Instance Property

GetFrameListTime

Returns the number of microseconds in each USB Frame.

Declaration

IOReturn (*GetFrameListTime)(void *self, UInt32 *microsecondsInFrame);

Parameters

self

Pointer to the IOUSBInterfaceInterface.

microsecondsInFrame

Pointer to UInt32 to hold the number of microseconds in each USB frame.

Return Value

Returns kIOReturnSuccess if successful, kIOReturnNoDevice if there is no connection to an IOService.

Discussion

This function can be used to determine whether the device is functioning in full speed or a high speed. In the case of a full speed device, the returned value will be kUSBFullSpeedMicrosecondsInFrame. In the case of a high speed device, the return value will be kUSBHighSpeedMicrosecondsInFrame. (This API should really be called GetUSBFrameTime).

The interface does not have to be open to use this function.