V-Series Transceiver PHY IP Core User Guide

ID 683171
Date 7/26/2022
Document Table of Contents

17.9.1. EyeQ Usage Example

This section provides an example of accessing the EyeQ registers and using the Bit Error Rate Block (BERB).

When the BERB is enabled, the serial bit checker compares the data from CDR path and EyeQ path. The BERB accumulates the total received bit numbers and the error bit numbers. You can use the BERB block as a diagnostic tool to perform in-system link analysis without interrupting the link traffic. The steps below provide BERB operation example:

  • Write 3'b111 to bit[2:0] in offset 0x0 to enable BERB
  • Set Horizontal Phase and/or Vertical High in offset 0x1 and/or 0x2
  • Set 2'b01 to bit[4:3] in offset 0x0 to reset the counters
  • Set 2'b10 to bit [4:3] in offset 0x0 to take a snapshot of the counters. Read the counter values from offsets 0x5 to 0x8.
  • Repeat steps 2 to 4 to measure the bit error rate (BER) for another horizontal phase / veritical height.