Embedded Memory User Guide: Agilex™ 5 FPGAs and SoCs

ID 813901
Date 9/03/2024
Public
Document Table of Contents

3.3.1.1. Same-Port Read-During-Write Mode

Same-port read-during-write mode refers to a memory access scenario where a single port of a memory device performs both a read and a write operation to the same memory address simultaneously.

The same-port read-during-write mode applies to a single-port RAM, simple quad-port RAM or the same port of a true dual-port RAM.

Table 12.  Output Modes for Embedded Memory Blocks in Same-Port Read-During-Write ModeThis table lists the available output modes if you select the embedded memory blocks in the same-port read-during-write mode.
Output Mode Memory Type Description Supported Operation Mode
New Data M20K The new data is available on the rising edge of the same clock cycle on which the new data is written.
  • True Dual-port RAM
Old Data M20K The RAM output reflects the old data at that address before the write operation proceeds.
  • Single-port RAM
Don't Care
Note: This output mode is applicable in simulation only.
M20K, MLAB The RAM produces Don't Care values for a read-during-write operation.
  • Quad-port RAM (for M20K only)
  • Single-port RAM
 
Figure 23. Same-Port Read-During-Write: New Data ModeThis figure shows sample functional waveforms of same-port read-during-write behavior in the New Data mode.


Figure 24. Same-Port Read-During-Write: Don't Care ModeThis figure shows sample functional waveforms of same-port read-during-write behavior in the Don't Care mode.