Export Yosys netlists to a logic simulator

Usage no npm install needed!

<script type="module">
  import yosys2digitaljs from 'https://cdn.skypack.dev/yosys2digitaljs';



This program converts JSON netlist output generated by Yosys circuit synthesis software for use with the DigitalJS graphical circuit simulator.


You need to have Yosys installed to run yosys2digitaljs. For example, in Debian/Ubuntu, run:

apt install yosys

Clone the repository and install dependencies using npm:

git clone https://github.com/tilk/yosys2digitaljs.git
cd yosys2digitaljs
npm install

Now you can run yosys2digitaljs on your Verilog or SystemVerilog files:

./process.js file.v file.sv ...

The generated JSON is printed on standard output.


Yosys2digitaljs can be used as a library. The API is promise (or async/await) based. Available functions are:

  • yosys2digitaljs(json, options) - converts the Yosys JSON output json (passed as an JS object) to a DigitalJS representation of the same circuit.
  • process_sv(sv_text, options) - converts a single SystemVerilog source passed as a string.
  • process_files(texts, options) - converts multiple Verilog/SystemVerilog sources. The texts parameter is an object, with keys being file names, and corresponding values containing the file contents as strings. Example: { 'test.sv': 'module test; ...' }.
  • process(filenames, dirname, options) - converts Verilog/SystemVerilog sources saved on the filesystem under names filenames in the directory dirname.

The functions return a promise, which fulfills with an object value with following keys:

  • output: the conversion result as JS object, which can be stringified to JSON.
  • yosys_stdout and yosys_stderr: standard output and error output received from Yosys.

For bigger example, see the online app demo.