Arria 10 GX Transceiver Signal Integrity Development Kit User Guide

ID 683553
Date 8/08/2017
Public
Document Table of Contents

5.7.1. Transceiver Dedicated Clocks

The figure below shows the dedicated transceiver clocking that will be implemented for the FPGA. This clocking scheme will allow 4 different protocols to be running simultaneously by the Intel® Arria® 10 GX FPGA.

Four differential clock sources are provided from an I2C programmable VCO oscillator to the dedicated REFCLK input pins of transceiver blocks on both sides of the FPGA. The default frequencies for these four oscillators at startup are:-
  • 644.53125 MHz (Y3 left side xcvrs)
  • 706.25 MHz (Y4 left side xcvrs)
  • 625 MHz (Y5 right side xcvrs)
  • 875 MHz (Y6 right side xcvrs)

The default frequencies can be overridden and a different frequency can be programmed into the oscillators for support of other protocols.

CAUTION:
Programmed frequencies will be lost upon a board power down condition. Oscillator frequencies return to their default frequency upon power up.

Each oscillator will support a programmable frequency range of 10 MHz - 1.4 GHz and provide a differential LVDS trigger output to SMA connectors for scope or other lab equipment triggering purposes.

In addition to the four oscillators, each side will have a dedicated differential REFCLK input from a pair of SMA connectors to allow use of lab equipment clock generators as the transceiver clock source.

The clock inputs described above all pass through a clock buffer first, the two inputs below connect directly to the transceiver clock inputs:-
  • J122/J123 SMA connectors direct connection to REFCLK_GXBL1F block.
  • J124/J125 SMA connectors direct connection to REFCLK_GXBR4F block.
Figure 9. Transceiver Dedicated Clocking