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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262--, Revision: 004US
379
USB 2.0 Host Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
9.12.5
CTRLDSSEGMENT
Address:
Base + 150h
Default Value: 0x00000000
Attribute:
Read Only
Size:
32 bits
This register is not used in this implementation.
9.12.6
PERIODICLISTBASE
Address:
Base + 154h
Default Value: 0x00000000
Attribute:
Read/Write (Writes must be DWord Writes)
Size:
32 bits
9.12.6.1
Host Controller (PERIODICLISTBASE)
This 32-bit register contains the beginning address of the Periodic Frame List in the
system memory. HCD loads this register prior to starting the schedule execution by the
Host Controller. The memory structure referenced by this physical memory pointer is
assumed to be 4-Kbyte aligned. The contents of this register are combined with the
Frame Index Register (FRINDEX) to enable the Host Controller to step through the
Periodic Frame List in sequence.
Table 137.
FRINDEX – USB Frame Index
Field
Description
(Reserved)
These bits are reserved and should be zero.
FRINDEX
Frame Index.
The value, in this register, increments at the end of each time frame (e.g. micro-frame). Bits
[N: 3] are used for the Frame List current index. This means that each location of the frame
list is accessed 8 times (frames or micro-frames) before moving to the next index.
The following illustrates values of N based on the value of the Frame List Size field in the
USBCMD register, when used in host mode.
USBCMD (Frame List Size) Number Elements N
000b
(1024)
12
001b
(512)
11
010b
(256)
10
011b
(128)
9
100b
(64)
8
101b
(32)
7
110b
(16)
6
111b
(8)
5
bits 2:0 indicate the current microframe.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
PERBASE[31:12]
(Reserved)