Technical data

Basic Verilog simulation

140

ModelSim EE Lessons ModelSim EE Tutorial

Let’s move through the Verilog source functions with Model

Sim

’s Step and Step Over

commands. Click

Step Over

on the toolbar.

This causes the debugger to step over the function call on line 30. The Step

button

on the toolbar would have single-stepped the debugger, including each line of the

increment function.

Experiment by yourself for awhile; setting and clearing breakpoints as well as Step’ing

and Step Over’ing function calls until you feel comfortable with the operation of these

commands.

Now let’s get a Wave window view of the simulation.

When the Wave window is first drawn, there is one cursor in it at time zero.

Clicking anywhere in the waveform display brings that cursor to the mouse

location.

Up to ten cursors can be present at the same time. Cursors are displayed with a

time box showing the precise simulation time at the bottom. When you have more

than one cursor, each time box appears in a separate track at the bottom of the

display.

Try adding or removing cursors with the

Add Cursor

and

Delete

Cursor

buttons.