Intel 440GX manual PCI-to-ISA/IDE Xcelerator PIIX4E, PCI Interface, System Clocking, Introduction

Introduction

1.3.2.4PCI Interface

The 82443GX PCI interface is 33 MHz Revision 2.1 compliant and supports up to five external PCI bus masters in addition to the I/O bridge (PIIX4E).

1.3.2.5System Clocking

The 82443GX operates the system bus interface at 100 MHz, PCI at 33 MHz and AGP at 66/133 MHz. The 443GX clocking scheme uses an external clock synthesizer which produces reference clocks for the system bus and PCI interfaces. The 82443GX produces a single 100 MHz SDRAM clock output which is fed to a 1 to 18 clock buffer to support 1 to 4 DIMMs.

1.3.3PCI-to-ISA/IDE Xcelerator (PIIX4E)

The PCI-to-ISA/IDE Xcelerator (PIIX4E) 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, the PIIX4E integrates many common I/O functions found in ISA-based PC systems; a seven channel DMA Controller, two 82C59 Interrupt Controllers, an 8254 Timer/Counter, and a Real Time Clock. In addition to Compatible transfers, each DMA channel also supports Type F transfers.

The PIIX4E 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 2 Programmable Chip Selects. The PIIX4E provides full Plug and Play compatibility. The PIIX4E can be configured as a Subtractive Decode bridge or as a Positive Decode bridge.

The PIIX4E supports two IDE connectors for up to four IDE devices providing an interface for IDE/EIDE hard disks and CD ROMs. Up to four IDE devices can be supported in Bus Master mode. The PIIX4E contains support for “Ultra DMA/33” synchronous DMA compatible devices.

The PIIX4E 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.

The PIIX4E 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) specification. The PIIX4E integrates both a System Management Bus (SMBus) Host and Slave interface for serial communication with other devices.

For more information on the PIIX4E, please refer to thePIIX4 datasheet.

1.3.4 Wired for Management Initiative

Wired for Management (WfM) is an Intel initiative to improve the manageability of desktop, and server systems. The goal of WfM is to reduce the Total Cost of Ownership (TCO) through improved manageability in the following four technology areas:

•Instrumentation

•Remote Service Boot

•Remote Wake-Up

•Power Management

Intel®440GX AGPset Design Guide 1-6