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

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

2.4.1.3. FGT Primary PLL Configuration

A pimay PLL cofiguatio is whe the TX PLL of oe lae is i factioal mode ad acts as the efeece clock souce fo the local CDR ad TX PLL ad RX CDR blocks of othe laes (cofigued i itege mode) withi the quad. Thee ae two diffeet pimay PLL cofiguatios: quad ad pai. These two cofiguatios ae the oly suppoted lae combiatios fo a pimay PLL cofiguatio.

I a quad cofiguatio, FGT3 is always the pimay. Fo example, i Quad3, FGT3_Quad3 is the pimay, ad the FGT3_Quad3 TX PLL output is the efeece clock fo the FGT3_Quad3 RX, FGT2_Quad3, FGT1_Quad3, ad FGT0_Quad3 TX PLL, ad RX CDR.

I a pai cofiguatio with oly two PMAs combied, FGT3 o FGT1 ca be the pimay. Fo example, whe usig FGT3_Quad3 ad FGT2_Quad3, FGT3_Quad3 is the pimay, ad the FGT3_Quad3 TX PLL output is the efeece clock fo the FGT3_Quad3 RX, FGT2_Quad3 TX PLL, ad RX CDR. If usig FGT1_Quad3 ad FGT0_Quad3 , FGT1_Quad3 is the pimay.

Figue 53. FGT Pimay PLL Cofiguatios