Embedded Memory User Guide: Agilex™ 3 FPGAs and SoCs

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ID 849316
Date 5/22/2025
Public
Document Table of Contents
Document Table of Contents x
1. Agilex™ 3 Embedded Memory Overview 2. Agilex™ 3 Embedded Memory Architecture and Features 3. Agilex™ 3 Embedded Memory Design Considerations 4. Agilex™ 3 Embedded Memory IP References 5. Agilex™ 3 Embedded Memory Debugging 6. Document Revision History for the Embedded Memory User Guide: Agilex™ 3 FPGAs and SoCs
1. Agilex™ 3 Embedded Memory Overview x
1.1. Agilex™ 3 Embedded Memory Features 1.2. Agilex™ 3 Embedded Memory Block Signals
2. Agilex™ 3 Embedded Memory Architecture and Features x
2.1. Byte Enable in Agilex™ 3 Embedded Memory Blocks 2.2. Address Hold Support 2.3. Asynchronous Clear and Synchronous Clear 2.4. Memory Blocks Error Correction Code Support 2.5. Agilex™ 3 Embedded Memory Clocking Modes 2.6. Agilex™ 3 Embedded Memory Configurations 2.7. Force-to-Zero 2.8. Coherent Read Memory 2.9. Freeze Logic 2.10. True Dual Port Dual Clock Emulator 2.11. Initial Value of Read and Write Address Registers 2.12. Automatic Timing/Power Optimization in M20K Blocks
2.1. Byte Enable in Agilex™ 3 Embedded Memory Blocks x
2.1.1. Byte Enable Controls 2.1.2. Data Byte Output 2.1.3. Byte Enable Behavior
2.4. Memory Blocks Error Correction Code Support x
2.4.1. Error Correction Code Truth Table 2.4.2. Parity Bit 2.4.3. ECC Parity Flip 2.4.4. ECC Read-During-Write Behavior
2.5. Agilex™ 3 Embedded Memory Clocking Modes x
2.5.1. Single Clock Mode 2.5.2. Read/Write Clock Mode 2.5.3. Input/Output Clock Mode 2.5.4. Asynchronous/Synchronous Clears in Clocking Modes 2.5.5. Output Read Data in Simultaneous Read/Write 2.5.6. Independent Clock Enables in Clocking Modes
2.6. Agilex™ 3 Embedded Memory Configurations x
2.6.1. Mixed-Width Port Configurations
2.8. Coherent Read Memory x
2.8.1. Forwarding Logic
2.10. True Dual Port Dual Clock Emulator x
2.10.1. True Dual-Port Mixed Port Read During Write New Data Emulation
3. Agilex™ 3 Embedded Memory Design Considerations x
3.1. Consider the Memory Block Selection 3.2. Consider the Concurrent Write Behavior 3.3. Read-During-Write 3.4. Consider Power-Up State and Memory Initialization 3.5. Reduce Power Consumption 3.6. Avoid Providing Non-Deterministic Input 3.7. Avoid Changing Clock Signals and Other Control Signals Simultaneously 3.8. Advanced Settings in Quartus® Prime Software for Memory 3.9. Consider the Memory Depth Setting 3.10. Consider Registering the Memory Output
3.3. Read-During-Write x
3.3.1. Customize Read-During-Write Behavior
3.3.1. Customize Read-During-Write Behavior x
3.3.1.1. Same-Port Read-During-Write Mode 3.3.1.2. Mixed-Port Read-During-Write Mode 3.3.1.3. Read-During-Write Data Output and Memory Location Behaviors
4. Agilex™ 3 Embedded Memory IP References x
4.1. On-Chip Memory RAM and ROM IPs 4.2. FIFO Intel® FPGA IP 4.3. Shift Register (RAM-based) IP
4.1. On-Chip Memory RAM and ROM IPs x
4.1.1. Release Information for RAM and ROM IPs 4.1.2. Features 4.1.3. Implementation Guide 4.1.4. Parameters and Interface Signals
4.1.2. Features x
4.1.2.1. On-Chip Memory RAM and ROM IPs
4.1.3. Implementation Guide x
4.1.3.1. Instantiating IP Cores using the Quartus® Prime Parameter Editor 4.1.3.2. Changing Parameter Settings Manually
4.1.4. Parameters and Interface Signals x
4.1.4.1. RAM: 1-PORT FPGA IP Parameters 4.1.4.2. RAM: 2-PORT FPGA IP Parameters 4.1.4.3. RAM: 4-PORT FPGA IP Parameters 4.1.4.4. ROM: 1-PORT FPGA IP Parameters 4.1.4.5. ROM: 2-PORT FPGA IP Parameters 4.1.4.6. RAM and ROM Manual Parameter Settings 4.1.4.7. RAM and ROM Interface Signals
4.2. FIFO Intel® FPGA IP x
4.2.1. Release Information for FIFO Intel® FPGA IP 4.2.2. Features 4.2.3. Implementation Guide 4.2.4. Parameters and Interface Signals 4.2.5. Design Considerations
4.2.3. Implementation Guide x
4.2.3.1. Instantiating IP Cores using Quartus® Prime Pro Edition Parameter Editor 4.2.3.2. Manual IP Instantiation through HDL
4.2.3.2. Manual IP Instantiation through HDL x
4.2.3.2.1. Verilog HDL Prototype 4.2.3.2.2. VHDL Component Declaration 4.2.3.2.3. VHDL LIBRARY-USE Declaration 4.2.3.2.4. HDL Code from Parameterizable Macros Template 4.2.3.2.5. Coding Example for Manual Instantiation 4.2.3.2.6. Instantiation Template
4.2.4. Parameters and Interface Signals x
4.2.4.1. FIFO Signals 4.2.4.2. FIFO Parameter Settings 4.2.4.3. FIFO Intel® FPGA IP Parameters
4.2.5. Design Considerations x
4.2.5.1. FIFO Functional Timing Requirements 4.2.5.2. SCFIFO ALMOST_EMPTY Functional Timing 4.2.5.3. FIFO Output Status Flag and Latency 4.2.5.4. FIFO Metastability Protection and Related Options 4.2.5.5. FIFO Synchronous Clear and Asynchronous Clear Effect 4.2.5.6. SCFIFO and DCFIFO Show-Ahead Mode 4.2.5.7. Different Input and Output Width 4.2.5.8. DCFIFO Timing Constraint Setting 4.2.5.9. Gray-Code Counter Transfer at the Clock Domain Crossing 4.2.5.10. Guidelines for Embedded Memory ECC Feature 4.2.5.11. Reset Scheme
4.2.5.5. FIFO Synchronous Clear and Asynchronous Clear Effect x
4.2.5.5.1. Recovery and Removal Timing Violation Warnings when Compiling a DCFIFO
4.2.5.8. DCFIFO Timing Constraint Setting x
4.2.5.8.1. Embedded Timing Constraint 4.2.5.8.2. User Configurable Timing Constraint
4.2.5.8.2. User Configurable Timing Constraint x
4.2.5.8.2.1. SDC Commands
4.3. Shift Register (RAM-based) IP x
4.3.1. Release Information for Shift Register (RAM-based) IP 4.3.2. Features 4.3.3. Implementation Guide 4.3.4. Parameters and Interface Signals
4.3.3. Implementation Guide x
4.3.3.1. Instantiating IP Cores using Quartus® Prime Pro Edition Parameter Editor
4.3.4. Parameters and Interface Signals x
4.3.4.1. Shift Register (RAM-based) IP Parameter Settings 4.3.4.2. Shift Register Ports and Parameters Setting
1. Agilex™ 3 Embedded Memory Overview
2. Agilex™ 3 Embedded Memory Architecture and Features
3. Agilex™ 3 Embedded Memory Design Considerations
4. Agilex™ 3 Embedded Memory IP References
5. Agilex™ 3 Embedded Memory Debugging
6. Document Revision History for the Embedded Memory User Guide: Agilex™ 3 FPGAs and SoCs

2.2. Address Hold Support

While active, the address hold captures and holds the previous address value until the next clock cycle. You can use this capability to control the pipeline, avoid metastability, or perform specific asynchronous operations. To enable the address hold feature, assert the addresstall signal.
Note:
  1. Simple dual-port mode only—address latching is supported only in simple dual-port mode and is not available in other dual-port configurations or single-port mode.
  2. First clock cycle restriction—to avoid unpredictable data output caused by potential initialization issues, do not assert the addressstall signal during the first clock cycle of operation after device configuration.
  3. Dual-port considerations—if you use dual-port memory blocks, each port has its own independent addressstall signal, allowing you to control address latching for each port individually.
Figure 2. Address HoldThis figure shows an address hold block diagram


Figure 3. Address Hold During Read CycleThis figure shows the address hold behavior during read cycle.


Figure 4. Address Hold During Write Cycle This figure shows the address hold behavior during write cycle.


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