Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Public
Document Table of Contents

1.3.1.8.2. Registered Mode

To eliminate the FIFO latency uncertainty for applications with stringent datapath latency uncertainty requirements, bypass the FIFO functionality in registered mode to incur only one clock cycle of datapath latency when interfacing the receiver channel to the FPGA fabric. Configure the FIFO to registered mode when interfacing the receiver channel to the PCIe hard IP block to reduce datapath latency. In registered mode, the low-speed parallel clock that is used in the receiver PCS clocks the FIFO.