Designer Reference Manual USB08 Evaluation Board
212 Universal USB Device Driver (USBIO) MOTOROLA
Universal USB Device Driver (USBIO)
USBIO_ISO_PACKET
The USBIO_ISO_PACKET structure defines the size and location of a
single isochronous data packet within the transfer buffer th at i s used for
isochronous data transfers.
Definition typedef struct _USBIO_ISO_PACKET{
ULONG Offset;
ULONG Length;
ULONG Status;
} USBIO_ISO_PACKET;
Members Offset
Specifies the offset, in bytes, of the packet relative to the start of the
data buffer. This parameter has to be specified by the caller for read
and write operations.
Length
Specifies the size, in bytes, of the packet. This parameter has to be
set by the caller for write operations. On read operations this field is
set by the USBIO when the request is returned.
Status
Contains the final status code for the transfer of this packet when the
request is returned by the USBIO.
Comments A variable size array of USBIO_ISO_PACKET structures is part of the
USBIO_ISO_TRANSFER_HEADER (page 213) that has to be used as
an input for ReadFile and WriteFile operations with an isochronous
pipe. An USBIO_ISO_PACKET structure is required for each data packet
to be transferred. The maximum number of data packets is limited b y the
registry parameter MaxIsoPackets.