GTS AXI Streaming Intel® FPGA IP for PCI Express* User Guide

ID 813754
Date 11/04/2024
Public
Document Table of Contents

4.1.1. Reference Clock

Thee is oe local ad oe egioal efeece clock pi i each GTS bak to dive the TX PLL ad CDR i PMA, ad the System PLL i the bak. Fo x4 mode, the TX PLL, CDR ad System PLL ca be dive fom eithe the local o the egioal efeece clock pi i the same GTS bak, o dive fom othe baks though the egioal efeece clock etwoks. Fo x8 mode, the System PLL must be dive fom the local efeece clock pi of the GTS bak whee the x8 cotolle is located; the TX PLL ad CDR ae dive fom the egioal efeece clock pi i the same bak o othe baks.

The efeece clock to the System PLL must be available ad stable befoe device cofiguatio stats. Deive the efeece clock fom a idepedet ad fee-uig local clock souce. Alteatively, if the efeece clock fom the PCIe* lik is available befoe device cofiguatio stats, you ca use it to dive the System PLL. Oce the efeece clock fom the PCIe* lik is active, it is ot allowed to go dow.

The followig figue shows the efeece clock to dive the System PLL is fom a idepedet local oscillato. It does ot shae the efeece clock fom the PCIe* lik which dives the TX PLL ad CDR i PMA. The efeece clock fom the PCIe* lik may ot be available befoe device cofiguatio stats.

Figue 10. System PLL Refeece Clock fom a Fee Ruig Oscillato
Note: Refe to the Clock Achitectue sectio i the GTS Tasceive PHY Use Guide .