ModelSim Tutorial for CSE 535

ModelSim Tutorial for CSE 535 • Michael Attig (mea1@arl.wustl.edu)

What is it? • ModelSim allows you to simulate VHDL code • We will use ModelSim extensively to test and verify our designs. • Spending the extra time to simulate your design can saves hours of in-lab testing.

Step 1 – Setting up Library Directory • Open a Cygwin Window • Engineering  FPGA Tools  Cygwin • Enter the ‘sim’ directory • Type ‘vlib work’

Step 2 – Compiling Your Design • Type ‘make compile’ to compile your vhd files

Step 3 – Simulating Your Design • Type ‘vsim testbench’ to Simulate the testbench • The main ModelSim window will appear. • You can type the name of the window you would like to open (i.e. ‘view signals’), or view * for all windows • Alternatively, you can select what to view from the View Menu

Step 4 – Add Signals to Wave Window • Highlight the Snort App Entity in the main window • The signals for this entity will appear in signals window • From the Signals Add Menu, choose Wave  Signals in Region – This adds the signals found within this particular entity

Step 5 – Running the Simulation • With an input_IP.DAT file in your sim directory, you can now type ‘run 5000’ • The simulator will now generate the waveforms for the design.

Step 6 – Typical Modifications – Signal Radix • To aid you in simulating, it is sometimes necessary to change the radix of your signals • Right click the signal, highlight radix, and select hexadecimal • You can do this for multiple signals at a time

Typical Modifications – Inserting Dividers • Dividers help you decipher which signals belong to which module. • When you insert signals from many entities into the wave window, dividers can help. • To Insert a Divider, in the Insert menu of the wave window, click on Divider

Typical Modifications – Signal Names • When you have many levels of entities, you don’t always want to see their path • You can just view the signal name • In the Tools Menu, select ‘Window Preferences’ • Change the Display Signal Path to 1 instead of 0 Change to 1

Saving a Wave List • After you’ve set up your waveform list, you can save it so next time you simulate it can be reloaded. • In the File menu, select ‘Save Format’ • This will be saved as a .do file. • To reload this when restarting ModelSim, in the main window, type do <filename>.do

ModelSim Tutorial for CSE 535