82801DB Datasheet, PDF (423/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

EHCI Controller Registers (D29:F7)
12.1.13 CAP_PTR—Capabilities Pointer Register
(USB EHCI—D29:F7)
Address Offset: 34h
Default Value: 50h
Attribute: RO
Size:
8 bits
Bit
Description
7: 0
Capabilities Pointer (CAP_PTR) — RO. This register points to the starting offset of the USB EHCI
capabilities ranges.
12.1.14
INT_LN—Interrupt Line Register (USB EHCI—D29:F7)
Address Offset: 3Ch
Default Value: 00h
Attribute: R/W
Size:
8 bits
Bit
Description
7:0
Interrupt Line (INT_LN) — R/W. This data is not used by the ICH4. It is used as a scratchpad
register to communicate to software the interrupt line that the interrupt pin is connected to.
12.1.15 INT_PN—Interrupt Pin Register (USB EHCI—D29:F7)
Address Offset: 3Dh
Default Value: 04h
Attribute: RO
Size:
8 bits
Bit
Description
Interrupt Pin (INT_PN) — RO. The value of 04h indicates that the USB EHCI function within the
ICH4’s multi-function USB device will drive the fourth interrupt pin from the device (INTD# in PCI
terms). The value of 04h in function 7 is required because the PCI specification does not recognize
7:0 _{more than 4 interrupts and older APM-based OSs require that each function within a multi-function}
device has a different Interrupt Pin Register value.
NOTE: Internally the USB EHCI controller uses PIRQ[H]#.
12.1.16
PWR_CAPID—PCI Power Management Capability ID
Register (USB EHCI—D29:F7)
Address Offset: 50h
Default Value: 01h
Attribute: RO
Size:
8 bits
Bit
Description
7:0
Power Management Capability ID — RO. A value of 01h indicates that this is a PCI Power
Management capabilities field.
Intel^® 82801DB ICH4 Datasheet
423