This is an extension that brings the DigitalJS digital logic simulator and the yosys2digitaljs netlist format converter to VS code. It provides similar functionalities as the online version while allowing you to work directly with local source files and saving your progress, including source information and the synthesized circuit, for future use. It also includes other additional features like undo-redo, exporting the circuit to images and more.

This was made possible by DigitalJS, yosys2digitaljs and many other related projects by Marek Materzok, University of Wrocław as well as the Yosys open-source hardware synthesis framework. This also borrows idea and code heavily from the original online version: DigitalJS Online.

Contributions are welcome!

Features

• Simulation of circuit (using DigitalJS) including support for

  • Continuous simulation
  • Single step
  • Trigger
  • Signal monitor and plotting.

• Saving/backing up the circuit including the source file information in a portable format

  (The relative paths of the source files are saved and so that the project can be fully restored on another machine as long as the source files are also packaged/copied with the project/circuit file)

  The saved file can be loaded again using this extension, or in the online version for simulation.

• Open the JSON circuit saved by the online version for simulation. Accepted extensions are either .json or .digitaljs. .digitaljs will be openned by default using this extension.

• Exporting the synthesized circuit as vector (SVG) or raster images (PNG or JPEG).

• Undo and redo all the changes on the circuit including but not limited to resynthesize of the circuit and edits done from the graphic view of the circuit.

• Highlighting the source code that matches certain circuit element in the graphic view.

  This can be seen in the screenshot above.

• Using Lua scripts to customize/seed the simulation (using digitaljs_lua)

• Lua command line

• Viewing and simulation multiple circuits simultaneously

• Zoom and pan support with both mouse and touch screen.

• Can run either fully locally using the native version of VS Code, or fully on the web using the web version of VS Code (e.g. vscode.dev, github.dev or gitpod.io)

Basic workflow

• Creating and opening circuit

  New circuits can be created from as empty circuit or from existing source files.

  • To create a new circuit, using the DigitalJS: New Circuit command or clicking the DigitalJS icon next to the editor title when the current source file isn't one recognized by DigitalJS.

  • To create a circuit from an existing source file (.v, .sv, .vh and .lua supported) Use the DigitalJS icon when the source file is open or click Create circuit in DigitalJS in the context menu for the file in the explorer view. The source file will be added to the new circuit and the new circuit will by default have inherit the name from the source file.

    

  After the circuit is created, new files can be added to it either using the DigitalJS icon and the explorer context menu, or using the Add Files button from the Files view in the DigitalJS side panel.

  

  Files with extension .digitaljs will automatically be opened by the DigitalJS extension. Opening files with .json is also supported using either explorer context menu or Open With vscode command. One can also open the JSON files saved from DigitalJS Online. However, since DigitalJS Online does not save any source info, only simulation and graphic editor is supported on such files. Synthesis is only supported once new source files has been added.

  Note that the circuit file contains relative path to the source files. If the circuit is to be copied to a different machine, the source files also need to be copied with the same relative paths.

• The main UI for the DigitalJS extension includes the main circuit view/editor and three side panels.

  The main circuit view shows the synthesized circuit (if one exists). It includes interactive tools to view the circuit, edit connection, view and plot signal and trigger setup. The circuit view support zooming and panning using touch/drag, two-finger drag/pinch as well as Ctrl-key + scroll wheel. For complex circuit, the submodules in the circuit can be opened in a popup window.

  The three side panels shows the files in the circuit, the sythesis options and simulation control respectively.

• Synthesis

  Once the source files are added, the circuit can be synthesized using the synthesis side panel. The synthesis options can be set on the same panel and will be saved alone with the circuit.

  If the source file for the circuit is visible in an text editor, hovering the wires and devices on the main circuit view will highlight the corresponding lines of code in the source editor.

• Simulation

  The wires in the main circuit view are highlighted according to the simulation status and one can also hover on the wires to see the signal values. The input values for the toplevel module can be changed interactively in the circuit. The input and output port can also be seen/controlled in the control side panel.

  To start/pause the simulation, one can use the play/pause icon next to the editor title. For more complex simulation control including fast-forward, single-step, or wait for event, a more complete set of buttons are available in the control panel. The simulation time tick is also shown in the control panel.

  The magnifying glass icon on the wires allow one to monitor a signal and create a plot for it. Clicking the icon brings up the monitor view as part of the main circuit view. One can also setup triggering condition in the monitor view.

• Saving progress

  The main circuit view is implemented as a custom editor and all the normal saving/restoring operation on an editor is supported using the corresponding hotkey or menu from vscode. This includes, saving, saving as, reverting, undo and redo. Note that changes to the circuit layout from the graphic interface is saved and will be part of the undo/redo history. However, the signals in the circuit is not saved. Note that due to the limit of vscode, saving the circuit as a different name will close the circuit and open it under new name and the simulation status will be lost.

• Exporting image

  The circuit, including the signal levels can be exported as either vector or scalar images. SVG, PNG and JPEG formats are supported and additional format may also be available depending on the host browser.

  The exported image is for a single circuit view. Images for the subcircuits needs to be exported individually. Note that export of subcircuit image requires the corresponding subcircuit to be open.

• Lua scripting

  For more complex control of the simulation, one can use lua script.

  To run a script, one need to add the script as a source file to the circuit and use the run button in the digitaljs files view to start the script. The run button will be changed into a stop button to abort the script when the script is running. In addition to the API at https://github.com/tilk/digitaljs_lua/blob/master/docs/USAGE.md two additional functions sim.start() and sim.stop(synchronize=false) are also supported to start and stop the simulation.

  By default, the output of the script will be shown as notification messages in vscode. Alternatively, one can open a Lua terminal for the circuit using the Lua Terminal button in the DigitalJS files panel. When the terminal is visible, the output of the script will be printed to the terminal instead. One can also use the terminal to interactively run lua script similar to the normal Lua command line interface. Command line editing and command line history are supported. Pressing Ctrl-C in the command line abort the execution of the commands from the command line. (It does not stop the execution of other lua scripts).

  Starting, stopping the simulation from Lua terminal, setting input and getting output from the cirsuit: