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AR# 36100

Spartan-6 IBIS Model - No "left/right" LVDS Input Model Available

Description

The Spartan-6 IBIS file does not contain models for the LVDS inputs on the "left/right" side of the device. This causes theIBISWriter to issue the following warning:

"WARNING:PostProcessors - IBIS model LVDS_33_LR_33 for I/O port <pin name> (pin<pin number>) could not be found. This signal will be listed as a no connect (NC) in the output file."

Solution

The reason for this is that LVDS outputs are not supported in the "left/right" region of the device.
That is why there is no data for those standards in the IBIS file, however,LVDS inputs are supported in the left/right regions.

To work around this issue, usethe "top/bottom" models instead. These models use the same input structures and have a very similar die capacitance.

AR# 36100
Date Created 07/19/2011
Last Updated 12/15/2012
Status Active
Type General Article
Devices
  • Spartan-6 LX
  • Spartan-6 LXT