Memory Layout & Routing Guidelines

Motherboard Layout and Routing Guidelines

Figure 2-18. Matching the Reference Planes and Adding Decoupling Capacitor

2.9.1.3Trace Width vs. Trace Spacing

To minimize the crosstalk, a 1:2 trace width vs. trace spacing routing (e.g., 6 mils on 9 mils or 5 mils on 10 mils) should be used for all memory interface signals.

2.9.2Memory Layout & Routing Guidelines

Figure 2-19. 4 DIMMs (Single or Double-Sided)

CS_A[7:6]#,CS_B[7:6]#

CS_A[5:4]#,CS_B[5:4]#

CS_A[3:2]#,CS_B[3:2]#

CS_A[1:0]#,CS_B[1:0]#

SRAS_A#

SRAS_B#

SCAS_A#

SCAS_B#

DQM_A[1,5]

DQM_A[7,6,4:2,0]

DQM_B[1,5]

WE_A#

WE_B#

MAA[14:0]

MAB[12, 11, 9:0]#, MAB[14, 13,10]

MD[63:0]

FENA

MECC[7:0]

DIMM_CLK[3:0]

DIMM_CLK[7:4]

DIMM_CLK[11:8]

DIMM_CLK[15:12]

SMB_CLK

SMB_DATA

~ 16212

Group 0				Group 1

Layout Guidelines: All signals require careful routing for both min and max trace lengths

2-24	Intel®440GX AGPset Design Guide

Page 48

Image 48

Intel 440GX manual Memory Layout & Routing Guidelines, Trace Width vs. Trace Spacing

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.

Contents

Intel 440GX AGPset Design Guide Intel440GX AGPset Design Guide Contents Dimm Solution With FET Switches System Bus Clock Layout 6.36.4 6.5 PIIX4E Power And Ground Pins ISA and X-Bus SignalsThermals / Cooling Solutions 20.1 82371EB PIIX4E IntelPentiumII Processor LAI Issue FET Switches4 DIMM/FET DesignVoltage Regulator Control Silicon Intel440GX AGPset Platform Reference Design Example ATX Placement for a UP Pentium II processor Example NLX Placement for a UP Intel Pentium II processorSolution Space for Single Processor Design Based on Results Solution Space for Single Processor Designs With Single-End Tables Intel Pentium II Processor and Intel 440GX AGPsetIntel Pentium II Processor and Intel 440GX AGPset 100 MHz Motherboard Model MAB12,11,90#, MAB14,13,10, 4 DIMMs Revision History Date Revision Description Intel440GX AGPset Design Guide Introduction Page Introduction About This Design Guide References Intel Pentium II Processor / Intel 440GX AGPset Overview Intel Pentium II Processor Intel 440GX AGPset VCR System Bus Interface Dram InterfaceAccelerated Graphics Port Interface Wired for Management Initiative PCI-to-ISA/IDE Xcelerator PIIX4EPCI Interface System Clocking Remote Service Boot Instrumentation Power Management Design RecommendationsVoltage Definitions Remote Wake-Up General Design Recommendations Introduction Motherboard Design Page Major Signal Sections 82443GX Top View BGA Quadrant Assignment ATX Form Factor Board Description NLX Form Factor Four Layer Board Stack-up Routing Guidelines 1 GTL+ Description 2 GTL+ Layout RecommendationsSingle Processor Design Single Processor Network Topology and Conditions Single Processor Recommended Trace Lengths Recommended Trace Lengths for Single Processor DesignTrace Minimum Length Maximum Length Dual Processor Systems Single Processor Systems-Single-End Termination SETDual Processor Network Topology and Conditions Dual Processor Recommended Trace Lengths SET Trace Length Requirements SET Trace Length Requirements Additional Guidelines Minimizing CrosstalkPractical Considerations Design Methodology Performance Requirements 12. GTL+ Design Process Topology Definition Pre-Layout Simulation Sensitivity AnalysisSimulation Methodology Recommended 100 MHz System Flight Time Specs Placement & Layout Post-Layout Simulation Crosstalk and the Multi-Bit Adjustment Factor ValidationFlight Time Measurement Signal Quality Measurement Edge Guideline @ Processor Edge Spec @ Processor Core Timing Analysis Term Description 10. Recommended 100 MHz System Timing Parameters 11. Recommended 100 MHz System Flight Time SpecsTiming Term Intel Pentium II Processor Intel 440GX AGPset Timing Term Value AGP Connector Up Option Layout Guidelines ConnectorAGP Layout and Routing Guidelines 12. Data and Associated Strobe 14. Control Signal Line Length Recommendations On-board AGP Compliant Device Down Option Layout Guidelines13. Source Synchronous Motherboard Recommendations WidthSpace Trace Line Length Line Length Matching 16. Control Signal Line Length Recommendations Compliant 82443GX Graphics Data Routing Device15. Source Synchronous Motherboard Recommendations 82443GX Memory Subsystem Layout and Routing Guidelines 1 100 MHz 82443GX Memory Array ConsiderationsTo 82443GX MDs & MECCs To DIMM10 DQs To DIMM32 DQs Matching the Reference Planes Adding Additional Decoupling CapacitorRegister Register Data Control Clock Memory Layout & Routing Guidelines Trace Width vs. Trace Spacing 18. FET Switch DQ Route Example Switch 16212 Dimm Module 82443GX 0.6 0.4 0.6 0.4 Dimm Module 82443GX Dimm Module 24. Motherboard Model-DQMB1,5, 4 DIMMs 19. Motherboard Model SRASB#, 4 DIMMs 20. Motherboard Model SCASA#, 4 DIMMs21. Motherboard Model SCASB#, 4 DIMMs 22. Motherboard Model WEA#, 4 DIMMs 23. Motherboard Model WEB#, 4 DIMMs24. Motherboard Model MAA140, 4 DIMMs 3 4 Dimm Routing Guidelines no FET PCI Bus Routing Guidelines25. Motherboard Model MAB12,11,90#, MAB14,13,10, 4 DIMMs VCC3 Decoupling Guidelines Intel 440GX AGPset Platform Host Bridge Controller 492 BGA Intel 440GX AGPset Clock Layout Recommendations Clock Routing SpacingSystem Bus Clock Layout 014 018 Clock PCI Clock Layout Sdram Clock LayoutNet Trace Length Min Max Cap 440GX Ckbf Dlko AGP Clock Layout Net Trace Length Min Max Card Trace Design Checklist Page Overview Pull-up and Pull-down Resistor Values Intel Pentium II Processor Checklist Slot Connectivity Sheet 1Processor Pin Pin Connection Slot Connectivity Sheet 2 GND & Power Pin Definition Slot Connectivity Sheet 3Vtt VCC3 Reserved NC Vcc Intel Pentium II Processor Signals Intel Pentium II Processor Clocks Design Checklist Uni-Processor UP Slot 1 Checklist Dual-Processor DP Slot 1 ChecklistSlot 1 Decoupling Capacitors Voltage Regulator Module, VRM Intel 440GX AGPset Clocks 1 CK100 100 MHz Clock SynthesizerProcessor Frequency Select SEL100/66# Ckbf Sdram 1 to 18 Clock Buffer Gcke and Dclkwr Connection 82443GX Host Bridge 1 82443GX InterfaceGX Connectivity Sheet 1 GX Connectivity Sheet 2 2 82443GX GTL+ Bus Interface 3 82443GX PCI InterfaceGX Connectivity Sheet 3 VTTA, Vttb Signal Description Register Pulled to ‘0’ Pulled to ‘1’ 4 82443GX AGP InterfaceStrapping Options 82443GX Pins/Connection Dimm Pins Pin Function Intel 440GX AGPset Memory InterfaceSdram Connections Sdram Connectivity Dimm Solution With FET Switches Registered Sdram Signal Names Connection 82371EB PIIX4EPIIX4E Connections PIIX4E Connectivity Sheet 1 PIIX4E Connectivity Sheet 2 PIIX4E Connectivity Sheet 3 PIIX4E Connectivity Sheet 4 Signal Resistor IDE Routing GuidelinesCabling Motherboard Reset# PDD150 PDA20Pin32,34 IDE PCI Bus Signals PIIX4E Power And Ground PinsPIIX4E PWR & GND ISA Signals ISA and X-Bus Signals10. Non-PIIX4E PCI Signals 11. Non-PIIX4E ISA Signals USB Interface IDE Interface12. Non-PIIX4E IDE Flash Design Dual-Footprint Flash DesignFlash Design Considerations PLCC32 to TSOP40 PLCC32 to PSOP44 PDIP32 to TDIP40 XD70 13. Flash Vpp Recommendations Write Protection System and Test Signals Power Management Signals VCC3 Power Button Implementation Miscellaneous 17 82093AA Ioapic 18.1 Max1617 Temperature Sensor Manageability Devices18.2 LM79 Microprocessor System Hardware Monitor 18.3 82558B LOM Checklist Pin Number Pin Name Resistor Value CommentRequired in both a and B stepping designs Software/BIOS USB and Multi-processor BiosWake On LAN WOL Header Thermals / Cooling Solutions MechanicalsDesign Considerations Electricals Layout Checklist Applications and Add-in HardwareRouting and Board Fabrication Design Consideration Debug Recommendations Page Slot 1 Test Tools Debug/Simulation ToolsLogic Analyzer Interface LAI In-Target Probe ITP Debug Features Intel Pentium II Processor LAI IssueBus Functional Model BFM 4 I/O Buffer Models 150 330 ohm Kohm430 ohm 150 ohm Debug Logic Recommendations A20M# 150 330 ohmPICD0# 150 ohm PICD1# Debug Procedures Debug LayoutDebug Considerations Design Considerations Debug Recommendations Third Party Vendors Page Slot 1 Connector ProcessorsGTL+ Bus Slot 1 Terminator Cards Supplier Contact Phone Voltage Regulator Modules Voltage Regulator Control SiliconVoltage Regulator Modules Voltage Regulator Control Silicon Vendors Power Management Components FET Switches4 DIMM/FET DesignIntel 440GX AGPset Clock Drivers Other Processor Components Reference Design Schematics Page Intel 440GX AGPset Platform Reference Design 82443GX Component System bus and Dram Interfaces VRM Power Connectors Front Panel Jumpers