Arria® 10 Transceiver PHY User Guide

ID 683617
Date 4/01/2024
Document Table of Contents TX FIFO (Shared with Standard and Enhanced PCS)

The TX FIFO in each channel ensures a reliable transfer of data and status signals between the PCS channel and the FPGA fabric. The TX FIFO compensates for the phase difference between the low speed parallel PCS clock and the FPGA fabric clock. The RX and TX FIFOs are shared with standard and enhanced PCS. In Hard IP mode, the TX FIFO works in register mode. In PIPE mode, the TX FIFO works in low latency mode.

The TX FIFO operates in low latency mode in PIPE Gen1, Gen2, and Gen3 configurations. The Low Latency mode incurs 3-4 cycles of latency when connecting with the FPGA fabric. The FIFO empty and the FIFO full threshold values are made closer so that the depth of the FIFO decreases, which decreases the latency. <