Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents Block Synchronizer

PMA parallelization occurs at arbitrary word boundaries. Consequently, the parallel data from the RX PMA CDR needs to be realigned to meaningful character boundaries. The block sync module searches for the Electrical Idle Exit Sequence Ordered Set (or the last number of fast training sequences (NFTS) Ordered Set) and skip (SKP) Ordered Set to identify the correct boundary for the incoming stream and achieve the block alignment. The block is realigned to the new block boundary following the receipt of a SKP Ordered Set, as it can be of variable length.