求救，中断传输的问题

公司需要开发一个usb的采集系统，我想用中断传输的方式向设备端发送控制命令，这个函数UsbBuildGetInterruptOrBulkTransferRequest可以产生一个中断传输的urb，但是我看它里面的一个参数

TransferFlags
Specifies zero, one, or a combination of the following flags:
USBD_TRANSFER_DIRECTION_IN
Is set to request data from a device. To transfer data to a device, this flag must be clear. The flag must be set if the pipe is an interrupt transfer pipe.
USBD_SHORT_TRANSFER_OK
Can be used if USBD_TRANSFER_DIRECTION_IN is set. If set, directs the HCD not to return an error if a packet is received from the device that is shorter than the maximum packet size for the endpoint. Otherwise, a short request is returns an error condition.
好像说对于中断传输只能接收数据，不能发送数据？The flag must be set if the pipe is an interrupt transfer pipe.
怎么回事啊？

我看中断传输每个事务也只能最大传64字节啊？