events.h

LUFA (Lightweight USB Framework for AVRs) is my first foray into the world of USB. Originally based

/*
             LUFA Library
     Copyright (C) Dean Camera, 2009.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, and distribute this software
  and its documentation for any purpose and without fee is hereby
  granted, provided that the above copyright notice appear in all
  copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \ingroup Group_USB
 *  @defgroup Group_Events USB Events
 *
 *  This module contains macros and functions relating to the management of library events, which are small
 *  pieces of code similar to ISRs which are run when a given condition is met. Each event can be fired from
 *  multiple places in the user or library code, which may or may not be inside an ISR, thus each handler
 *  should be written to be as small and fast as possible to prevent possible problems.
 *
 *  Events can be hooked by the user application using the \ref EVENT_HANDLER() and \ref HANDLES_EVENT() macros. If an
 *  event with no associated handler is fired within the library, it by default fires an internal empty stub
 *  function. This is achieved through the use of the GCC compiler's "alias" attribute.
 *
 *  Each event must only have one associated event handler, but can be raised by multiple sources.
 *
 *  @{
 */
 
#ifndef __USBEVENTS_H__
#define __USBEVENTS_H__

	/* Includes: */
		#include <avr/io.h>
		
		#include "../../../Common/Common.h"
		#include "USBMode.h"

	/* Enable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			extern "C" {
		#endif

	/* Public Interface - May be used in end-application: */
		/* Macros: */
			/** Raises a given event name, with the specified parameters. For events with no parameters the
			 *  only argument to the macro is the event name, events with parameters list the parameter values
			 *  after the name as a comma separated list.
			 *
			 *  When a given event is fired, its corresponding event handler code is executed.
			 *
			 *  Usage Examples:
			 *  \code
			 *  // Raise the USB_VBUSChange event, which takes no parameters
			 *  RAISE_EVENT(USB_VBUSChange);
			 *
			 *  // Raise the USB_UnhandledControlPacket event which takes two parameters
			 *  RAISE_EVENT(USB_UnhandledControlPacket, 0, 1);
			 *  \endcode
			 *
			 *  \see RAISES_EVENT()
			 */
			#define RAISE_EVENT(e, ...)                 Event_ ## e (__VA_ARGS__)

			/** Indicates that a given module can raise a given event. This is the equivalent of putting the
			 *  event function's prototype into the module, but in a cleaner way. Each event which may be
			 *  fired via the \ref RAISE_EVENT macro in the module should have an accompanying \ref RAISES_EVENT
			 *  prototype in the module's header file.
			 *
			 *  Usage Examples:
			 *  \code
			 *  // Module can raise the USB_VBUSChange event
			 *  RAISES_EVENT(USB_VBUSChange);
			 *
			 *  // ...
			 *  // Inside a block of code in a function of the module, raise the USB_VBUSChange event
			 *  RAISE_EVENT(USB_VBUSChange);
			 *  \endcode
			 *
			 *  \see RAISE_EVENT()
			 */
			#define RAISES_EVENT(e)                     HANDLES_EVENT(e)

			/** Defines an event handler for the given event. Event handlers should be short in length, as they
			 *  may be raised from inside an ISR. The user application can react to each event as it sees fit,
			 *  such as logging the event, indicating the change to the user or performing some other action.
			 *
			 *  Only one event handler may be defined in any user project for each individual event. Events may
			 *  or may not have parameters - for each event, refer to its documentation elsewhere in this module
			 *  to determine the presence and purpose of any event parameters.
			 *
			 *  Usage Example:
			 *  \code
			 *  // Create an event handler for the USB_VBUSChange event
			 *  EVENT_HANDLER(USB_VBUSChange)
			 *  {
			 *      // Code to execute when the VBUS level changes
			 *  }
			 *  \endcode
			 *
			 *  \see HANDLES_EVENT()
			 */
			#define EVENT_HANDLER(e)                    void Event_ ## e e ## _P
			
			/** Indicates that a given module handles an event. This is the equivalent of putting the
			 *  event function's prototype into the module, but in a cleaner way. Each event which may be
			 *  handled via the \ref EVENT_HANDLER macro in the module should have an accompanying \ref HANDLES_EVENT
			 *  prototype in the module's header file.
			 *
			 *  Usage Examples:
			 *  \code
			 *  // Module handles the USB_VBUSChange event
			 *  HANDLES_EVENT(USB_VBUSChange);
			 *
			 *  // Create the USB_VBUSChange event handler
			 *  EVENT_HANDLER(USB_VBUSChange)
			 *  {
			 *      // Event handler code here
			 *  }
			 *  \endcode
			 *
			 *  \see EVENT_HANDLER()
			 */
			#define HANDLES_EVENT(e)                    EVENT_HANDLER(e)
			
		/* Pseudo-Functions for Doxygen: */
		#if defined(__DOXYGEN__)
			/** Event for VBUS level change. This event fires when the VBUS line of the USB AVR changes from
			 *  high to low or vice-versa.
			 *
			 *  \note This event is only available on USB AVR models which support VBUS notification interrupts.
			 */
			void USB_VBUSChange(void);

			/** Event for VBUS attachment. This event fires when the VBUS line of the USB AVR changes from
			 *  low to high, signalling the attachment of the USB device to a host, before the enumeration
			 *  process has begun.
			 *
			 *  \note This event is only available on USB AVR models which support VBUS notification interrupts.
			 */
			void USB_VBUSConnect(void);

			/** Event for VBUS detachment. This event fires when the VBUS line of the USB AVR changes from
			 *  high to low, signalling the USB device has been removed from a host whether it has been enumerated
			 *  or not.
			 *
			 *  \note This event is only available on USB AVR models which support VBUS notification interrupts.
			 */
			void USB_VBUSDisconnect(void);

			/** Event for USB device connection. This event fires when the AVR is in USB host mode and a device
			 *  has been attached (but not yet fully enumerated), or when in device mode and the device is connected
			 *  to a host, beginning the enumeration process.
			 *
			 *  When in device mode, this can be used to programmatically start the USB management task to reduce
			 *  CPU usage.
			 *
			 *  \note For the smaller USB AVRs (AT90USBXX2) with limited USB controllers, VBUS is not available to the USB controller.
			 *        this means that the current connection state is derived from the bus suspension and wake up events by default,
			 *        which is not always accurate (host may suspend the bus while still connected). If the actual connection state
			 *        needs to be determined, VBUS should be routed to an external pin, and the auto-detect behaviour turned off by
			 *        passing the NO_LIMITED_CONTROLLER_CONNECT token to the compiler via the -D switch at compile time. The connection
			 *        and disconnection events may be manually fired by \ref RAISE_EVENT(), and the \ref USB_IsConnected global changed manually.
			 *
			 *  \see USBTask.h for more information on the USB management task and reducing CPU usage.
			 */
			void USB_Connect(void);

			/** Event for USB device disconnection. This event fires when the AVR is in USB host mode and an
			 *  attached and enumerated device has been disconnected, or when in device mode and the device is
			 *  disconnected from the host.
			 *
			 *  When in device mode, this can be used to programmatically stop the USB management task to reduce
			 *  CPU usage.
			 *
			 *  \note For the smaller USB AVRs (AT90USBXX2) with limited USB controllers, VBUS is not available to the USB controller.
			 *        this means that the current connection state is derived from the bus suspension and wake up events by default,
			 *        which is not always accurate (host may suspend the bus while still connected). If the actual connection state
			 *        needs to be determined, VBUS should be routed to an external pin, and the auto-detect behaviour turned off by
			 *        passing the NO_LIMITED_CONTROLLER_CONNECT token to the compiler via the -D switch at compile time. The connection
			 *        and disconnection events may be manually fired by \ref RAISE_EVENT(), and the \ref USB_IsConnected global changed manually.
			 *
			 *  \see USBTask.h for more information on the USB management task and reducing CPU usage.
			 */
			void USB_Disconnect(void);
			
			/** Event for USB initialization failure. This event fires when the USB interface fails to
			 *  initialize correctly due to a hardware or software fault.
			 *
			 *  \note This event only exists on USB AVR models which support dual role modes.
			 *
			 *  \param ErrorCode  Error code indicating the failure reason, a value in \ref USB_InitErrorCodes_t
			 *                    located in LowLevel.h.
			 */
			void USB_InitFailure(const uint8_t ErrorCode);

			/** Event for USB mode pin level change. This event fires when the USB interface is set to dual role
			 *  mode, and the UID pin level has changed to indicate a new mode (device or host). This event fires
			 *  before the mode is switched to the newly indicated mode.
			 *
			 *  \note This event only exists on USB AVR models which support dual role modes.
			 *
			 *  \note This event does not exist if the USB_DEVICE_ONLY or USB_HOST_ONLY tokens have been supplied
			 *        to the compiler (see \ref Group_USBManagement documentation).