Dual-Footprint Flash Design | Intel 440GX manual

Design Checklist

3.13Flash Design

3.13.1Dual-Footprint Flash Design

New features are coming to the PC continue to increase the size of BIOS code, pushing the limits of the 1 Mbit boundary. OEMs have already converted many PC designs to 2 Mbit BIOS and higher, and more will follow. Since it is difficult to predict when BIOS code will exceed 1 Mbit, OEMs should design motherboards to be flexible. Design in a dual-footprint on the motherboard that accepts both Intel’s 1 Mbit flash chips and 2 Mbit boot block chips. This will make the 1M-to- 2M transition easier by removing the need for PCB changes to accommodate higher density components. Intel provides various layout tools to help OEMs design in the dual-footprint. These tools are available from Intel’s BBS, WWW (http://www.intel.com/design/flcomp/devtools/ flas4.html), and literature distribution center. Look for Application Note AP-623Multi-Site Layout Planning with Intel's Boot Block Flash Memory (Order #: 292178). This document provides detailed information on flexible layouts. Shown below are three of the reference layouts that Intel furnishes to customers. These layouts are described in AP-623 and are available electronically (Gerber and Postscript formats). Note the small amount of extra board space needed to implement the dual-footprint layouts.

Figure 3-5. Dual Footprint Flash Layouts






PLCC32 to TSOP40	PLCC32 to PSOP44	PDIP32 to TDIP40

3.13.2Flash Design Considerations

The Intel’s flash devices (GX/BL/BV/B5) use an Address Transition Detection (ATD) mechanism to improve their performance. When interfacing flash devices that employ the ATD mechanism, the designer needs to make sure that the address transition time is not more than 10 ns while CE# is active (low). If the address transition time is more than 10 ns invalid data can result on the data bus. When flash devices are interfaced to the ISA bus they can be exposed to address transitions in excess of 10 ns. Other types of interfacing considerations, specific to flash, can be referenced in Application Note AP-636 “Preventing BIOS Failures Using Intel’s Boot Block Flash Memory” (Order# 292192 or on WWW).

Intel®440GX AGPset Design Guide

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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.

Intel 440GX manual Dual-Footprint Flash Design, Flash Design Considerations

Models: 440GX