Online Verilog Simulation Guide

If you don’t have a local Verilog simulator (e.g., Icarus Verilog or Vivado XSim) installed, you can run this lab directly in your web browser using free online tools such as EDA Playground or Makerchip. These platforms allow you to paste your Verilog source and testbench, simulate, and view console outputs or waveforms.

🧩 Option 1 — Using EDA Playground (Recommended)

Website: https://edaplayground.com

Steps

  1. Open the website and click “Create New Playground”.
  2. In the left code pane, paste your design source file:
    • e.g., src/reg_multifunc.v or src/regfile_2r1w.v
  3. In the right code pane, paste the corresponding testbench:
    • e.g., tb/tb_reg_multifunc.v or tb/tb_regfile_2r1w.v
  4. In the Tools & Simulators panel:
    • Set Language to Verilog 2001 or SystemVerilog 2012
    • Choose Simulator: Icarus Verilog (vvp)
    • Uncheck “Enable Design for UVM” if it appears
  5. Click Run ▶️ at the top.
  6. Watch the console output:
    • You should see [PASS] and [FAIL] messages from the testbench.
    • All “PASS” messages indicate correct behavior.

Saving & Sharing

  • Click Share → Save & Share Link.
  • Include the generated link in your lab report or submission.

⚙️ Option 2 — Using Makerchip (Advanced Visualizer)

Website: https://makerchip.com

Steps

  1. Go to the Makerchip homepage → click “Start Designing”.
  2. Paste both your design and testbench codes into the editor.
  3. Click Build & Run.
  4. View the console log for pass/fail messages and use the waveform viewer for debugging.
  5. Makerchip automatically recognizes any module ending with _tb as the top-level testbench.

âś… Expected Output

A successful run will produce console logs like:

[PASS] LOAD: q=A5 @ t=10
[PASS] SHL:  q=4A @ t=20
[PASS] SHR:  q=25 @ t=30
tb_reg_multifunc completed OK

If something fails, you’ll see:

[FAIL] SAR from 0x80: got 40 expected C0 @ t=70

Fix your RTL code and re-run the simulation.

đź’ˇ Tips

  • Use Ctrl + Enter (EDA Playground) or Ctrl + R (Makerchip) to rerun quickly.
  • To view waveforms in EDA Playground:
    • Check “Enable VCD dump” under Run Options, then open the waveform viewer.
  • Always verify reset behavior and edge timing (posedge clock updates).
  • Record your simulation logs and include screenshots in your report.

End of Online Simulation Guide