // Get the current buffer information to allow us to write directly to
    // the transmit buffer (we already have enough information from the
    // parameters to access the receive buffer directly).
    //
    USBBufferInfoGet(&g_sTxBuffer, &sTxRing);

    //
    // How much space is there in the transmit buffer?
    //
    ui32Space = USBBufferSpaceAvailable(&g_sTxBuffer);

    //
    // How many characters can we process this time round?
    //
    ui32Loop = (ui32Space < ui32NumBytes) ? ui32Space : ui32NumBytes;
    ui32Count = ui32Loop;

    //
    // Update our receive counter.
    //
    g_ui32RxCount += ui32NumBytes;

    //
    // Dump a debug message.
    //
    DEBUG_PRINT("Received %d bytes\n", ui32NumBytes);

    //
    // Set up to process the characters by directly accessing the USB buffers.
    //
    ui32ReadIndex = (uint32_t)(pi8Data - g_pui8USBRxBuffer);
    ui32WriteIndex = sTxRing.ui32WriteIndex;

    while(ui32Loop)
    {
        //
        // Copy from the receive buffer to the transmit buffer converting
        // character case on the way.
        //

        //
        // Is this a lower case character?
        //
        if((g_pui8USBRxBuffer[ui32ReadIndex] >= 'a') &&
           (g_pui8USBRxBuffer[ui32ReadIndex] <= 'z'))
        {
            //
            // Convert to upper case and write to the transmit buffer.
            //
            g_pui8USBTxBuffer[ui32WriteIndex] =
                (g_pui8USBRxBuffer[ui32ReadIndex] - 'a') + 'A';
        }
        else
        {
            //
            // Is this an upper case character?
            //
            if((g_pui8USBRxBuffer[ui32ReadIndex] >= 'A') &&
               (g_pui8USBRxBuffer[ui32ReadIndex] <= 'Z'))
            {
                //
                // Convert to lower case and write to the transmit buffer.
                //
                g_pui8USBTxBuffer[ui32WriteIndex] =
                    (g_pui8USBRxBuffer[ui32ReadIndex] - 'Z') + 'z';
            }
            else
            {
                //
                // Copy the received character to the transmit buffer.
                //
                g_pui8USBTxBuffer[ui32WriteIndex] =
                    g_pui8USBRxBuffer[ui32ReadIndex];
            }
        }

        //
        // Move to the next character taking care to adjust the pointer for
        // the buffer wrap if necessary.
        //
        ui32WriteIndex++;
        ui32WriteIndex =
            (ui32WriteIndex == BULK_BUFFER_SIZE) ? 0 : ui32WriteIndex;

        ui32ReadIndex++;
        ui32ReadIndex = (ui32ReadIndex == BULK_BUFFER_SIZE) ? 0 : ui32ReadIndex;

        ui32Loop--;
    }

    //
    // We've processed the data in place so now send the processed data
    // back to the host.
    //
    USBBufferDataWritten(&g_sTxBuffer, ui32Count);

    DEBUG_PRINT("Wrote %d bytes\n", ui32Count);

    //
    // We processed as much data as we can directly from the receive buffer so
    // we need to return the number of bytes to allow the lower layer to
    // update its read pointer appropriately.
    //
    return(ui32Count);
}

//*****************************************************************************
//
// Handles bulk driver notifications related to the transmit channel (data to
// the USB host).
//
// \param pvCBData is the client-supplied callback pointer for this channel.
// \param ui32Event identifies the event we are being notified about.
// \param ui32MsgValue is an event-specific value.
// \param pvMsgData is an event-specific pointer.
//
// This function is called by the bulk driver to notify us of any events
// related to operation of the transmit data channel (the IN channel carrying
// data to the USB host).
//
// \return The return value is event-specific.
//
//*****************************************************************************
uint32_t
TxHandler(void *pvCBData, uint32_t ui32Event, uint32_t ui32MsgValue,
          void *pvMsgData)
{
	uint32_t ui32Space;
    //
    // We are not required to do anything in response to any transmit event
    // in this example. All we do is update our transmit counter.
    //
    if(ui32Event == USB_EVENT_TX_COMPLETE)
    {
//        g_ui32TxCount += ui32MsgValue;
		ui32Space = USBDBulkTxPacketAvailable(&g_sBulkDevice);

		if(ui32Space)
			USBDBulkPacketWrite(&g_sBulkDevice, buffer, ui32Space, true);
    }

    //
    // Dump a debug message.
    //
//    DEBUG_PRINT("TX complete %d\n", ui32MsgValue);

    return(0);
}

//*****************************************************************************
//
// Handles bulk driver notifications related to the receive channel (data from
// the USB host).
//
// \param pvCBData is the client-supplied callback pointer for this channel.
// \param ui32Event identifies the event we are being notified about.
// \param ui32MsgValue is an event-specific value.
// \param pvMsgData is an event-specific pointer.
//
// This function is called by the bulk driver to notify us of any events
// related to operation of the receive data channel (the OUT channel carrying
// data from the USB host).
//
// \return The return value is event-specific.
//
//*****************************************************************************
uint32_t
RxHandler(void *pvCBData, uint32_t ui32Event, uint32_t ui32MsgValue,
          void *pvMsgData)
{
    //
    // Which event are we being sent?
    //
    switch(ui32Event)
    {
        //
        // We are connected to a host and communication is now possible.
        //
    case USB_EVENT_CONNECTED:
    {
        g_bUSBConfigured = true;
            g_pcStatus = "Host connected.";
            g_ui32Flags |= COMMAND_STATUS_UPDATE;

            //
        // Flush our buffers.
            //
//        USBBufferFlush(&g_sTxBuffer);
//        USBBufferFlush(&g_sRxBuffer);
        g_bConnected = true;

        break;
    }

        //
    // The host has disconnected.
        //
    case USB_EVENT_DISCONNECTED:
    {
        g_bUSBConfigured = false;
            g_pcStatus = "Host disconn.";
            g_ui32Flags |= COMMAND_STATUS_UPDATE;
            g_bConnected = false;
        break;
    }

        //
    // A new packet has been received.
        //
//    case USB_EVENT_RX_AVAILABLE:
//    {
//        tUSBDBulkDevice *psDevice;
//
//            //
//        // Get a pointer to our instance data from the callback data
//        // parameter.
//            //
//        psDevice = (tUSBDBulkDevice *)pvCBData;
//
//            //
//        // Read the new packet and echo it back to the host.
//            //
//            return(EchoNewDataToHost(psDevice, pvMsgData, ui32MsgValue));
//    }

        //
    // Ignore SUSPEND and RESUME for now.
        //
    case USB_EVENT_SUSPEND:
    case USB_EVENT_RESUME:
        break;

        //
    // Ignore all other events and return 0.
        //
    default:
        break;
    }

    return(0);
}

#ifdef DEBUG
//*****************************************************************************
//
// Configure the UART and its pins.  This must be called before UARTprintf().
//
//*****************************************************************************
void
ConfigureUART(void)
{
    //
    // Enable UART0
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_SCI1);

    //
    // Configure GPIO Pins for UART mode.
    //
    EALLOW;
    GpioCtrlRegs.GPAMUX2.bit.GPIO28 = 1;
    GpioCtrlRegs.GPAPUD.bit.GPIO28 = 0;
    GpioCtrlRegs.GPAQSEL2.bit.GPIO28 = 3;
    GpioCtrlRegs.GPADIR.bit.GPIO28 = 0;

    GpioCtrlRegs.GPAMUX2.bit.GPIO29 = 1;
    GpioCtrlRegs.GPAPUD.bit.GPIO29 = 0;
    GpioCtrlRegs.GPADIR.bit.GPIO29 = 1;
    EDIS;

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, SysCtlLowSpeedClockGet(SYSTEM_CLOCK_SPEED));

}
#endif

//*****************************************************************************
//
// USB Mode callback
//
// \param ui32Index is the zero-based index of the USB controller making the
//        callback.
// \param eMode indicates the new operating mode.
//
// This function is called by the USB library whenever an OTG mode change
// occurs and, if a connection has been made, informs us of whether we are to
// operate as a host or device.
//
// \return None.
//
//*****************************************************************************
void
ModeCallback(uint32_t ui32Index, tUSBMode eMode)
{
    //
    // Save the new mode.
    //
    g_eCurrentUSBMode = eMode;

}

//*****************************************************************************
//
// This is the main application entry function.
//
//*****************************************************************************
int
main(void)
{
	unsigned char index, firstPacket;
	unsigned long ui32Space;

	firstPacket = 1;

	for(index = 0; index < 256; index++){
		buffer[index] = index;
	}

#ifdef _FLASH
// Copy time critical code and Flash setup code to RAM
// This includes the following functions:  InitFlash();
// The  RamfuncsLoadStart, RamfuncsLoadSize, and RamfuncsRunStart
// symbols are created by the linker. Refer to the device .cmd file.
    memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);
#endif
    //
    // Set the clocking to run from the PLL at 50MHz
    //
    SysCtlClockSet(SYSCTL_OSCSRC_XTAL | SYSCTL_PLL_ENABLE | SYSCTL_IMULT(20) | SYSCTL_SYSDIV(2));
    SysCtlAuxClockSet(SYSCTL_OSCSRC_XTAL | SYSCTL_PLL_ENABLE | SYSCTL_IMULT(12) | SYSCTL_SYSDIV(4));


#ifdef _FLASH
// Call Flash Initialization to setup flash waitstates
// This function must reside in RAM
    InitFlash();
#endif

    //
    // Initialize interrupt controller and vector table
    //
    InitPieCtrl();
    InitPieVectTable();

#ifdef DEBUG
    //
    // Configure the UART for debug output.
    //
    ConfigureUART();
#endif

    //
    // Not configured initially.
    //
    g_bUSBConfigured = false;

    //
    // Enable the GPIO peripheral used for USB, and configure the USB
    // pins.
    //
    USBGPIOEnable();
    USBIntRegister(USB0_BASE, f28x_USB0DeviceIntHandler);

    //
    // Enable the system tick.
    //
//    SysTickInit();
//    SysTickPeriodSet(SysCtlClockGet(SYSTEM_CLOCK_SPEED) / SYSTICKS_PER_SECOND);
//    SysTickIntRegister(SysTickIntHandler);
//    SysTickIntEnable();
//    SysTickEnable();

    //
    // Show the application name on the display and UART output.
    //
    DEBUG_PRINT("\nC2000 F2837x Series USB bulk device example\n");
    DEBUG_PRINT("---------------------------------\n\n");

    //
    // Initialize the transmit and receive buffers.
    //
//    USBBufferInit(&g_sTxBuffer);
//    USBBufferInit(&g_sRxBuffer);
    
    USBStackModeSet(0, eUSBModeForceDevice, ModeCallback);

    //
    // Pass our device information to the USB library and place the device
    // on the bus.
    //
    USBDBulkInit(0, &g_sBulkDevice);

    //
    // Enable global interrupts
    //
    IntMasterEnable();

    //
    // Main application loop.
    //
    while(1)
    {
    	//
    	// Nothing to do...everything happens in the interrupt context.
    	//
    	if(g_bConnected)
    	{
			//
			// How much space is there in the transmit buffer?
			//
    		if(firstPacket)
    		{
				ui32Space = USBDBulkTxPacketAvailable(&g_sBulkDevice);

				if(ui32Space)
					USBDBulkPacketWrite(&g_sBulkDevice, buffer, ui32Space, true);

				firstPacket = 0;
    		}

//			USBEndpointDataPut(USB0_BASE, USB_EP_1, buffer, 64);
//			USBEndpointDataSend(USB0_BASE, USB_EP_1, USB_TRANS_IN);
    	}
    }
}