External Memory Interface Handbook Volume 2: Design Guidelines: For UniPHY-based Device Families

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ID 683385
Date 3/06/2023
Public
Document Table of Contents
Document Table of Contents x
1. Planning Pin and FPGA Resources 2. DDR2 and DDR3 SDRAM Board Design Guidelines 3. Dual-DIMM DDR2 and DDR3 SDRAM Board Design Guidelines 4. LPDDR2 SDRAM Board Design Guidelines 5. RLDRAM II and RLDRAM 3 Board Design Guidelines 6. QDR II/II+ SRAM Board Design Guidelines 7. Implementing and Parameterizing Memory IP 8. Simulating Memory IP 9. Analyzing Timing of Memory IP 10. Debugging Memory IP 11. Optimizing the Controller 12. PHY Considerations 13. Power Estimation Methods for External Memory Interfaces
1. Planning Pin and FPGA Resources x
1.1. Interface Pins 1.2. Guidelines for UniPHY-based External Memory Interface IP 1.3. Using PLL Guidelines 1.4. PLL Cascading 1.5. DLL 1.6. Other FPGA Resources 1.7. Document Revision History
1.1. Interface Pins x
1.1.1. Estimating Pin Requirements 1.1.2. DDR, DDR2, and DDR3 SDRAM Clock Signals 1.1.3. DDR, DDR2, and DDR3 SDRAM Command and Address Signals 1.1.4. DDR, DDR2, and DDR3 SDRAM Data, Data Strobes, DM/DBI, and Optional ECC Signals 1.1.5. DDR, DDR2, and DDR3 SDRAM DIMM Options 1.1.6. QDR II and QDR II+ SRAM Clock Signals 1.1.7. QDR II and QDR II+ SRAM Command Signals 1.1.8. QDR II and QDR II+ SRAM Address Signals 1.1.9. QDR II and QDR II+ SRAM Data, BWS, and QVLD Signals 1.1.10. RLDRAM II and RLDRAM 3 Clock Signals 1.1.11. RLDRAM II and RLDRAM 3 Commands and Addresses 1.1.12. RLDRAM II and RLDRAM 3 Data, DM and QVLD Signals 1.1.13. LPDDR2 Clock Signal 1.1.14. LPDDR2 Command and Address Signal 1.1.15. LPDDR2 Data, Data Strobe, and DM Signals 1.1.16. Maximum Number of Interfaces 1.1.17. OCT Support
1.1.16. Maximum Number of Interfaces x
1.1.16.1. Maximum Number of DDR SDRAM Interfaces Supported per FPGA 1.1.16.2. Maximum Number of DDR2 SDRAM Interfaces Supported per FPGA 1.1.16.3. Maximum Number of DDR3 SDRAM Interfaces Supported per FPGA 1.1.16.4. Maximum Number of QDR II and QDR II+ SRAM Interfaces Supported per FPGA 1.1.16.5. Maximum Number of RLDRAM II Interfaces Supported per FPGA 1.1.16.6. Maximum Number of LPDDR2 SDRAM Interfaces Supported per FPGA
1.2. Guidelines for UniPHY-based External Memory Interface IP x
1.2.1. General Pin-out Guidelines for UniPHY-based External Memory Interface IP 1.2.2. Pin-out Rule Exceptions for ×36 Emulated QDR II and QDR II+ SRAM Interfaces in Arria II, Stratix III and Stratix IV Devices 1.2.3. Pin-out Rule Exceptions for RLDRAM II and RLDRAM 3 Interfaces 1.2.4. Pin-out Rule Exceptions for QDR II and QDR II+ SRAM Burst-length-of-two Interfaces 1.2.5. Pin Connection Guidelines Tables 1.2.6. PLLs and Clock Networks
1.2.2. Pin-out Rule Exceptions for ×36 Emulated QDR II and QDR II+ SRAM Interfaces in Arria II, Stratix III and Stratix IV Devices x
1.2.2.1. Timing Impact on x36 Emulation 1.2.2.2. Rules to Combine Groups 1.2.2.3. Determining the CQ/CQn Arrival Time Skew
1.2.3. Pin-out Rule Exceptions for RLDRAM II and RLDRAM 3 Interfaces x
1.2.3.1. Interfacing with ×9 RLDRAM II CIO Devices 1.2.3.2. Interfacing with ×18 RLDRAM II and RLDRAM 3 CIO Devices 1.2.3.3. Interfacing with RLDRAM II and RLDRAM 3 ×36 CIO Devices
1.2.5. Pin Connection Guidelines Tables x
1.2.5.1. DDR3 SDRAM With Leveling Interface Pin Utilization Applicable for Arria V GZ, Stratix III, Stratix IV, and Stratix V Devices 1.2.5.2. QDR II and QDR II+ SRAM Pin Utilization for Arria II, Arria V, Stratix III, Stratix IV, and Stratix V Devices 1.2.5.3. RLDRAM II CIO Pin Utilization for Arria II GZ, Arria V, Stratix III, Stratix IV, and Stratix V Devices  1.2.5.4. LPDDR2 Pin Utilization for Arria V, Cyclone V, and MAX 10 FPGA Devices 1.2.5.5. Additional Guidelines for Arria V GZ and Stratix V Devices 1.2.5.6. Additional Guidelines for Arria V ( Except Arria V GZ) Devices 1.2.5.7. Additional Guidelines for MAX 10 Devices 1.2.5.8. Additional Guidelines for Cyclone V Devices
1.2.6. PLLs and Clock Networks x
1.2.6.1. Number of PLLs Available in Intel® Device Families 1.2.6.2. Number of Enhanced PLL Clock Outputs and Dedicated Clock Outputs Available in Intel® Device Families 1.2.6.3. Number of Clock Networks Available in Intel® Device Families 1.2.6.4. Clock Network Usage in UniPHY-based Memory Interfaces—DDR2 and DDR3 SDRAM (1) (2) 1.2.6.5. Clock Network Usage in UniPHY-based Memory Interfaces—RLDRAM II, and QDR II and QDR II+ SRAM 1.2.6.6. PLL Usage for DDR, DDR2, and DDR3 SDRAM Without Leveling Interfaces 1.2.6.7. PLL Usage for DDR3 SDRAM With Leveling Interfaces
2. DDR2 and DDR3 SDRAM Board Design Guidelines x
2.1. Leveling and Dynamic Termination 2.2. DDR2 Terminations and Guidelines 2.3. DDR3 Terminations in Arria V, Cyclone V, Stratix III, Stratix IV, and Stratix V 2.4. Layout Approach 2.5. Channel Signal Integrity Measurement 2.6. Design Layout Guidelines 2.7. Package Deskew 2.8. Document Revision History
2.1. Leveling and Dynamic Termination x
2.1.1. Read and Write Leveling 2.1.2. Dynamic ODT 2.1.3. Dynamic On-Chip Termination 2.1.4. Dynamic On-Chip Termination in Stratix III and Stratix IV Devices 2.1.5. Dynamic OCT in Stratix V Devices
2.1.3. Dynamic On-Chip Termination x
2.1.3.1. FPGA Writing to Memory 2.1.3.2. FPGA Reading from Memory
2.2. DDR2 Terminations and Guidelines x
2.2.1. Termination for DDR2 SDRAM 2.2.2. DDR2 Design Layout Guidelines 2.2.3. General Layout Guidelines 2.2.4. Layout Guidelines for DDR2 SDRAM Interface
2.2.1. Termination for DDR2 SDRAM x
2.2.1.1. External Parallel Termination 2.2.1.2. On-Chip Termination 2.2.1.3. Recommended Termination Schemes
2.3. DDR3 Terminations in Arria V, Cyclone V, Stratix III, Stratix IV, and Stratix V x
2.3.1. Terminations for Single-Rank DDR3 SDRAM Unbuffered DIMM 2.3.2. Terminations for Multi-Rank DDR3 SDRAM Unbuffered DIMM 2.3.3. Terminations for DDR3 SDRAM Registered DIMM 2.3.4. Terminations for DDR3 SDRAM Load-Reduced DIMM 2.3.5. Terminations for DDR3 SDRAM Components With Leveling
2.3.5. Terminations for DDR3 SDRAM Components With Leveling x
2.3.5.1. DDR3 SDRAM Components With or Without Leveling
2.5. Channel Signal Integrity Measurement x
2.5.1. Importance of Accurate Channel Signal Integrity Information 2.5.2. Understanding Channel Signal Integrity Measurement 2.5.3. How to Enter Calculated Channel Signal Integrity Values 2.5.4. Guidelines for Calculating DDR3 Channel Signal Integrity
2.6. Design Layout Guidelines x
2.6.1. General Layout Guidelines 2.6.2. Layout Guidelines for DDR3 SDRAM Interfaces 2.6.3. Length Matching Rules 2.6.4. Spacing Guidelines 2.6.5. Layout Guidelines for DDR3 SDRAM Wide Interface (>72 bits)
2.6.5. Layout Guidelines for DDR3 SDRAM Wide Interface (>72 bits) x
2.6.5.1. Fly-By Network Design for Clock, Command, and Address Signals
2.7. Package Deskew x
2.7.1. Package Deskew Recommendation for Stratix V Devices 2.7.2. DQ/DQS/DM Deskew 2.7.3. Address and Command Deskew 2.7.4. Deskew Example 2.7.5. Package Migration 2.7.6. Package Deskew for RLDRAM II and RLDRAM 3
3. Dual-DIMM DDR2 and DDR3 SDRAM Board Design Guidelines x
3.1. General Layout Guidelines 3.2. Dual-Slot Unbuffered DDR2 SDRAM 3.3. Dual-Slot Unbuffered DDR3 SDRAM 3.4. Document Revision History
3.2. Dual-Slot Unbuffered DDR2 SDRAM x
3.2.1. Overview of ODT Control 3.2.2. DIMM Configuration 3.2.3. Dual-DIMM Memory Interface with Slot 1 Populated 3.2.4. Dual-DIMM with Slot 2 Populated 3.2.5. Dual-DIMM Memory Interface with Both Slot 1 and Slot 2 Populated 3.2.6. Dual-DIMM DDR2 Clock, Address, and Command Termination and Topology 3.2.7. Control Group Signals 3.2.8. Clock Group Signals
3.2.3. Dual-DIMM Memory Interface with Slot 1 Populated x
3.2.3.1. FPGA Writing to Memory 3.2.3.2. Write to Memory Using an ODT Setting of 150-ohm 3.2.3.3. Reading from Memory
3.2.4. Dual-DIMM with Slot 2 Populated x
3.2.4.1. FPGA Writing to Memory 3.2.4.2. Write to Memory Using an ODT Setting of 150-ohm 3.2.4.3. Reading from Memory
3.2.5. Dual-DIMM Memory Interface with Both Slot 1 and Slot 2 Populated x
3.2.5.1. FPGA Writing to Memory 3.2.5.2. Write to Memory in Slot 1 Using an ODT Setting of 75-ohm 3.2.5.3. Reading From Memory
3.3. Dual-Slot Unbuffered DDR3 SDRAM x
3.3.1. Comparison of DDR3 and DDR2 DQ and DQS ODT Features and Topology 3.3.2. Dual-DIMM DDR3 Clock, Address, and Command Termination and Topology 3.3.3. FPGA OCT Features
3.3.2. Dual-DIMM DDR3 Clock, Address, and Command Termination and Topology x
3.3.2.1. Address and Command Signals 3.3.2.2. Control Group Signals 3.3.2.3. Clock Group Signals
3.3.3. FPGA OCT Features x
3.3.3.1. Arria V, Cyclone V, Stratix III, Stratix IV, and Stratix V Devices 3.3.3.2. Arria II GX Devices
4. LPDDR2 SDRAM Board Design Guidelines x
4.1. LPDDR2 Guidance 4.2. Document Revision History
4.1. LPDDR2 Guidance x
4.1.1. LPDDR2 SDRAM Configurations 4.1.2. OCT Signal Terminations for Arria V and Cyclone V Devices 4.1.3. General Layout Guidelines 4.1.4. LPDDR2 Layout Guidelines
4.1.2. OCT Signal Terminations for Arria V and Cyclone V Devices x
4.1.2.1. Outputs from the FPGA to the LPDDR2 Component 4.1.2.2. Input to the FPGA from the LPDDR2 SDRAM Component 4.1.2.3. Termination Schemes
5. RLDRAM II and RLDRAM 3 Board Design Guidelines x
5.1. RLDRAM II Configurations 5.2. RLDRAM 3 Configurations 5.3. Signal Terminations 5.4. PCB Layout Guidelines 5.5. General Layout Guidelines 5.6. RLDRAM II and RLDRAM 3 Layout Guidelines 5.7. Layout Approach 5.8. Package Deskew for RLDRAM II and RLDRAM 3 5.9. Document Revision History
5.3. Signal Terminations x
5.3.1. Input to the FPGA from the RLDRAM Components 5.3.2. Outputs from the FPGA to the RLDRAM II and RLDRAM 3 Components 5.3.3. RLDRAM II Termination Schemes 5.3.4. RLDRAM 3 Termination Schemes
5.7. Layout Approach x
5.7.1. Arria V and Stratix V Board Setting Parameters
6. QDR II/II+ SRAM Board Design Guidelines x
6.1. QDR II SRAM Configurations 6.2. Signal Terminations 6.3. General Layout Guidelines 6.4. QDR II Layout Guidelines 6.5. QDR II SRAM Layout Approach 6.6. Package Deskew for QDR II 6.7. Document Revision History
6.2. Signal Terminations x
6.2.1. Output from the FPGA to the QDR II SRAM Component 6.2.2. Input to the FPGA from the QDR II SRAM Component 6.2.3. Termination Schemes
7. Implementing and Parameterizing Memory IP x
7.1. Design Flow 7.2. UniPHY-Based External Memory Interface IP 7.3. Document Revision History
7.1. Design Flow x
7.1.1. IP Catalog Design Flow 7.1.2. Platform Designer System Integration Tool Design Flow
7.1.1. IP Catalog Design Flow x
7.1.1.1. IP Catalog and Parameter Editor 7.1.1.2. Specifying Parameters for the IP Catalog Flow 7.1.1.3. Using Example Designs 7.1.1.4. Constraining the Design 7.1.1.5. Compiling the Design
7.1.1.4. Constraining the Design x
7.1.1.4.1. Adding Pins and DQ Group Assignments
7.1.2. Platform Designer System Integration Tool Design Flow x
7.1.2.1. Specify Parameters for the Platform Designer Flow 7.1.2.2. Completing the Platform Designer System
7.2. UniPHY-Based External Memory Interface IP x
7.2.1. Platform Designer Interfaces 7.2.2. Generated Files for Memory Controllers with the UniPHY IP 7.2.3. Parameterizing Memory Controllers 7.2.4. Board Settings 7.2.5. Controller Settings for UniPHY IP 7.2.6. Diagnostics for UniPHY IP
7.2.1. Platform Designer Interfaces x
7.2.1.1. DDR2 SDRAM Controller with UniPHY Intel FPGA IP Interfaces 7.2.1.2. DDR3 SDRAM Controller with UniPHY Intel FPGA IP Interfaces 7.2.1.3. LPDDR2 SDRAM Controller with UniPHY Intel FPGA IP Interfaces 7.2.1.4. QDR II and QDR II+ SRAM Controller with UniPHY Intel FPGA IP Interfaces 7.2.1.5. RLDRAM II Controller with UniPHY Intel FPGA IP Interfaces 7.2.1.6. RLDRAM 3 UniPHY Intel FPGA IP Interface
7.2.3. Parameterizing Memory Controllers x
7.2.3.1. PHY Settings for UniPHY IP 7.2.3.2. Memory Parameters for LPDDR2, DDR2 and DDR3 SDRAM Controller with UniPHY Intel FPGA IP 7.2.3.3. Memory Parameters for QDR II and QDR II+ SRAM Controller with UniPHY Intel FPGA IP 7.2.3.4. Memory Parameters for RLDRAM II Controller with UniPHY Intel FPGA IP 7.2.3.5. Memory Timing Parameters for DDR2, DDR3, and LPDDR2 SDRAM Controller with UniPHY Intel FPGA IP 7.2.3.6. Memory Timing Parameters for QDR II and QDR II+ SRAM Controller with UniPHY Intel FPGA IP 7.2.3.7. Memory Timing Parameters for RLDRAM II Controller with UniPHY Intel FPGA IP 7.2.3.8. Memory Parameters for RLDRAM 3 UniPHY Intel FPGA IP
7.2.3.2. Memory Parameters for LPDDR2, DDR2 and DDR3 SDRAM Controller with UniPHY Intel FPGA IP x
7.2.3.2.1. Memory Initialization Options for DDR2 7.2.3.2.2. Memory Initialization Options for DDR3 7.2.3.2.3. Memory Initialization Options for LPDDR2
7.2.4. Board Settings x
7.2.4.1. Setup and Hold Derating for UniPHY IP 7.2.4.2. Intersymbol Interference Channel Signal Integrity for UniPHY IP 7.2.4.3. Board Skews for UniPHY IP
7.2.4.3. Board Skews for UniPHY IP x
7.2.4.3.1. Board Skew Parameters for LPDDR2/DDR2/DDR3 SDRAM FPGA DQ/DQS Package Skews Deskewed on Board Address/Command Package Deskew Maximum CK delay to DIMM/device Maximum DQS delay to DIMM/device Minimum delay difference between CK and DQS Maximum delay difference between CK and DQS Maximum skew within DQS group Maximum skew between DQS groups Average delay difference between DQ and DQS Maximum skew within address and command bus Average delay difference between address and command and CK 7.2.4.3.2. Board Skew Parameters for QDR II and QDR II+ 7.2.4.3.3. Board Skew parameters for RLDRAM II and RLDRAM 3
8. Simulating Memory IP x
8.1. Simulation Options 8.2. Simulation Walkthrough with UniPHY IP 8.3. Document Revision History
8.2. Simulation Walkthrough with UniPHY IP x
8.2.1. Simulation Scripts 8.2.2. Preparing the Vendor Memory Model 8.2.3. Functional Simulation with Verilog HDL 8.2.4. Functional Simulation with VHDL 8.2.5. Simulating the Example Design 8.2.6. UniPHY Abstract PHY Simulation 8.2.7. PHY-Only Simulation 8.2.8. Post-fit Functional Simulation 8.2.9. Simulation Issues
8.2.8. Post-fit Functional Simulation x
8.2.8.1. Running Post-fit Simulation
9. Analyzing Timing of Memory IP x
9.1. Memory Interface Timing Components 9.2. FPGA Timing Paths 9.3. Timing Constraint and Report Files for UniPHY IP 9.4. Timing Analysis Description 9.5. Timing Report DDR 9.6. Report SDC 9.7. Calibration Effect in Timing Analysis 9.8. Timing Model Assumptions and Design Rules 9.9. Common Timing Closure Issues 9.10. Optimizing Timing 9.11. Timing Deration Methodology for Multiple Chip Select DDR2 and DDR3 SDRAM Designs 9.12. Performing I/O Timing Analysis 9.13. Document Revision History
9.1. Memory Interface Timing Components x
9.1.1. Source-Synchronous Paths 9.1.2. Calibrated Paths 9.1.3. Internal FPGA Timing Paths 9.1.4. Other FPGA Timing Parameters
9.2. FPGA Timing Paths x
9.2.1. Arria II Device PHY Timing Paths 9.2.2. Stratix III and Stratix IV PHY Timing Paths 9.2.3. Arria V, Arria V GZ, Cyclone V, and Stratix V Timing paths
9.4. Timing Analysis Description x
9.4.1. UniPHY IP Timing Analysis
9.4.1. UniPHY IP Timing Analysis x
9.4.1.1. Address and Command 9.4.1.2. PHY or Core 9.4.1.3. PHY or Core Reset 9.4.1.4. Read Capture and Write 9.4.1.5. Read Resynchronization 9.4.1.6. DQS versus CK—Arria II GX and Cyclone IV Devices 9.4.1.7. Write Leveling tDQSS 9.4.1.8. Write Leveling tDSH/tDSS 9.4.1.9. DK versus CK (RLDRAM II with UniPHY) 9.4.1.10. Bus Turnaround Time
9.4.1.4. Read Capture and Write x
9.4.1.4.1. Stratix III 9.4.1.4.2. Arria II, Arria V, Cyclone V, Stratix IV and Stratix V
9.7. Calibration Effect in Timing Analysis x
9.7.1. Calibration Emulation for Calibrated Path 9.7.2. Calibration Error or Quantization Error 9.7.3. Calibration Uncertainties 9.7.4. Memory Calibration
9.8. Timing Model Assumptions and Design Rules x
9.8.1. Memory Clock Output Assumptions 9.8.2. Write Data Assumptions 9.8.3. Read Data Assumptions 9.8.4. DLL Assumptions 9.8.5. PLL and Clock Network Assumptions for Stratix III Devices
9.8.1. Memory Clock Output Assumptions x
9.8.1.1. Memory Clock Assumptions for Stratix III Devices
9.8.2. Write Data Assumptions x
9.8.2.1. Write Data Assumptions for Stratix III Devices
9.8.3. Read Data Assumptions x
9.8.3.1. Read Data Assumptions for Stratix III Devices
9.9. Common Timing Closure Issues x
9.9.1. Missing Timing Margin Report 9.9.2. Incomplete Timing Margin Report 9.9.3. Read Capture Timing 9.9.4. Write Timing 9.9.5. Address and Command Timing 9.9.6. PHY Reset Recovery and Removal 9.9.7. Clock-to-Strobe (for DDR and DDR2 SDRAM Only) 9.9.8. Read Resynchronization and Write Leveling Timing (for SDRAM Only)
9.11. Timing Deration Methodology for Multiple Chip Select DDR2 and DDR3 SDRAM Designs x
9.11.1. Multiple Chip Select Configuration Effects 9.11.2. Timing Deration using the Board Settings
9.11.1. Multiple Chip Select Configuration Effects x
9.11.1.1. ISI Effects 9.11.1.2. Calibration Effects 9.11.1.3. Board Effects
9.11.2. Timing Deration using the Board Settings x
9.11.2.1. Slew Rates 9.11.2.2. Slew Rate Setup, Hold, and Derating Calculation 9.11.2.3. Intersymbol Interference 9.11.2.4. Measuring Eye Reduction for Address/Command, DQ, and DQS Setup and Hold Time
9.12. Performing I/O Timing Analysis x
9.12.1. Performing I/O Timing Analysis with Third-Party Simulation Tools 9.12.2. Performing Advanced I/O Timing Analysis with Board Trace Delay Model
10. Debugging Memory IP x
10.1. Resource and Planning Issues 10.2. Interface Configuration Performance Issues 10.3. Functional Issue Evaluation 10.4. Timing Issue Characteristics 10.5. Verifying Memory IP Using the Signal Tap II Logic Analyzer 10.6. Hardware Debugging Guidelines 10.7. Categorizing Hardware Issues 10.8. EMIF Debug Toolkit Overview 10.9. Document Revision History
10.1. Resource and Planning Issues x
10.1.1. Dedicated DLL Resources 10.1.2. Dedicated IOE DQS Group Resources and Pins 10.1.3. Specific PLL Resources 10.1.4. Specific Global, Regional and Dual-Regional Clock Net Resources 10.1.5. Planning Your Design 10.1.6. Optimizing Design Utilization
10.2. Interface Configuration Performance Issues x
10.2.1. Interface Configuration Bottleneck and Efficiency Issues
10.3. Functional Issue Evaluation x
10.3.1. Correct Combination of the Quartus Prime Software and ModelSim* - Intel® FPGA Edition Device Models 10.3.2. Intel® IP Memory Model 10.3.3. Vendor Memory Model 10.3.4. Insufficient Memory in Your PC 10.3.5. Transcript Window Messages 10.3.6. Passing Simulation 10.3.7. Modifying the Example Driver to Replicate the Failure
10.4. Timing Issue Characteristics x
10.4.1. Evaluating FPGA Timing Issues 10.4.2. Evaluating External Memory Interface Timing Issues
10.5. Verifying Memory IP Using the Signal Tap II Logic Analyzer x
10.5.1. Signals to Monitor with the Signal Tap II Logic Analyzer
10.6. Hardware Debugging Guidelines x
10.6.1. Create a Simplified Design that Demonstrates the Same Issue 10.6.2. Measure Power Distribution Network 10.6.3. Measure Signal Integrity and Setup and Hold Margin 10.6.4. Vary Voltage 10.6.5. Use Freezer Spray and Heat Gun 10.6.6. Operate at a Lower Speed 10.6.7. Determine Whether the Issue Exists in Previous Versions of Software 10.6.8. Determine Whether the Issue Exists in the Current Version of Software 10.6.9. Try A Different PCB 10.6.10. Try Other Configurations 10.6.11. Debugging Checklist
10.7. Categorizing Hardware Issues x
10.7.1. Signal Integrity Issues 10.7.2. Hardware and Calibration Issues
10.7.1. Signal Integrity Issues x
10.7.1.1. Characteristics of Signal Integrity Issues 10.7.1.2. Evaluating SignaI Integrity Issues
10.7.1.2. Evaluating SignaI Integrity Issues x
10.7.1.2.1. Skew 10.7.1.2.2. Crosstalk 10.7.1.2.3. Power System 10.7.1.2.4. Clock Signals 10.7.1.2.5. Read Data Valid Window and Eye Diagram 10.7.1.2.6. Write Data Valid Window and Eye Diagram 10.7.1.2.7. OCT and ODT Usage
10.7.2. Hardware and Calibration Issues x
10.7.2.1. Evaluating Hardware and Calibration Issues
10.7.2.1. Evaluating Hardware and Calibration Issues x
10.7.2.1.1. Write Timing Margin 10.7.2.1.2. Read Timing Margin 10.7.2.1.3. Address and Command Timing Margin 10.7.2.1.4. Resynchronization Timing Margin 10.7.2.1.5. Postamble Timing Issues and Margin 10.7.2.1.6. Intermittent Issue Evaluation
11. Optimizing the Controller x
11.1. Factors Affecting Efficiency 11.2. Ways to Improve Efficiency 11.3. Document Revision History
11.1. Factors Affecting Efficiency x
11.1.1. Interface Standard 11.1.2. Bank Management Efficiency 11.1.3. Data Transfer
11.2. Ways to Improve Efficiency x
11.2.1. DDR2 SDRAM Controller 11.2.2. Auto-Precharge Commands 11.2.3. Additive Latency 11.2.4. Bank Interleaving 11.2.5. Command Queue Look-Ahead Depth 11.2.6. Additive Latency and Bank Interleaving 11.2.7. User-Controlled Refresh 11.2.8. Frequency of Operation 11.2.9. Burst Length 11.2.10. Series of Reads or Writes 11.2.11. Data Reordering 11.2.12. Starvation Control 11.2.13. Command Reordering 11.2.14. Bandwidth 11.2.15. Efficiency Monitor
12. PHY Considerations x
12.1. Core Logic and User Interface Data Rate 12.2. Hard and Soft Memory PHY 12.3. Sequencer 12.4. PLL, DLL and OCT Resource Sharing 12.5. Pin Placement Consideration 12.6. Document Revision History
13. Power Estimation Methods for External Memory Interfaces x
13.1. Performing Vector-Based Power Analysis with the Power Analyzer 13.2. Document Revision History
1. Planning Pin and FPGA Resources
2. DDR2 and DDR3 SDRAM Board Design Guidelines
3. Dual-DIMM DDR2 and DDR3 SDRAM Board Design Guidelines
4. LPDDR2 SDRAM Board Design Guidelines
5. RLDRAM II and RLDRAM 3 Board Design Guidelines
6. QDR II/II+ SRAM Board Design Guidelines
7. Implementing and Parameterizing Memory IP
8. Simulating Memory IP
9. Analyzing Timing of Memory IP
10. Debugging Memory IP
11. Optimizing the Controller
12. PHY Considerations
13. Power Estimation Methods for External Memory Interfaces

7.2.4.3.1. Board Skew Parameters for LPDDR2/DDR2/DDR3 SDRAM

The following paragraphs describe board skew parameters for LPDDR2, DDR2, and DDR3 interfaces.

FPGA DQ/DQS Package Skews Deskewed on Board

Enable this parameter if you will deskew the FPGA package with your board traces on the DQ and DQS pins. This option increases the read capture and write margins. Enable this option when memory clock frequency is larger than 800 MHz. Enabling this option improves the read capture and write timing margin. You can also rely on the read capture and write timing margin in timing report to enable this option.

When this option is enabled, package skews are output on the DQ and DQS pins in the Pin-Out File (.pin) and package skew is not included in timing analysis. All of the other board delay and skew parameters related to DQ or DQS must consider the package and the board together. For more information, refer to DDR2 and DDR3 Board Layout Guidelines .

Address/Command Package Deskew

Enable this parameter if you will deskew the FPGA package with your board traces on the address and command pins. This option increases the address and command margins. Enable this option when memory clock frequency is larger than 800 MHz.Enabling this option will improve the address and command timing margin. You can also rely on the address and command margin in timing report to enable this option.

When this option is enabled, package skews are output on the address and command pins in the Pin-Out File (.pin) and package skew is not included in timing analysis. All of the other board delay and skew parameters related to Address and Command must consider the package and the board together. For more information, refer to DDR2 and DDR3 Board Layout Guidelines.

Maximum CK delay to DIMM/device

The delay of the longest CK trace from the FPGA to the memory device, whether on a DIMM or the same PCB as the FPGA is expressed by the following equation:

Where n is the number of memory clock and r is number rank of DIMM/device. For example in dual-rank DIMM implementation, if there are 2 pairs of memory clocks in each rank DIMM, the maximum CK delay is expressed by the following equation:

Maximum DQS delay to DIMM/device

The delay of the longest DQS trace from the FPGA to the memory device, whether on a DIMM or the same PCB as the FPGA is expressed by the following equation:

Where n is the number of DQS and r is number of rank of DIMM/device. For example in dual-rank DIMM implementation, if there are 2 DQS in each rank DIMM, the maximum DQS delay is expressed by the following equation:

Minimum delay difference between CK and DQS

The minimum skew or smallest positive skew (or largest negative skew) between the CK signal and any DQS signal when arriving at the same DIMM/device over all DIMMs/devices is expressed by the following equation:

Where n is the number of memory clock, m is the number of DQS, and r is the number of rank of DIMM/device. For example in dual-rank DIMM implementation, if there are 2 pairs of memory clock and 4 DQS signals (two for each clock) for each rank DIMM, the minimum delay difference between CK and DQS is expressed by the following equation:

This parameter value affects the write leveling margin for DDR3 interfaces with leveling in multi-rank configurations. This parameter value also applies to non-leveling configurations of any number of ranks with the requirement that DQS must have positive margins in Report DDR.

For multiple boards, the minimum skew between the CK signal and any DQS signal when arriving at the same DIMM over all DIMMs is expressed by the following equation, if you want to use the same design for several different boards:

Note: If you are using a clamshell topology in a multirank/multi chip-select design with either DIMM or discrete devices, or using dual-die devices, the above calculations do not apply; you may use the default values in the GUI.

Maximum delay difference between CK and DQS

The maximum skew or smallest negative skew (or largest positive skew) between the CK signal and any DQS signal when arriving at the same DIMM/device over all DIMMs/devices is expressed by the following equation:

Where n is the number of memory clock, m is the number of DQS, and r is the number of rank of DIMM/device. For example in dual-rank DIMM implementation, if there are 2 pairs of memory clock and 4 DQS signals (two for each clock) for each rank DIMM, the maximum delay difference between CK and DQS is expressed by the following equation:

This value affects the write Leveling margin for DDR3 interfaces with leveling in multi-rank configurations. This parameter value also applies to non-leveling configurations of any number of ranks with the requirement that DQS must have positive margins in Report DDR.

For multiple boards, the maximum skew (or largest positive skew) between the CK signal and any DQS signal when arriving at the same DIMM over all DIMMs is expressed by the following equation, if you want to use the same design for several different boards:

Note: If you are using a clamshell topology in a multirank/multi chip-select design with either DIMM or discrete devices, or using dual-die devices, the above calculations do not apply; you may use the default values in the GUI.

Maximum skew within DQS group

The largest skew among DQ and DM signals in a DQS group. This value affects the read capture and write margins for DDR2 and DDR3 SDRAM interfaces in all configurations (single or multiple chip-select, DIMM or component).

For multiple boards, the largest skew between DQ and DM signals in a DQS group is expressed by the following equation:

Maximum skew between DQS groups

The largest skew between DQS signals in different DQS groups. This value affects the resynchronization margin in memory interfaces without leveling such as DDR2 SDRAM and discrete-device DDR3 SDRAM in both single- or multiple chip-select configurations. For protocols or families that do not have read resynchronization analysis, this parameter has no effect.

For multiple boards, the largest skew between DQS signals in different DQS groups is expressed by the following equation, if you want to use the same design for several different boards:

Average delay difference between DQ and DQS

The average delay difference between each DQ signal and the DQS signal, calculated by averaging the longest and smallest DQ signal delay values minus the delay of DQS. The average delay difference between DQ and DQS is expressed by the following equation:

where n is the number of DQS groups. For multi-rank or multiple CS configuration, the equation is:

Maximum skew within address and command bus

The largest skew between the address and command signals for a single board is expressed by the following equation:

For multiple boards, the largest skew between the address and command signals is expressed by the following equation, if you want to use the same design for several different boards:

Average delay difference between address and command and CK

A value equal to the average of the longest and smallest address and command signal delay values, minus the delay of the CK signal. The value can be positive or negative. Positive values represent address and command signals that are longer than CK signals; negative values represent address and command signals that are shorter than CK signals. The average delay difference between address and command and CK is expressed by the following equation:

where n is the number of memory clocks. For multi-rank or multiple CS configuration, the equation is:

The Quartus Prime software uses this skew to optimize the delay of the address and command signals to have appropriate setup and hold margins for DDR2 and DDR3 SDRAM interfaces. You should derive this value through board simulation.

For multiple boards, the average delay difference between address and command and CK is expressed by the following equation, if you want to use the same design for several different boards:

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