dkilfoyle / logic

Simulate logic circuits in javascript using custom DSL

Logic Simulator

** Deprecated: see Logic 2 **

An IDE for experimentation with Francis Stokes (Low Level Javascript) Digital Circuit Simulator

Installation

npm install
quasar dev

Features

1. Micro-subset verilog-like DSL for coding the array of logic gates (Parsed using Arcsecond.js of course!)
2. CodeMirror-based code editor with automatic linting/error reporting, smart indentation, code folding, hints
3. Visualisation of the generated gate array by hierachical table or a (experimental toy really) dagre graph
4. Testbench simulation with graphical trace output
5. Coming soon: d3-hwschematic view with simulation state animation

DSL

1. Modules define a group of gates (eg a logic chip) and the inputs and outputs (eg the pins) between modules

     module MyModule(input A,
                     input B,
                     output Q)
       // gate, wire and instance statements here
     endmodule

2. Gates define a basic logic function, a unique identifier for this gate, and the inputs to the gate

     wire myAndGate;
     and(myAndGate, A, B); // equivalent to myAndGate = A & B

3. Instances of gates define a namespaced copy of a module and the connections between the parent module and the instance module

     MyModule m1(.A(parentVar1), .B(parentVar2), .Q(parentVar3))

4. All programs must have a "main" module which is automatically instanced and serves as the entry point.

   a) The main module automatically includes a "clock" input.

   b) The inputs to the main module will be external "control" gates eg buttons/sensors

5. The main module should include a testbench section to define the value of the control gates at different time points

    test begin
        #00 {a=0, b=0};
        #05 {a=0, b=1};
        #10 {a=1, b=0};
        #15 {a=1, b=1};
    end

TODO

1. More sample code circuits
   1. One hot encoder
   2. 2 to 1 multiplexer2_1
   3. 7 segment encoder
   4. 1 bit adder
   5. D flip-flop
   6. 4 bit ripple adder
   7. 4 to 1 multiplexer with bit vector select line
   8. Ripple counter
   9. Shift register
   10. FSMs
2. Support bitwise statements to generate the logic gates eg Q = (A & B) | ~C
3. Reuse intermediary gates
4. Support bit vector type
5. Improve traces with time slider to animate state
6. Improve schematic with time slider to animate state
7. Experiment with better schematic graph layouts, custom combo
8. More linting
9. Code hints (Ctrl-Space), snippets (Ctrl-Shift-Space), comment hotkey,
10. Future? a) Truth tables to generate optimised logic gates

Acknowledgements

1. LowLevelJavascript Digital Circuit Simulator
2. Arcsecond.js
3. Quasar.dev
4. G6 Graph
5. CodeMirror
6. Dygraphs
7. d3-hwschematic