NO:
W90P710 Programming Guide
VERSION:
2.1
PAGE:
74
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed,
distributed or reproduced without permission from Winbond.
Table No.: 1200-0003-07-A
to/from where the
TD
data is to be transferred.
Host Controller Driver
adds TDs to the queue and
Host Controller
removes TDs from the queue. Once the transfer of a TD was completed,
Host
Controller
removed it from TD queue to the
Done Queue
. There are two
TD
types in OpenHCI,
General
TD
and Isochronous
TD
. The
TD
formats are listed below:
Figure 6-2 General Transfer Descriptor Format
3
2 2 2 2 2 2
2 2 1 1
0
0
1
8 7 6 5 4 3
1 0 9 8
3
0
Dword 0
CC
EC T
DI
DP R
—
Dword 1
Current Buffer Pointer (CBP)
Dword 2
Next TD (NextTD)
0
Dword 3
Buffer End (BE)
Figure 6-3 Isochronous Transfer Descriptor Format
3
2 2 2 2 2
2 2
1 1
1 1
0 0
0
1
8 7 6 4 3
1 0
6 5
2 1
5 4
0
Dword 0
CC
– FC
DI
—
SF
Dword 1
Buffer Page 0 (BP0)
—
Dword 2
NextTD
0
Dword 3
Buffer End (BE)
Dword 4
Offset1/PSW1
Offset0/PSW0
Dword 5
Offset3/PSW3
Offset2/PSW2
Dword 6
Offset5/PSW5
Offset4/PSW4
Dword 7
Offset7/PSW7
Offset6/PSW6
The General and Isochronous
Transfer Descriptor
formats of W90P710 USB
Host Controller
are
compliant to OpenHCI Specification 1.0a. You can find detail descriptions about each field in a
General/Isochronous
Transfer Descriptor
in this document.
Transfer Descriptor
s are created and filled by
HCD
. After receiving an
IRP
(I/O Request Packet)
from USB Driver (refer to USB 1.1 Specification), according to the pipe,
HCD
must create appropriate
number of
TD
s to describe the data transfer. For example, for a control pipe
IRP
,
HCD
may create
three
TD
s for the SETUP stage, DATA stage, and STATUS stage transfers. The
TD
s must be linked
