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diff --git a/machxo2/examples/README.md b/machxo2/examples/README.md index 87f50f6d..aac80fb4 100644 --- a/machxo2/examples/README.md +++ b/machxo2/examples/README.md @@ -2,18 +2,37 @@ This contains a simple example of running `nextpnr-machxo2`: -* `simple.sh` generates JSON output (`pnrblinky.json`) of a classic blinky - example from `blinky.v`. +* `simple.sh` generates JSON output (`{pack,place,pnr}blinky.json`) of a + classic blinky example from `blinky.v`. * `simtest.sh` will use `yosys` to generate a Verilog file from - `pnrblinky.json`, called `pnrblinky.v`. It will then and compare - `pnrblinky.v`'s simulation behavior to the original verilog file (`blinky.v`) - using the [`iverilog`](http://iverilog.icarus.com) compiler and `vvp` - runtime. This is known as post-place-and-route simulation. + `{pack,place,pnr}blinky.json`, called `{pack,place,pnr}blinky.v`. It will + then and compare `{pack,place,pnr}blinky.v`'s simulation behavior to the + original verilog file (`blinky.v`) using the [`iverilog`](http://iverilog.icarus.com) + compiler and `vvp` runtime. This is known as post-place-and-route simulation. +* `mitertest.sh` is similar to `simtest.sh`, but more comprehensive. This + script creates a [miter circuit](https://www21.in.tum.de/~lammich/2015_SS_Seminar_SAT/resources/Equivalence_Checking_11_30_08.pdf) + to compare the output port values of `{pack,place,pnr}blinky.v` against the + original `blinky.v` _when both modules are fed the same values on their input + ports._ -As `nextpnr-machxo2` is developed the contents `simple.sh` and `simtest.sh` -are subject to change. + All possible inputs and resulting outputs can be tested in reasonable time by + using yosys' built-in SAT solver. -## Environment Variables For `simple.sh` And `simtest.sh` +As `nextpnr-machxo2` is developed the contents `simple.sh`, `simtest.sh`, and +`mitertest.sh` are subject to change. + +## How To Run + +Each `sh` script runs yosys and nextpnr to validate a blinky design in various +ways. The `mode` argument to each script- `pack`, `place`, or `pnr`- stop +`nextpnr-machxo2` after the specified phase and writes out a JSON file of the +results in `{pack,place,pnr}blinky.json`; `pnr` runs all of the Pack, Place, +and Route phases. + +To keep file count lower, all yosys scripts are written inline inside the +`sh` scripts using the `-p` option. + +## Environment Variables For Scripts * `YOSYS`- Set to the location of the `yosys` binary to test. Defaults to the `yosys` on the path. You may want to set this to a `yosys` binary in your |