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AR# 62617

2013.4 Vivado Implementation - New DRC check is flagging use of BUFR driven by GTH reference clock


Since upgrading to 2014.3, my design which previously worked now fails with the following DRC error.

Is this a valid error?

ERROR: [Drc 23-20] Rule violation (REQP-1739) GTx R/TXOUTCLK drives inappropriate load - GTHE2_CHANNEL cell_name abc pin  pin_name (net:  net_name) should only drive BUFG, BUFH, BUFMR, MMCM or PLL loads, but drives one or more invalid loads such as BUFR cell  xyz/rxoutclk_bufr1_i. Please insert a BUFHCE (or a BUFMR, if the load is a BUFR) between the GT and its load(s).


This DRC was implemented as a direct result of an investigation into a non-working design. 

BUFRs have been removed from the list of legal loads for TX/RXOUTCLK.

A BUFHCE is the correct buffer to use for clock loads in the local clock region.
AR# 62617
Date 11/05/2014
Status Active
Type General Article
  • Virtex-7
  • Vivado Design Suite - 2014.3