![Intel IXP45X Скачать руководство пользователя страница 395](http://html1.mh-extra.com/html/intel/ixp45x/ixp45x_developers-manual_2073092395.webp)
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262--, Revision: 004US
395
USB 2.0 Host Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
9.13.4
Split Transaction Isochronous Transfer Descriptor (siTD)
All full-speed isochronous transfers through the internal transaction translator are
managed using the siTD data structure. This data structure satisfies the operational
requirements for managing the split transaction protocol.
9.13.4.1
Next Link Pointer
DWord0 of a siTD is a pointer to the next schedule data structure.
Table 148.
iTD Buffer Pointer Page 2 (Plus)
Bit
Description
31:12
Buffer Pointer. This is a 4K aligned pointer to physical memory. Corresponds to memory
address bits [31:12].
11:2
(Reserved). This bit reserved for future use and should be zero.
1:0
Multi. This field is used to indicate to the host controller the number of transactions that should
be executed per transaction description (e.g. per micro-frame). 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
Table 149.
iTD Buffer Pointer Page 3-6
Bit
Description
31:12
Buffer Pointer. This is a 4K aligned pointer to physical memory. Corresponds to memory address
bits [31:12].
11:0
(Reserved). These bits reserved for future use and should be zero.
Figure 48.
Split-transaction Isochronous Transaction Descriptor (siTD)
B4465-01