Triple-Speed Ethernet Intel® FPGA IP User Guide

ID 683402
Date 11/25/2022

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Document Table of Contents Synchronization

The link synchronization constantly monitors the decoded data stream and determines if the underlying receive channel is ready for operation. The link synchronization state machine acquires link synchronization if the state machine receives three code groups with comma consecutively without error.

When link synchronization is acquired, the link synchronization state machine counts the number of invalid characters received. The state machine increments an internal error counter for each invalid character received and incorrectly positioned comma character. The internal error counter is decremented when four consecutive valid characters are received. When the counter reaches 4, the link synchronization is lost.

The PCS function drives the led_link signal to 1 when link synchronization is acquired. This signal can be used as a common visual activity check using a board LED.

The PCS function drives the led_panel_link signal to 1 when link synchronization is acquired for the PCS operating in 1000 Base-X without auto negotiation and SGMII mode without auto negotiation.