//*****************************************************************************
//
// This function must be called periodically from the main loop of the
// application to handle connection and disconnection of the USB keyboard.
//
//*****************************************************************************
void USBKeyboardProcess(void)
{
    //
    // Periodically call the main loop for the Host controller driver.
    //
    USBHCDMain();

    switch(g_eUSBState)
    {
        //
        // This state is entered when they keyboard is first detected.
        //
        case STATE_KEYBOARD_INIT:
        {
            //
            // Initialized the newly connected keyboard.
            //
            USBHKeyboardInit(g_ulKeyboardInstance);

            //
            // Proceed to the keyboard connected state.
            //
            g_eUSBState = STATE_KEYBOARD_CONNECTED;

            break;
        }

        default:
        {
            break;
        }
    }
}
//*****************************************************************************
//
// The main routine for handling the USB keyboard.
//
//*****************************************************************************
void
KeyboardMain(void)
{
    switch(g_iKeyboardState)
    {
        //
        // This state is entered when they keyboard is first detected.
        //
        case eStateKeyboardInit:
        {
            //
            // Initialized the newly connected keyboard.
            //
            USBHKeyboardInit(g_psKeyboard);

            //
            // Proceed to the keyboard connected state.
            //
            g_iKeyboardState = eStateKeyboardConnected;

            //
            // Set the current state of the modifiers.
            //
            USBHKeyboardModifierSet(g_psKeyboard, g_sStatus.ui32Modifiers);

            break;
        }
        case eStateKeyboardUpdate:
        {
            //
            // If the application detected a change that required an
            // update to be sent to the keyboard to change the modifier
            // state then call it and return to the connected state.
            //
            g_iKeyboardState = eStateKeyboardConnected;

            USBHKeyboardModifierSet(g_psKeyboard, g_sStatus.ui32Modifiers);

            //
            // Update the modifier status.
            //
            UIUpdateStatus();

            break;
        }
        case eStateKeyboardConnected:
        default:
        {
            break;
        }
    }
}
//*****************************************************************************
//
// This is the main loop that runs the application.
//
//*****************************************************************************
int
main(void)
{
    tRectangle sRect;
    tUSBMode eLastMode;
    char *pcString;

    //
    // Enable lazy stacking for interrupt handlers.  This allows floating-point
    // instructions to be used within interrupt handlers, but at the expense of
    // extra stack usage.
    //
    ROM_FPULazyStackingEnable();

    //
    // Set the system clock to run at 50MHz from the PLL.
    //
    ROM_SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |
                       SYSCTL_XTAL_16MHZ);

    //
    // Initially wait for device connection.
    //
    g_eUSBState = STATE_NO_DEVICE;
    eLastMode = USB_MODE_OTG;
    g_eCurrentUSBMode = USB_MODE_OTG;

    //
    // Enable Clocking to the USB controller.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_USB0);
    
    //
    // Configure the required pins for USB operation.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOG);
    ROM_GPIOPinConfigure(GPIO_PG4_USB0EPEN);
    ROM_GPIOPinTypeUSBDigital(GPIO_PORTG_BASE, GPIO_PIN_4);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOL);
    ROM_GPIOPinTypeUSBAnalog(GPIO_PORTL_BASE, GPIO_PIN_6 | GPIO_PIN_7);
    ROM_GPIOPinTypeUSBAnalog(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Configure SysTick for a 100Hz interrupt.
    //
    ROM_SysTickPeriodSet(ROM_SysCtlClockGet() / TICKS_PER_SECOND);
    ROM_SysTickEnable();
    ROM_SysTickIntEnable();

    //
    // Enable Interrupts
    //
    ROM_IntMasterEnable();

    //
    // Enable clocking to the UART and associated GPIO
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

    //
    // Configure the relevant pins such that UART0 owns them.
    //
    ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Open UART0 for debug output.
    //
    UARTStdioInit(0);

    //
    // Initialize the USB stack mode and pass in a mode callback.
    //
    USBStackModeSet(0, USB_MODE_OTG, ModeCallback);

    //
    // Register the host class drivers.
    //
    USBHCDRegisterDrivers(0, g_ppHostClassDrivers, g_ulNumHostClassDrivers);

    //
    // Open an instance of the keyboard driver.  The keyboard does not need
    // to be present at this time, this just save a place for it and allows
    // the applications to be notified when a keyboard is present.
    //
    g_ulKeyboardInstance = USBHKeyboardOpen(KeyboardCallback, g_pucBuffer,
                                            KEYBOARD_MEMORY_SIZE);

    //
    // Initialize the power configuration. This sets the power enable signal
    // to be active high and does not enable the power fault.
    //
    USBHCDPowerConfigInit(0, USBHCD_VBUS_AUTO_HIGH | USBHCD_VBUS_FILTER);

    //
    // Initialize the USB controller for OTG operation with a 2ms polling
    // rate.
    //
    USBOTGModeInit(0, 2000, g_pHCDPool, HCD_MEMORY_SIZE);

    //
    // Initialize the display driver.
    //
    CFAL96x64x16Init();

    //
    // Initialize the graphics context.
    //
    GrContextInit(&g_sContext, &g_sCFAL96x64x16);

    //
    // Fill the top part of the screen with blue to create the banner.
    //
    sRect.sXMin = 0;
    sRect.sYMin = 0;
    sRect.sXMax = GrContextDpyWidthGet(&g_sContext) - 1;
    sRect.sYMax = (2 * DISPLAY_BANNER_HEIGHT) - 1;
    GrContextForegroundSet(&g_sContext, DISPLAY_BANNER_BG);
    GrRectFill(&g_sContext, &sRect);

    //
    // Change foreground for white text.
    //
    GrContextForegroundSet(&g_sContext, DISPLAY_TEXT_FG);

    //
    // Put the application name in the middle of the banner.
    //
    GrContextFontSet(&g_sContext, g_pFontFixed6x8);
    GrStringDrawCentered(&g_sContext, "usb-host-", -1,
                         GrContextDpyWidthGet(&g_sContext) / 2, 4, 0);
    GrStringDrawCentered(&g_sContext, "keyboard", -1,
                             GrContextDpyWidthGet(&g_sContext) / 2, 14, 0);


    //
    // Calculate the number of characters that will fit on a line.
    // Make sure to leave a small border for the text box.
    //
    g_ulCharsPerLine = (GrContextDpyWidthGet(&g_sContext) - 4) /
                        GrFontMaxWidthGet(g_pFontFixed6x8);

    //
    // Calculate the number of lines per usable text screen.  This requires
    // taking off space for the top and bottom banners and adding a small bit
    // for a border.
    //
    g_ulLinesPerScreen = (GrContextDpyHeightGet(&g_sContext) -
                          (3*(DISPLAY_BANNER_HEIGHT + 1)))/
                          GrFontHeightGet(g_pFontFixed6x8);

    //
    // Open and instance of the keyboard class driver.
    //
    UARTprintf("Host Keyboard Application\n");

    //
    // Initial update of the screen.
    //
    UpdateStatus();

    //
    // The main loop for the application.
    //
    while(1)
    {
        //
        // Tell the OTG library code how much time has passed in
        // milliseconds since the last call.
        //
        USBOTGMain(GetTickms());

        //
        // Has the USB mode changed since last time we checked?
        //
        if(g_eCurrentUSBMode != eLastMode)
        {
            //
            // Remember the new mode.
            //
            eLastMode = g_eCurrentUSBMode;

            switch(eLastMode)
            {
                case USB_MODE_HOST:
                    pcString = "HOST";
                    break;

                case USB_MODE_DEVICE:
                    pcString = "DEVICE";
                    break;

                case USB_MODE_NONE:
                    pcString = "NONE";
                    break;

                default:
                    pcString = "UNKNOWN";
                    break;
            }

            UARTprintf("USB mode changed to %s\n", pcString);
        }

        switch(g_eUSBState)
        {
            //
            // This state is entered when they keyboard is first detected.
            //
            case STATE_KEYBOARD_INIT:
            {
                //
                // Initialized the newly connected keyboard.
                //
                USBHKeyboardInit(g_ulKeyboardInstance);

                //
                // Proceed to the keyboard connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                //
                // Update the screen now that the keyboard has been
                // initialized.
                //
                UpdateStatus();

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }
            case STATE_KEYBOARD_UPDATE:
            {
                //
                // If the application detected a change that required an
                // update to be sent to the keyboard to change the modifier
                // state then call it and return to the connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }
            case STATE_KEYBOARD_CONNECTED:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is connected.
                //
                break;
            }

            case STATE_UNKNOWN_DEVICE:
            {
                //
                // Nothing to do as the device is unknown.
                //
                break;
            }

            case STATE_NO_DEVICE:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is not connected.
                //
                break;
            }
            default:
            {
                break;
            }
        }
    }
}
//*****************************************************************************
//
// This is the main loop that runs the application.
//
//*****************************************************************************
int
main(void)
{
    tRectangle sRect;

    //
    // Set the clocking to run directly from the crystal.
    //
    SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_8MHZ);

    //
    // Enable the peripherals used by this example.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

    //
    // Configure the relevant pins such that UART0 owns them.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Open UART0 for debug output.
    //
    UARTStdioInit(0);

    //
    // Enable the USB mux GPIO.
    //
    SysCtlPeripheralEnable(USB_MUX_GPIO_PERIPH);

    //
    // The LM3S3748 board uses a USB mux that must be switched to use the
    // host connector and not the device connector.
    //
    GPIOPinTypeGPIOOutput(USB_MUX_GPIO_BASE, USB_MUX_GPIO_PIN);
    GPIOPinWrite(USB_MUX_GPIO_BASE, USB_MUX_GPIO_PIN, USB_MUX_SEL_HOST);

    //
    // Configure the power pins for host controller.
    //
    GPIOPinTypeUSBDigital(GPIO_PORTH_BASE, GPIO_PIN_3 | GPIO_PIN_4);

    //
    // Initialize the display driver.
    //
    Formike128x128x16Init();

    //
    // Turn on the backlight.
    //
    Formike128x128x16BacklightOn();

    //
    // Initialize the graphics context.
    //
    GrContextInit(&g_sContext, &g_sFormike128x128x16);

    //
    // Fill the top 15 rows of the screen with blue to create the banner.
    //
    sRect.sXMin = 0;
    sRect.sYMin = 0;
    sRect.sXMax = GrContextDpyWidthGet(&g_sContext) - 1;
    sRect.sYMax = DISPLAY_BANNER_HEIGHT;
    GrContextForegroundSet(&g_sContext, DISPLAY_BANNER_BG);
    GrRectFill(&g_sContext, &sRect);

    //
    // Put a white box around the banner.
    //
    GrContextForegroundSet(&g_sContext, ClrWhite);
    GrRectDraw(&g_sContext, &sRect);

    //
    // Put the application name in the middle of the banner.
    //
    GrContextFontSet(&g_sContext, g_pFontFixed6x8);
    GrStringDrawCentered(&g_sContext, "usb_host_keyboard", -1,
                         GrContextDpyWidthGet(&g_sContext) / 2, 7, 0);

    //
    // Calculate the number of characters that will fit on a line.
    // Make sure to leave a small border for the text box.
    //
    g_ulCharsPerLine = (GrContextDpyWidthGet(&g_sContext) - 4) /
                        GrFontMaxWidthGet(g_pFontFixed6x8);

    //
    // Calculate the number of lines per usable text screen.  This requires
    // taking off space for the top and bottom banners and adding a small bit
    // for a border.
    //
    g_ulLinesPerScreen = (GrContextDpyHeightGet(&g_sContext) -
                          (2*(DISPLAY_BANNER_HEIGHT + 1)))/
                          GrFontHeightGet(g_pFontFixed6x8);

    //
    // Register the host class drivers.
    //
    USBHCDRegisterDrivers(0, g_ppHostClassDrivers, g_ulNumHostClassDrivers);

    //
    // Open and instance of the keyboard class driver.
    //
    UARTprintf("Host Keyboard Application\n");

    //
    // Open an instance of the keyboard driver.  The keyboard does not need
    // to be present at this time, this just save a place for it and allows
    // the applications to be notified when a keyboard is present.
    //
    g_ulKeyboardInstance = USBHKeyboardOpen(KeyboardCallback, g_pucBuffer,
                                            KEYBOARD_MEMORY_SIZE);

    //
    // Initialize the power configuration. This sets the power enable signal
    // to be active high and does not enable the power fault.
    //
    USBHCDPowerConfigInit(0, USBHCD_VBUS_AUTO_HIGH);

    //
    // Initialize the host controller stack.
    //
    USBHCDInit(0, g_pHCDPool, HCD_MEMORY_SIZE);

    //
    // Call the main loop for the Host controller driver.
    //
    USBHCDMain();

    //
    // Initial update of the screen.
    //
    UpdateStatus();

    //
    // The main loop for the application.
    //
    while(1)
    {
        switch(g_eUSBState)
        {
            //
            // This state is entered when they keyboard is first detected.
            //
            case STATE_KEYBOARD_INIT:
            {
                //
                // Initialized the newly connected keyboard.
                //
                USBHKeyboardInit(g_ulKeyboardInstance);

                //
                // Proceed to the keyboard connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                //
                // Update the screen now that the keyboard has been
                // initialized.
                //
                UpdateStatus();

                break;
            }
            case STATE_KEYBOARD_UPDATE:
            {
                //
                // If the application detected a change that required an
                // update to be sent to the keyboard to change the modifier
                // state then call it and return to the connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }
            case STATE_KEYBOARD_CONNECTED:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is connected.
                //
                break;
            }
            case STATE_UNKNOWN_DEVICE:
            {
                //
                // Nothing to do as the device is unknown.
                //
                break;
            }
            case STATE_NO_DEVICE:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is not connected.
                //
                break;
            }
            default:
            {
                break;
            }
        }

        //
        // Periodic call the main loop for the Host controller driver.
        //
        USBHCDMain();
    }
}
Esempio n. 5
0
//*****************************************************************************
//
// This is the main loop that runs the application.
//
//*****************************************************************************
int
main(void)
{
    tRectangle sRect;
    unsigned int i;
    unsigned char *src, *dest;

    //
    //configures arm interrupt controller to generate raster interrupt 
    //
    SetupIntc();

    //
    //Configures raster to display image 
    //
    SetUpLCD();

    /* configuring the base ceiling */
    RasterDMAFBConfig(SOC_LCDC_0_REGS, 
                      (unsigned int)(g_pucBuffer+PALETTE_OFFSET),
                      (unsigned int)(g_pucBuffer+PALETTE_OFFSET) + sizeof(g_pucBuffer) - 2 - PALETTE_OFFSET,
                      0);

    RasterDMAFBConfig(SOC_LCDC_0_REGS, 
                      (unsigned int)(g_pucBuffer+PALETTE_OFFSET),
                      (unsigned int)(g_pucBuffer+PALETTE_OFFSET) + sizeof(g_pucBuffer) - 2 - PALETTE_OFFSET,
                      1);

    // Copy palette info into buffer
    src = (unsigned char *) palette_32b;
    dest = (unsigned char *) (g_pucBuffer+PALETTE_OFFSET);
    
    for( i = 4; i < (PALETTE_SIZE+4); i++)
    {
        *dest++ = *src++;
    }

    GrOffScreen16BPPInit(&g_sSHARP480x272x16Display, g_pucBuffer, LCD_WIDTH, LCD_HEIGHT);
    GrContextInit(&g_sContext, &g_sSHARP480x272x16Display);

    /* enable End of frame interrupt */
    RasterEndOfFrameIntEnable(SOC_LCDC_0_REGS);

    /* enable raster */
    RasterEnable(SOC_LCDC_0_REGS);
    ConfigRasterDisplayEnable();

    //
    // Fill the top 15 rows of the screen with blue to create the banner.
    //
    sRect.sXMin = 0;
    sRect.sYMin = 0;
    sRect.sXMax = GrContextDpyWidthGet(&g_sContext) - 1;
    sRect.sYMax = DISPLAY_BANNER_HEIGHT;

    //
    // Set the banner background.
    //
    GrContextForegroundSet(&g_sContext, DISPLAY_BANNER_BG);
    GrRectFill(&g_sContext, &sRect);

    //
    // Put a white box around the banner.
    //
    GrContextForegroundSet(&g_sContext, ClrWhite);
    GrRectDraw(&g_sContext, &sRect);

    //
    // Put the application name in the middle of the banner.
    //
    GrContextFontSet(&g_sContext, &g_sFontCm20);
    GrStringDrawCentered(&g_sContext, "usb host keyboard", -1,
                         GrContextDpyWidthGet(&g_sContext) / 2, 10, 0);

    //
    //Setup the interrupt controller
    //
#ifdef _TMS320C6X
    SetupDSPINTCInt();
    ConfigureDSPINTCIntUSB();
#else
    SetupAINTCInt(); 
    ConfigureAINTCIntUSB();
#endif
    
    DelayTimerSetup();
    
    //
    // Calculate the number of characters that will fit on a line.
    // Make sure to leave a small border for the text box.
    //
    g_ulCharsPerLine = (GrContextDpyWidthGet(&g_sContext) - 4) /
                        GrFontMaxWidthGet(&g_sFontCm20);

    //
    // Calculate the number of lines per usable text screen.  This requires
    // taking off space for the top and bottom banners and adding a small bit
    // for a border.
    //
    g_ulLinesPerScreen = (GrContextDpyHeightGet(&g_sContext) -
                          (2*(DISPLAY_BANNER_HEIGHT + 1)))/
                          GrFontHeightGet(&g_sFontCm20);


    //
    // Register the host class drivers.
    //
    USBHCDRegisterDrivers(0, g_ppHostClassDrivers, g_ulNumHostClassDrivers);

    // Open an instance of the keyboard driver.  The keyboard does not need
    // to be present at this time, this just save a place for it and allows
    // the applications to be notified when a keyboard is present.
    //
    g_ulKeyboardInstance = USBHKeyboardOpen(KeyboardCallback, g_pucBuffer,
                                            KEYBOARD_MEMORY_SIZE);

    //
    // Initialize the power configuration. This sets the power enable signal
    // to be active high and does not enable the power fault.
    //
    USBHCDPowerConfigInit(0, USBHCD_VBUS_AUTO_HIGH);

    //
    // Initialize the host controller stack.
    //
    USBHCDInit(0, g_pHCDPool, HCD_MEMORY_SIZE);

    //
    // Call the main loop for the Host controller driver.
    //
    USBHCDMain();

    //
    // Initial update of the screen.
    //
    UpdateStatus();

    //
    // The main loop for the application.
    //
    while(1)
    {
        switch(g_eUSBState)
        {
            //
            // This state is entered when they keyboard is first detected.
            //
            case STATE_KEYBOARD_INIT:
            {
                //
                // Initialized the newly connected keyboard.
                //
                USBHKeyboardInit(g_ulKeyboardInstance);

                //
                // Proceed to the keyboard connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                //
                // Update the screen now that the keyboard has been
                // initialized.
                //
                UpdateStatus();

                break;
            }
            case STATE_KEYBOARD_UPDATE:
            {
                //
                // If the application detected a change that required an
                // update to be sent to the keyboard to change the modifier
                // state then call it and return to the connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }
            case STATE_KEYBOARD_CONNECTED:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is connected.
                //
                break;
            }
            case STATE_UNKNOWN_DEVICE:
            {
                //
                // Nothing to do as the device is unknown.
                //
                break;
            }
            case STATE_NO_DEVICE:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is not connected.
                //
                break;
            }
            default:
            {
                break;
            }
        }

        //
        // Periodic call the main loop for the Host controller driver.
        //
        USBHCDMain();
    }
}
//*****************************************************************************
//
// This is the main loop that runs the application.
//
//*****************************************************************************
int
main(void)
{
    //
    // Set the clocking to run from the PLL at 50MHz.
    //
    ROM_SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN |
                       SYSCTL_XTAL_16MHZ);

    //
    // Enable the peripherals used by this example.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOH);

    //
    // Enable the UART.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    UARTStdioInit(0);
    UARTprintf("\033[2JHost Keyboard Application\n");

    //
    // Configure SysTick for a 100Hz interrupt.
    //
    ROM_SysTickPeriodSet(ROM_SysCtlClockGet() / TICKS_PER_SECOND);
    ROM_SysTickEnable();
    ROM_SysTickIntEnable();

    //
    // Enable Clocking to the USB controller.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_USB0);

    //
    // Configure the power pins for host controller.
    //
    GPIOPinConfigure(GPIO_PH3_USB0EPEN);
    GPIOPinConfigure(GPIO_PH4_USB0PFLT);
    ROM_GPIOPinTypeUSBDigital(GPIO_PORTH_BASE, GPIO_PIN_3 | GPIO_PIN_4);

    //
    // Initially wait for device connection.
    //
    g_eUSBState = STATE_NO_DEVICE;

    //
    // Initialize the USB stack mode and pass in a mode callback.
    //
    USBStackModeSet(0, USB_MODE_OTG, ModeCallback);

    //
    // Register the host class drivers.
    //
    USBHCDRegisterDrivers(0, g_ppHostClassDrivers, g_ulNumHostClassDrivers);

    //
    // Open an instance of the keyboard driver.  The keyboard does not need
    // to be present at this time, this just save a place for it and allows
    // the applications to be notified when a keyboard is present.
    //
    g_ulKeyboardInstance = USBHKeyboardOpen(KeyboardCallback, g_pucBuffer,
                                            KEYBOARD_MEMORY_SIZE);

    //
    // Initialize the power configuration. This sets the power enable signal
    // to be active high and does not enable the power fault.
    //
    USBHCDPowerConfigInit(0, USBHCD_VBUS_AUTO_HIGH | USBHCD_VBUS_FILTER);

    //
    // Initialize the USB controller for OTG operation with a 2ms polling
    // rate.
    //
    USBOTGModeInit(0, 2000, g_pHCDPool, HCD_MEMORY_SIZE);

    //
    // The main loop for the application.
    //
    while(1)
    {
        //
        // Tell the OTG state machine how much time has passed in
        // milliseconds since the last call.
        //
        USBOTGMain(GetTickms());

        switch(g_eUSBState)
        {
            //
            // This state is entered when they keyboard is first detected.
            //
            case STATE_KEYBOARD_INIT:
            {
                //
                // Initialized the newly connected keyboard.
                //
                USBHKeyboardInit(g_ulKeyboardInstance);

                //
                // Proceed to the keyboard connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }

            case STATE_KEYBOARD_UPDATE:
            {
                //
                // If the application detected a change that required an
                // update to be sent to the keyboard to change the modifier
                // state then call it and return to the connected state.
                //
                g_eUSBState = STATE_KEYBOARD_CONNECTED;

                USBHKeyboardModifierSet(g_ulKeyboardInstance, g_ulModifiers);

                break;
            }

            case STATE_KEYBOARD_CONNECTED:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is connected.
                //
                break;
            }

            case STATE_UNKNOWN_DEVICE:
            {
                //
                // Nothing to do as the device is unknown.
                //
                break;
            }

            case STATE_NO_DEVICE:
            {
                //
                // Nothing is currently done in the main loop when the keyboard
                // is not connected.
                //
                break;
            }

            default:
            {
                break;
            }
        }
    }
}