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discretize

Warning

This is still in the early alpha stages, the output logic, netlist, and KiCad files may be sub-optimal, or require an obscene number of devices.

discretize is a set of a Yosys plugin, synth_discretize, and a set of utility scripts for synthesizing an HDL design into a netlist of discrete MOSFETs and generating a KiCad netlist and schematic for the design.

How It Works

TODO

Usage

To convert an HDL design into it's discrete representation synth_discretize is used like any other Yosys pass to apply technology mapping and optimization onto the design, converting it to an equivalent design made out of MOSFETs

For example, the following yosys script will synthesize the counter.v file into a discrete netlist, and then dump the statistics and generated module.

plugin -i ./build/src/techlib/synth_discretize.so
read_verilog ./tests/counter.v
synth_discretize -techlib ./src/techlib
tee -o counter.stat.json stat -json
write_verilog -noexpr counter.discrete.v

You can run that like $ yosys -s counter.ys, and you should two files counter.stats.json and counter.discrete.v.

The first file, counter.stats.json describes the design statistics, in the case of the example above it would be something like:

"design": {
  "num_wires":         826,
  "num_wire_bits":     2066,
  "num_pub_wires":     5,
  "num_pub_wire_bits": 19,
  "num_memories":      0,
  "num_memory_bits":   0,
  "num_processes":     0,
  "num_cells":         478,
  "num_cells_by_type": {
      "$_SDFF_PN0_": 8,
      "GND": 1,
      "NFET": 246,
      "PFET": 222,
      "VCC": 1
  }
}

Notice two cells called GND and VCC those are added to ensure that constant highs and lows are tied properly, in a fully implemented design, those would be a ground pour and a power pour on the board.

The next file, counter.discrete.v contains the dumped verilog module with all of the logic broken into wires and instances of PFET's or NFETs.

Configuring and Building

The following steps describe how to build discretize, it should be consistent for Linux, macOS, and Windows, but macOS and Windows remain untested.

NOTE: The minimum C++ standard to build discretize is C++17.

Prerequisites

To build discretize, ensure you have the following build time dependencies:

  • git
  • meson
  • ninja
  • g++ >= 11 or clang++ >= 11
  • python >= 3.9
  • yosys >= 0.28

Configuring

You can build discretize with the default options, all of which can be found in meson_options.txt. You can change these by specifying -D<OPTION_NAME>=<VALUE> at initial meson invocation time, or with meson configure in the build directory post initial configure.

To change the install prefix, which is /usr/local by default ensure to pass --prefix <PREFIX> when running meson for the first time.

In either case, simply running meson build from the root of the repository will be sufficient and place all of the build files in the build subdirectory.

Building

Once you have configured discretize appropriately, to simply build and install simply run the following:

$ ninja -C build
$ ninja -C build test # Optional: Run Tests
$ ninja -C build install

This will build and install discretize into the default prefix which is /usr/local, to change that see the configuration steps above.

Notes to Package Maintainers

If you are building discretize for inclusion in a distributions package system then ensure to set DESTDIR prior to running meson install.

There is also a bugreport_url configuration option that is set to this repositories issues tracker by default, it is recommended to change it to your distributions bug tracking page.

License

Discretize is licensed under the BSD-3-Clause, the full text of which can be found in the LICENSE file.