From Simulation to Real Hardware: Run Your Circuit on an FPGA

Here is the moment simulation becomes real: the circuit you drew in Logisim-evolution — the same gates and wires you have been testing on screen — can be turned into configuration data for a physical FPGA chip. Press a real button on the board, and a real LED lights up, driven by your logic. Logisim-evolution has this workflow built in: it generates the HDL, maps your inputs and outputs to the board’s switches and LEDs, and hands off to the board vendor’s toolchain for the final step.

How it works, in five steps

  1. Finish the circuit in simulation first. The FPGA does exactly what your schematic says — including the bugs. Test thoroughly with Simulate → Ticks Enabled and the Chronogram before you touch hardware. Good first candidates: a counter driving LEDs, or the CPU from Building a Simple CPU.
  2. Describe your board. Open the FPGA menu and choose FPGA Board Editor. You can start from one of the built-in board descriptions bundled with Logisim-evolution, or load a board image and mark out its switches, buttons, LEDs, and pins yourself. Then use Configure FPGA to enter the chip, clock, and download settings.
  3. Map your circuit’s I/O to the board. Open FPGA → FPGA Commander. This is where you connect each input and output pin of your top-level circuit to a physical resource on the board — e.g. your clock to the board’s oscillator pin, your 4-bit counter output to four LEDs. The Commander also runs a design-rule check and tells you what will not map cleanly.
  4. Generate the HDL. Still in FPGA Commander, generate the HDL (VHDL/Verilog) and the constraints file. Read through the generated code once — it is your circuit, translated, and a great way to learn what HDL actually describes.
  5. Synthesize and download with the vendor toolchain. The generated files go into your FPGA board vendor’s own toolchain for synthesis and programming. Follow your board’s official getting-started guide for this step — the exact buttons differ per vendor, and their guide is always current.

What to buy to get started

You need exactly one thing: an FPGA development board. Everything else (USB cable, free vendor software) comes with it or downloads free.

The student classic: Digilent Basys 3. This is the board most digital-design courses standardize on — an Artix-7 FPGA with 16 switches, 16 LEDs, 5 buttons, and 7-segment displays, which maps beautifully to the circuits in these tutorials. If your course uses a different board, buy that one instead; the workflow above is the same.

Check the Basys 3 price

Starter kits for the electronics around it: jumper wires, a breadboard, and a basic component assortment are useful the moment you go beyond the board’s built-in I/O.

ELEGOO starter kits DFRobot kits

As an affiliate partner, we may earn a commission on qualifying purchases — at no extra cost to you.

Honest caveats before you order

  • Not every circuit maps. Asynchronous tricks, combinational loops, and exotic clocking that “works” in simulation may fail design-rule checks or misbehave on silicon. Start with clean synchronous designs.
  • The vendor toolchain is a separate big install (gigabytes) with its own license registration. Budget an evening for it.
  • One board per course is enough. If your university lab already has boards, you don’t need your own — everything in steps 1–4 works without hardware.

Go further

Build something worth putting on silicon first: a simple CPU or the MIPS processor. Then come back here and make it real.