How To Run ModelSim Simulator - Xilinx

Step 1 :
  

Step 2:

•  After Right Clicking go to Design Properties.
•  Click on Simulator option and select type of simulator.
•  Select ModelSim PE VHDL (student edition)
•  Click  Ok.

 Step 3 :   

• In the Design Window select Simulation and Select your module (Here its Dff) . 
• Then Right Click on Simulate Behavioral Model.
• Now Go to Process Properties -> Simulation Properties.

    In Simulation Properties Set 

•   Simulation Runtime time = 0 ns (it will start the simulation from time 0 ns)
•   Set the Step Size or keep default value.
•   Click Apply and Ok after setting everything.

Step 4 :

• Right Click on Simulate Behavioral Model.
• And do Run.
• ModelSim Simulator window will open with the loaded project.

Errors :

1.) Simulator Version Mismatch ! 
       

     How to Fix It :

• Right Click on Simulate Behavioral Model.
• And Go to Process Properties -> Simulation Properties.
• Then Select Ignore Simulator / Compiled Library Version Check.
• Re Run the simulation.