Stratix V Device Handbook: Volume 2: Transceivers

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

1.3.1.4. Rate Match (Clock Rate Compensation) FIFO

The rate match (clock rate compensation) FIFO compensates for small clock frequency differences between the upstream transmitter and the local receiver clocks by inserting or removing skip (SKP) symbols or ordered sets from the interpacket gap (IPG) or idle streams. The rate match FIFO deletes SKP symbols or ordered sets when the upstream transmitter reference clock frequency is higher than the local receiver reference clock frequency. The rate match FIFO inserts SKP symbols or ordered sets when the local receiver reference clock frequency is higher than the upstream transmitter reference clock frequency.

Note: For the Gigabit Ethernet protocol, if you have the auto-negotiation state machine in the FPGA core with rate match FIFO enabled, refer to the "Rate Match FIFO" section in the "Gigabit Ethernet" section in the Transceiver Configurations in Stratix V Devices chapter.