GTS Transceiver PHY User Guide

ID 817660
Date 4/01/2024
Public
Document Table of Contents

3.6. Clocking

The GTS transceivers supports three different clock output options from TX and RX that you can use for FPGA core clocking.

Word Clock

The word clock is a PMA parallel clock and equals the data rate divided by the PMA width. For example: 25.78125 Gbps data rate with 32-bit PMA width has a word clock of 25.78125 Gbps ÷ 32 = 805.6640625 MHz.

User Clock

User clock is the divided version of the PMA data rate. The available division factor for user clock is shown below.

The user clock is calculated as the VCO frequency divided by a division factor, which you specify in the TX/RX user clock div by parameter in the TX/RX User clock settings in the parameter editor.

User clock = VCO frequency / Division factor

The valid range of division factors is from 12 to 139.5, in increments of 0.5; for example, 12, 12.5,13,13.5, ……, 139, 139.5.

The TX and RX clocks for the word clock and user clock are two different clocks, derived from TX and RX PMA, respectively.

Sys PLL Clock

The Sys PLL clock is the output clock from system PLL. The frequency of this clock is the same as the output frequency of the system PLL connected to the current instance of the GTS PMA/FEC Direct PHY Intel FPGA IP.