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AR# 41226

Spartan-3 family - IDDR2 simulation in DDR_ALIGNMENT C1 mode


Spartan-3 family IDDR2 simulation in DDR_ALIGNMENT C1 mode does not work correctly in ISE 11.2 software and higher.


The output of the simulation in this mode swaps the Q1 and Q2 outputs. The simulation shows the signal that is on Q1 in hardware, on Q2 in the simulation, and what is on Q2 in hardware shows up on the Q1 signal in the simulation.

Work-arounds include:
  1. Simulate using a post route simulation.
  2. Use an earlier version of the ISE software for the behavioral simulation. It is already recommended that these earlier designs not be migrated to new versions of the ISE software.
  3. Open a WebCase and obtain a tactical patch to fix the simulation model.

This Answer Record is in response to CR-594421.
AR# 41226
Date 03/23/2011
Status Active
Type General Article
  • Spartan-3A
  • Spartan-3A DSP
  • Spartan-3AN
  • Spartan-3E