External Memory Interfaces (EMIF) IP User Guide: Agilex™ 5 FPGAs and SoCs

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ID 817467
Date 7/08/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the External Memory Interfaces Agilex™ 5 FPGA IP 2. Agilex™ 5 FPGA EMIF IP – Introduction 3. Agilex™ 5 FPGA EMIF IP – Product Architecture 4. Agilex™ 5 FPGA EMIF IP – End-User Signals 5. Agilex™ 5 FPGA EMIF IP – Simulating Memory IP 6. Agilex™ 5 FPGA EMIF IP - DDR4 Support 7. Agilex™ 5 FPGA EMIF IP - DDR5 Support 8. Agilex™ 5 FPGA EMIF IP - LPDDR4 Support 9. Agilex™ 5 FPGA EMIF IP - LPDDR5 Support 10. Agilex™ 5 FPGA EMIF IP – Timing Closure 11. Agilex™ 5 FPGA EMIF IP – Controller Optimization 12. Agilex™ 5 FPGA EMIF IP – Debugging 13. Document Revision History for External Memory Interfaces (EMIF) IP User Guide
1. About the External Memory Interfaces Agilex™ 5 FPGA IP x
1.1. Release Information
2. Agilex™ 5 FPGA EMIF IP – Introduction x
2.1. Agilex™ 5 EMIF IP Protocol and Feature Support 2.2. Agilex™ 5 EMIF IP Design Flow
2.2. Agilex™ 5 EMIF IP Design Flow x
2.2.1. Agilex™ 5 EMIF IP Design Checklist
3. Agilex™ 5 FPGA EMIF IP – Product Architecture x
3.1. Agilex™ 5 EMIF Architecture: Protocol and Maximum Interface Width Support 3.2. Agilex™ 5 EMIF Architecture: Introduction 3.3. Agilex™ 5 EMIF Sequencer 3.4. Agilex™ 5 EMIF Controller 3.5. Agilex™ 5 EMIF IP for Hard Processor Subsystem (HPS)
3.2. Agilex™ 5 EMIF Architecture: Introduction x
3.2.1. Agilex™ 5 EMIF Architecture: I/O Subsystem 3.2.2. Agilex™ 5 EMIF Architecture: I/O SSM 3.2.3. Agilex™ 5 EMIF Architecture: HSIO Bank 3.2.4. Agilex™ 5 EMIF Architecture: I/O Lane 3.2.5. Agilex™ 5 EMIF Architecture: Input DQS Clock Tree 3.2.6. Agilex™ 5 EMIF Architecture: PHY Clock Tree 3.2.7. Agilex™ 5 EMIF Architecture: PLL Reference Clock Networks 3.2.8. Agilex™ 5 EMIF Architecture: Clock Phase Alignment 3.2.9. User Clock in Different Core Access Modes
3.2.3. Agilex™ 5 EMIF Architecture: HSIO Bank x
3.2.3.1. Lockstep Configuration 3.2.3.2. Pin Placement 3.2.3.3. HSIO Sub-Bank Usage
3.3. Agilex™ 5 EMIF Sequencer x
3.3.1. Agilex™ 5 Mailbox Structure and Register Definitions
3.3.1. Agilex™ 5 Mailbox Structure and Register Definitions x
3.3.1.1. Mailbox Supported Commands 3.3.1.2. Mailbox Command Definitions
3.4. Agilex™ 5 EMIF Controller x
3.4.1. Hard Memory Controller
3.4.1. Hard Memory Controller x
3.4.1.1. Hard Memory Controller Features
4. Agilex™ 5 FPGA EMIF IP – End-User Signals x
4.1. Agilex 5 EMIF IP Interfaces for DDR4 4.2. Agilex 5 EMIF IP Interfaces for DDR5 4.3. Agilex 5 EMIF IP Interfaces for LPDDR4 4.4. Agilex 5 EMIF IP Interfaces for LPDDR5 4.5. Agilex 5 EMIF IP Interfaces for the EMIF Calibration Component
4.1. Agilex 5 EMIF IP Interfaces for DDR4 x
4.1.1. ref_clk for EMIF IP 4.1.2. core_init_n for EMIF IP 4.1.3. usr_async_clk for EMIF IP 4.1.4. usr_clk for EMIF IP 4.1.5. usr_rst_n for EMIF IP 4.1.6. s0_axi4 for EMIF IP 4.1.7. mem for EMIF IP 4.1.8. oct for EMIF IP
4.2. Agilex 5 EMIF IP Interfaces for DDR5 x
4.2.1. ref_clk for EMIF IP 4.2.2. core_init_n for EMIF IP 4.2.3. usr_async_clk for EMIF IP 4.2.4. usr_clk for EMIF IP 4.2.5. usr_rst_n for EMIF IP 4.2.6. s0_axi4 for EMIF IP 4.2.7. mem for EMIF IP 4.2.8. i3c for EMIF IP 4.2.9. mem_lbd for EMIF IP 4.2.10. mem_lbs for EMIF IP 4.2.11. oct for EMIF IP
4.3. Agilex 5 EMIF IP Interfaces for LPDDR4 x
4.3.1. ref_clk for EMIF IP 4.3.2. core_init_n for EMIF IP 4.3.3. usr_async_clk for EMIF IP 4.3.4. usr_clk for EMIF IP 4.3.5. usr_rst_n for EMIF IP 4.3.6. s0_axi4 for EMIF IP 4.3.7. mem for EMIF IP 4.3.8. oct for EMIF IP
4.4. Agilex 5 EMIF IP Interfaces for LPDDR5 x
4.4.1. ref_clk for EMIF IP 4.4.2. core_init_n for EMIF IP 4.4.3. usr_async_clk for EMIF IP 4.4.4. usr_clk for EMIF IP 4.4.5. usr_rst_n for EMIF IP 4.4.6. s0_axi4 for EMIF IP 4.4.7. mem for EMIF IP 4.4.8. oct for EMIF IP
4.5. Agilex 5 EMIF IP Interfaces for the EMIF Calibration Component x
4.5.1. s0_axi4lite_clk for EMIF IP Calibration Component 4.5.2. s0_axi4lite_rst_n for EMIF IP Calibration Component 4.5.3. s0_axil for EMIF IP Calibration Component
5. Agilex™ 5 FPGA EMIF IP – Simulating Memory IP x
5.1. Simulation Walkthrough
5.1. Simulation Walkthrough x
5.1.1. Calibration 5.1.2. Simulation Scripts 5.1.3. Functional Simulation with Verilog HDL 5.1.4. Simulating the Design Example
6. Agilex™ 5 FPGA EMIF IP - DDR4 Support x
6.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for DDR4 6.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning 6.3. Agilex™ 5 EMIF Pin Swapping Guidelines 6.4. DDR4 Layout Design Guidelines
6.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for DDR4 x
6.1.1. Agilex 5 FPGA External Memory Interfaces (EMIF) IP Parameter Descriptions for DDR4 6.1.2. Agilex 5 FPGA EMIF Memory Device Description IP (DDR4) Parameter Descriptions 6.1.3. Agilex 5 FPGA EMIF Calibration IP Parameter Descriptions
6.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning x
6.2.1. Agilex™ 5 FPGA EMIF IP Resources 6.2.2. Pin Guidelines for Agilex™ 5 FPGA EMIF IP 6.2.3. Pin Placements for Agilex™ 5 FPGA DDR4 EMIF IP
6.2.1. Agilex™ 5 FPGA EMIF IP Resources x
6.2.1.1. OCT 6.2.1.2. PLL
6.2.2. Pin Guidelines for Agilex™ 5 FPGA EMIF IP x
6.2.2.1. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning
6.2.2.1. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning x
6.2.2.1.1. Agilex™ 5 FPGA EMIF IP Interface Pins 6.2.2.1.2. Estimating Pin Requirements 6.2.2.1.3. Maximum Number of Interfaces
6.2.3. Pin Placements for Agilex™ 5 FPGA DDR4 EMIF IP x
6.2.3.1. Address and Command Pin Placement for DDR4 6.2.3.2. DDR4 Data Width Mapping 6.2.3.3. General Guidelines 6.2.3.4. x4 DIMM Implementation 6.2.3.5. Specific Pin Connection Requirements 6.2.3.6. Command and Address Signals 6.2.3.7. Clock Signals 6.2.3.8. Data, Data Strobes, DM/DBI, and Optional ECC Signals
6.3. Agilex™ 5 EMIF Pin Swapping Guidelines x
6.3.1. DDR4 Byte Lane Swapping 6.3.2. DDR4 Address and Command and CLK Lane 6.3.3. DDR4 Interface x8 Data Lane 6.3.4. DDR4 Interface x4 Data Lane
6.4. DDR4 Layout Design Guidelines x
6.4.1. DDR4 PCB Stackup and Design Considerations 6.4.2. DDR4 General Design Considerations 6.4.3. DDR4 Routing Guidelines - Memory-Down (Discrete) Topologies
6.4.3. DDR4 Routing Guidelines - Memory-Down (Discrete) Topologies x
6.4.3.1. 1 Rank x 8 Discrete (Memory Down) Topology 6.4.3.2. 1 Rank x 16 Discrete (Memory Down) Topology 6.4.3.3. VREF_CA/RESET Signal Routing Guidelines for 1 Rank x 8 and 1 Rank x 16 Discrete (Memory Down) Topology 6.4.3.4. Skew Matching Guidelines for DDR4 (Memory Down) Discrete Configurations 6.4.3.5. Power Delivery Recommendation for DDR4 Discrete Configurations 6.4.3.6. DDR4 Simulation Strategy
7. Agilex™ 5 FPGA EMIF IP - DDR5 Support x
7.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for DDR5 7.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning
7.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for DDR5 x
7.1.1. Agilex 5 FPGA External Memory Interfaces (EMIF) IP Parameter Descriptions for DDR5 7.1.2. Agilex 5 FPGA EMIF Memory Device Description IP (DDR5) Parameter Descriptions 7.1.3. Agilex 5 FPGA EMIF Calibration IP Parameter Descriptions
7.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning x
7.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins 7.2.2. Agilex™ 5 FPGA EMIF IP Resources 7.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP 7.2.4. Pin Placements for Agilex™ 5 FPGA DDR5 EMIF IP 7.2.5. Agilex™ 5 EMIF Pin Swapping Guidelines
7.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins x
7.2.1.1. Estimating Pin Requirements 7.2.1.2. DIMM Options 7.2.1.3. Maximum Number of Interfaces
7.2.2. Agilex™ 5 FPGA EMIF IP Resources x
7.2.2.1. OCT 7.2.2.2. PLL
7.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP x
7.2.3.1. General Guidelines - DDR5 7.2.3.2. x4 DIMM Implementation 7.2.3.3. Specific Pin Connection Requirements 7.2.3.4. Command and Address Signals 7.2.3.5. Clock Signals 7.2.3.6. Data, Data Strobes, DM, and Optional ECC Signals
7.2.4. Pin Placements for Agilex™ 5 FPGA DDR5 EMIF IP x
7.2.4.1. Address and Command Pin Placement for DDR5 7.2.4.2. DDR5 Data Width Mapping
7.2.5. Agilex™ 5 EMIF Pin Swapping Guidelines x
7.2.5.1. DDR5 Byte Lane Swapping 7.2.5.2. DDR5 Address and Command and CLK Lane 7.2.5.3. DDR5 Interface x8 Data Lane 7.2.5.4. DDR5 Interface x4 Data Lane 7.2.5.5. Pin Swizzling
8. Agilex™ 5 FPGA EMIF IP - LPDDR4 Support x
8.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for LPDDR4 8.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning 8.3. LPDDR4 Layout Design Guidelines
8.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for LPDDR4 x
8.1.1. Agilex 5 FPGA External Memory Interfaces (EMIF) IP Parameter Descriptions for LPDDR4 8.1.2. Agilex 5 FPGA EMIF Memory Device Description IP (LPDDR4) Parameter Descriptions 8.1.3. Agilex 5 FPGA EMIF Calibration IP Parameter Descriptions
8.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning x
8.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins 8.2.2. Agilex™ 5 FPGA EMIF IP Resources 8.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP
8.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins x
8.2.1.1. Estimating Pin Requirements 8.2.1.2. LPDDR4 Component Options 8.2.1.3. Maximum Number of Interfaces
8.2.2. Agilex™ 5 FPGA EMIF IP Resources x
8.2.2.1. OCT 8.2.2.2. PLL
8.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP x
8.2.3.1. General Guidelines 8.2.3.2. Specific Pin Connection Requirements 8.2.3.3. Command and Address Signals 8.2.3.4. Clock Signals 8.2.3.5. Address and Command Pin Placement for LPDDR4 8.2.3.6. LPDDR4 Data Width Mapping 8.2.3.7. Pin Swapping Guidelines
8.3. LPDDR4 Layout Design Guidelines x
8.3.1. LPDDR4 PCB Stackup and Design Considerations 8.3.2. LPDDR4 General Design Considerations 8.3.3. LPDDR4 Interface Design Guidelines
8.3.3. LPDDR4 Interface Design Guidelines x
8.3.3.1. LPDDR4 Discrete Component/Memory Down Topology (up to 32 bits interface) 8.3.3.2. LPDDR4 Simulation Strategy
9. Agilex™ 5 FPGA EMIF IP - LPDDR5 Support x
9.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for LPDDR5 9.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning 9.3. LPDDR5 Layout Design Guidelines
9.1. Agilex 5 FPGA EMIF IP Parameter Descriptions for LPDDR5 x
9.1.1. Agilex 5 FPGA External Memory Interfaces (EMIF) IP Parameter Descriptions for LPDDR5 9.1.2. Agilex 5 FPGA EMIF Memory Device Description IP (LPDDR5) Parameter Descriptions 9.1.3. Agilex 5 FPGA EMIF Calibration IP Parameter Descriptions
9.2. Agilex™ 5 FPGA EMIF IP Pin and Resource Planning x
9.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins 9.2.2. Agilex™ 5 FPGA EMIF IP Resources 9.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP 9.2.4. Pin Placements for Agilex™ 5 FPGA LPDDR5 EMIF IP
9.2.1. Agilex™ 5 FPGA EMIF IP Interface Pins x
9.2.1.1. Estimating Pin Requirements 9.2.1.2. LPDDR5 Component Options 9.2.1.3. Maximum Number of Interfaces
9.2.2. Agilex™ 5 FPGA EMIF IP Resources x
9.2.2.1. OCT 9.2.2.2. PLL
9.2.3. Pin Guidelines for Agilex™ 5 FPGA EMIF IP x
9.2.3.1. General Guidelines - LPDDR5 9.2.3.2. Specific Pin Connection Requirements 9.2.3.3. Command and Address Signals 9.2.3.4. Clock Signals
9.2.4. Pin Placements for Agilex™ 5 FPGA LPDDR5 EMIF IP x
9.2.4.1. Address and Command Pin Placement for LPDDR5 9.2.4.2. LPDDR5 Data Width Mapping 9.2.4.3. LPDDR5 Byte Lane Swapping
9.3. LPDDR5 Layout Design Guidelines x
9.3.1. LPDDR5 PCB Stackup and Design Considerations 9.3.2. LPDDR5 General Design Considerations 9.3.3. LPDDR5 Interface Design Guidelines
9.3.3. LPDDR5 Interface Design Guidelines x
9.3.3.1. LPDDR5 Discrete Component/Memory Down Topology (Single Rank or Dual-Rank) 9.3.3.2. Example of an LPDDR5 Layout on an Intel FPGA Platform Board 9.3.3.3. LPDDR5 Simulation Strategy
10. Agilex™ 5 FPGA EMIF IP – Timing Closure x
10.1. Timing Closure 10.2. Optimizing Timing
10.1. Timing Closure x
10.1.1. Timing Analysis
10.1.1. Timing Analysis x
10.1.1.1. PHY or Core
11. Agilex™ 5 FPGA EMIF IP – Controller Optimization x
11.1. Interface Standard 11.2. Bank Management Efficiency 11.3. Data Transfer 11.4. Improving Controller Efficiency
11.4. Improving Controller Efficiency x
11.4.1. Frequency of Operation 11.4.2. Series of Reads or Writes
12. Agilex™ 5 FPGA EMIF IP – Debugging x
12.1. Interface Configuration Performance Issues 12.2. Functional Issue Evaluation 12.3. Timing Issue Characteristics 12.4. Verifying Memory IP Using the Signal Tap Logic Analyzer 12.5. Debugging with the External Memory Interface Debug Toolkit 12.6. Generating Traffic with the Test Engine IP 12.7. Guidelines for Developing HDL for Traffic Generator 12.8. Guidelines for Traffic Generator Status Check 12.9. Hardware Debugging Guidelines 12.10. Create a Simplified Design that Demonstrates the Same Issue 12.11. Measure Power Distribution Network 12.12. Measure Signal Integrity and Setup and Hold Margin 12.13. Vary Voltage 12.14. Operate at a Lower Speed 12.15. Determine Whether the Issue Exists in Previous Versions of Software 12.16. Determine Whether the Issue Exists in the Current Version of Software 12.17. Try A Different PCB 12.18. Try Other Configurations 12.19. Debugging Checklist 12.20. Categorizing Hardware Issues 12.21. Signal Integrity Issues 12.22. Characteristics of Signal Integrity Issues 12.23. Evaluating Signal Integrity Issues 12.24. Skew 12.25. Crosstalk 12.26. Power System 12.27. Clock Signals 12.28. Address and Command Signals 12.29. Read Data Valid Window and Eye Diagram 12.30. Write Data Valid Window and Eye Diagram 12.31. Hardware and Calibration Issues 12.32. Memory Timing Parameter Evaluation 12.33. Verify that the Board Has the Correct Memory Component or DIMM Installed
12.1. Interface Configuration Performance Issues x
12.1.1. Interface Configuration Bottleneck and Efficiency Issues
12.2. Functional Issue Evaluation x
12.2.1. Altera IP Memory Model 12.2.2. Vendor Memory Model 12.2.3. Transcript Window Messages
12.3. Timing Issue Characteristics x
12.3.1. Evaluating FPGA Timing Issues 12.3.2. Evaluating External Memory Interface Timing Issues
12.5. Debugging with the External Memory Interface Debug Toolkit x
12.5.1. Prerequisites for Using the EMIF Debug Toolkit 12.5.2. Configuring a Design to Use the Debug Toolkit 12.5.3. Launching the EMIF Debug Toolkit 12.5.4. Using the EMIF Debug Toolkit
12.5.2. Configuring a Design to Use the Debug Toolkit x
12.5.2.1. Generating a Design Example with the Debug Toolkit
12.5.4. Using the EMIF Debug Toolkit x
12.5.4.1. Running Re-Calibration 12.5.4.2. Running the Test Engine
12.8. Guidelines for Traffic Generator Status Check x
12.8.1. Status Check Using the Signal Tap Logic Analyzer 12.8.2. Exporting the Status Interface to the Top-Level Design
1. About the External Memory Interfaces Agilex™ 5 FPGA IP
2. Agilex™ 5 FPGA EMIF IP – Introduction
3. Agilex™ 5 FPGA EMIF IP – Product Architecture
4. Agilex™ 5 FPGA EMIF IP – End-User Signals
5. Agilex™ 5 FPGA EMIF IP – Simulating Memory IP
6. Agilex™ 5 FPGA EMIF IP - DDR4 Support
7. Agilex™ 5 FPGA EMIF IP - DDR5 Support
8. Agilex™ 5 FPGA EMIF IP - LPDDR4 Support
9. Agilex™ 5 FPGA EMIF IP - LPDDR5 Support
10. Agilex™ 5 FPGA EMIF IP – Timing Closure
11. Agilex™ 5 FPGA EMIF IP – Controller Optimization
12. Agilex™ 5 FPGA EMIF IP – Debugging
13. Document Revision History for External Memory Interfaces (EMIF) IP User Guide

9.2.3.1. General Guidelines - LPDDR5

You should follow the recommended guidelines when performing pin placement for all external memory interface pins targeting Agilex™ 5 devices, whether you are using the hard memory controller or your own solution.
Note: PHY only, RLDRAMx, and QDRx are not supported with HPS.

Observe the following general guidelines when placing pins for your Agilex™ 5 external memory interface:

  1. Ensure that the pins of a single external memory interface reside on the same edge I/O.
  2. The address and command pins and their associated clock pins in the address and command bank must follow a fixed pin-out scheme, as defined in the table in the Address and Command Pin Placement for LPDDR5 topic.
  3. Not every byte lane can function as an address and command lane or a data lane. The pin assignment must adhere to the LPDDR5 data width mapping defined in LPDDR5 Data Width Mapping .
  4. A byte lane must not be used by both address and command pins and data pins.
  5. An external memory interface can occupy one or more banks on the same edge. When an interface must occupy multiple banks, ensure that those banks are adjacent to one another.
    • If an I/O bank is shared between two interfaces—meaning that two sub-banks belong to two different EMIF interfaces—then both the interfaces must share the same voltage.
    • Sharing of I/O lanes within a sub-bank for two different EMIF interfaces is not permitted; I/O lanes within a sub-bank can be assigned to one EMIF interface only.
  6. Any pin in the same bank that is not used by an external memory interface may not be available for use as a general purpose I/O pin:
    • For fabric EMIF, unused pins in an I/O lane assigned to an EMIF interface cannot be used as general-purpose I/O pins. In the same sub-bank, pins in an I/O lane that is not assigned to an EMIF interface, can be used as general-purpose I/O pins.
    • For HPS EMIF, unused pins in an I/O lane assigned to an EMIF interface cannot be used as general-purpose I/O pins. Pins in any lane in the same IO96 bank that are not assigned to an EMIF interface cannot be used as general-purpose I/O pins either.
  7. All address and command pins and their associated clock pins (CK_t and CK_c) must reside within a single sub-bank. The sub-bank containing the address and command pins is identified as the address and command sub-bank. Refer to the table in LPDDR5 Data Width Mapping for the supported address and command and data lane placements for DDR5.
  8. An external memory interface can occupy one or more banks on the same edge. When an interface must occupy multiple banks, ensure the following:
    • That the banks are adjacent to one another.
    • That you used only the supported data width mapping as defined in the table in LPDDR5 Data Width Mapping . Be aware that not every byte lane can be used as an address and command lane or a data lane.
  9. An unused I/O lane in the address and command sub-bank can serve to implement a data group, such as a x8 DQS group. The data group must be from the same controller as the address and command signals.
  10. An I/O lane must not be used by both address and command pins and data pins.
  11. Place read data groups according to the DQS grouping in the pin table and Pin Planner. Read data strobes (such as RDQS_t and RDQS_c) must reside at physical pins capable of functioning as RDQS_t and RDQS_c for a specific read data group size. You must place the associated read data pins (DQ), within the same group.
  12. One of the sub-banks in the device (typically the sub-bank within corner bank 3A) may not be available if you use certain device configuration schemes. For some schemes, there may be an I/O lane available for EMIF data group.
    • AVST-8 – This is contained entirely within the SDM, therefore all lanes of sub-bank 3A can be used by the external memory interface.
    • AVST-16 – Lanes 4, 5, 6, and 7 are all effectively occupied and are not usable by the external memory interface.
  13. Two memory interfaces cannot share an I/O 48 sub-bank.
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