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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
408
Order Number: 306262-004US
9.13.7
Periodic Frame Span Traversal Node (FSTN)
This data structure is to be used only for managing Full- and Low-speed transactions
that span a Host-frame boundary. See
“Host Controller Operational Model for FSTNs”
for full operational details. Software must not use an FSTN in the
Asynchronous Schedule. An FSTN in the Asynchronous schedule results in undefined
behavior. Software must not use the FSTN feature with a host controller whose
HCIVERSION register indicates a revision implementation below 0096h. FSTNs are not
defined for implementations before 0.96 and their use will yield undefined results.
9.13.7.1
FSTN Normal Path Pointer
The first DWord of an FSTN contains a link pointer to the next schedule object. This
object can be of any valid periodic schedule data type.
Table 164.
Host-Controller Rules for Bits in Overlay (DWords 5, 6, 8 and 9)
DWord
Bit
Description
5
4:1
Nak Counter (NakCnt)
μ
RW. This field is a counter the host controller decrements
whenever a transaction for the endpoint associated with this queue head results in a Nak
or Nyet response. This counter is reloaded from RL before a transaction is executed
during the first pass of the reclamation list (relative to an Asynchronous List Restart
condition). It is also loaded from RL during an overlay.
6
31
Data Toggle. The Data Toggle Control controls whether the host controller preserves
this bit when an overlay operation is performed.
6
15
Interrupt On Complete (IOC). The IOC control bit is always inherited from the source
qTD when the overlay operation is performed.
6
11:10
Error Counter (C_ERR). This two-bit field is copied from the qTD during the overlay
and written back during queue advancement.
6
0
Ping State (P)/ERR. If the EPS field indicates a high-speed endpoint, then this field
should be preserved during the overlay operation.
8
7:0
Split-transaction Complete-split Progress (C-prog-mask). This field is initialized
to zero during any overlay. This field is used to track the progress of an interrupt split-
transaction.
9
4:0
Split-transaction Frame Tag (Frame Tag). This field is initialized to zero during any
overlay. This field is used to track the progress of an interrupt split-transaction.
9
11:5
S-bytes. Software must ensure that the S-bytes field in a qTD is zero before activating
the qTD. This field is used to keep track of the number of bytes sent or received during
an IN or OUT split transaction.
Figure 51.
Frame Span Traversal Node Structure Layout
B4468-01