Intel 440GX User Manual

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Intel
®
 440GX AGPset Design Guide
1-6
Introduction
1.3.2.4
PCI 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). 
1.3.2.5
System 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. 
1.3.3
PCI-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