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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—USB 2.0 Host Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
406
Order Number: 306262-004US
14
Data Toggle Control (DTC). This bit specifies where the host controller should get the initial
data toggle on an overlay transition.
0b Ignore DT bit from incoming qTD.
Host controller preserves DT bit in
the queue head.
1b Initial data toggle comes from incoming qTD DT bit.
Host controller
replaces DT bit in the queue head from the DT bit in the qTD.
13:12
Endpoint Speed (EPS). This is the speed of the associated endpoint. Bit combinations are:
00b
Full-Speed (12Mbs)
01b
Low-Speed (1.5Mbs)
10b
High-Speed (480 Mb/s)
11b
(Reserved)
This field must not be modified by the host controller.
11:8
Endpoint Number (Endpt). This 4-bit field selects the particular endpoint number on the
device serving as the data source or sink.
7
Inactivate on Next Transaction (I). This bit is used by system software to request that the
host controller set the Active bit to zero. See
“Rebalancing the Periodic Schedule” on page 467
for full operational details. This field is only valid when the queue head is in the Periodic Schedule
and the EPS field indicates a Full or Low-speed endpoint. Setting this bit to a one when the
queue head is in the Asynchronous Schedule or the EPS field indicates a high-speed device yields
undefined results.
6:0
Device Address. This field selects the specific device serving as the data source or sink.
Table 162.
Endpoint Capabilities: Queue Head DWord 2 (Sheet 1 of 2)
Bit
Description
31:30
High-Bandwidth Pipe Multiplier (Mult). This field is a multiplier used to key the host
controller as the number of successive packets the host controller may submit to the endpoint in
the current execution. The host controller makes the simplifying assumption that software
properly initializes this field (regardless of location of queue head in the schedules or other run
time parameters). The valid values are:
Value
Meaning
00b
(Reserved). A zero in this field yields undefined results.
01b
One transaction to be issued for this endpoint per micro-frame
10b
Two transactions to be issued for this endpoint per micro-frame
11b
Three transactions to be issued for this endpoint per micro-frame
29:23
Port Number. This field is ignored by the host controller unless the EPS field indicates a full- or
low-speed device. The value is the port number identifier on the USB 2.0 hub (for hub at device
address Hub Addr below), below which the full- or low-speed device associated with this endpoint
is attached. This information is used in the split-transaction protocol.
Table 161.
Endpoint Characteristics: Queue Head DWord 1 (Sheet 2 of 2)
Bit
Description