Migrating from Vivado

This page is WIP.

At this point it is not possible to work with Xilinx FPGAs by using only free software. If you are looking for a full free software toolchain for working with FPGAs, see Project IceStorm.

That being said, most of your workflow can still be done using Yosys, Icarus Verilog and other free software tools. You will have to use Vivado for place&route, bitstream generation and writing your bit file onto your device. However, this can be done by using tcl scripts, meaning that you will not have to open Vivado GUI at all.

This page will show how to get commonly used Vivado functionality with Yosys.

Simulation

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Wave Viewer

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Post-Synthesis Simulation

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Elaborated Design Schematic / RTL Schematic

All you have to do is load your Verilog source files and run prep. Then, use show to see parts that are of any interest to you. You probably also want to use -colors and -stretch flags to make the graph a bit more readable.

Therefore, the command you want to use is:

yosys -p 'prep; show -colors 42 -stretch show top' top.sv foo.sv bar.sv

You can also export this graph directly to SVG file:

yosys -p 'prep; show -colors 42 -stretch -format svg -prefix mygraph show top' top.sv foo.sv bar.sv

See also Yosys AppNote 011: Interactive Design Investigation.

Synthesized Design Schematic / Technology Schematic

TODO

Bitstream and Programming

You can run Vivado in batch or tcl modes. The difference is that in batch mode it will run the script and exit, while in tcl you will be left with the tcl shell. The problem with Vivado is that it has a very long startup delay, therefore running it in batch mode is very likely not what you want (but you can still do it, if you wish).

1. place&route and bitstream generation. This script does not have open_hw command, so perhaps consider adding it (otherwise you will get an error message).
2. writing the bitstream file to your device

The first one is where all of the magic happens. Feel free to add a couple of other commands, for example report_power. You may also want to modify the second file if you are working with multiple devices at the same time.

You will also need an .xdc file (you are probably already aware of it). See this example. You can use Vivado GUI to generate it, or you can just write it by hand. The structure of the file is simple enough so there should be no problem.

So, you can run it in batch mode:

vivado -mode batch -source run_vivado.tcl

Or, you can run it tcl mode:

vivado -mode tcl

Once it is loaded, you will see the tcl shell. Write source run_vivado.tcl to run your tcl script. The latter approach might be slightly more preferable to you if you do not like the startup delay of vivado.

Both examples assume that you have vivado binary in your PATH. If you don't, feel free to substitute it with an actual path (e.g. ~/opt/Xilinx/Vivado/2016.2/bin/vivado).

Makefile to the Rescue!

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Conclusion ?

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