HP XA manual PIIX4, PCI/ISA Bridge Chip 82371AB, Second Level Cache

2 System Board

Chip-Set

The PIIX4, PCI/ISA Bridge Chip (82371AB)

The universal host controller interface (UHCI) chip, known as PIIX4, is encapsulated in a Ball Grid Array (BGA) package.

The PIIX4 chip is a multi-function PCI device implementing a PCI-to-ISA bridge function, a PCI IDE function, a Universal Bus host/hub function, and an Enhanced Power Management function.

The following figure shows an example of the system block diagram using the PIIX4 chip.

Second Level

Cache

Processor

Host Bus

Cirrus AGP

CL5465

PCI Bus (3.3V or 5V, 30/33 MHz)

AGP Bus

Host-to-PCI

Bridge

Memory Bus

Main Memory

DRAM

Hard Disk Hard Disk

BMI IDE

Ultra DMA/33

PCI/ISA Bridge (PIIX4)

82371AB

USB 1

USB2

PCI Slots

CD-ROM

GP[I,O] (30+)

SM Bus

Audio	KBD	SP, PP,	BIOS
		FDC, IR

ISA/EIO Bus (3.3V; 5V Tolerant)

32