I have a small floating point unit, described in VHDL, and synthesizable. I'd like to buy an FPGA (not an expensive one) that would allow me to test in practice the unit.

I've used an FPGA in the past, a virtex-5, which is too expensive for what I have to do. I wanted to buy the cheapest I need for the task I have in mind.

I'm not an expert in purchasing this stuff however so I was wondering.

  1. When I buy an FPGA is usually some licence to use some EDA tool also sold?
  2. If the answer to 1. is NO, how much could cost a licences?
  3. Is there anything else I need to buy for what I want to do?



2 Answers 2


First, you need to determine the necessary size of FPGA. Get Free Xilinx WebPack, it supports plenty of devices. I would recommend to install/launch the tool, and virtually create a project with the most affordable Spartan-6 family. It is supported up to 75,000 logic sells with 93,000 flip-flops. Or you can start with newest Kintex or Artix series up to 200,000 slices. Then compile your code with no pin constraints (only basic timing), and get the cell/gate count for your design. Then you can scale down the project to a more affordable minimal FPGA size.
You can do this before buying any hardware.


Depending on the resource requirements of your design, you can buy an entry level development board that includes I/O interfaces sufficient for your application. There are boards for both the Xilinx and Altera FPGAs. Just check the cheapest board available and make sure that your design fits to the FPGA on the board.

Another thing is that you don't have to buy a development board from the FPGA vendor itself (Xilinx, Altera etc.). There are cheaper boards that is designed by a 3rd party developer. Check the following link: https://joelw.id.au/FPGA/CheapFPGADevelopmentBoards

Answers to your questions:

  1. A free license is provided for both of the vendors I have mentioned above. But again you have to make sure that your FPGA is supported by the free version. For example; Xilinx ISE Webpack (Free) version does not support all Virtex-5 devices. You have to buy a full license to unlock all of them. Entry/Mid level FPGAs are generally supported with a free license though. More expensive boards also include a node-locked license provided with the purchase but since the board itself is expensive, it will not be a viable option.

  2. A full license is expensive but if you are in a college, you might get/request a license for academic use. Other than that it is not viable to buy a license in your case.

  3. Depending on your test case, you might need peripheral modules or connection cables. But I think it is very unlikely that you will require more than an RS232/USB cable.

  • \$\begingroup\$ I need to know what features does a free licence usually provides, does it allows synthesis (or whatever is called in case of FPGA). And no, I'm not in college. The only features I'm interested in is basically comparing software vs hardware. \$\endgroup\$ Oct 29, 2016 at 14:57
  • \$\begingroup\$ I have only used Xilinx tools and their free license allows you to synthesize and implement (Map, Translate, Place and Route) a design if the target device is supported. It even allows you to synthesize without a license if I am not mistaken. Info for ISE , Info for Vivado \$\endgroup\$
    – Chief
    Oct 29, 2016 at 15:02
  • \$\begingroup\$ Actel provide a free synth & layout tool as well. What none of them provide is a simulator (well Xilinx ISE comes with an intro modelsim) \$\endgroup\$
    – user16222
    Oct 29, 2016 at 15:13
  • \$\begingroup\$ Altera also offers free licensing for many of its devices and cores, even some as complex as Cyclone V. Many cores are free to test as long as your board is tethered to the PC you use for design \$\endgroup\$ Oct 29, 2016 at 20:20

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