82801DB Datasheet, PDF (443/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

EHCI Controller Registers (D29:F7)
12.2.2.7
ASYNCLISTADDR—Current Asynchronous List Address Register
Offset:
Default Value:
CAPLENGTH + 18–1Bh
00000000h
Attribute: R/W
Size:
32 bits
This 32-bit register contains the address of the next asynchronous queue head to be executed. Since
the ICH4 host controller operates in 64-bit mode (as indicated by a one in 64-bit Addressing
Capability field in the HCCPARAMS register), then the most significant 32 bits of every control
data structure address comes from the CTRLDSSEGMENT register. Bits [4:0] of this register
cannot be modified by system software and will always return zeros when read. The memory
structure referenced by this physical memory pointer is assumed to be 32-byte aligned.
12.2.2.8
Bit
Description
31:5
Link Pointer Low (LPL) — R/W. These bits correspond to memory address signals [31:5],
respectively. This field may only reference a Queue Head (QH).
4:0 Reserved. These bits are reserved and their value has no effect on operation.
CONFIGFLAG—Configure Flag Register
Offset:
Default Value:
CAPLENGTH + 40–43h
00000000h
Attribute: R/W
Size:
32 bits
This 32-bit register contains the address of the next asynchronous queue head to be executed. Since
the ICH4 host controller operates in 64-bit mode (as indicated by a one in 64-bit Addressing
Capability field in the HCCPARAMS register), then the most significant 32 bits of every control
data structure address comes from the CTRLDSSEGMENT register. Bits [4:0] of this register
cannot be modified by system software and will always return zeros when read. The memory
structure referenced by this physical memory pointer is assumed to be 32-byte aligned.
Bit
Description
31:1 Reserved. Read from this field will always return 0.
Configure Flag (CF) — R/W. Host software sets this bit as the last action in its process of
configuring the Host controller. This bit controls the default port-routing control logic. Bit values and
side-effects are listed below. For operation details, see Chapter 4 of the Enhanced Host Controller
0 _{Interface (EHCI) Specification for Universal Serial Bus.}
0 = Port routing control logic default-routes each port to the classic host controllers. (Default)
1 = Port routing control logic default-routes all ports to this host controller.
Intel^® 82801DB ICH4 Datasheet
443