USB HOST DRIVER V03 Freescale Semiconductor / Motorola, USB HOST DRIVER V03 Datasheet - Page 24

• Manufacturer Part Number: USB HOST DRIVER V03
• Description: USB Host Driver v03
• Manufacturer: Freescale Semiconductor / Motorola

The MOTUSB Driver does not limit the transfer size. Each endpoint object should be
configured to the preferred transfer size. This value is specified in the
member of the
IOCTL_USB_SET_INTERFACE
that is larger that the endpoint transfer size is received, the MOTUSB Driver performs a
staging I/O which breaks the data buffer into parts which fit into the maximum transfer
size and requests a data I/O operation for each such part.
3.3.1.
A write operation on a bulk-out endpoint performs bulk data transfer from the Host (PC)
to the Device. To perform bulk write transfers the Client application should first establish
a connection to the pipe and to call
specifying the pipe object handle into the
size should be specified in the corresponding
arguments.
The transfer consists of packets. These packets are sent to the USB Device. If the last
packet of the buffer is smaller than the maximum packet size of the endpoint, a smaller
data packet is transferred. If the size of the last packet of the buffer is equal to the
maximum packet size this packet is sent. No additional zero length packet is sent by the
Driver. In order to send a zero length data packet, it is necessary to set the buffer length
to zero and use a NULL buffer pointer.
3.3.2.
A read operation on bulk-in or interrupt endpoints performs a bulk or interrupt data
transfer from the Device to the Host (PC). To issue bulk or interrupt read transfers the
Client application should first establish a connection to the pipe and to call
ReadFileEx
handle in the
specified in the corresponding
A read operation will be completed if the whole buffer is filled or a short packet is
transmitted. A short packet is a packet that is shorter than the maximum transfer size of
the endpoint. To read a data packet with a length of zero, the buffer size has to be at least
one byte. A read operation with a NULL buffer will be completed with success by the
system without performing a read operation on the USB. The behavior of short packets
depends on the registry parameter
operation that returns a data packet that is shorter than the maximum packet size of the
endpoint is completed with success. Otherwise, every data packet from the endpoint that
is smaller than the maximum packet size causes an error.
M
Bulk Write Transfers.
Bulk and Interrupt Read Transfers.
) Win32 API functions, to perform transfers specifying the pipe object
hFile
USBIO_INTERFACE_SETTING
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
function argument. The data buffer and buffer size should be
requests. If an application request to transfer a data buffer
lpBuffer
Programming Interface.
ShortTransferOk
WriteFile
and
hFile
nNumberOfBytesToRead
on the
lpBuffer
(
argument. The data buffer and buffer
WriteFileEx
IOCTL_USB_SET_CONFIGURATION
. If this parameter value is set, a read
and
nNumberOfBytesToWrite
) Win32 API functions,
arguments.
MaxTransferSize
ReadFile
3-2
or
(