USB Events
[USB - LUFA/Drivers/USB/USB.h]


Defines

#define RAISE_EVENT(e,...)   Event_ ## e (__VA_ARGS__)
#define RAISES_EVENT(e)   HANDLES_EVENT(e)
#define EVENT_HANDLER(e)   void Event_ ## e e ## _P
#define HANDLES_EVENT(e)   EVENT_HANDLER(e)

Functions

void USB_VBUSChange (void)
void USB_VBUSConnect (void)
void USB_VBUSDisconnect (void)
void USB_Connect (void)
void USB_Disconnect (void)
void USB_InitFailure (const uint8_t ErrorCode)
void USB_UIDChange (void)
void USB_HostError (const uint8_t ErrorCode)
void USB_DeviceAttached (void)
void USB_DeviceUnattached (void)
void USB_DeviceEnumerationFailed (const uint8_t ErrorCode, const uint8_t SubErrorCode)
void USB_DeviceEnumerationComplete (void)
void USB_UnhandledControlPacket (void)
void USB_ConfigurationChanged (void)
void USB_Suspend (void)
void USB_WakeUp (void)
void USB_Reset (void)
void USB_DeviceError (const uint8_t ErrorCode)

Detailed Description

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 EVENT_HANDLER() and 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.


Define Documentation

#define EVENT_HANDLER (  )     void Event_ ## e e ## _P

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:

  // Create an event handler for the USB_VBUSChange event
  EVENT_HANDLER(USB_VBUSChange)
  {
      // Code to execute when the VBUS level changes
  }

See also:
HANDLES_EVENT()

#define HANDLES_EVENT (  )     EVENT_HANDLER(e)

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 EVENT_HANDLER macro in the module should have an accompanying HANDLES_EVENT prototype in the module's header file.

Usage Examples:

  // Module handles the USB_VBUSChange event
  HANDLES_EVENT(USB_VBUSChange);

  // Create the USB_VBUSChange event handler
  EVENT_HANDLER(USB_VBUSChange)
  {
      // Event handler code here
  }

See also:
EVENT_HANDLER()

#define RAISE_EVENT ( e,
...   )     Event_ ## e (__VA_ARGS__)

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:

  // 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);

See also:
RAISES_EVENT()

#define RAISES_EVENT (  )     HANDLES_EVENT(e)

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 RAISE_EVENT macro in the module should have an accompanying RAISES_EVENT prototype in the module's header file.

Usage Examples:

  // 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);

See also:
RAISE_EVENT()


Function Documentation

void USB_ConfigurationChanged ( void   ) 

Event for USB configuration number changed. This event fires when a the USB host changes the selected configuration number while in device mode. This event should be hooked in device applications to create the endpoints and configure the device for the selected configuration.

This event fires after the value of USB_ConfigurationNumber has been changed.

Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).

void USB_Connect ( 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 RAISE_EVENT(), and the USB_IsConnected global changed manually.
See also:
USBTask.h for more information on the USB management task and reducing CPU usage.

void USB_DeviceAttached ( void   ) 

Event for USB device attachment. This event fires when a the USB interface is in host mode, and a USB device has been connected to the USB interface. This is interrupt driven, thus fires before the standard USB_Connect event and so can be used to programmatically start the USB management task to reduce CPU consumption.

Note:
This event only exists on USB AVR models which supports host mode.

This event does not exist if the USB_DEVICE_ONLY token is supplied to the compiler (see USB Interface Management documentation).

See also:
TASK(USB_USBTask) for more information on the USB management task and reducing CPU usage.

void USB_DeviceEnumerationComplete ( void   ) 

Event for USB device enumeration completion. This event fires when a the USB interface is in host mode and an attached USB device has been completely enumerated and is ready to be controlled by the user application, or when the library is in device mode, and the Host has finished enumerating the device.

void USB_DeviceEnumerationFailed ( const uint8_t  ErrorCode,
const uint8_t  SubErrorCode 
)

Event for USB device enumeration failure. This event fires when a the USB interface is in host mode, and an attached USB device has failed to enumerate completely.

Parameters:
ErrorCode Error code indicating the failure reason, a value in USB_Host_EnumerationErrorCodes_t located in Host.h.
SubErrorCode Sub error code indicating the reason for failure - for example, if the ErrorCode parameter indicates a control error, this will give the error code returned by the USB_Host_SendControlRequest() function.
Note:
This event only exists on USB AVR models which supports host mode.

This event does not exist if the USB_DEVICE_ONLY token is supplied to the compiler (see USB Interface Management documentation).

void USB_DeviceError ( const uint8_t  ErrorCode  ) 

Event for USB device mode error. This event fires when the USB interface is in device mode, and an error occurs which prevents it from operating normally.

Parameters:
ErrorCode Error code indicating the source of the error. One of the values in the USB_Device_ErrorCodes_t enum located in Device.h.
Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).

void USB_DeviceUnattached ( void   ) 

Event for USB device removal. This event fires when a the USB interface is in host mode, and a USB device has been removed the USB interface whether or not it has been enumerated. This can be used to programmatically stop the USB management task to reduce CPU consumption.

Note:
This event only exists on USB AVR models which supports host mode.

This event does not exist if the USB_DEVICE_ONLY token is supplied to the compiler (see USB Interface Management documentation).

See also:
TASK(USB_USBTask) for more information on the USB management task and reducing CPU usage.

void USB_Disconnect ( 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 RAISE_EVENT(), and the USB_IsConnected global changed manually.
See also:
USBTask.h for more information on the USB management task and reducing CPU usage.

void USB_HostError ( const uint8_t  ErrorCode  ) 

Event for USB host error. This event fires when a hardware fault has occurred whilst the USB interface is in host mode.

Parameters:
ErrorCode Error code indicating the failure reason, a value in USB_Host_ErrorCodes_t located in Host.h.
Note:
This event only exists on USB AVR models which supports host mode.

This event does not exist if the USB_DEVICE_ONLY token is supplied to the compiler (see USB Interface Management documentation).

void USB_InitFailure ( const uint8_t  ErrorCode  ) 

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.
Parameters:
ErrorCode Error code indicating the failure reason, a value in USB_InitErrorCodes_t located in LowLevel.h.

void USB_Reset ( void   ) 

Event for USB interface reset. This event fires when a the USB interface is in device mode, and a the USB host requests that the device reset its interface. This is generally hooked so that the USB control endpoint can be switched to interrupt driven mode, by selecting it and calling USB_INT_Enable(ENDPOINT_INT_SETUP). Before this event fires, all device endpoints are reset and disabled.

Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).

void USB_Suspend ( void   ) 

Event for USB suspend. This event fires when a the USB host suspends the device by halting its transmission of Start Of Frame pulses to the device. This is generally hooked in order to move the device over to a low power state until the host wakes up the device.

Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).
See also:
USB_WakeUp() event for accompanying Wake Up event.

void USB_UIDChange ( void   ) 

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.

This event does not exist if the USB_DEVICE_ONLY or USB_HOST_ONLY tokens have been supplied to the compiler (see USB Interface Management documentation).

void USB_UnhandledControlPacket ( void   ) 

Event for unhandled control requests. This event fires when a the USB host issues a control request to the control endpoint (address 0) that the library does not handle. This may either be a standard request that the library has no handler code for, or a class specific request issued to the device which must be handled appropriately. Due to the strict timing requirements on control transfers, interrupts are disabled during control request processing.

Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).

Requests should be handled in the same manner as described in the USB 2.0 Specification, or appropriate class specification. In all instances, the library has already read the request SETUP parameters into the USB_ControlRequest structure which should then be used by the application to determine how to handle the issued request.

void USB_VBUSChange ( void   ) 

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_VBUSConnect ( 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_VBUSDisconnect ( 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_WakeUp ( void   ) 

Event for USB wake up. This event fires when a the USB interface is suspended while in device mode, and the host wakes up the device by supplying Start Of Frame pulses. This is generally hooked to pull the user application out of a lowe power state and back into normal operating mode.

Note:
This event does not exist if the USB_HOST_ONLY token is supplied to the compiler (see USB Interface Management documentation).
See also:
USB_Suspend() event for accompanying Suspend event.


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