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Intel IXP46X, IXP45X manual 7.2Simulation Results, 7.2.1Clock Group

Models: IXP45X IXP46X

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7.2Simulation Results

Intel® IXP45X and Intel® IXP46X Product Line of Network Processors—Category

7.2Simulation Results

This section contains the simulation results for each of the DDR signal groups. Each of the signal groups may have different overall topologies based on the number of banks and ECC usage.

Each signal group simulated below uses a two-bank, 32-bit data bus with ECC based on 16-bit DDR devices.

7.2.1Clock Group

The clock signal group includes the differential clock pairs DDRI_CK[2:0] and

DDRI_CK_N[2:0]. The following simulation was constructed for the 2 bank x16 device configuration where each clock would have two receivers.

Table 36 identifies the transmission line lengths for the clock topology shown in Figure 37 on page 91. These lengths were chosen as realistic goals given the IXP45X/ IXP46X network processors to DDR device body to body separation of no more than 500 mils.

Table 36. Clock Group Topology Transmission Line Characteristics

Transmission Line	Length

TL1 (Tpd = 175 ps/in)	~100 mils
TL2 (Tpd = 175 ps/in)	~1300 mils
TL3 (Tpd = 175 ps/in)	~50 mils
TL4, TL5 (Tpd = 175 ps/in)	~300 mils

Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
HDD	February 2007
90	Document Number: 305261, Revision: 004

Image 90

Intel IXP46X, IXP45X manual 7.2Simulation Results, 7.2.1Clock Group

Contents

Hardware Design Guidelines FebruaryDocument No 305261 Revision February Contents Introduction6.0 PCI Interface Design Considerations February5.0 General Layout and Routing Guide Document Number 305261, RevisionFigures Tables Revision Revision HistoryDate DescriptionFebruary 1.1Content Overview 1.0Introduction1.2Related Documentation 1.3Acronyms and Abbreviations 1.4OverviewList of Acronyms and Abbreviations 32-bitPCI interface Master/Target 33/66 MHz Cryptography Figure 1. Intel IXP465 Component Block DiagramMII/SMII Unit1.5Typical Applications 2.0System Architecture 2.1System Architecture Description2.2System Memory Map Line of Network JTAGIntelIXP46X Product Processors3.0General Hardware Design Considerations 3.1Soft Fusible FeaturesSignal Type Definitions Table3.2DDR-266SDRAM Interface 3.2.1Signal InterfaceSoft Fusible Features DDR SDRAM Interface Pin Description Sheet 1 ofDDR SDRAM Interface Pin Description Sheet 2 of 3.3Expansion Bus 3.2.2DDR SDRAM Memory Interface3.2.3DDR SDRAM Initialization 3.3.1Signal Interface 3.3.2Reset Configuration StrapsExpansion Bus Signal Recommendations Name Boot/Reset Strapping Configuration Sheet 1 ofTable FunctionBoot/Reset Strapping Configuration Sheet 2 of 3.3.38-BitDevice Interface3.3.416-BitDevice Interface 3.3.532-BitDevice Interface 32-Bit-WordAccess Byte Access16-Bit-WordAccess 8-BitDevice32-Bit-WordAccess Byte Access16-Bit-WordAccess 8-BitDeviceFigure 5. Flash Interface Example Intel Flash3.3.6Flash Interface 16-Bit-WordAccess3.3.8Design Notes 3.4UART Interface3.3.7SRAM Interface Figure 6. Expansion Bus SRAM Interface3.4.1Signal Interface UART Signal RecommendationsFigure 7. UART Interface Example ConnectorMII/SMII Interface UART Interface3.5.1Signal Interface MII MII NPE A Signal RecommendationsMII NPE B Signal Recommendations Sheet 1 of MII NPE B Signal Recommendations Sheet 2 of MII NPE C Signal Recommendations3.5.2Device Connection, MII Figure 8. MII Interface Example10/100 3.5.3Signal Interface, SMII 3.6GPIO Interface 3.5.4Device Connection, SMIIFigure 9. SMII Interface Example 3.6.1Signal Interface GPIO Signal Recommendations3.6.2Design Notes 3.7I2C Interface 3.7.1Signal InterfaceI2C Signal Recommendations 3.7.2Device ConnectionProduct Line 3.8USB InterfaceFigure 10. I2C EEPROM Interface Example Network Processor3.8.1Signal Interface USB Host/Device Signal RecommendationsHost 3.8.2Device ConnectionFigure 11. USB Host Down Stream Interface Example DeviceDevice 3.9UTOPIA Level 2 InterfaceFigure 12. USB Device Interface Example Host3.9.1Signal Interface UTOPIA Signal Recommendations3.9.2Device Connection Analog Front 3.10HSS InterfaceFigure 13. UTOPIA Interface Example ATM Layer Device3.10.1Signal Interface High-Speed,Serial InterfaceHigh-Speed,Serial Interface Transmit frame3.11SSP Interface 3.10.2Device ConnectionFigure 14. HSS Interface Example Synchronous Serial Peripheral Port Interface 3.11.1Signal Interface3.11.2Device Connection SPI Flash3.12.1Signal Interface 3.12PCI InterfacePCI Controller Sheet 1 of 3.12.2PCI Interface Block Diagram PCI Controller Sheet 2 ofCompact PCI Bus 3.12.3Supporting 5 V PCI InterfaceFigure 16. PCI Interface cPCI J1PCI Device 3.12.4PCI Option Interface3.3V Logic PCI DevicePage 3.13JTAG Interface 3.12.5Design NotesClock Signals 3.13.1Signal Interface3.14.1Clock Signals 3.14Input System Clock3.15Power 3.14.3Device ConnectionIntel IXP46X Power Interface Sheet 2 of 3.15.5Power Sequence3.15.6Reset Timing 3.15.1De-CouplingCapacitance RecommendationsFebruary Document Number 305261 RevisionFebruary Document Number 305261 Revision4.1PCB Overview 4.4Component Placement4.0General PCB Guide 4.2General RecommendationsInexpensive Figure 19. Component Placement on a PCB4.5Stack-UpSelection Medium FrequencyHigher cost More weight Uncontrolled signal trace impedanceLow-impedancepower distribution Poor routing densityFigure 20. 8-LayerStackup Figure 21. 6-LayerStackup5.0General Layout and Routing Guide 5.1Overview5.2General Layout Guidelines Figure 22. Signal Changing Reference Planes 5.2.1General Component SpacingVIAs Figure 24. Poor Design Practice for VIA Placement 25 mils min 25 mils min 25 mils minFlush Via min Potential Bridge min 5.2.2Clock Signal Considerations PGA or BGA Package5.2.3SMII Signal Considerations 5.2.4MII Signal Considerations5.2.5USB Considerations 5.2.6Cross-Talk 5.2.7EMI-DesignConsiderationsFebruary 5.2.9Power and Ground Plane5.2.8Trace Impedance Document Number 305261 RevisionFebruary Document Number 305261 Revision6.0PCI Interface Design Considerations 6.1Electrical Interface6.2Topology PCI Slot 6.3Clock DistributionFigure 26. PCI Address/Data Topology Table 25. PCI Address/Data Routing GuidelinesClock 6.3.1Trace Length LimitsPCI Devices Driver6.3.3Signal Loading 6.3.2Routing GuidelinesFebruary 7.1Introduction DDR Signal Groups7.0DDR-SDRAM TableLine of Network Figure 28. Processor-DDRInterfaceProcessors DDR SDRAMFebruary Document Number: 305261, Revision:Supported Memory Configurations Termination VTT Signal TerminationSignal Intel IXP46XIXP46X 7.1.1Selecting VTT Power SupplyFigure 30. VTT Terminating Circuitry DDR SDRAMDDR M CLK Figure 31. DDR Command and Control Setup and HoldControl/Command Valid 7.1.2Signal-TimingAnalysisFigure 32. DDR Data to DQS Read Timing Parameters DataDDR Data to DQS Read Timing Parameters DDR Data to DQS Write Timing Parameters Figure 33. DDR-Data-to-DQS-WriteTiming ParametersData Valid Data7.1.3Printed Circuit Board Layer Stackup DDR-Clock-to-DQS-WriteTiming Parameters7.1.4Printed Circuit Board Controlled Impedance Figure 35. Printed Circuit Board Layer StackupFebruary —Table 30 on page —Table 31 on page 7.1.5Timing RelationshipsFigure 31 on page -Table 29 on page Figure 32 on page -Table 30 on page7.1.6Resistive Compensation Register Rcomp 7.1.7Routing Guidelines7.1.7.1Clock Group 7.1.7.2Data, Command, and Control Groups Clock Signal Group Routing Guidelines7.2Simulation Results 7.2.1Clock GroupFebruary Document Number: 305261, Revision:7.2.2Data Group FebruaryTL1 Tpd = 175 ps/in Figure 39. DDR Data Topology Two-Bankx16 Devices FebruaryFebruary Document Number: 305261, Revision:February February Document Number 305261, Revision7.2.3Control Group February Document Number 305261, RevisionTL2 Tpd = 175 ps/in 7.2.4Command GroupTL1 Tpd = 175 ps/in TL3 Tpd = 175 ps/inFebruary Document Number 305261, RevisionFebruary February Document Number 305261, RevisionFebruary 7.2.5RCVENIN and RCVENOUT Figure 49. DDR RCVENIN/RCVENOUT TopologyFebruary February Document Number 305261, RevisionFebruary Document Number 305261, Revision