Starting Active-HDL as the Default Simulator in Xilinx ISE


This document describes how to start Active-HDL simulator from Xilinx ISE Project Navigator to run behavioral and timing simulations. This application note has been verified on Active-HDL 10.3 and Xilinx ISE 14.7. This interface allows users to run mixed VHDL, Verilog and System Verilog (design) simulation using Active-HDL as a default simulator.

Installing Xilinx libraries in Active-HDL

In order to run the simulation successfully, depending on the design both VHDL and Verilog libraries for Xilinx may have to be installed in Active-HDL. You can check what libraries are currently installed in your Active-HDL using Library Manager tool. You can access the Library Manager from the menu View>Library Manger>.

You can install precompiled libraries in multiple ways:

  1. If you are using Active-HDL DVD to install the software, during the installation, you will get the option to select and install the Xilinx libraries.

  2. If you have received a web link to download Active-HDL, on the same page you will find the links to download Xilinx libraries.

  3. At any time you can visit the update center to download the latest Xilinx libraries at

  4. You can generate the libraries yourself by using the compile_simlib command.

Set Active-HDL as Simulator in Xilinx Project Navigator

After creating a project, open your Xilinx project in ISE Project Navigator. Now we will have to replace the link to Model Tech simulator with the Active-HDL executable file. To do that open Preferences window in Project Navigator (use menu Edit | Preferences). In the Preferences window, go to the Integrated Tools section under ISE General category. Point to the Xilinx ISE .bat file (C:\Program File\Aldec\Active-HDL X.X\BIN\xilinx_ise.bat) in the Model Tech Simulator box as shown below.

Figure 1 Setting up the executable for Active-HDL

Click Open and then OK to close the Preferences window.

Setting Simulator Properties in Xilinx Project Navigator

After setting up Active-HDL as a simulator, you need to set up the simulator properties. In the Project menu, go to Design Properties and set the Simulator setting to Modelsim-SE Mixed.

Figure 2 Setting the Simulator to Modelsim-SE Mixed

After that you should be able to see the ModelSim Simulator command in the Processes tab as shown below.

Figure 3 Selecting Simulation Property

Now right-click on Simulate Behavioral Model and select the Process Properties option from the context menu. In the Process Properties window select Simulation Properties.

  • Change the Compiled Library Directory to point to Vlib within the Active-HDL installation.

    NOTE: For users who are using Active-HDL 9.3 or later, you will need to change the directory as follows:

    • VHDL: C:\Aldec\Active-HDL<version>\vlib\xilinx_ise\vhdl

    • Verilog: C:\Aldec\Active-HDL<version>\vlib\xilinx_ise\verilog

  • In the Other VSIM Command Line Options field, add +access+r. This enables the access to add signals to the waveform viewer.

Figure 4 Setting up the display property

Under the Display Properties. Make sure all the options are unchecked as shown below in the figure 5.

Figure 5 Setting up the display property

Starting Active-HDL from Xilinx ISE

To start Active-HDL simulator, right-click on Simulate Behavioral Model in the Processes tab and select Run. Active-HDL will be started. The source and script files will be added to the created design, compiled, and simulated.

Figure 6 Simulation launched in Active-HDL

To Run A Timing simulation

To run a timing simulation, switch the design view to Implementation.

Figure 7 Design View: Implementation

  • Run the synthesis and implementation process by pressing the Implement Top Module button or by right-clicking the top-level module and selecting Implement Top Module.

    Figure 8 Run Synthesis and Implementation Process

  • Expand Implement Design and run the Generate Post-Place & Route Simulation Model process.

    Figure 9 Generate Post-Place & Route Simulation Model

  • Switch the design view to Simulation and change the drop down box from Behavioral to Post Route.

    Figure 10 Post Route Simulation

  • Right-click on Simulate Post-Place & Route Model in the processes window and select Process Properties.

  • You can observe the additional field Delay Values To Be Read from SDF, this indicates an SDF was created to run a timing simulation.

    Figure 11 Process Properties for Timing Simulation

  • The Display Properties should remain the same as the previous simulation.

  • Under Simulation Model Properties you can also observe the -sdf switches used for the timing simulation.

    Figure 12 Simulation Model Properties

  • Run the simulation by right-clicking on Simulate Post-Place & Route Model and select run.

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