82801DB Datasheet, PDF (244/587 Pages) Intel Corporation – Intel 82801DB I/O Controller Hub 4 (ICH4)

Register and Memory Mapping
6.1
PCI Devices and Functions
The ICH4 incorporates a variety of PCI functions as shown in Table 6-1. These functions are
divided into four logical devices (B0:D30, B0:D31, B0:D29 and B1:D8). D30 is the hub interface-
to-PCI bridge, D31 contains the PCI-to-LPC Bridge, IDE controller, SMBus controller and the
AC ’97 Audio and Modem controller functions and D29 contains the three USB UHCI controllers
and one USB EHCI controller. B1:D8 is the integrated LAN controller.
Note: From a software perspective, the integrated LAN controller resides on the ICH4’s external PCI bus
(See Section 5.1.2). This is typically Bus 1, but may be assigned a different number depending
upon system configuration.
If for some reason, the particular system platform does not want to support any one of Device 31’s
Functions 1–6, Device 29’s functions, or Device 8, they can individually be disabled. The
integrated LAN controller will be disabled if no Platform LAN Connect component is detected
(See Section 5.2.1.3). When a function is disabled, it does not appear at all to the software. A
disabled function will not respond to any register reads or writes. This is intended to prevent
software from thinking that a function is present (and reporting it to the end-user).
Table 6-1. PCI Devices and Functions
Bus:Device:Function
Bus 0:Device 30:Function 0
Bus 0:Device 31:Function 0
Bus 0:Device 31:Function 1
Bus 0:Device 31:Function 3
Bus 0:Device 31:Function 5
Bus 0:Device 31:Function 6
Bus 0:Device 29:Function 0
Bus 0:Device 29:Function 1
Bus 0:Device 29:Function 2
Bus 0:Device 29:Function 7
Bus n:Device 8:Function 0
Function Description
Hub Interface to PCI Bridge
PCI to LPC Bridge¹
IDE Controller
SMBus Controller
AC ’97 Audio Controller
AC ’97 Modem Controller
USB UHCI Controller #1
USB UHCI Controller #2
USB UHCI Controller #3
USB 2.0 EHCI Controller
LAN Controller
NOTES:
1. The PCI to LPC bridge contains registers that control LPC, power management, system management, GPIO,
processor interface, RTC, interrupts, timers, DMA.
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Intel^® 82801DB ICH4 Datasheet