Embedded Memory User Guide: Agilex™ 5 FPGAs and SoCs

ID 813901
Date 4/15/2025
Public
Document Table of Contents

4.2.5.6. SCFIFO and DCFIFO Show-Ahead Mode

You can set the read request/rdreq signal read access behavior by selecting normal or show-ahead mode.

For normal mode, the FIFO Intel FPGA IP core treats the rdreq port as a normal read request that only performs read operation when the port is asserted.

For show-ahead mode, the FIFO Intel FPGA IP core treats the rdreq port as a read-acknowledge that automatically outputs the first word of valid data in the FIFO Intel FPGA IP core (when the empty is low) without asserting the rdreq signal. Asserting the rdreq signal causes the FIFO Intel FPGA IP core to output the next data word, if available.

Figure 38. Normal Mode Waveform

Data appears after the rdreq asserted.

Figure 39. Show-Ahead Mode Waveform

Data appears before the rdreq asserted.