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AR# 44513

14.x Timing - Is there any specific reason why the internal Hold of GTP is given by -Th?

Description

Is there any specific reason why the internal Hold of GTP is given by -Th?
SLICE_X7Y118.DQ Tcko 0.368 TX_GTP{3}
XLXI_6794/XLXI_773/Q_1
GTPA1_DUAL_X0Y0.TXDATA030 net (fanout=1) 0.548 TX_GTP{3}
GTPA1_DUAL_X0Y0.TXUSRCLK20 Tgtpckc_TXDATA(-Th) 1.000 XLXI_15111/XLXI_15404/tile0_laser_and_sdi_spartan_6_i/gtpa1_dual_i
XLXI_15111/XLXI_15404/tile0_laser_and_sdi_spartan_6_i/gtpa1_dual_i
------------------------------------------------------- ---------------------------
Total -0.084ns (-0.632ns logic, 0.548ns route)
(752.4% logic, -652.4% route)

Solution

The data path portion has more delay than the clock path portion of the component, so the hold analysis is negative. The Hold time for a specific element is subtracted from the data path, so the analysis is correct.
AR# 44513
Date Created 01/17/2013
Last Updated 01/17/2013
Status Active
Type General Article
Tools
  • ISE Design Suite - 12
  • ISE Design Suite - 13
  • ISE Design Suite - 14