2.10.1. True Dual-Port 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