Spartan-6 GTP Transceiver - GTPCLKOUT must be routed through a BUFIO

AR#	33572	Search For Another Answer
Topic	HW-Rocket_IO
Last Updated	09/25/2009
Status	Active

Description

Keywords: BUFG, BUFIO, GTPCLKOUT, REFCLKOUT, global clock

The Spartan-6 GTP Transceiver has different clocking requirements than previous Xilinx transceivers.

This Answer Record discusses how to correctly provide clocks to the fabric from the GTP.

Solution

The primary output clock from the GTP Transceiver is GTPOUTCLK and can be fed from either the output divider of the PLL or directly from the reference clock input. GTPOUTCLK needs to be fed directly to a BUFIO to be used in fabric.