Embedded Memory User Guide: Agilex™ 3 FPGAs and SoCs

ID 849316
Date 5/22/2025
Public
Document Table of Contents

2.10.1. True Dual-Port Mixed Port Read During Write New Data Emulation

Figure 20. Schematic Diagram for TDP Mixed-Port Read-During-Write New Data Emulation

The Quartus® Prime software emulates new data output behavior through soft logic that checks the following items:

  • Input signals—to determine the occurrence of the mixed-port read-during-write operation
  • Multiplexers—to determine whether to take RAM output data from altera_syncram module or the soft logic circuit

When mixed-port read-during-write operation occurs, the Quartus® Prime software bypasses the altera_syncram module and feeds the input data directly to the RAM's output port to emulate the new data output behavior. Otherwise, the RAM always selects the altera_syncram output.

Because the altera_syncram module is synchronous RAM, you must register all input signals of the soft logic circuit to mimic the latency of the altera_syncram module. You only need to register the output signals if the altera_syncram output is registered. The new data behavior applies to TDP RAM in M20K block only.

If you select the new data behavior for TDP mixed-port read-during-write, these features are not supported:

  • Dual clock (due to TDP being an emulated configuration)
  • Output data register/latch clear
  • Byte enable
  • Clock enable