beautypg.com

Option rom mapping, Pci interrupts, Pci power management support – Compaq W4000 User Manual

Page 62: Pci sub-busses, Hub link bus, Lpc bus

background image

Chapter 4 System Support

4.2.3 OPTION ROM MAPPING

4.2.4 PCI INTERRUPTS

ay be generated by on-board PCI devices

installed in the PCI slots. For more

information on interrupts incl

“System Resources” section

4.4.


4.2.5 PCI POWER MANAGEMENT SUPPORT

T

m

lies with the PCI

Ma

tion (rev 1.0). The PCI

Power Man

able (PME-)

l is

d allows complia

a

p

itiate the

an

ent ro

4.2.6 P

B

T

set

a bu

at a

e

I bu

4.2.6.1

Hub Link Bus

he chip

e MCH and the ICH2. This bus is transparent

software and is not accessible for expansion purposes.

4.2.6.2 LPC

Bus


The 82801 ICH2 implements a Low Pin Count (LPC) bus for handling transactions to and from
the 47B367 Super I/O Controller as well as the 82802 Firmware Hub (FWH). The LPC bus
transfers data a nibble (4 bits) at a time at a 33-MHz rate. Generally transparent in operation, the
only consideration required of the LPC bus is during the configuration of DMA channel modes
(see section 4.4.3 “DMA”).

During POST, the PCI bus is scanned for devices that contain their own specific firmware in
ROM. Such option ROM data, if detected, is loaded into system memory’s DOS compatibility
area (refer to the system memory map shown in chapter 3).

E
m

ight interrupt signals (INTA- thru INTH-) are available for use by PCI devices. These signals

or by devices

rrupt mappi

uding PCI inte

ng refer to the

his syste comp

Power

nagement Interface Specifica

agement En

signa

supported by the chipset an

nt PCI

nd AGP eripherals to in

p

m

ower

agem

utine.

CI SU -BUSSES

he chip

implements two dat

s

h

ses t

re supplem ntary in operation to the PC

s:

T
to

set implements a Hub Link bus between th

Compaq Evo and Workstation Personal Computers

Featuring the Intel Pentium 4 Processor

Second Edition – January 2003

4-8