TMS320F28377D: usb_dev_serial example code question

//###########################################################################
//
// FILE:   usb_dev_serial.c
//
// TITLE:  Main routines for the USB CDC serial example.
//
//###########################################################################
// $TI Release: F2837xD Support Library v3.03.00.00 $
// $Release Date: Thu Dec  7 18:51:32 CST 2017 $
// $Copyright:
// Copyright (C) 2013-2017 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without 
// modification, are permitted provided that the following conditions 
// are met:
// 
//   Redistributions of source code must retain the above copyright 
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the 
//   documentation and/or other materials provided with the   
//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################

//
// Included Files
//
#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 "inc/hw_uart.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 "include/usblib.h"
#include "include/usbcdc.h"
#include "include/usb_ids.h"
#include "include/device/usbdevice.h"
#include "include/device/usbdcdc.h"
#include "utils/ustdlib.h"
#include "usb_serial_structs.h"

//*****************************************************************************
//
//! \addtogroup cpu01_example_list
//! <h1>USB Serial Device (usb_dev_serial)</h1>
//!
//! This example application turns the evaluation kit into a virtual serial
//! port when connected to the USB host system.  The application supports the
//! USB Communication Device Class, Abstract Control Model to redirect UART0
//! traffic to and from the USB host system.
//!
//! Connect USB cables from your PC to both the mini and microUSB connectors on
//! the controlCARD.Figure out what COM ports your controlCARD is enumerating
//! (typically done using Device Manager in Windows) and open a serial terminal
//! to each of with the settings 115200 Baud 8-N-1.  Characters typed in one
//! terminal should be echoed in the other and vice versa.
//!
//! A driver information (INF) file for use with Windows XP and
//! Windows 7 can be found in the windows_drivers directory.
//
//*****************************************************************************

//*****************************************************************************
//
// Configuration and tuning parameters.
//
//*****************************************************************************

//*****************************************************************************
//
// 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)

//*****************************************************************************
//
// Variables tracking transmit and receive counts.
//
//*****************************************************************************
volatile uint32_t g_ui32UARTTxCount = 0;
volatile uint32_t g_ui32UARTRxCount = 0;
#ifdef DEBUG
uint32_t g_ui32UARTRxErrors = 0;
#endif

//*****************************************************************************
//
// The base address, peripheral ID and interrupt ID of the UART that is to
// be redirected.
//
//*****************************************************************************

//*****************************************************************************
//
// Defines required to redirect UART0 via USB.
//
//*****************************************************************************
#define USB_UART_BASE           UARTA_BASE
#define USB_UART_PERIPH         SYSCTL_PERIPH_SCI1
#define USB_UART_INT            INT_SCIRXINTA

//*****************************************************************************
//
// Default line coding settings for the redirected UART.
//
//*****************************************************************************
#define DEFAULT_BIT_RATE        115200
#define DEFAULT_UART_CONFIG     (UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | \
                                 UART_CONFIG_STOP_ONE)

//*****************************************************************************
//
// GPIO peripherals and pins muxed with the redirected UART.  These will depend
// upon the IC in use and the UART selected in USB_UART_BASE.  Be careful that
// these settings all agree with the hardware you are using.
//
//*****************************************************************************

//*****************************************************************************
//
// Defines required to redirect UART0 via USB.
//
//*****************************************************************************
//#define TX_GPIO_BASE            GPIO_PORTA_BASE
//#define TX_GPIO_PERIPH          SYSCTL_PERIPH_GPIOA
//#define TX_GPIO_PIN             GPIO_PIN_1
//
//#define RX_GPIO_BASE            GPIO_PORTA_BASE
//#define RX_GPIO_PERIPH          SYSCTL_PERIPH_GPIOA
//#define RX_GPIO_PIN             GPIO_PIN_0

//*****************************************************************************
//
// Flag indicating whether or not we are currently sending a Break condition.
//
//*****************************************************************************
static bool g_bSendingBreak = false;

//*****************************************************************************
//
// Global system tick counter
//
//*****************************************************************************
volatile uint32_t g_ui32SysTickCount = 0;

//*****************************************************************************
//
// 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;

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

//ADD
uint32_t RxLengthFromHost = 0;
uint32_t USBBuffSpace = 0;
uint8_t USBRxBuf[256];
uint8_t USBTxBuf[256];
uint8_t UsbTxTest = 0;
uint32_t UsbTxTest2 = 0;
#define USB_RX_LENGTH 255

__interrupt void cpu_timer0_isr(void);
//*****************************************************************************
//
// Internal function prototypes.
//
//*****************************************************************************
static void USBUARTPrimeTransmit(uint32_t ui32Base);
static void CheckForSerialStateChange(const tUSBDCDCDevice *psDevice,
                                      int32_t i32Errors);
static void SetControlLineState(uint16_t ui16State);
static bool SetLineCoding(tLineCoding *psLineCoding);
static void GetLineCoding(tLineCoding *psLineCoding);
static void SendBreak(bool bSend);

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
    while(1)
    {
    }
}
#endif

//*****************************************************************************
//
// This function is called whenever serial data is received from the UART.
// It is passed the accumulated error flags from each character received in
// this interrupt and determines from them whether or not an interrupt
// notification to the host is required.
//
// If a notification is required and the control interrupt endpoint is idle,
// we send the notification immediately.  If the endpoint is not idle, we
// accumulate the errors in a global variable which will be checked on
// completion of the previous notification and used to send a second one
// if necessary.
//
//*****************************************************************************
static void
CheckForSerialStateChange(const tUSBDCDCDevice *psDevice, int32_t i32Errors)
{
    uint16_t ui16SerialState;

    //
    // Clear our USB serial state.  Since we are faking the handshakes, always
    // set the TXCARRIER (DSR) and RXCARRIER (DCD) bits.
    //
    ui16SerialState = USB_CDC_SERIAL_STATE_TXCARRIER |
                    USB_CDC_SERIAL_STATE_RXCARRIER;

    //
    // Are any error bits set?
    //
    if(i32Errors)
    {
        //
        // At least one error is being notified so translate from our hardware
        // error bits into the correct state markers for the USB notification.
        //
        if(i32Errors & UART_RXST_OE)
        {
            ui16SerialState |= USB_CDC_SERIAL_STATE_OVERRUN;
        }

        if(i32Errors & UART_RXST_PE)
        {
            ui16SerialState |= USB_CDC_SERIAL_STATE_PARITY;
        }

        if(i32Errors & UART_RXST_FE)
        {
            ui16SerialState |= USB_CDC_SERIAL_STATE_FRAMING;
        }

        if(i32Errors & UART_RXST_BRKDT)
        {
            ui16SerialState |= USB_CDC_SERIAL_STATE_BREAK;
        }

        // Call the CDC driver to notify the state change.
        USBDCDCSerialStateChange((void *)psDevice, ui16SerialState);
    }
}

//*****************************************************************************
//
// Read as many characters from the UART FIFO as we can and move them into
// the CDC transmit buffer.
//
// \return Returns UART error flags read during data reception.
//
//*****************************************************************************
static int32_t
ReadUARTData(void)
{
    int32_t i32Char, i32Errors;
    uint8_t ui8Char;
    uint32_t ui32Space;

    //
    // Clear our error indicator.
    //
    i32Errors = 0;

    //
    // How much space do we have in the buffer?
    //
    ui32Space = USBBufferSpaceAvailable((tUSBBuffer *)&g_sTxBuffer);

    //
    // Read data from the UART FIFO until there is none left or we run
    // out of space in our receive buffer.
    //
    while(ui32Space && UARTCharsAvail(USB_UART_BASE))
    {
        //
        // Read a character from the UART FIFO into the ring buffer if no
        // errors are reported.
        //
        i32Char = UARTCharGetNonBlocking(USB_UART_BASE);

        //
        // If the character did not contain any error notifications,
        // copy it to the output buffer.
        //
        if(!(i32Char & ~0xFF))
        {
            ui8Char = (uint8_t)(i32Char & 0xFF);
            USBBufferWrite((tUSBBuffer *)&g_sTxBuffer,
                           (uint8_t *)&ui8Char, 1);

            //
            // Decrement the number of bytes we know the buffer can accept.
            //
            ui32Space--;
        }
        else
        {
#ifdef DEBUG
            //
            // Increment our receive error counter.
            //
            g_ui32UARTRxErrors++;
#endif
            //
            // Update our error accumulator.
            //
            i32Errors |= i32Char;
        }

        //
        // Update our count of bytes received via the UART.
        //
        g_ui32UARTRxCount++;
    }

    //
    // Pass back the accumulated error indicators.
    //
    return(i32Errors);
}

//*****************************************************************************
//
// Take as many bytes from the transmit buffer as we have space for and move
// them into the USB UART's transmit FIFO.
//
//*****************************************************************************
static void
USBUARTPrimeTransmit(uint32_t ui32Base)
{
    uint32_t ui32Read;
    uint8_t ui8Char;

    //
    // If we are currently sending a break condition, don't receive any
    // more data. We will resume transmission once the break is turned off.
    //
    if(g_bSendingBreak)
    {
        return;
    }

    //
    // If there is space in the UART FIFO, try to read some characters
    // from the receive buffer to fill it again.
    //
    while(UARTSpaceAvail(ui32Base))
    {
        //
        // Get a character from the buffer.
        //
        ui32Read = USBBufferRead((tUSBBuffer *)&g_sRxBuffer, &ui8Char, 1);

        //
        // Did we get a character?
        //
        if(ui32Read)
        {
            //
            // Place the character in the UART transmit FIFO.
            //
            UARTCharPutNonBlocking(ui32Base, ui8Char);

            //
            // Update our count of bytes transmitted via the UART.
            //
            g_ui32UARTTxCount++;
        }
        else
        {
            //
            // We ran out of characters so exit the function.
            //
            return;
        }
    }
}

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

//*****************************************************************************
//
// Interrupt handler for the UART TX which is being redirected via USB.
//
//*****************************************************************************
__interrupt void
USBUARTTXIntHandler(void)
{
    uint32_t ui32Ints;

    ui32Ints = UARTIntStatus(USB_UART_BASE, true);
    //
    // Handle transmit interrupts.
    //
    if(ui32Ints & UART_INT_TXRDY)
    {
        //
        // Move as many bytes as possible into the transmit FIFO.
        //
        USBUARTPrimeTransmit(USB_UART_BASE);

        //
        // If the output buffer is empty, turn off the transmit interrupt.
        //
        if(!USBBufferDataAvailable(&g_sRxBuffer))
        {
            UARTIntDisable(USB_UART_BASE, UART_INT_TXRDY);
        }
    }

    PieCtrlRegs.PIEACK.all = 0x100;
}

//*****************************************************************************
//
// Interrupt handler for the UART RX which is being redirected via USB.
//
//*****************************************************************************
__interrupt void
USBUARTRXIntHandler(void)
{
    uint32_t u3i2Ints;

    u3i2Ints = UARTIntStatus(USB_UART_BASE, true);
    //
    // Handle receive interrupts.
    //
    if(u3i2Ints & UART_INT_RXRDY_BRKDT)
    {
        //
        // Read the UART's characters into the buffer.
        //
        ReadUARTData();

    }
    else if(u3i2Ints & UART_INT_RXERR)
    {
        //
        //Notify Host of our error
        //
        CheckForSerialStateChange(&g_sCDCDevice, UARTRxErrorGet(USB_UART_BASE));

        //
        //Clear the error and continue
        //
        UARTRxErrorClear(USB_UART_BASE);
    }

    PieCtrlRegs.PIEACK.all = 0x100;

}


//*****************************************************************************
//
// Set the state of the RS232 RTS and DTR signals.
//
//*****************************************************************************
static void
SetControlLineState(uint16_t ui16State)
{
    //
    // TODO: If configured with GPIOs controlling the handshake lines,
    // set them appropriately depending upon the flags passed in the wValue
    // field of the request structure passed.
    //
}

//*****************************************************************************
//
// Set the communication parameters to use on the UART.
//
//*****************************************************************************
static bool
SetLineCoding(tLineCoding *psLineCoding)
{
    uint32_t ui32Config;
    bool bRetcode;

    //
    // Assume everything is OK until we detect any problem.
    //
    bRetcode = true;

    //
    // Word length.  For invalid values, the default is to set 8 bits per
    // character and return an error.
    //
    switch(psLineCoding->ui8Databits)
    {
        case 5:
        {
            ui32Config = UART_CONFIG_WLEN_5;
            break;
        }

        case 6:
        {
            ui32Config = UART_CONFIG_WLEN_6;
            break;
        }

        case 7:
        {
            ui32Config = UART_CONFIG_WLEN_7;
            break;
        }

        case 8:
        {
            ui32Config = UART_CONFIG_WLEN_8;
            break;
        }

        default:
        {
            ui32Config = UART_CONFIG_WLEN_8;
            bRetcode = false;
            break;
        }
    }

    //
    // Parity.  For any invalid values, we set no parity and return an error.
    //
    switch(psLineCoding->ui8Parity)
    {
        case USB_CDC_PARITY_NONE:
        {
            ui32Config |= UART_CONFIG_PAR_NONE;
            break;
        }

        case USB_CDC_PARITY_ODD:
        {
            ui32Config |= UART_CONFIG_PAR_ODD;
            break;
        }

        case USB_CDC_PARITY_EVEN:
        {
            ui32Config |= UART_CONFIG_PAR_EVEN;
            break;
        }

        case USB_CDC_PARITY_MARK:
        {
            ui32Config |= UART_CONFIG_PAR_ONE;
            break;
        }

        case USB_CDC_PARITY_SPACE:
        {
            ui32Config |= UART_CONFIG_PAR_ZERO;
            break;
        }

        default:
        {
            ui32Config |= UART_CONFIG_PAR_NONE;
            bRetcode = false;
            break;
        }
    }

    //
    // Stop bits.  Our hardware only supports 1 or 2 stop bits whereas CDC
    // allows the host to select 1.5 stop bits.  If passed 1.5 (or any other
    // invalid or unsupported value of ui8Stop, we set up for 1 stop bit but
    // return an error in case the caller needs to Stall or otherwise report
    // this back to the host.
    //
    switch(psLineCoding->ui8Stop)
    {
        //
        // One stop bit requested.
        //
        case USB_CDC_STOP_BITS_1:
        {
            ui32Config |= UART_CONFIG_STOP_ONE;
            break;
        }

        //
        // Two stop bits requested.
        //
        case USB_CDC_STOP_BITS_2:
        {
            ui32Config |= UART_CONFIG_STOP_TWO;
            break;
        }

        //
        // Other cases are either invalid values of ui8Stop or values that we
        // cannot support so set 1 stop bit but return an error.
        //
        default:
        {
            ui32Config = UART_CONFIG_STOP_ONE;
            bRetcode |= false;
            break;
        }
    }

    //
    // Set the UART mode appropriately.
    //
    UARTConfigSetExpClk(USB_UART_BASE, SysCtlLowSpeedClockGet(SYSTEM_CLOCK_SPEED),
                            readusb32_t(&(psLineCoding->ui32Rate)), ui32Config);

    //
    // Let the caller know if we had a problem or not.
    //
    return(bRetcode);
}

//*****************************************************************************
//
// Get the communication parameters in use on the UART.
//
//*****************************************************************************
static void
GetLineCoding(tLineCoding *psLineCoding)
{
    uint32_t ui32Config;
    uint32_t ui32Rate;

    //
    // Get the current line coding set in the UART.
    //
    UARTConfigGetExpClk(USB_UART_BASE, SysCtlLowSpeedClockGet(SYSTEM_CLOCK_SPEED),
                        &ui32Rate, &ui32Config);
    writeusb32_t(&(psLineCoding->ui32Rate), ui32Rate);

    //
    // Translate the configuration word length field into the format expected
    // by the host.
    //
    switch(ui32Config & UART_CONFIG_WLEN_MASK)
    {
        case UART_CONFIG_WLEN_8:
        {
            psLineCoding->ui8Databits = 8;
            break;
        }

        case UART_CONFIG_WLEN_7:
        {
            psLineCoding->ui8Databits = 7;
            break;
        }

        case UART_CONFIG_WLEN_6:
        {
            psLineCoding->ui8Databits = 6;
            break;
        }

        case UART_CONFIG_WLEN_5:
        {
            psLineCoding->ui8Databits = 5;
            break;
        }
    }

    //
    // Translate the configuration parity field into the format expected
    // by the host.
    //
    switch(ui32Config & UART_CONFIG_PAR_MASK)
    {
        case UART_CONFIG_PAR_NONE:
        {
            psLineCoding->ui8Parity = USB_CDC_PARITY_NONE;
            break;
        }

        case UART_CONFIG_PAR_ODD:
        {
            psLineCoding->ui8Parity = USB_CDC_PARITY_ODD;
            break;
        }

        case UART_CONFIG_PAR_EVEN:
        {
            psLineCoding->ui8Parity = USB_CDC_PARITY_EVEN;
            break;
        }
    }

    //
    // Translate the configuration stop bits field into the format expected
    // by the host.
    //
    switch(ui32Config & UART_CONFIG_STOP_MASK)
    {
        case UART_CONFIG_STOP_ONE:
        {
            psLineCoding->ui8Stop = USB_CDC_STOP_BITS_1;
            break;
        }

        case UART_CONFIG_STOP_TWO:
        {
            psLineCoding->ui8Stop = USB_CDC_STOP_BITS_2;
            break;
        }
    }
}

//*****************************************************************************
//
// This function sets or clears a break condition on the redirected UART RX
// line.  A break is started when the function is called with \e bSend set to
// \b true and persists until the function is called again with \e bSend set
// to \b false.
//
//*****************************************************************************
static void
SendBreak(bool bSend)
{
	//
	//C28x SCI cannot send break conditions
	//
	return;
}

//*****************************************************************************
//
// Handles CDC driver notifications related to control and setup of the device.
//
// \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 CDC driver to perform control-related
// operations on behalf of the USB host.  These functions include setting
// and querying the serial communication parameters, setting handshake line
// states and sending break conditions.
//
// \return The return value is event-specific.
//
//*****************************************************************************
uint32_t
ControlHandler(void *pvCBData, uint32_t ui32Event,
               uint32_t ui32MsgValue, void *pvMsgData)
{
    uint32_t ui32IntsOff;

    //
    // Which event are we being asked to process?
    //
    switch(ui32Event)
    {
        //
        // We are connected to a host and communication is now possible.
        //
        case USB_EVENT_CONNECTED:
            g_bUSBConfigured = true;

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

            //
            // Tell the main loop to update the display.
            //
            ui32IntsOff = IntMasterDisable();
            g_pcStatus = "Connected";
            g_ui32Flags |= COMMAND_STATUS_UPDATE;
            if(!ui32IntsOff)
            {
                IntMasterEnable();
            }
            break;

        //
        // The host has disconnected.
        //
        case USB_EVENT_DISCONNECTED:
            g_bUSBConfigured = false;
            ui32IntsOff = IntMasterDisable();
            g_pcStatus = "Disconnected";
            g_ui32Flags |= COMMAND_STATUS_UPDATE;
            if(!ui32IntsOff)
            {
                IntMasterEnable();
            }
            break;

        //
        // Return the current serial communication parameters.
        //
        case USBD_CDC_EVENT_GET_LINE_CODING:
            GetLineCoding(pvMsgData);
            break;

        //
        // Set the current serial communication parameters.
        //
        case USBD_CDC_EVENT_SET_LINE_CODING:
            SetLineCoding(pvMsgData);
            break;

        //
        // Set the current serial communication parameters.
        //
        case USBD_CDC_EVENT_SET_CONTROL_LINE_STATE:
            SetControlLineState((uint16_t)ui32MsgValue);
            break;

        //
        // Send a break condition on the serial line.
        //
        case USBD_CDC_EVENT_SEND_BREAK:
            SendBreak(true);
            break;

        //
        // Clear the break condition on the serial line.
        //
        case USBD_CDC_EVENT_CLEAR_BREAK:
            SendBreak(false);
            break;

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

        //
        // We don't expect to receive any other events.  Ignore any that show
        // up in a release build or hang in a debug build.
        //
        default:
#ifdef DEBUG
            while(1);
#else
            break;
#endif

    }

    return(0);
}

//*****************************************************************************
//
// Handles CDC 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 CDC 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)
{
    //
    // Which event have we been sent?
    //
    switch(ui32Event)
    {
        case USB_EVENT_TX_COMPLETE:
            //
            // Since we are using the USBBuffer, we don't need to do anything
            // here.
            //
            break;

        //
        // We don't expect to receive any other events.  Ignore any that show
        // up in a release build or hang in a debug build.
        //
        default:
#ifdef DEBUG
            while(1);
#else
            break;
#endif

    }
    return(0);
}

void
SendDataToUSBHost(void)
{
    if(g_bSendingBreak)
    {
        return;
    }

    //
    // How much space do we have in the buffer?
    //
    USBBuffSpace = USBBufferSpaceAvailable((tUSBBuffer *)&g_sTxBuffer);

    //
    // Get a character from the buffer.
    //
    RxLengthFromHost = USBBufferRead((tUSBBuffer *)&g_sRxBuffer, (uint8_t *)&USBRxBuf, USB_RX_LENGTH);

//    USBBufferWrite((tUSBBuffer *)&g_sTxBuffer,
//                   (uint8_t *)&USBRxBuf, RxLengthFromHost);

    //
    // Did we get a character?
    //
//    while(g_ui32UARTTxCount < RxLengthFromHost)
//    {
//        USBBufferWrite((tUSBBuffer *)&g_sTxBuffer,
//                       (uint8_t *)&USBRxBuf[g_ui32UARTTxCount], 1);
//
//        fUSBWriteCnt ++;
//
//        USBBuffSpace--;
//
//        g_ui32UARTTxCount++;
//
//    }

    g_ui32UARTTxCount = 0;

    return;
}

//*****************************************************************************
//
// Handles CDC driver notifications related to the receive channel (data from
// the USB host).
//
// \param pvCBData is the client-supplied callback data value 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 CDC 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)
{
    uint32_t ui32Count;

    //
    // Which event are we being sent?
    //
    switch(ui32Event)
    {
        //
        // A new packet has been received.
        //
        case USB_EVENT_RX_AVAILABLE:
        {
            //
            // Feed some characters into the UART TX FIFO and enable the
            // interrupt so we are told when there is more space.
            //
//            USBUARTPrimeTransmit(USB_UART_BASE);
//            UARTIntEnable(USB_UART_BASE, UART_INT_TXRDY);
        	SendDataToUSBHost();
            break;
        }

        //
        // We are being asked how much unprocessed data we have still to
        // process. We return 0 if the UART is currently idle or 1 if it is
        // in the process of transmitting something. The actual number of
        // bytes in the UART FIFO is not important here, merely whether or
        // not everything previously sent to us has been transmitted.
        //
        case USB_EVENT_DATA_REMAINING:
        {
            //
            // Get the number of bytes in the buffer and add 1 if some data
            // still has to clear the transmitter.
            //
            ui32Count = UARTBusy(USB_UART_BASE) ? 1 : 0;
            return(ui32Count);
        }

        //
        // We are being asked to provide a buffer into which the next packet
        // can be read. We do not support this mode of receiving data so let
        // the driver know by returning 0. The CDC driver should not be sending
        // this message but this is included just for illustration and
        // completeness.
        //
        case USB_EVENT_REQUEST_BUFFER:
        {
            return(0);
        }

        //
        // We don't expect to receive any other events.  Ignore any that show
        // up in a release build or hang in a debug build.
        //
        default:
#ifdef DEBUG
            while(1);
#else
            break;
#endif
    }

    return(0);
}

//*****************************************************************************
//
// This is the main application entry function.
//
//*****************************************************************************
int
main(void)
{
    uint32_t ui32TxCount;
    uint32_t ui32RxCount;
    char pcBuffer[16];
    volatile uint32_t ui32Fullness;

#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();

    EALLOW;
    // This is needed to write to EALLOW protected registers
    PieVectTable.TIMER0_INT = &cpu_timer0_isr;

    EDIS;

    InitCpuTimers();   // For this example, only initialize the Cpu Timers

//
// Configure CPU-Timer 0, 1, and 2 to interrupt every second:
// 200MHz CPU Freq, 1 second Period (in uSeconds)
//
    ConfigCpuTimer(&CpuTimer0, 200, 1000);

    CpuTimer0Regs.TCR.all = 0x4000;

    IER |= M_INT1;
    PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

    //
    // Configure the required pins for USB operation.
    //
    USBGPIOEnable();
    USBIntRegister(USB0_BASE, f28x_USB0DeviceIntHandler);

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

    //
//    // Enable the UART that we will be redirecting.
//    //
//    SysCtlPeripheralEnable(USB_UART_PERIPH);
//
//    //
//    // 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;
//
//    //
//    // TODO: Add code to configure handshake GPIOs if required.
//    //
//
//    //
//    // Set the default UART configuration.
//    //
//    UARTConfigSetExpClk(USB_UART_BASE, SysCtlLowSpeedClockGet(SYSTEM_CLOCK_SPEED),
//                            DEFAULT_BIT_RATE, DEFAULT_UART_CONFIG);
//    UARTFIFOIntLevelSet(USB_UART_BASE, UART_FIFO_TX4_8, UART_FIFO_RX4_8);
//
//    //
//    // Configure and enable UART interrupts.
//    //
//    UARTIntClear(USB_UART_BASE, UARTIntStatus(USB_UART_BASE, false));
//	UARTIntEnable(USB_UART_BASE, (UART_INT_RXERR | UART_INT_RXRDY_BRKDT |
//                                  UART_INT_TXRDY ));
//	UARTTXIntRegister(USB_UART_BASE, USBUARTTXIntHandler);
//	UARTRXIntRegister(USB_UART_BASE, USBUARTRXIntHandler);
//
//    //
//    // Enable the system tick.
//    //
//    SysTickInit();
//    SysTickPeriodSet(SysCtlClockGet(SYSTEM_CLOCK_SPEED) / SYSTICKS_PER_SECOND);
//    SysTickIntRegister(SysTickIntHandler);
//    SysTickIntEnable();
//    SysTickEnable();

    //
    // Initialize the transmit and receive buffers.
    //
    USBBufferInit(&g_sTxBuffer);
    USBBufferInit(&g_sRxBuffer);

    //
    // Set the USB stack mode to Device mode with VBUS monitoring.
    //
    USBStackModeSet(0, eUSBModeForceDevice, 0);

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

    //
    // Clear our local byte counters.
    //
    ui32RxCount = 0;
    ui32TxCount = 0;

    //
    // Enable interrupts now that the application is ready to start.
    //
    IntEnable(USB_UART_INT);
    IntMasterEnable();

    GPIO_SetupPinMux(15U, GPIO_MUX_CPU1, 0);
    GPIO_SetupPinOptions(15U, GPIO_OUTPUT, GPIO_PUSHPULL);
    GPIO_WritePin(15U, 1);
    //
    // Main application loop.
    //
    while(1)
    {
        //
        // Have we been asked to update the status display?
        //
//        if(g_ui32Flags & COMMAND_STATUS_UPDATE)
//        {
//            //
//            // Clear the command flag
//            //
//            IntMasterDisable();
//            g_ui32Flags &= ~COMMAND_STATUS_UPDATE;
//            IntMasterEnable();
//        }
//
//        //
//        // Has there been any transmit traffic since we last checked?
//        //
//        if(ui32TxCount != g_ui32UARTTxCount)
//        {
//            //
//            // Take a snapshot of the latest transmit count.
//            //
//            ui32TxCount = g_ui32UARTTxCount;
//
//            //
//            // Update the display of bytes transmitted by the UART.
//            //
//            usnprintf(pcBuffer, 16, "%d ", ui32TxCount);
//
//            //
//            // Update the RX buffer fullness. Remember that the buffers are
//            // named relative to the USB whereas the status display is from
//            // the UART's perspective. The USB's receive buffer is the UART's
//            // transmit buffer.
//            //
//            ui32Fullness = ((USBBufferDataAvailable(&g_sRxBuffer) * 100) /
//                          UART_BUFFER_SIZE);
//        }
//
//        //
//        // Has there been any receive traffic since we last checked?
//        //
//        if(ui32RxCount != g_ui32UARTRxCount)
//        {
//            //
//            // Take a snapshot of the latest receive count.
//            //
//            ui32RxCount = g_ui32UARTRxCount;
//
//            //
//            // Update the display of bytes received by the UART.
//            //
//            usnprintf(pcBuffer, 16, "%d ", ui32RxCount);
//
//            //
//            // Update the TX buffer fullness. Remember that the buffers are
//            // named relative to the USB whereas the status display is from
//            // the UART's perspective. The USB's transmit buffer is the UART's
//            // receive buffer.
//            //
//            ui32Fullness = ((USBBufferDataAvailable(&g_sTxBuffer) * 100) /
//                          UART_BUFFER_SIZE);
//        }
    }
}

__interrupt void cpu_timer0_isr(void)
{
	static uint32_t ui32TxCountNum;
    CpuTimer0.InterruptCount++;

    if(RxLengthFromHost != 0)
    {
        UsbTxTest ++;

        if(UsbTxTest > 100)
        {
            UsbTxTest = 0;
        }
        USBTxBuf[8] = UsbTxTest;
        GPIO_WritePin(15U, 1);
        ui32TxCountNum += USBBufferWrite((tUSBBuffer *)&g_sTxBuffer,(uint8_t *)&USBTxBuf,168);
        GPIO_WritePin(15U, 0);
        UsbTxTest2 ++;

        if(UsbTxTest2 == 60000)
        {
            RxLengthFromHost = 0;
            UsbTxTest2 = 0;
        }
    }

    //
    // Acknowledge this interrupt to receive more interrupts from group 1
    //
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
//
// End of file
//