Design Checklist

3.7.2IDE Routing Guidelines

This section contains guidelines for connecting and routing the PIIX4E IDE interface. The PIIX4E has two independent IDE channels. This section provides guidelines for IDE connector cabling and motherboard design, including component and resistor placement, and signal termination for both IDE channels. The current recommendations use 33 ohm resistors on all the signals running to the two ATA connectors, while the remaining signals use resistors between 22 and 47 ohm resistors.

3.7.2.1Cabling

1.Length of cable: Each IDE cable must be equal to or less than 18 inches.

2.Capacitance: Less than 30 pF.

3.Placement: A maximum of 6 inches between drive connectors on the cable. If a single drive is placed on the cable it should be placed at the end of the cable. If a second drive is placed on the same cable it should be placed on the next closest connector to the end of the cable

(6” from the end of the cable).

4.Grounding: Provide a direct low impedance chassis path between the motherboard ground and hard disk drives.

3.7.2.2Motherboard

1.PIIX4E Placement: The PIIX4E should be placed as close as possible to the ATA connector(s).

2.Resistor Location: When the distance between the PIIX4E and the ATA connectors exceeds 4 inches, the series termination resistors should be placed within 1 inch of the PIIX4E. Designs that place the PIIX4E within 4 inches of the ATA connectors can place the series resistors anywhere along the trace.

3.PC97 requirement: Support Cable Select for master-slave configuration is a system design requirement for Microsoft* PC97. CSEL signal needs to be ground at host side by using a 470 ohm pull-down resistor for each ATA connector.

4.Capacitance: The capacitance of each pin of the IDE connector on the host should be below 25 pF when the cables are disconnected from the host.

5.Series Termination: The following resistor values are the current recommendations.

Table 3-8. IDE Series Termination

Signal

Resistor

 

 

PDD[15:0]

33 ohm

 

 

PDA[2:0]

33 ohm

 

 

PDIOR#

33 ohm

 

 

PDIOW#

33 ohm

 

 

PDDREQ

33 ohm

 

 

PDCS1#

33 ohm

 

 

PDCS3#

33 ohm

 

 

PDDACK#

33 ohm

 

 

IRQ14

22-47 ohm

 

 

RESET#

22-47 ohm

 

 

Signal

Resistor

 

 

SDD[15:0]

33 ohm

 

 

SDA[2:0]

33 ohm

 

 

SDIOR#

33 ohm

 

 

SDIOW#

33 ohm

 

 

SDDREQ

33 ohm

 

 

SDCS1#

33 ohm

 

 

SDCS3#

33 ohm

 

 

SDDACK#

33 ohm

 

 

IRQ15

22-47 ohm

 

 

 

 

Intel®440GX AGPset Design Guide

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Intel 440GX manual IDE Routing Guidelines, Cabling, Motherboard, IDE Series Termination, Signal Resistor
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440GX specifications

The Intel 440GX chipset was launched in 1997 as part of Intel's series of chipsets known as the 440 family, and it served as a critical component for various Pentium II and Pentium III-based motherboard architectures. Specifically designed for the second generation of Intel’s processors, the 440GX delivered enhanced performance and supported a range of important technologies that defined PC architectures of its time.

One of the main features of the Intel 440GX was its support for a 100 MHz front-side bus (FSB), which significantly improved data transfer rates between the CPU and the memory subsystem. This advancement allowed the 440GX to accommodate both the original Pentium II processors as well as the later Pentium III chips, providing compatibility and flexibility for system builders and consumers alike.

The 440GX chipset included an integrated AGP (Accelerated Graphics Port) controller, which supported AGP 2x speeds. This enabled high-performance graphics cards to be utilized effectively, delivering many enhanced graphics capabilities for gaming and multimedia applications. The AGP interface was crucial at the time as it offered a dedicated pathway for graphics data, increasing bandwidth compared to traditional PCI slots.

In terms of memory support, the 440GX could address up to 512 MB of SDRAM, allowing systems built with this chipset to run comfortably with sufficient memory for the era’s demanding applications. The memory controller was capable of supporting both single and double-sided DIMMs, which provided versatility in memory configuration for system builders.

Another notable feature of the Intel 440GX was its support for multi-processor configurations through its Dual Processors support feature. This allowed enterprise and workstation computers to leverage the performance advantages of multiple CPUs, making the chipset suitable for business and professional environments where multitasking and high-performance computing were essential.

On the connectivity front, the chipset supported up to six PCI slots, enhancing peripheral device integration and expansion capabilities. It also included integrated IDE controllers, facilitating connections for hard drives and CD-ROM devices.

Overall, the Intel 440GX chipset represented a balanced combination of performance, flexibility, and technology advancements for its time. Its introduction helped establish a foundation for subsequent advancements in PC technology and set the stage for more powerful computing systems in the years to come.
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