E-Tile Transceiver PHY User Guide

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

9.2.6. 0x0008: Internal Serial Loopback and Reverse Parallel Loopback Control

Attribute Code



Controls turning on/off internal serial loopback or reverse parallel loopback.

  • 0x84[0]: 1'b1 to select internal serial loopback. 1'b0 to disable internal serial loopback.
  • 0x84[3:1]: 3'h0
  • 0x84[4]: 1'b1 to select reverse parallel loopback. 1'b0 to disable reverse parallel loopback.
  • 0x84[7:5]: 3'h0
  • 0x85[0]: 1'b1 to change the internal serial loopback settings
  • 0x85[1]: 1'b1 to change the reverse parallel loopback settings
  • 0x85[7:2]: 6'h00

Only one loopback mode can be enabled at a time. For example, set 0x84[7:0] to 0x01 and 0x85[7:0] to 0x03 to enable internal serial loopback and disable reverse parallel loopback.

PMA Can Be Running While Updating PMA Attribute?


Return Value {0x89[7:0],0x88[7:0]}