NHE6300ESB S L7XJ Intel, NHE6300ESB S L7XJ Datasheet - Page 205

• Manufacturer Part Number: NHE6300ESB S L7XJ
• Manufacturer: Intel

Specifications of NHE6300ESB S L7XJ

• Lead Free Status / RoHS Status: Compliant

5—Intel
Figure 19. Example Queue Conditions
November 2007
Order Number: 300641-004US
®
6300ESB ICH
The QH contains two link pointers and is organized as two contiguous DWORDs. The
first DWORD is a horizontal pointer (Queue Head Link Pointer), used to link a single
transfer queue with either another transfer queue, or a TD (target data structure
depends on Q bit). When the T bit is set, this QH represents the last data structure in
the current Frame. The T bit informs the Intel
processing is required until the beginning of the next frame. The second DWORD is a
vertical pointer (Queue Element Link Pointer) to the first data structure (TD or QH)
being managed by this QH. When the T bit is set, the queue is empty. This pointer may
reference a TD or another QH.
Figure 19
example of an “empty” queue; the termination bit (T Bit), in the vertical link pointer
field, is set to 1. The horizontal link pointer references another QH. The next queue is
the expected typical configuration. The horizontal link pointer references another QH,
and the vertical link pointer references a valid TD.
Typically, the vertical pointer in a QH points to a TD. However, as shown in
(third example from left side of figure) the vertical pointer could point to another QH.
When this occurs, a new Q Context is entered and the Q Context just exited is NULL
(The Intel
The far right QH is an example of a frame ‘termination’ node. Since its horizontal link
pointer has its termination bit set, the Intel
work to complete for the current Frame.
Transfer Queues are based on the following characteristics:
In the simplest model, the Intel
element, then executes the element. When the completion status of the TD satisfies
the advance criteria as shown in
•
•
Indicates 'NULL' Queue Head
A QH’s vertical link pointer (Queue Element Link Pointer) references the ‘Top’ queue
member. A QH’s horizontal link pointer (Queue Head Link Pointer) references the
“next” work element in the Frame.
Each queue member’s link pointer references the next element within the queue.
Link Pointer (Horz)=Queue Head Link Pointer
field in QH DWord 0
Link Pointer (Vert)=Queue Element Link Pointer
field in QH DWord 1
31
31
Frame List Pointer
Link Pointer (Horiz) Q T
Link Pointer (Vert)
®
illustrates four example queue conditions. The first QH (on far left) is an
QH
6300ESB ICH will not update the vertical pointer field).
2
2
1
Q T
1
Q T
0
0
31
Link Pointer (Horiz) Q T
Link Pointer (Vert)
Link Pointer
Link Pointer
QH
®
Table
TD
TD
6300ESB ICH follows vertical link point to a queue
2
95, the Intel
1
Q T
Q T
Q T
0
®
6300ESB ICH assumes there is no more
®
31
31
Link Pointer (Vert)
Link Pointer (Horiz) Q T
Link Pointer (Horiz) Q T
Link Pointer (Vert)
6300ESB ICH that no further
Link Pointer
Link Pointer
®
QH
QH
6300ESB ICH advances the queue
TD
TD
2
2
Q T
1
1
Q T
Q T
Q T
Intel
0
0
®
6300ESB I/O Controller Hub
Indicates 'Nil' Next Pointer
31
Indicates 'Nil' Next Pointer
Link Pointer (Horiz) Q T
Link Pointer (Vert)
Link Pointer
QH
TD
Figure 19
2
1
Q T
Q T
0
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