// This code example shows all CDC Function Driver events 
// and a possible scheme for handling these events. In this example
// event responses are not deferred. usbDeviceHandle is obtained while
// opening the USB Device Layer through the USB_DEVICE_Open function.

uint16_t * breakData;
USB_DEVICE_HANDLE    usbDeviceHandle;
USB_CDC_LINE_CODING  lineCoding;
USB_CDC_CONTROL_LINE_STATE * controlLineStateData;

USB_DEVICE_CDC_EVENT_RESPONSE USBDeviceCDCEventHandler
(
    USB_DEVICE_CDC_INDEX instanceIndex, 
    USB_DEVICE_CDC_EVENT event, 
    void * pData,
    uintptr_t userData
)
{
    switch(event)
    {
        case USB_DEVICE_CDC_EVENT_SET_LINE_CODING:

            // In this case, the application should read the line coding
            // data that is sent by the host. The application must use the
            // USB_DEVICE_ControlReceive function to receive the 
            // USB_CDC_LINE_CODING type of data.
            
            USB_DEVICE_ControlReceive(usbDeviceHandle, &lineCoding, sizeof(USB_CDC_LINE_CODING));
            break;

        case USB_DEVICE_CDC_EVENT_GET_LINE_CODING:

            // In this case, the application should send the line coding
            // data to the host. The application must send the 
            // USB_DEVICE_ControlSend function to send the data. 

            USB_DEVICE_ControlSend(usbDeviceHandle, &lineCoding, sizeof(USB_CDC_LINE_CODING));
            break;

        case USB_DEVICE_CDC_EVENT_SET_CONTROL_LINE_STATE:
            
            // In this case, pData should be interpreted as a
            // USB_CDC_CONTROL_LINE_STATE pointer type.  The application
            // acknowledges the parameters by calling the
            // USB_DEVICE_ControlStatus function with the
            // USB_DEVICE_CONTROL_STATUS_OK option.
         
            controlLineStateData = (USB_CDC_CONTROL_LINE_STATE *)pData;
            USB_DEVICE_ControlStatus(usbDeviceHandle, USB_DEVICE_CONTROL_STATUS_OK);   
            break;

        case USB_DEVICE_CDC_EVENT_SEND_BREAK:
           
            // In this case, pData should be interpreted as a uint16_t
            // pointer type to the break duration. The application
            // acknowledges the parameters by calling the
            // USB_DEVICE_ControlStatus() function with the
            // USB_DEVICE_CONTROL_STATUS_OK option.
            
            breakDuration = (uint16_t *)pData; 
            USB_DEVICE_ControlStatus(usbDeviceHandle, USB_DEVICE_CONTROL_STATUS_OK);
            break;

        case USB_DEVICE_CDC_EVENT_CONTROL_TRANSFER_DATA_SENT:

            // This event indicates the data send request associated with
            // the latest USB_DEVICE_ControlSend function was
            // completed.  The application could use this event to track
            // the completion of the USB_DEVICE_CDC_EVENT_GET_LINE_CODING
            // request. 

            break;

        case USB_DEVICE_CDC_EVENT_CONTROL_TRANSFER_DATA_RECEIVED:

            // This event indicates the data that was requested using the
            // USB_DEVICE_ControlReceive function is available for the
            // application to peruse. The application could use this event
            // to track the completion of the
            // USB_DEVICE_CDC_EVENT_SET_LINE_CODING_EVENT event. The
            // application can then either accept the line coding data (as
            // shown here) or decline it by using the
            // USB_DEVICE_CONTROL_STATUS_ERROR flag in the
            // USB_DEVICE_ControlStatus function.
            
            USB_DEVICE_ControlStatus(usbDeviceHandle, USB_DEVICE_CONTROL_STATUS_OK);
            break;
        
        case USB_DEVICE_CDC_EVENT_WRITE_COMPLETE:
            
            // This event indicates that a CDC Write Transfer request has
            // completed.  pData should be interpreted as a 
            // USB_DEVICE_CDC_EVENT_DATA_WRITE_COMPLETE pointer type. This
            // contains the transfer handle of the write transfer that
            // completed and amount of data that was written.

            break;

        case USB_DEVICE_CDC_EVENT_READ_COMPLETE:
            
            // This event indicates that a CDC Read Transfer request has
            // completed.  pData should be interpreted as a 
            // USB_DEVICE_CDC_EVENT_DATA_READ_COMPLETE pointer type. This
            // contains the transfer handle of the read transfer that
            // completed and amount of data that was written.
       
            break;
        
        case USB_DEVICE_CDC_EVENT_SERIAL_STATE_NOTIFICATION_COMPLETE:

            // This event indicates that a CDC Serial State Notification
            // Send request has completed. pData should be interpreted as a
            // USB_DEVICE_CDC_EVENT_DATA_SERIAL_STATE_NOTIFICATION_COMPLETE
            // pointer type. This will contain the transfer handle
            // associated with the send request and the amount of data that
            // was sent.     

        break

         default:
            break;
     }

    return(USB_DEVICE_CDC_EVENT_RESPONSE_NONE);
}