Intel® Cyclone® 10 GX Transceiver PHY User Guide

ID 683054
Date 4/14/2023
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2.6.1.2. Word Alignment for GbE, GbE with IEEE 1588v2

The word aligner for the GbE and GbE with IEEE 1588v2 protocols is configured in automatic synchronization state machine mode. The Intel® Quartus® Prime software automatically configures the synchronization state machine to indicate synchronization when the receiver receives three consecutive synchronization ordered sets. A synchronization ordered set is a /K28.5/ code group followed by an odd number of valid /Dx.y/ code groups. The fastest way for the receiver to achieve synchronization is to receive three continuous {/K28.5/, /Dx.y/} ordered sets.

The GbE PHY IP core signals receiver synchronization status on the rx_syncstatus port of each channel. A high on the rx_syncstatus port indicates that the lane is synchronized; a low on the rx_syncstatus port indicates that the lane has fallen out of synchronization. The receiver loses synchronization when it detects three invalid code groups separated by less than three valid code groups or when it is reset.

Table 83.  Synchronization State Machine Parameter Settings for GbE
Synchronization State Machine Parameter Setting
Number of word alignment patterns to achieve sync 3
Number of invalid data words to lose sync 3
Number of valid data words to decrement error count 3

The following figure shows rx_syncstatus high when three consecutive ordered sets are sent through rx_parallel_data.

Figure 35. rx_syncstatus High