Embedded Memory User Guide: Agilex™ 5 FPGAs and SoCs

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

3.3.1.3. Read-During-Write Data Output and Memory Location Behaviors

The following shows the data output and the memory location behaviors of true dual-port (TDP) and simple quad-port (SQP) when multiple read and write operations happen on the same address. The data output behavior of each scenario either provides the same-port RDW or mixed-port RDW output depending on the input signal. When both port A and port B are writing data to the same address, the content of the memory location is either corrupted or the input data from port A is written if the option "ENA_NON_CORRUPT=1" is enabled. Refer to Consider the Concurrent Write Behavior for more details.
Table 15.  True Dual-Port (TDP) Read-Dring-Write (RDW) Behaviors on Data Outputs and Memory Location
Port A Write Port A Read Port B Write Port B Read Port A Data Output Port B Data Output Data at Memory Location
Yes Yes Yes Yes New data from port A data input. 6 New data from port B data input. 6 Memory corruption or port A data input is written.
Yes Yes Yes No New data from port A data input. 6 Unchanged Memory corruption or port A data input is written.
Yes Yes No Yes New data from port A data input. 6 Don't care or new data from port A data input. 7 Memory corruption or port A data input is written.
Yes Yes No No New data from port A data input. 6 Unchanged Memory corruption or port A data input is written.
Yes No Yes Yes Unchanged New data from port B data input. 6 Memory corruption or port A data input is written.
Yes No Yes No Unchanged Unchanged Memory corruption or port A data input is written.
Yes No No Yes Unchanged Don't care or new data from port A data input. 7 Memory corruption or port A data input is written.
Yes No No No Unchanged Unchanged Memory corruption or port A data input is written.
No Yes Yes Yes Don't care or new data from port B data input 7 New data from port B data input. 6 Memory corruption or port A data input is written.
No Yes Yes No Don't care or new data from port B data input. 7 Unchanged Memory corruption or port A data input is written.
No Yes No Yes Data from memory Data from memory Unchanged
No Yes No No Data from memory Unchanged Unchanged
No No Yes Yes Unchanged New data from port B data input. 6 Memory corruption or port A data input is written.
No No Yes No Unchanged Unchanged Memory corruption or port A data input is written.
No No No Yes Unchanged Data from memory. Unchanged
No No No No Unchanged Unchanged Unchanged
Table 16.  Simple Quad-Port (SQP) Read-Dring-Write (RDW) Behaviors on Data Outputs and Memory Location
Port A Write Port A Read Port B Write Port B Read Port A Data Output Port B Data Output Data at Memory Location
Yes Yes Yes Yes Don't care 8 Don't care8 Memory corruption or port A data input is written.
Yes Yes Yes No Don't care8 Unchanged Memory corruption or port A data input is written.
Yes Yes No Yes Don't care8 Old data9 Memory corruption or port A data input is written.
Yes Yes No No Don't care8 Unchanged Memory corruption or port A data input is written.
Yes No Yes Yes Unchanged Don't care8 Memory corruption or port A data input is written.
Yes No Yes No Unchanged Unchanged Memory corruption or port A data input is written.
Yes No No Yes Unchanged Old data9 Memory corruption or port A data input is written.
Yes No No No Unchanged Unchanged Memory corruption or port A data input is written.
No Yes Yes Yes New data from port B data input 9 Don't care8 Memory corruption or port A data input is written.
No Yes Yes No New data from port B data input9 Unchanged Memory corruption or port A data input is written.
No Yes No Yes Data from memory Data from memory Unchanged
No Yes No No Data from memory Unchanged Unchanged
No No Yes Yes Unchanged Don't care8 Memory corruption or port A data input is written.
No No Yes No Unchanged Unchanged Memory corruption or port A data input is written.
No No No Yes Unchanged Data from memory Unchanged
No No No No Unchanged Unchanged Unchanged
6 Indicates same-port RDW output behavior.
7 Indicates mixed-port RDW output behavior.
8 Indicates same-port RDW output behavior.
9 Indicates mixed-port RDW output behavior.