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Device Management (XMEGA)

USB Device definitions for the AVR XMEGA microcontrollers. More...




void USB_Device_SendRemoteWakeup (void)
static uint16_t USB_Device_GetFrameNumber (void) ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT
static void USB_Device_EnableSOFEvents (void) ATTR_ALWAYS_INLINE
static void USB_Device_DisableSOFEvents (void) ATTR_ALWAYS_INLINE

USB Device Mode Option Masks

#define USB_DEVICE_OPT_LOWSPEED   (1 << 0)

Detailed Description

Architecture specific USB Device definitions for the Atmel AVR XMEGA microcontrollers.

Macro Definition Documentation


Length of the device's unique internal serial number, in bits, if present on the selected microcontroller model.


Start address of the internal serial number, in the appropriate address space, if present on the selected microcontroller model.

#define USB_DEVICE_OPT_LOWSPEED   (1 << 0)

Mask for the Options parameter of the USB_Init() function. This indicates that the USB interface should be initialized in low speed (1.5Mb/s) mode.

Low Speed mode is not available on all USB AVR models.
Restrictions apply on the number, size and type of endpoints which can be used when running in low speed mode - refer to the USB 2.0 specification.

String descriptor index for the device's unique serial number string descriptor within the device. This unique serial number is used by the host to associate resources to the device (such as drivers or COM port number allocations) to a device regardless of the port it is plugged in to on the host. Some microcontrollers contain a unique serial number internally, and setting the device descriptors serial number string index to this value will cause it to use the internal serial number.

On unsupported devices, this will evaluate to NO_DESCRIPTOR and so will force the host to create a pseudo-serial number for the device.

Function Documentation

static void USB_Device_DisableSOFEvents ( void  )

Disables the device mode Start Of Frame events. When disabled, this stops the firing of the EVENT_USB_Device_StartOfFrame() event when enumerated in device mode.

This function is not available when the NO_SOF_EVENTS compile time token is defined.
static void USB_Device_EnableSOFEvents ( void  )

Enables the device mode Start Of Frame events. When enabled, this causes the EVENT_USB_Device_StartOfFrame() event to fire once per millisecond, synchronized to the USB bus, at the start of each USB frame when enumerated in device mode.

This function is not available when the NO_SOF_EVENTS compile time token is defined.
static uint16_t USB_Device_GetFrameNumber ( void  )

Returns the current USB frame number, when in device mode. Every millisecond the USB bus is active (i.e. enumerated to a host) the frame number is incremented by one.

Current USB frame number from the USB controller.
void USB_Device_SendRemoteWakeup ( void  )

Sends a Remote Wakeup request to the host. This signals to the host that the device should be taken out of suspended mode, and communications should resume.

Typically, this is implemented so that HID devices (mice, keyboards, etc.) can wake up the host computer when the host has suspended all USB devices to enter a low power state.

This function should only be used if the device has indicated to the host that it supports the Remote Wakeup feature in the device descriptors, and should only be issued if the host is currently allowing remote wakeup events from the device (i.e., the USB_Device_RemoteWakeupEnabled flag is set). When the NO_DEVICE_REMOTE_WAKEUP compile time option is used, this function is unavailable.

The USB clock must be running for this function to operate. If the stack is initialized with the USB_OPT_MANUAL_PLL option enabled, the user must ensure that the PLL is running before attempting to call this function.
See Also
USB Descriptors for more information on the RMWAKEUP feature and device descriptors.