Split Transaction Isochronous Transfer Descriptor (Sitd) - Freescale Semiconductor MPC8313E Family Reference Manual

Universal Serial Bus Interface
Bits Name
31–12 Buffer Pointer
11–2 —
16.5.4

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.
Figure 16-39 shows the split-transaction isochronous transfer descriptor (siTD).
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
I/O Port Number
0000_0000_0000_00000
1
ioc P 0000
Buffer Pointer (Page 0)
Buffer Pointer (Page 1)
Figure 16-39. Split-Transaction Isochronous Transaction Descriptor (siTD)
1
Host controller read/write; all others read-only.
16.5.4.1 Next Link Pointer
DWord0 of a siTD is a pointer to the next schedule data structure.
pointer fields.
Bits Name
31–5 Next Link This field contains the address of the next data object to be processed in the periodic list and
Pointer corresponds to memory address signals [31:5], respectively.
4–3 — Reserved, should be cleared. These bits must be written as zeros.
2–1 Typ Indicates to the host controller whether the item referenced is an iTD/siTD or a QH. This allows the host
controller to perform the proper type of processing on the item after it is fetched. Value encodings are:
00 iTD (isochronous transfer descriptor)
01 QH (queue head)
10 siTD (split transaction isochronous transfer descriptor
11 FSTN (frame span traversal node)
0 T Terminate.
0 Link pointer is valid.
1 Link pointer field is not valid.
MPC8313E PowerQUICC II Pro Integrated Processor Family Reference Manual, Rev. 3
16-54
Table 16-45. Buffer Pointer Page 3–6
This is a 4K aligned pointer to physical memory. Corresponds to memory address bits 31–12.
Reserved, should be cleared. These bits reserved for future use and should be cleared.
Next Link Pointer
0 Hub Address
1
Total Bytes to Transfer
Back Pointer
Table 16-46. Next Link Pointer
Description
15 14 13 12 11 10 9 8
0000 EndPt
µFrame C-mask
1
µFrame C-prog-mask
000_0000
Table 16-46
Description
7 6 5 4 3 2 1
00 Typ
0 Device Address
µFrame S-mask
1
Status
1
Current Offset
1
TP T-count
0000
describes the next link
Freescale Semiconductor
0 offset
T 0x00
0x04
0x08
0x0C
0x10
1
0x14
T 0x18