Motorola USB08 - page 211

Universal USB Device Driver (USBIO)
Programming Interface
USB08 Evaluation Board Designer Reference Manual
MOTOROLA Universal USB Device Driver (USBIO) 211
If USBIO_START_TRANSFER_ASAP is not specified in Flags, this
member has to be set by the caller to the frame number this transfer
shall start with. An error occurs if the frame number is outside of the
valid range.
ErrorCount
Contains the total number of errors occurred during this transaction
when the request is returned by the USBIO.
Comments This structure is the fixed size 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. the transfer buffer has to contain an
USBIO_ISO_TRANSFER_HEADER (page 213) structure at offset zero.