Fstn Back Path Link Pointer; Host Operational Model; Fstn Normal Path Pointer Signals; Fstn Back Path Link Pointer Signals - Intel IXP45X Developer's Manual

USB 2.0 Host Controller—Intel
Table 165.

FSTN Normal Path Pointer Signals

Bit
31:5
4:3
2:1
0
9.13.7.2

FSTN Back Path Link Pointer

The second DWord of an FTSN node contains a link pointer to a queue head. If the T-bit
in this pointer is a zero, then this FSTN is a Save-Place indicator. Its Typ field must be
set by software to indicate the target data structure is a queue head. If the T-bit in this
pointer is set to a one, then this FSTN is the Restore indicator. When the T-bit is a one,
the host controller ignores the Typ field.
Table 166.

FSTN Back Path Link Pointer Signals

Bit
31:5
4:3
2:1
0
9.14

Host Operational Model

The general operational model is for the enhanced interface host controller hardware
and enhanced interface host controller driver (generally referred to as system
software). Each significant operational feature of the EHCI host controller is discussed
in a separate section. Each section presents the operational model requirements for the
host controller hardware. Where appropriate, recommended system software
operational models for features are also presented.
August 2006
Order Number: 306262--, Revision: 004US
® ®
IXP45X and Intel IXP46X Product Line of Network Processors
Normal Path Link Pointer (NPLP). This field contains the address of the next data object to be
processed in the periodic list and corresponds to memory address signals [31:5], respectively.
(Reserved). These bits must be written as 0s.
QH/(s)iTD/FSTN Select (Typ). This field indicates to the Host Controller whether the item
referenced is a iTD/siTD, a QH or an FSTN. This allows the Host Controller to perform the proper
type of processing on the item after it is fetched. Value encodings are:
Value Meaning
00b iTD (isochronous transfer descriptor)
01b QH (queue head)
10b siTD (split transaction isochronous transfer descriptor)
11b FSTN (Frame Span Traversal Node)
Terminate (T).
0 = Link Pointer is valid.
1 = Link Pointer field is not valid.
Back Path Link Pointer (BPLP). This field contains the address of a Queue Head. This field
corresponds to memory address signals [31:5], respectively.
(Reserved). These bits must be written as 0s.
Typ. Software must ensure this field is set to indicate the target data structure is a Queue
Head. Any other value in this field yields undefined results.
Terminate (T).
0 = Link Pointer is valid (i.e. the host controller may use bits [31:5] (in combination with the
CTRLDSSEGMENT register if applicable) as a valid memory address). This value also
indicates that this FSTN is a Save-Place indicator.
1 = Link Pointer field is not valid (i.e. the host controller must not use bits [31:5] (in
combination with the CTRLDSSEGMENT register if applicable) as a valid memory address).
This value also indicates that this FSTN is a Restore indicator.
Description
Description
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Intel IXP45X and Intel IXP46X Product Line of Network Processors
Developer's Manual
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