F-Tile Architecture and PMA and FEC Direct PHY IP User Guide

ID 683872
Date 11/04/2024
Public
Document Table of Contents

2.3.2.4. FGT PMA Loopback Modes

The PHY cotais multiple paallel, seial data, ad clock loopbacks acoss PHY itefaces fo BIST. These loopbacks povide suppot fo multiple PHY cofiguatios.

Figue 49. FGT PMA Loopback ModesThe IP paamete edito does ot cuetly suppot the loopback modes. Use egiste settigs to specify loopback modes.
  • A. PMA-Tasmitte-to-Receive Iteal Seial Loopback: Loops back the tasmitte pe-dive diffeetial I/O sigals to the midpoit of the eceive equalize. The iteal seial loopback path sets the CDR to ecove data fom the seialize istead of the eceive seial iput pi. The tasmitte buffe seds data omally, but the iteal seial loopback takes the data befoe the buffe. It is implemeted completely i the PMA ad does ot equie ay coecto o the seial path.
  • B. PMA-Tasmitte-to-Receive Digital Paallel Loopback: Paallel loopback fom the PMA tasmit lae 64 bit data pots to the eceive lae 64 bit data pots. I a digital paallel loopback path, the paallel data steam of the tasmitte is looped back as the paallel data iput steam fo the eceive.
  • C. PMA-Receive-to-Tasmitte Revese Paallel Loopback: Paallel loopback fom the PMA eceive lae 64 bit data pots to the tasmit lae 64 bit data pots. The evese paallel loopback path sets the tasmitte buffe to tasmit data fed diectly fom the CDR ecoveed data. Fom a exteal istumet, data is fed to the eceive buffe, ad the deseialized paallel data steam of the eceive is looped back as the paallel data iput steam fo the tasmitte.