Tutorial 5: Simulating a Design
Introduction This tutorial covers how to perform a functional simulation as well as a timing simulation with the Xilinx software. A one-bit comparator was chosen as the example circuit.
One-Bit Comparator
Opening the Simulator Simulation Icon Tools -> Simulation/Verification -> Gate Simulator Update Netlist
Selecting input and output signals Chip Icon Signal -> Add Signal
Component Selection Select Inputs and Outputs Add button Double-Clicking Close button
Test Pins SC button Tools -> Schematic Capture Simulation Toolbox Icon Mode -> Testpoint Click on net name to create probe Sim Icon to return
Adding Stimuli Stimulator icon Signal -> Add Stimulators Binary Counter to mark inputs Close Stimulator window
Defining the Frequency of the free-running Counter Options -> Preferences B0 Period drop-down list B0 Frequency adjusts automatically
Doing the Simulation and Viewing the Waveforms “Functional” from pull down menu Simulation Step (footstep) Adjust step size with pull down menu Ruler Icon – adjust scale of time axis
Schematic Simulation SC Icon Logic Values of each signal Gray Boxes -> Colored Boxes
Timing Simulation Detailed information of timing delays First implement design – Implementation Icon Verification Button (Timing Simulation) Select components from Signals Selection and Chip Selection Close to return
Doing the Simulation and Measuring Delays “Timing” from pull down menu Step Icon (footsteps) Measure Delay – Waveform -> Measurements -> Measurements on Select start and end points