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Using Spinal from CLI with SBT

First, open a terminal in the root of the template you have downloaded earlier in Create a first SpinalHDL project.

Commands can be executed right from the terminal:

sbt "firstCommand with arguments" "secondCommand with more arguments"

But sbt has a quite long boot time so the we recommend to use its interactive mode:


Now sbt shows a prompt. Let’s start by doing Scala compilation. It will fetch dependencies so it can take time the first time:


Actually you never need to just compile as it is done automatically when needed. The first build time will take a few moments longer compared to future builds as the sbt tool builds the entire project from a cold start and then uses incremental building where possible from that point on. sbt supports autocompletion inside the interactive shell to assist discovery and usage of the available commands. You can start the interactive shell with sbt shell or running sbt with no arguments from the command line.

To run a specific HDL code-generation or simulation, the command is runMain. So if you type runMain, space, and tab, you should get this:

sbt:SpinalTemplateSbt> runMain
   ;                               projectname.MyTopLevelVerilog
   projectname.MyTopLevelFormal    projectname.MyTopLevelVhdl

The autocompletion suggests all things that can be run. Let’s run the Verilog generation for instance:

runMain projectname.MyTopLevelVerilog

Look at the directory ./hw/gen/: there is a new MyTopLevel.v file!

Now add a ~ at the beginning of the command:

~ runMain projectname.MyTopLevelVerilog

It prints this:

 sbt:SpinalTemplateSbt> ~ runMain mylib.MyTopLevelVerilog
 [info] running (fork) mylib.MyTopLevelVerilog
 [info] [Runtime] SpinalHDL v1.7.3    git head : aeaeece704fe43c766e0d36a93f2ecbb8a9f2003
 [info] [Runtime] JVM max memory : 3968,0MiB
 [info] [Runtime] Current date : 2022.11.17 21:35:10
 [info] running (fork) projectname.MyTopLevelVerilog
 [info] [Runtime] SpinalHDL v1.9.3    git head : 029104c77a54c53f1edda327a3bea333f7d65fd9
 [info] [Runtime] JVM max memory : 4096.0MiB
 [info] [Runtime] Current date : 2023.10.05 19:30:19
 [info] [Progress] at 0.000 : Elaborate components
 [info] [Progress] at 0.508 : Checks and transforms
 [info] [Progress] at 0.560 : Generate Verilog
[info] [Done] at 0.603
[success] Total time: 1 s, completed Oct 5, 2023, 7:30:19 PM
[info] 1. Monitoring source files for projectname/runMain projectname.MyTopLevelVerilog...
[info]    Press <enter> to interrupt or '?' for more options.

So now, each time you save a source file, it will re-generate MyTopLevel.v. To do this, it automatically compiles the source files and it performs lint checks. This way you can get errors printed on the terminal almost in real-time while you are editing the source files.

You can press Enter to stop automatic generation, then Ctrl-D to exit sbt.

It is also possible to start it right from the terminal, without using sbt’s interactive prompt:

sbt "~ runMain mylib.MyTopLevelVerilog"

Now you can use your environment, let’s explore the code: A simple example.