External Memory Interfaces Stratix® 10 FPGA IP User Guide

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ID 683741
Date 11/28/2024
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Document Table of Contents
Document Table of Contents x
1. Release Information 2. External Memory Interfaces Stratix® 10 FPGA IP Introduction 3. Stratix® 10 EMIF IP Product Architecture 4. Stratix® 10 EMIF IP End-User Signals 5. Stratix® 10 EMIF – Simulating Memory IP 6. Stratix® 10 EMIF IP for DDR3 7. Stratix® 10 EMIF IP for DDR4 8. Stratix® 10 EMIF IP for QDR II/II+/II+ Xtreme 9. Stratix® 10 EMIF IP for QDR-IV 10. Stratix® 10 EMIF IP for RLDRAM 3 11. Stratix® 10 EMIF IP Timing Closure 12. Optimizing Controller Performance 13. Stratix® 10 EMIF IP Debugging 14. External Memory Interfaces Stratix® 10 FPGA IP User Guide Archives 15. Document Revision History for External Memory Interfaces Stratix® 10 FPGA IP User Guide
2. External Memory Interfaces Stratix® 10 FPGA IP Introduction x
2.1. Stratix® 10 EMIF IP Design Flow 2.2. Stratix® 10 EMIF IP Design Checklist
3. Stratix® 10 EMIF IP Product Architecture x
3.1. Stratix® 10 EMIF Architecture: Introduction 3.2. Stratix® 10 EMIF Sequencer 3.3. Stratix® 10 EMIF Calibration 3.4. Intel Stratix 10 EMIF IP Controller 3.5. Hardware Resource Sharing Among Multiple Stratix® 10 EMIFs 3.6. User-requested Reset in Stratix® 10 EMIF IP 3.7. Stratix® 10 EMIF for Hard Processor Subsystem 3.8. Stratix® 10 EMIF Ping Pong PHY
3.1. Stratix® 10 EMIF Architecture: Introduction x
3.1.1. Stratix® 10 EMIF Architecture: I/O Subsystem 3.1.2. Stratix® 10 EMIF Architecture: I/O Column 3.1.3. Stratix® 10 EMIF Architecture: I/O SSM 3.1.4. Stratix® 10 EMIF Architecture: I/O Bank 3.1.5. Stratix® 10 EMIF Architecture: I/O Lane 3.1.6. Stratix® 10 EMIF Architecture: Input DQS Clock Tree 3.1.7. Stratix® 10 EMIF Architecture: PHY Clock Tree 3.1.8. Stratix® 10 EMIF Architecture: PLL Reference Clock Networks 3.1.9. Stratix® 10 EMIF Architecture: Clock Phase Alignment
3.2. Stratix® 10 EMIF Sequencer x
3.2.1. Stratix® 10 EMIF DQS Tracking
3.3. Stratix® 10 EMIF Calibration x
3.3.1. Stratix® 10 Calibration Stages 3.3.2. Stratix® 10 Calibration Stages Descriptions 3.3.3. Stratix® 10 Calibration Flowchart 3.3.4. Stratix® 10 Calibration Algorithms
3.4. Intel Stratix 10 EMIF IP Controller x
3.4.1. Hard Memory Controller 3.4.2. Stratix® 10 Hard Memory Controller Rate Conversion Feature
3.4.1. Hard Memory Controller x
3.4.1.1. Hard Memory Controller Features 3.4.1.2. Hard Memory Controller Main Control Path 3.4.1.3. Data Buffer Controller
3.5. Hardware Resource Sharing Among Multiple Stratix® 10 EMIFs x
3.5.1. I/O SSM Sharing 3.5.2. I/O Bank Sharing 3.5.3. PLL Reference Clock Sharing 3.5.4. Core Clock Network Sharing
3.7. Stratix® 10 EMIF for Hard Processor Subsystem x
3.7.1. Restrictions on I/O Bank Usage for Stratix® 10 EMIF IP with HPS 3.7.2. Using the Legacy EMIF Debug Toolkit with Stratix® 10 HPS Interfaces 3.7.3. HPS EMIF Simulation
3.8. Stratix® 10 EMIF Ping Pong PHY x
3.8.1. Stratix® 10 Ping Pong PHY Feature Description 3.8.2. Stratix® 10 Ping Pong PHY Architecture 3.8.3. Stratix® 10 Ping Pong PHY Limitations 3.8.4. Stratix® 10 Ping Pong PHY Calibration 3.8.5. Using the Ping Pong PHY 3.8.6. Ping Pong PHY Simulation Example Design
4. Stratix® 10 EMIF IP End-User Signals x
4.1. Interface and Signal Descriptions 4.2. AFI Signals 4.3. AFI 4.0 Timing Diagrams 4.4. Stratix® 10 Memory Mapped Register (MMR) Tables
4.1. Interface and Signal Descriptions x
4.1.1. Intel Stratix 10 EMIF IP Interfaces for DDR3 4.1.2. Intel Stratix 10 EMIF IP Interfaces for DDR4 4.1.3. Intel Stratix 10 EMIF IP Interfaces for QDR II/II+/II+ Xtreme 4.1.4. Intel Stratix 10 EMIF IP Interfaces for QDR-IV 4.1.5. Intel Stratix 10 EMIF IP Interfaces for RLDRAM 3
4.1.1. Intel Stratix 10 EMIF IP Interfaces for DDR3 x
4.1.1.1. local_reset_req for DDR3 4.1.1.2. local_reset_status for DDR3 4.1.1.3. pll_ref_clk for DDR3 4.1.1.4. pll_locked for DDR3 4.1.1.5. pll_extra_clk_0 for DDR3 4.1.1.6. pll_extra_clk_1 for DDR3 4.1.1.7. pll_extra_clk_2 for DDR3 4.1.1.8. pll_extra_clk_3 for DDR3 4.1.1.9. oct for DDR3 4.1.1.10. mem for DDR3 4.1.1.11. status for DDR3 4.1.1.12. afi_reset_n for DDR3 4.1.1.13. afi_clk for DDR3 4.1.1.14. afi_half_clk for DDR3 4.1.1.15. afi for DDR3 4.1.1.16. emif_usr_reset_n for DDR3 4.1.1.17. emif_usr_clk for DDR3 4.1.1.18. emif_usr_reset_n_sec for DDR3 4.1.1.19. emif_usr_clk_sec for DDR3 4.1.1.20. cal_debug_reset_n for DDR3 4.1.1.21. cal_debug_clk for DDR3 4.1.1.22. cal_debug_out_reset_n for DDR3 4.1.1.23. cal_debug_out_clk for DDR3 4.1.1.24. clks_sharing_master_out for DDR3 4.1.1.25. clks_sharing_slave_in for DDR3 4.1.1.26. clks_sharing_slave_out for DDR3 4.1.1.27. ctrl_amm for DDR3 4.1.1.28. ctrl_auto_precharge for DDR3 4.1.1.29. ctrl_user_priority for DDR3 4.1.1.30. ctrl_ecc_user_interrupt for DDR3 4.1.1.31. ctrl_ecc_readdataerror for DDR3 4.1.1.32. ctrl_ecc_status for DDR3 4.1.1.33. ctrl_mmr_slave for DDR3 4.1.1.34. hps_emif for DDR3 4.1.1.35. cal_debug for DDR3 4.1.1.36. cal_debug_out for DDR3
4.1.2. Intel Stratix 10 EMIF IP Interfaces for DDR4 x
4.1.2.1. local_reset_req for DDR4 4.1.2.2. local_reset_status for DDR4 4.1.2.3. pll_ref_clk for DDR4 4.1.2.4. pll_locked for DDR4 4.1.2.5. pll_extra_clk_0 for DDR4 4.1.2.6. pll_extra_clk_1 for DDR4 4.1.2.7. pll_extra_clk_2 for DDR4 4.1.2.8. pll_extra_clk_3 for DDR4 4.1.2.9. ac_parity_err for DDR4 4.1.2.10. oct for DDR4 4.1.2.11. mem for DDR4 4.1.2.12. status for DDR4 4.1.2.13. afi_reset_n for DDR4 4.1.2.14. afi_clk for DDR4 4.1.2.15. afi_half_clk for DDR4 4.1.2.16. afi for DDR4 4.1.2.17. emif_usr_reset_n for DDR4 4.1.2.18. emif_usr_clk for DDR4 4.1.2.19. emif_usr_reset_n_sec for DDR4 4.1.2.20. emif_usr_clk_sec for DDR4 4.1.2.21. cal_debug_reset_n for DDR4 4.1.2.22. cal_debug_clk for DDR4 4.1.2.23. cal_debug_out_reset_n for DDR4 4.1.2.24. cal_debug_out_clk for DDR4 4.1.2.25. clks_sharing_master_out for DDR4 4.1.2.26. clks_sharing_slave_in for DDR4 4.1.2.27. clks_sharing_slave_out for DDR4 4.1.2.28. ctrl_amm for DDR4 4.1.2.29. ctrl_auto_precharge for DDR4 4.1.2.30. ctrl_user_priority for DDR4 4.1.2.31. ctrl_ecc_user_interrupt for DDR4 4.1.2.32. ctrl_ecc_readdataerror for DDR4 4.1.2.33. ctrl_ecc_status for DDR4 4.1.2.34. ctrl_mmr_slave for DDR4 4.1.2.35. hps_emif for DDR4 4.1.2.36. cal_debug for DDR4 4.1.2.37. cal_debug_out for DDR4
4.1.3. Intel Stratix 10 EMIF IP Interfaces for QDR II/II+/II+ Xtreme x
4.1.3.1. local_reset_req for QDR II/II+/II+ Xtreme 4.1.3.2. local_reset_status for QDR II/II+/II+ Xtreme 4.1.3.3. pll_ref_clk for QDR II/II+/II+ Xtreme 4.1.3.4. pll_locked for QDR II/II+/II+ Xtreme 4.1.3.5. pll_extra_clk_0 for QDR II/II+/II+ Xtreme 4.1.3.6. pll_extra_clk_1 for QDR II/II+/II+ Xtreme 4.1.3.7. pll_extra_clk_2 for QDR II/II+/II+ Xtreme 4.1.3.8. pll_extra_clk_3 for QDR II/II+/II+ Xtreme 4.1.3.9. oct for QDR II/II+/II+ Xtreme 4.1.3.10. mem for QDR II/II+/II+ Xtreme 4.1.3.11. status for QDR II/II+/II+ Xtreme 4.1.3.12. emif_usr_reset_n for QDR II/II+/II+ Xtreme 4.1.3.13. emif_usr_clk for QDR II/II+/II+ Xtreme 4.1.3.14. cal_debug_reset_n for QDR II/II+/II+ Xtreme 4.1.3.15. cal_debug_clk for QDR II/II+/II+ Xtreme 4.1.3.16. cal_debug_out_reset_n for QDR II/II+/II+ Xtreme 4.1.3.17. cal_debug_out_clk for QDR II/II+/II+ Xtreme 4.1.3.18. clks_sharing_master_out for QDR II/II+/II+ Xtreme 4.1.3.19. clks_sharing_slave_in for QDR II/II+/II+ Xtreme 4.1.3.20. clks_sharing_slave_out for QDR II/II+/II+ Xtreme 4.1.3.21. ctrl_amm for QDR II/II+/II+ Xtreme 4.1.3.22. cal_debug for QDR II/II+/II+ Xtreme 4.1.3.23. cal_debug_out for QDR II/II+/II+ Xtreme
4.1.4. Intel Stratix 10 EMIF IP Interfaces for QDR-IV x
4.1.4.1. local_reset_req for QDR-IV 4.1.4.2. local_reset_status for QDR-IV 4.1.4.3. pll_ref_clk for QDR-IV 4.1.4.4. pll_locked for QDR-IV 4.1.4.5. pll_extra_clk_0 for QDR-IV 4.1.4.6. pll_extra_clk_1 for QDR-IV 4.1.4.7. pll_extra_clk_2 for QDR-IV 4.1.4.8. pll_extra_clk_3 for QDR-IV 4.1.4.9. oct for QDR-IV 4.1.4.10. mem for QDR-IV 4.1.4.11. status for QDR-IV 4.1.4.12. afi_reset_n for QDR-IV 4.1.4.13. afi_clk for QDR-IV 4.1.4.14. afi_half_clk for QDR-IV 4.1.4.15. afi for QDR-IV 4.1.4.16. emif_usr_reset_n for QDR-IV 4.1.4.17. emif_usr_clk for QDR-IV 4.1.4.18. cal_debug_reset_n for QDR-IV 4.1.4.19. cal_debug_clk for QDR-IV 4.1.4.20. cal_debug_out_reset_n for QDR-IV 4.1.4.21. cal_debug_out_clk for QDR-IV 4.1.4.22. clks_sharing_master_out for QDR-IV 4.1.4.23. clks_sharing_slave_in for QDR-IV 4.1.4.24. clks_sharing_slave_out for QDR-IV 4.1.4.25. ctrl_amm for QDR-IV 4.1.4.26. cal_debug for QDR-IV 4.1.4.27. cal_debug_out for QDR-IV
4.1.5. Intel Stratix 10 EMIF IP Interfaces for RLDRAM 3 x
4.1.5.1. local_reset_req for RLDRAM 3 4.1.5.2. local_reset_status for RLDRAM 3 4.1.5.3. pll_ref_clk for RLDRAM 3 4.1.5.4. pll_locked for RLDRAM 3 4.1.5.5. pll_extra_clk_0 for RLDRAM 3 4.1.5.6. pll_extra_clk_1 for RLDRAM 3 4.1.5.7. pll_extra_clk_2 for RLDRAM 3 4.1.5.8. pll_extra_clk_3 for RLDRAM 3 4.1.5.9. oct for RLDRAM 3 4.1.5.10. mem for RLDRAM 3 4.1.5.11. status for RLDRAM 3 4.1.5.12. afi_reset_n for RLDRAM 3 4.1.5.13. afi_clk for RLDRAM 3 4.1.5.14. afi_half_clk for RLDRAM 3 4.1.5.15. afi for RLDRAM 3 4.1.5.16. cal_debug_reset_n for RLDRAM 3 4.1.5.17. cal_debug_clk for RLDRAM 3 4.1.5.18. cal_debug_out_reset_n for RLDRAM 3 4.1.5.19. cal_debug_out_clk for RLDRAM 3 4.1.5.20. clks_sharing_master_out for RLDRAM 3 4.1.5.21. clks_sharing_slave_in for RLDRAM 3 4.1.5.22. clks_sharing_slave_out for RLDRAM 3 4.1.5.23. cal_debug for RLDRAM 3 4.1.5.24. cal_debug_out for RLDRAM 3
4.2. AFI Signals x
4.2.1. AFI Clock and Reset Signals 4.2.2. AFI Address and Command Signals 4.2.3. AFI Write Data Signals 4.2.4. AFI Read Data Signals 4.2.5. AFI Calibration Status Signals 4.2.6. AFI Shadow Register Management Signals
4.3. AFI 4.0 Timing Diagrams x
4.3.1. AFI Address and Command Timing Diagrams 4.3.2. AFI Write Sequence Timing Diagrams 4.3.3. AFI Read Sequence Timing Diagrams 4.3.4. AFI Calibration Status Timing Diagram
4.4. Stratix® 10 Memory Mapped Register (MMR) Tables x
4.4.1. ctrlcfg0 4.4.2. ctrlcfg1 4.4.3. dramtiming0 4.4.4. caltiming0 4.4.5. caltiming1 4.4.6. caltiming2 4.4.7. caltiming3 4.4.8. caltiming4 4.4.9. caltiming9 4.4.10. dramaddrw 4.4.11. sideband0 4.4.12. sideband1 4.4.13. sideband4 4.4.14. sideband6 4.4.15. sideband7 4.4.16. sideband9 4.4.17. sideband11 4.4.18. sideband12 4.4.19. sideband13 4.4.20. sideband14 4.4.21. dramsts 4.4.22. niosreserve0 4.4.23. niosreserve1 4.4.24. sideband16 4.4.25. ecc3: ECC Error and Interrupt Configuration 4.4.26. ecc4: Status and Error Information 4.4.27. ecc5: Address of Most Recent SBE/DBE 4.4.28. ecc6: Address of Most Recent Correction Command Dropped 4.4.29. ecc7: Extension for Address of Most Recent SBE/DBE 4.4.30. ecc8: Extension for Address of Most Recent Correction Command Dropped
5. Stratix® 10 EMIF – Simulating Memory IP x
5.1. Simulation Options 5.2. HPS EMIF Simulation 5.3. Simulation Walkthrough
5.3. Simulation Walkthrough x
5.3.1. Calibration Modes 5.3.2. Abstract PHY Simulation 5.3.3. Simulation Scripts 5.3.4. Functional Simulation with Verilog HDL 5.3.5. Functional Simulation with VHDL 5.3.6. Simulating the Design Example
5.3.6. Simulating the Design Example x
5.3.6.1. User-requested Reset in Stratix® 10 EMIF IP
6. Stratix® 10 EMIF IP for DDR3 x
6.1. Parameter Descriptions 6.2. Register Map IP-XACT Support for Stratix® 10 EMIF DDR3 IP 6.3. Board Skew Equations 6.4. Pin and Resource Planning 6.5. DDR3 Board Design Guidelines
6.1. Parameter Descriptions x
6.1.1. Intel Stratix 10 EMIF IP DDR3 Parameters: General 6.1.2. Intel Stratix 10 EMIF IP DDR3 Parameters: Memory 6.1.3. Intel Stratix 10 EMIF IP DDR3 Parameters: Mem I/O 6.1.4. Intel Stratix 10 EMIF IP DDR3 Parameters: FPGA I/O 6.1.5. Intel Stratix 10 EMIF IP DDR3 Parameters: Mem Timing 6.1.6. Intel Stratix 10 EMIF IP DDR3 Parameters: Board 6.1.7. Intel Stratix 10 EMIF IP DDR3 Parameters: Controller 6.1.8. Intel Stratix 10 EMIF IP DDR3 Parameters: Diagnostics 6.1.9. Intel Stratix 10 EMIF IP DDR3 Parameters: Example Designs
6.3. Board Skew Equations x
6.3.1. Equations for DDR3 Board Skew Parameters
6.4. Pin and Resource Planning x
6.4.1. Interface Pins 6.4.2. FPGA Resources 6.4.3. Pin Guidelines for Stratix® 10 EMIF IP
6.4.1. Interface Pins x
6.4.1.1. Estimating Pin Requirements 6.4.1.2. DIMM Options 6.4.1.3. Maximum Number of Interfaces
6.4.2. FPGA Resources x
6.4.2.1. OCT 6.4.2.2. PLL
6.4.3. Pin Guidelines for Stratix® 10 EMIF IP x
6.4.3.1. General Guidelines 6.4.3.2. x4 DIMM Implementation 6.4.3.3. Command and Address Signals 6.4.3.4. Clock Signals 6.4.3.5. Data, Data Strobes, DM/DBI, and Optional ECC Signals 6.4.3.6. Resource Sharing Guidelines (Multiple Interfaces) 6.4.3.7. Ping-Pong PHY Implementation
6.5. DDR3 Board Design Guidelines x
6.5.1. Terminations and Slew Rates with Stratix® 10 Devices 6.5.2. Channel Signal Integrity Measurement 6.5.3. Layout Approach 6.5.4. Design Layout Guidelines 6.5.5. Package Deskew
6.5.1. Terminations and Slew Rates with Stratix® 10 Devices x
6.5.1.1. Dynamic On-Chip Termination (OCT) in Stratix® 10 Devices 6.5.1.2. Choosing Terminations on Stratix® 10 Devices 6.5.1.3. On-Chip Termination Recommendations for Stratix® 10 Devices 6.5.1.4. Slew Rates
6.5.2. Channel Signal Integrity Measurement x
6.5.2.1. Importance of Accurate Channel Signal Integrity Information 6.5.2.2. Understanding Channel Signal Integrity Measurement 6.5.2.3. How to Enter Calculated Channel Signal Integrity Values 6.5.2.4. Guidelines for Calculating DDR3 Channel Signal Integrity
6.5.4. Design Layout Guidelines x
6.5.4.1. General Layout Guidelines 6.5.4.2. Layout Guidelines 6.5.4.3. Length Matching Rules 6.5.4.4. Spacing Guidelines 6.5.4.5. Fly-By Network Design for Clock, Command, and Address Signals
6.5.5. Package Deskew x
6.5.5.1. DQ/DQS/DM Deskew 6.5.5.2. Address and Command Deskew 6.5.5.3. Package Deskew Recommendations for Stratix® 10 Devices 6.5.5.4. Deskew Example 6.5.5.5. Package Migration
7. Stratix® 10 EMIF IP for DDR4 x
7.1. Parameter Descriptions 7.2. Register Map IP-XACT Support for Stratix® 10 EMIF DDR4 IP 7.3. Board Skew Equations 7.4. Pin and Resource Planning 7.5. DDR4 Board Design Guidelines
7.1. Parameter Descriptions x
7.1.1. Intel Stratix 10 EMIF IP DDR4 Parameters: General 7.1.2. Intel Stratix 10 EMIF IP DDR4 Parameters: Memory 7.1.3. Intel Stratix 10 EMIF IP DDR4 Parameters: Mem I/O 7.1.4. Intel Stratix 10 EMIF IP DDR4 Parameters: FPGA I/O 7.1.5. Intel Stratix 10 EMIF IP DDR4 Parameters: Mem Timing 7.1.6. Intel Stratix 10 EMIF IP DDR4 Parameters: Board 7.1.7. Intel Stratix 10 EMIF IP DDR4 Parameters: Controller 7.1.8. Intel Stratix 10 EMIF IP DDR4 Parameters: Diagnostics 7.1.9. Intel Stratix 10 EMIF IP DDR4 Parameters: Example Designs
7.3. Board Skew Equations x
7.3.1. Equations for DDR4 Board Skew Parameters
7.4. Pin and Resource Planning x
7.4.1. Interface Pins 7.4.2. FPGA Resources 7.4.3. Pin Guidelines for Stratix® 10 EMIF IP 7.4.4. Resource Sharing Guidelines (Multiple Interfaces)
7.4.1. Interface Pins x
7.4.1.1. Estimating Pin Requirements 7.4.1.2. DIMM Options 7.4.1.3. Maximum Number of Interfaces
7.4.2. FPGA Resources x
7.4.2.1. OCT 7.4.2.2. PLL
7.4.3. Pin Guidelines for Stratix® 10 EMIF IP x
7.4.3.1. General Guidelines 7.4.3.2. x4 DIMM Implementation 7.4.3.3. Command and Address Signals 7.4.3.4. Clock Signals 7.4.3.5. Data, Data Strobes, DM/DBI, and Optional ECC Signals 7.4.3.6. alert_n Pin Termination Recommendation
7.5. DDR4 Board Design Guidelines x
7.5.1. Terminations and Slew Rates with Stratix® 10 Devices 7.5.2. Channel Signal Integrity Measurement 7.5.3. Layout Approach 7.5.4. Design Layout Guidelines 7.5.5. Package Deskew
7.5.1. Terminations and Slew Rates with Stratix® 10 Devices x
7.5.1.1. Dynamic On-Chip Termination (OCT) in Stratix® 10 Devices 7.5.1.2. Dynamic On-Die Termination (ODT) in DDR4 7.5.1.3. Choosing Terminations on Stratix® 10 Devices 7.5.1.4. On-Chip Termination Recommendations for Stratix® 10 Devices 7.5.1.5. Slew Rates
7.5.2. Channel Signal Integrity Measurement x
7.5.2.1. Importance of Accurate Channel Signal Integrity Information 7.5.2.2. Understanding Channel Signal Integrity Measurement 7.5.2.3. How to Enter Calculated Channel Signal Integrity Values 7.5.2.4. Guidelines for Calculating DDR4 Channel Signal Integrity
7.5.4. Design Layout Guidelines x
7.5.4.1. General Layout Guidelines 7.5.4.2. Layout Guidelines 7.5.4.3. Length Matching Rules 7.5.4.4. Spacing Guidelines 7.5.4.5. Layout Guidelines for DDR3 and DDR4 SDRAM Wide Interface (>72 bits) 7.5.4.6. Fly-By Network Design for Clock, Command, and Address Signals 7.5.4.7. Clamshell Topology 7.5.4.8. Additional Layout Guidelines for DDR4 Twin-die Devices
7.5.5. Package Deskew x
7.5.5.1. DQ/DQS/DM Deskew 7.5.5.2. Address and Command Deskew 7.5.5.3. Package Deskew Recommendations for Stratix® 10 Devices 7.5.5.4. Deskew Example 7.5.5.5. Package Migration
8. Stratix® 10 EMIF IP for QDR II/II+/II+ Xtreme x
8.1. Parameter Descriptions 8.2. Board Skew Equations 8.3. Pin and Resource Planning 8.4. QDR II/II+/II+ Xtreme Board Design Guidelines
8.1. Parameter Descriptions x
8.1.1. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: General 8.1.2. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Memory 8.1.3. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: FPGA I/O 8.1.4. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Mem Timing 8.1.5. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Board 8.1.6. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Controller 8.1.7. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Diagnostics 8.1.8. Intel Stratix 10 EMIF IP QDR II/II+/II+ Xtreme Parameters: Example Designs
8.2. Board Skew Equations x
8.2.1. Equations for QDRII, QDRII+, and QDRII+ Xtreme Board Skew Parameters
8.3. Pin and Resource Planning x
8.3.1. Interface Pins
8.3.1. Interface Pins x
8.3.1.1. Estimating Pin Requirements 8.3.1.2. Maximum Number of Interfaces 8.3.1.3. FPGA Resources 8.3.1.4. OCT 8.3.1.5. PLL 8.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP
8.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP x
8.3.1.6.1. General Guidelines 8.3.1.6.2. QDR II, QDR II+ and QDR II+ Xtreme SRAM Command Signals 8.3.1.6.3. QDR II, QDR II+ and QDR II+ Xtreme SRAM Address Signals 8.3.1.6.4. QDR II, QDR II+, and QDR II+ Xtreme SRAM Clock Signals 8.3.1.6.5. QDR II, QDR II+ and QDR II+ Xtreme SRAM Data, BWS, and QVLD Signals 8.3.1.6.6. Resource Sharing Guidelines (Multiple Interfaces)
8.4. QDR II/II+/II+ Xtreme Board Design Guidelines x
8.4.1. QDR II SRAM Configurations 8.4.2. General Layout Guidelines 8.4.3. QDR II Layout Guidelines 8.4.4. QDR II SRAM Layout Approach 8.4.5. Package Deskew 8.4.6. Package Migration 8.4.7. Slew Rates
9. Stratix® 10 EMIF IP for QDR-IV x
9.1. Parameter Descriptions 9.2. Board Skew Equations 9.3. Pin and Resource Planning 9.4. QDR-IV Board Design Guidelines
9.1. Parameter Descriptions x
9.1.1. Intel Stratix 10 EMIF IP QDR-IV Parameters: General 9.1.2. Intel Stratix 10 EMIF IP QDR-IV Parameters: Memory 9.1.3. Intel Stratix 10 EMIF IP QDR-IV Parameters: FPGA I/O 9.1.4. Intel Stratix 10 EMIF IP QDR-IV Parameters: Mem Timing 9.1.5. Intel Stratix 10 EMIF IP QDR-IV Parameters: Board 9.1.6. Intel Stratix 10 EMIF IP QDR-IV Parameters: Controller 9.1.7. Intel Stratix 10 EMIF IP QDR-IV Parameters: Diagnostics 9.1.8. Intel Stratix 10 EMIF IP QDR-IV Parameters: Example Designs
9.2. Board Skew Equations x
9.2.1. Equations for QDR-IV Board Skew Parameters
9.3. Pin and Resource Planning x
9.3.1. Interface Pins
9.3.1. Interface Pins x
9.3.1.1. Estimating Pin Requirements 9.3.1.2. Maximum Number of Interfaces 9.3.1.3. FPGA Resources 9.3.1.4. OCT 9.3.1.5. PLL 9.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP 9.3.1.7. Resource Sharing Guidelines (Multiple Interfaces)
9.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP x
9.3.1.6.1. General Guidelines 9.3.1.6.2. QDR IV SRAM Commands and Addresses, AP, and AINV Signals 9.3.1.6.3. QDR IV SRAM Clock Signals 9.3.1.6.4. QDR IV SRAM Data, DINV, and QVLD Signals
9.4. QDR-IV Board Design Guidelines x
9.4.1. QDR-IV Layout Approach 9.4.2. General Layout Guidelines 9.4.3. QDR-IV Layout Guidelines 9.4.4. Package Deskew 9.4.5. Package Migration 9.4.6. Slew Rates
10. Stratix® 10 EMIF IP for RLDRAM 3 x
10.1. Parameter Descriptions 10.2. Board Skew Equations 10.3. Pin and Resource Planning 10.4. RLDRAM 3 Board Design Guidelines
10.1. Parameter Descriptions x
10.1.1. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: General 10.1.2. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: Memory 10.1.3. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: FPGA I/O 10.1.4. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: Mem Timing 10.1.5. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: Board 10.1.6. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: Diagnostics 10.1.7. Intel Stratix 10 EMIF IP RLDRAM 3 Parameters: Example Designs
10.2. Board Skew Equations x
10.2.1. Equations for RLDRAM 3 Board Skew Parameters
10.3. Pin and Resource Planning x
10.3.1. Interface Pins
10.3.1. Interface Pins x
10.3.1.1. Estimating Pin Requirements 10.3.1.2. Maximum Number of Interfaces 10.3.1.3. FPGA Resources 10.3.1.4. OCT 10.3.1.5. PLL 10.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP 10.3.1.7. Resource Sharing Guidelines (Multiple Interfaces)
10.3.1.6. Pin Guidelines for Stratix® 10 EMIF IP x
10.3.1.6.1. General Guidelines 10.3.1.6.2. RLDRAM 3 Commands and Addresses 10.3.1.6.3. RLDRAM 3 Clock Signals 10.3.1.6.4. RLDRAM 3 Data, DM and QVLD Signals
10.4. RLDRAM 3 Board Design Guidelines x
10.4.1. RLDRAM 3 Configurations 10.4.2. General Layout Guidelines 10.4.3. RLDRAM 3 Layout Guidelines 10.4.4. Layout Approach 10.4.5. Package Deskew 10.4.6. Package Migration 10.4.7. Slew Rates
11. Stratix® 10 EMIF IP Timing Closure x
11.1. Timing Closure 11.2. Timing Report DDR 11.3. Optimizing Timing 11.4. Early I/O Timing Estimation
11.1. Timing Closure x
11.1.1. Timing Analysis
11.1.1. Timing Analysis x
11.1.1.1. PHY or Core 11.1.1.2. I/O Timing
11.1.1.2. I/O Timing x
11.1.1.2.1. Read Capture 11.1.1.2.2. Write 11.1.1.2.3. Address and Command 11.1.1.2.4. DQS Gating / Postamble 11.1.1.2.5. Write Leveling
11.4. Early I/O Timing Estimation x
11.4.1. Performing Early I/O Timing Analysis
12. Optimizing Controller Performance x
12.1. Interface Standard 12.2. Bank Management Efficiency 12.3. Data Transfer 12.4. Improving Controller Efficiency
12.4. Improving Controller Efficiency x
12.4.1. Auto-Precharge Commands 12.4.2. Latency 12.4.3. Calibration 12.4.4. Bank Interleaving 12.4.5. Additive Latency and Bank Interleaving 12.4.6. User-Controlled Refresh 12.4.7. Frequency of Operation 12.4.8. Series of Reads or Writes 12.4.9. Data Reordering 12.4.10. Starvation Control 12.4.11. Command Reordering 12.4.12. Bandwidth 12.4.13. Enable Command Priority Control
12.4.2. Latency x
12.4.2.1. Additive Latency
12.4.6. User-Controlled Refresh x
12.4.6.1. Back-to-Back User-Controlled Refresh Usage
13. Stratix® 10 EMIF IP Debugging x
13.1. Interface Configuration Performance Issues 13.2. Functional Issue Evaluation 13.3. Timing Issue Characteristics 13.4. Verifying Memory IP Using the Signal Tap II Logic Analyzer 13.5. Hardware Debugging Guidelines 13.6. Categorizing Hardware Issues 13.7. Debugging Stratix® 10 EMIF IP 13.8. Using the Default Traffic Generator 13.9. Using the Configurable Traffic Generator (TG2)
13.1. Interface Configuration Performance Issues x
13.1.1. Interface Configuration Bottleneck and Efficiency Issues
13.2. Functional Issue Evaluation x
13.2.1. Intel® IP Memory Model 13.2.2. Vendor Memory Model 13.2.3. Transcript Window Messages 13.2.4. Modifying the Example Driver to Replicate the Failure
13.3. Timing Issue Characteristics x
13.3.1. Evaluating FPGA Timing Issues 13.3.2. Evaluating External Memory Interface Timing Issues
13.4. Verifying Memory IP Using the Signal Tap II Logic Analyzer x
13.4.1. Signals to Monitor with the Signal Tap II Logic Analyzer
13.5. Hardware Debugging Guidelines x
13.5.1. Create a Simplified Design that Demonstrates the Same Issue 13.5.2. Measure Power Distribution Network 13.5.3. Measure Signal Integrity and Setup and Hold Margin 13.5.4. Vary Voltage 13.5.5. Operate at a Lower Speed 13.5.6. Determine Whether the Issue Exists in Previous Versions of Software 13.5.7. Determine Whether the Issue Exists in the Current Version of Software 13.5.8. Try A Different PCB 13.5.9. Try Other Configurations 13.5.10. Debugging Checklist
13.6. Categorizing Hardware Issues x
13.6.1. Signal Integrity Issues 13.6.2. Hardware and Calibration Issues
13.6.1. Signal Integrity Issues x
13.6.1.1. Characteristics of Signal Integrity Issues 13.6.1.2. Evaluating SignaI Integrity Issues
13.6.1.2. Evaluating SignaI Integrity Issues x
13.6.1.2.1. Skew 13.6.1.2.2. Crosstalk 13.6.1.2.3. Power System 13.6.1.2.4. Clock Signals 13.6.1.2.5. Read Data Valid Window and Eye Diagram 13.6.1.2.6. Write Data Valid Window and Eye Diagram 13.6.1.2.7. OCT and ODT Usage
13.6.2. Hardware and Calibration Issues x
13.6.2.1. Postamble Timing Issues and Margin 13.6.2.2. Intermittent Issue Evaluation
13.7. Debugging Stratix® 10 EMIF IP x
13.7.1. Debugging With the Legacy External Memory Interface Debug Toolkit 13.7.2. Debugging with the External Memory Interface Unified Calibration Debug Toolkit 13.7.3. On-Chip Debug Port for Stratix® 10 EMIF IP 13.7.4. Legacy Efficiency Monitor and Protocol Checker 13.7.5. New Efficiency Monitor
13.7.1. Debugging With the Legacy External Memory Interface Debug Toolkit x
13.7.1.1. User Interface 13.7.1.2. Communication 13.7.1.3. Setup and Use 13.7.1.4. Configuring Your EMIF IP for Use with the Legacy Debug Toolkit 13.7.1.5. Reports 13.7.1.6. On-Die Termination Calibration 13.7.1.7. Eye Diagram 13.7.1.8. Driver Margining for Stratix® 10 EMIF IP 13.7.1.9. Example Tcl Script for Running the Legacy EMIF Debug Toolkit 13.7.1.10. Using the Legacy EMIF Debug Toolkit with Stratix® 10 HPS Interfaces
13.7.1.4. Configuring Your EMIF IP for Use with the Legacy Debug Toolkit x
13.7.1.4.1. Daisy-Chaining Additional EMIF IP Cores for Debugging 13.7.1.4.2. General Workflow 13.7.1.4.3. Linking the Project to a Device 13.7.1.4.4. Establishing Communication to Connections 13.7.1.4.5. Selecting an Active Interface
13.7.1.8. Driver Margining for Stratix® 10 EMIF IP x
13.7.1.8.1. Determining Margin
13.7.2. Debugging with the External Memory Interface Unified Calibration Debug Toolkit x
13.7.2.1. Prerequisites for Using the EMIF Unified Calibration Debug Toolkit 13.7.2.2. Configuring a Design to use the EMIF Unified Calibration Debug Toolkit 13.7.2.3. Launching the EMIF Debug Toolkit 13.7.2.4. Using the EMIF Debug Toolkit 13.7.2.5. Exporting Tables 13.7.2.6. Viewing Diagrams in the Eye Viewer 13.7.2.7. Guidelines for Debugging Calibration Issues
13.7.2.2. Configuring a Design to use the EMIF Unified Calibration Debug Toolkit x
13.7.2.2.1. Generating a Design Example with the Debug Toolkit 13.7.2.2.2. Adding Interfaces to an Design Example 13.7.2.2.3. Enabling the EMIF Unified Calibration Debug Toolkit in an Existing Design
13.7.2.4. Using the EMIF Debug Toolkit x
13.7.2.4.1. Memory Configuration Tab 13.7.2.4.2. Calibration Tab 13.7.2.4.3. Calibration Report Tab 13.7.2.4.4. Calibrate Termination Tab 13.7.2.4.5. Vref Margining Tab 13.7.2.4.6. Driver Margining Tab 13.7.2.4.7. ISSP Tab 13.7.2.4.8. Pin Delay Settings Tab
13.7.2.7. Guidelines for Debugging Calibration Issues x
13.7.2.7.1. Debugging Calibration Failure Using Information from the Calibration report 13.7.2.7.2. Debugging Address and Command Leveling Calibration Failure 13.7.2.7.3. Debugging Address and Command Deskew Failure 13.7.2.7.4. Debugging DQS Enable Failure 13.7.2.7.5. Debugging Read Deskew Calibration Failure 13.7.2.7.6. Debugging VREFIN Calibration Failure 13.7.2.7.7. Debugging LFIFO Calibration Failure 13.7.2.7.8. Debugging Write Leveling Failure 13.7.2.7.9. Debugging Write Deskew Calibration Failure 13.7.2.7.10. Debugging VREFOUT Calibration Failure
13.7.3. On-Chip Debug Port for Stratix® 10 EMIF IP x
13.7.3.1. EMIF On-Chip Debug Port 13.7.3.2. Access Protocol
13.7.4. Legacy Efficiency Monitor and Protocol Checker x
13.7.4.1. Including the Legacy Efficiency Monitor and Protocol Checker in Your Generated IP 13.7.4.2. Running the Legacy Efficiency Monitor with the External Memory Debug Toolkit 13.7.4.3. Communicating Directly to the Legacy Efficiency Monitor and Protocol Checker
13.7.5. New Efficiency Monitor x
13.7.5.1. Enabling the Efficiency Monitor in a Design Example 13.7.5.2. Efficiency Monitor Block Descriptions 13.7.5.3. Control and Status Registers 13.7.5.4. Opening the Efficiency Monitor
13.8. Using the Default Traffic Generator x
13.8.1. Reading the Default Traffic Generator Status 13.8.2. Running Infinite Traffic using the Default Traffic Generator 13.8.3. Changing the Reset Trigger of the Default Traffic Generator 13.8.4. Observing Generated Traffic with Signal Tap
13.9. Using the Configurable Traffic Generator (TG2) x
13.9.1. Enabling the Traffic Generator in a Design Example 13.9.2. Traffic Generator Block Description 13.9.3. Default Traffic Pattern 13.9.4. Configuration and Status Registers 13.9.5. User Pattern 13.9.6. Traffic Generator Status 13.9.7. Starting Traffic with the Traffic Generator 13.9.8. Traffic Generator Configuration User Interface 13.9.9. Examples of Configuring the TG2 Traffic Generator
13.9.5. User Pattern x
13.9.5.1. Test Duration / Instruction pattern 13.9.5.2. Address Pattern 13.9.5.3. Data Pattern and Byte Enable
13.9.5.2. Address Pattern x
13.9.5.2.1. Address Generator Modes 13.9.5.2.2. Address Generator MSB Indices 13.9.5.2.3. Address Generator Effective Width 13.9.5.2.4. Address Generator Relative Frequencies 13.9.5.2.5. Address Pattern Examples - Basic Mode 13.9.5.2.6. Address Pattern Examples - Advanced Mode
13.9.8. Traffic Generator Configuration User Interface x
13.9.8.1. Connecting the Traffic Generator 13.9.8.2. Claiming and Releasing the TG Config Interface 13.9.8.3. Configuring the Traffic Generator 13.9.8.4. Traffic Generator Preset Selection 13.9.8.5. Traffic Generator Status Report
1. Release Information
2. External Memory Interfaces Stratix® 10 FPGA IP Introduction
3. Stratix® 10 EMIF IP Product Architecture
4. Stratix® 10 EMIF IP End-User Signals
5. Stratix® 10 EMIF – Simulating Memory IP
6. Stratix® 10 EMIF IP for DDR3
7. Stratix® 10 EMIF IP for DDR4
8. Stratix® 10 EMIF IP for QDR II/II+/II+ Xtreme
9. Stratix® 10 EMIF IP for QDR-IV
10. Stratix® 10 EMIF IP for RLDRAM 3
11. Stratix® 10 EMIF IP Timing Closure
12. Optimizing Controller Performance
13. Stratix® 10 EMIF IP Debugging
14. External Memory Interfaces Stratix® 10 FPGA IP User Guide Archives
15. Document Revision History for External Memory Interfaces Stratix® 10 FPGA IP User Guide

6.1.5. Intel Stratix 10 EMIF IP DDR3 Parameters: Mem Timing

These parameters should be read from the table in the datasheet associated with the speed bin of the memory device (not necessarily the frequency at which the interface is running).
Table 188.  Group: Mem Timing / Parameters dependent on Speed Bin
Display Name Description
Speed bin The speed grade of the memory device used. This parameter refers to the maximum rate at which the memory device is specified to run. (Identifier: MEM_DDR3_SPEEDBIN_ENUM)
tIS (base) tIS (base) refers to the setup time for the Address/Command/Control (A) bus to the rising edge of CK. (Identifier: MEM_DDR3_TIS_PS)
tIS (base) AC level tIS (base) AC level refers to the voltage level which the address/command signal must cross and remain above during the setup margin window. The signal is considered stable only if it remains above this voltage level (for a logic 1) or below this voltage level (for a logic 0) for the entire setup period. (Identifier: MEM_DDR3_TIS_AC_MV)
tIH (base) tIH (base) refers to the hold time for the Address/Command (A) bus after the rising edge of CK. Depending on what AC level the user has chosen for a design, the hold margin can vary (this variance will be automatically determined when the user chooses the "tIH (base) AC level"). (Identifier: MEM_DDR3_TIH_PS)
tIH (base) DC level tIH (base) DC level refers to the voltage level which the address/command signal must not cross during the hold window. The signal is considered stable only if it remains above this voltage level (for a logic 1) or below this voltage level (for a logic 0) for the entire hold period. (Identifier: MEM_DDR3_TIH_DC_MV)
tDS (base) tDS(base) refers to the setup time for the Data(DQ) bus before the rising edge of the DQS strobe. (Identifier: MEM_DDR3_TDS_PS)
tDS (base) AC level tDS (base) AC level refers to the voltage level which the data bus must cross and remain above during the setup margin window. The signal is considered stable only if it remains above this voltage level (for a logic 1) or below this voltage level (for a logic 0) for the entire setup period. (Identifier: MEM_DDR3_TDS_AC_MV)
tDH (base) tDH (base) refers to the hold time for the Data (DQ) bus after the rising edge of CK. (Identifier: MEM_DDR3_TDH_PS)
tDH (base) DC level tDH (base) DC level refers to the voltage level which the data bus must not cross during the hold window. The signal is considered stable only if it remains above this voltage level (for a logic 1) or below this voltage level (for a logic 0) for the entire hold period. (Identifier: MEM_DDR3_TDH_DC_MV)
tDQSQ tDQSQ describes the latest valid transition of the associated DQ pins for a READ. tDQSQ specifically refers to the DQS, DQS# to DQ skew. It is the length of time between the DQS, DQS# crossing to the last valid transition of the slowest DQ pin in the DQ group associated with that DQS strobe. (Identifier: MEM_DDR3_TDQSQ_PS)
tQH tQH specifies the output hold time for the DQ in relation to DQS, DQS#. It is the length of time between the DQS, DQS# crossing to the earliest invalid transition of the fastest DQ pin in the DQ group associated with that DQS strobe. (Identifier: MEM_DDR3_TQH_CYC)
tDQSCK tDQSCK describes the skew between the memory clock (CK) and the input data strobes (DQS) used for reads. It is the time between the rising data strobe edge (DQS, DQS#) relative to the rising CK edge. (Identifier: MEM_DDR3_TDQSCK_PS)
tDQSS tDQSS describes the skew between the memory clock (CK) and the output data strobes used for writes. It is the time between the rising data strobe edge (DQS, DQS#) relative to the rising CK edge. (Identifier: MEM_DDR3_TDQSS_CYC)
tQSH tQSH refers to the differential High Pulse Width, which is measured as a percentage of tCK. It is the time during which the DQS is high for a read. (Identifier: MEM_DDR3_TQSH_CYC)
tDSH tDSH specifies the write DQS hold time. This is the time difference between the rising CK edge and the falling edge of DQS, measured as a percentage of tCK. (Identifier: MEM_DDR3_TDSH_CYC)
tWLS tWLS describes the write leveling setup time. It is measured from the rising edge of CK to the rising edge of DQS. (Identifier: MEM_DDR3_TWLS_PS)
tWLH tWLH describes the write leveling hold time. It is measured from the rising edge of DQS to the rising edge of CK (Identifier: MEM_DDR3_TWLH_PS)
tDSS tDSS describes the time between the falling edge of DQS to the rising edge of the next CK transition. (Identifier: MEM_DDR3_TDSS_CYC)
tINIT tINIT describes the time duration of the memory initialization after a device power-up. After RESET_n is de-asserted, wait for another 500us until CKE becomes active. During this time, the DRAM starts internal initialization; this happens independently of external clocks. (Identifier: MEM_DDR3_TINIT_US)
tMRD The mode register set command cycle time, tMRD is the minimum time period required between two MRS commands. (Identifier: MEM_DDR3_TMRD_CK_CYC)
tRAS tRAS describes the activate to precharge duration. A row cannot be deactivated until the tRAS time has been met. Therefore tRAS determines how long the memory has to wait after a activate command before a precharge command can be issued to close the row. (Identifier: MEM_DDR3_TRAS_NS)
tRCD tRCD, row command delay, describes the active to read/write time. It is the amount of delay between the activation of a row through the RAS command and the access to the data through the CAS command. (Identifier: MEM_DDR3_TRCD_NS)
tRP tRP refers to the Precharge (PRE) command period. It describes how long it takes for the memory to disable access to a row by precharging and before it is ready to activate a different row. (Identifier: MEM_DDR3_TRP_NS)
tWR tWR refers to the Write Recovery time. It specifies the amount of clock cycles needed to complete a write before a precharge command can be issued. (Identifier: MEM_DDR3_TWR_NS)
Table 189.  Group: Mem Timing / Parameters dependent on Speed Bin, Operating Frequency, and Page Size
Display Name Description
tRRD tRRD refers to the Row Active to Row Active Delay. It is the minimum time interval (measured in memory clock cycles) between two activate commands to rows in different banks in the same rank (Identifier: MEM_DDR3_TRRD_CYC)
tFAW tFAW refers to the four activate window time. It describes the period of time during which only four banks can be active. (Identifier: MEM_DDR3_TFAW_NS)
tWTR tWTR or Write Timing Parameter describes the delay from start of internal write transaction to internal read command, for accesses to the same bank. The delay is measured from the first rising memory clock edge after the last write data is received to the rising memory clock edge when a read command is received. (Identifier: MEM_DDR3_TWTR_CYC)
tRTP tRTP refers to the internal READ Command to PRECHARGE Command delay. It is the number of memory clock cycles that is needed between a read command and a precharge command to the same rank. (Identifier: MEM_DDR3_TRTP_CYC)
Table 190.  Group: Mem Timing / Parameters dependent on Density and Temperature
Display Name Description
tRFC tRFC refers to the Refresh Cycle Time. It is the amount of delay after a refresh command before an activate command can be accepted by the memory. This parameter is dependent on the memory density and is necessary for proper hardware functionality. (Identifier: MEM_DDR3_TRFC_NS)
tREFI tREFI refers to the average periodic refresh interval. It is the maximum amount of time the memory can tolerate in between each refresh command (Identifier: MEM_DDR3_TREFI_US)
Level Two Title