Motorola USB08 - Manual (Page 210)

Designer Reference Manual USB08 Evaluation Board
210 Universal USB Device Driver (USBIO) MOTOROLA
Universal USB Device Driver (USBIO)
USBIO_ISO_TRANSFER
The USBIO_ISO_TRANSFER structure provides information used for
isochronous data transfers.
Definition typedef struct _USBIO_ISO_TRANSFER{
ULONG NumberOfPackets;
ULONG Flags;
ULONG StartFrame;
ULONG ErrorCount;
} USBIO_ISO_TRANSFER;
Members NumberOfPackets
Specifies the number of packets to be sent to or received from the
device. Each packet corresponds to an USB frame. The maximum
number of packets in a read or write operation is limited by the registry
parameter
MaxIsoPackets .
Flags
This field contains zero or any combination (bit-wise or) of the
following values.
USBIO_SHORT_TRANSFER_OK
If this flag is set, the USBIO driver does not return an error if a data
packet received from the device is shorter than the maximum
packet size of the endpoint. Otherwise, a short packet causes an
error condition.
USBIO_START_TRANSFER_ASAP
If this flag is set, the transfer will be started as soon as possible
and the
StartFrame parameter is ignored. This flag has to be
used if a continuous data stream shall be sent to the isochronous
endpoint of the USB device.
StartFrame
Specifies the frame number the transfer shall start with. The value has
to be within a system-defined range relative to the current frame. The
range is normally set to 1024 frames.
If USBIO_START_TRANSFER_ASAP is specified in Flags , this
member has not to be set by the caller. It contains the frame number
that the transfer started with, when the request is returned by the
USBIO.