82801DB Datasheet, PDF (402/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

USB UHCI Controllers Registers
11.1.7
11.1.8
11.1.9
SCC—Sub Class Code Register (USB—D29:F0/F1/F2)
Address Offset:
0Ah
Default Value:
03h
Attribute:
Size:
RO
8 bits
Bit
Description
Sub Class Code — RO.
7:0
03h = Universal Serial Bus Host controller.
BCC—Base Class Code Register (USB—D29:F0/F1/F2)
Address Offset:
0Bh
Default Value:
0Ch
Attribute:
Size:
RO
8 bits
Bit
Base Class Code — RO.
7:0
0Ch = Serial Bus controller.
Description
HTYPE—Header Type Register (USB—D29:F0/F1/F2)
Address Offset:
Default Value:
0Eh
FN 0: 80h
FN 1: 00h
FN 2: 00h
Attribute:
Size:
RO
8 bits
For functions 1 and 2, this register is hard-wired to 00h. For function 0, bit 7 is determined by the
values in bits 15, 10, and 9 of the function disable register (D31:F0:F2h).
Bit
Description
Multi-Function Bit — RO. When set to 1, this bit indicates to software that this is a multi-function
device. A 0 indicates a single-function device. Since the upper functions in this device can be
individually hidden, this bit must be based on the function-disable bits in Device 31, Function 0,
Offset F2h as follows:
D29:F7_Disable D29:F2_Disable D29:F1_Disable Multi-Function Bit
7
(bit 15)
(bit 10)
(bit 9)
0
X
X
1
X
0
X
1
X
X
0
1
1
1
1
0
6:0 Header Type — RO. Hardwired to 00h, which indicates the standard PCI configuration layout.
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Intel^® 82801DB ICH4 Datasheet