E-Tile Transceiver PHY User Guide

ID 683723
Date 4/01/2024
Public
Document Table of Contents

8.7. Configuring the Post Emphasis Value

This usage model covers configuring the Post Emphasis value in the TX Equalizer for decimal values 2 and -2. The negative decimal value is represented as an 8-bit 2's complement.

Example 1: Setting the post_tap emphasis of the TX Equalizer with PMA attribute values of 2 (decimal) and 0x02 (hexadecimal) or -2 (decimal) and 0xFE (hexadecimal) and PMA attribute code of 0x15

  1. Write 0x84[7:0] = 0x02 for 2 (decimal), or write 0x84[7:0] = 0xFE for -2 (decimal).
  2. Write 0x85[7:0] = 0x80.
  3. Write 0x86[7:0] = 0x15.
  4. Write 0x87[7:0] = 0x00.
  5. Write 0x90[0] = 1’b1.
  6. Read 0x8A[7]. It should be 1.
  7. Read 0x8B [0] until it changes to 0.
  8. Write 0x8A[7] to 1 to clear the 0x8A[7] flag.
  9. Read 0x8A[7]. It should be 0.

Example 2: Setting the post_tap emphasis of the TX Equalizer with PMA attribute values of -18 (decimal) and 0xEE (2’s complement) and PMA attribute code of 0x15

  1. Write 0x84[7:0] = 0xEE.
  2. Write 0x85[7:0] = 0x80.
  3. Write 0x86[7:0] = 0x15.
  4. Write 0x87[7:0] = 0x00.
  5. Write 0x90[0] = 1’b1.
  6. Read 0x8A[7]. It should be 1
  7. Read 0x8B [0] until it changes to 0.
  8. Write 0x8A[7] to 1 to clear the 0x8A[7] flag.
  9. Read 0x8A[7]. It should be 0.