4-8 Hardware Functional Overview
82371EE (PIIX4) Features
The 82371EE PCI ISA IDE Xcelerator (PIIX4) is a multi-function PCI device
implementing a PCI-to-ISA bridge function, a PCI IDE function, a Universal
Serial Bus host/hub function, and an Enhanced Power Management function. As
a PCI-to-ISA bridge, PIIX4 integrates many common I/O functions found in
ISA-based PC systems - two 82C37 DMA Controllers, two 82C59 Interrupt
Controllers, an 82C54 Timer/Counter, and a Real Time Clock. In addition to
compatible transfers, each DMA channel supports Type F transfers. PIIX4 also
contains full support for both PC/PCI and Distributed DMA protocols
implementing PCI-based DMA. The Interrupt Controller has Edge or Level
sensitive programmable inputs and fully supports the use of an external I/O
Advanced Programmable Interrupt Controller (APIC) and Serial Interrupts.
Chip select decoding is provided for BIOS, Real Time Clock, Keyboard
Controller, second external microcontroller as well as two Programmable
bridges or as a Positive Decode bridge. This allows the use of a subtractive
decode PCI-to-PCI bridge such as the Intel 380FB PCIset which implements a
PCI/ISA docking station environment.
PIIX4 supports two IDE connectors for up to four IDE devices providing an
interface for IDE hard disks and CD-ROMs. Up to four IDE devices can be
supported in Bus Master mode while PIIX4 contains support for "Ultra
DMA/33" synchronous to DMA compatible devices.
PIIX4 contains a Universal Serial Bus (USB) Host Controller that is Universal
Host Controller Interface (UHCI) compatible. The Host Controller's root hub
has two programmable USB ports.
PIIX4 supports Enhanced Power Management, including full Clock Control,
Device Management for up to 14 devices, and Suspend and Resume logic with
Power On Suspend, Suspend to RAM or Suspend to Disk. It fully supports
Operating System Directed Power Management via the Advanced Configuration
and Power Interface (ACPI) specifications. PIIX4 integrates both a System
Management Bus (SMBus) and a Host and Slave interface for serial
communication with other devices.
Feature summary of the Intel PIIX4:
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Supported Kits for both Pentium and Pentium II Microprocessors
82430TX ISA Kit
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82440LX ISA.DP Kit
Multifunction PCI to ISA Bridge
Supports PCI at 30 MHz and 33 MHz
Supports PCI Rev 2.1 Specification
Supports Full ISA or Extended I/O (EIO) Bus
Supports Full Positive Decode or Subtractive Decode of PCI
