OSS CAD Suite

Important

[!WARNING] Base images for building various releases are updated 2026-07-28, if you experience any new problem please create an issue.

Release before changes is here in case you need fast solution.

[!IMPORTANT]
Since Apple is done with support of Intel based machines, we will stop delivering darwin-x64 soon.

[!TIP] For best experience on Windows use WSL and linux-x64 version on it. Follow instructions here on how to setup WSL.

Introduction

OSS CAD Suite is a binary software distribution for a number of open source software used in digital logic design. You will find tools for RTL synthesis, formal hardware verification, place & route, FPGA programming, and testing with support for HDLs like Verilog, Migen, and Amaranth.

OSS CAD Suite is a component of YosysHQ's Tabby CAD Suite:

See Tabby CAD Datasheet for details on Tabby CAD Suite; see OSS CAD Suite GitHub (this page) for details on OSS CAD Suite.

RTL Synthesis

• Yosys RTL synthesis with extensive Verilog 2005 support
• Amaranth refreshed Python toolbox for building complex digital hardware
• Migen Python toolbox for building complex digital hardware
• ABC A System for Sequential Synthesis and Verification
• GHDL VHDL 2008/93/87 simulator (linux-x64 and darwin-arm64 platforms only)
• Slang SystemVerilog Language Services

Did you know that the Tabby CAD version of yosys supports industry standard SystemVerilog, VHDL and SVA? Contact us at contact@yosyshq.com to arrange a free evaluation license.

Plugins

• GHDL plugin VHDL synthesis based on GHDL (linux-x64 and darwin-arm64 platforms only)
• Slang plugin SystemVerilog synthesis based on Slang

Formal Tools

• sby (formerly SymbiYosys) a front-end driver program for Yosys-based formal hardware verification flows.
• mcy Mutation Cover with Yosys
• eqy Equivalence Checking with Yosys
• sby-gui GUI for sby (formerly SymbiYosys)
• aiger AIGER tools including bounded model checker
• avy Interpolating Property Directed Reachability tool
• Boolector SMT solver and BTOR model checker
• Yices 2 SMT solver
• Super prove ABC-based AIGER hardware model checker (linux-x64 platform only)
• Pono an SMT-based model checker built on smt-switch
• Z3 SMT solver
• Bitwuzla SMT solver
• rIC3 SMT solver

PnR (Place and Route)

• nextpnr a portable FPGA place and route tool (generic, ice40, ecp5, machxo2, nexus, gowin)
• Project IceStorm tools for working with Lattice ICE40 bitstreams
• Project Trellis tools for working with Lattice ECP5 bitstreams
• Project Oxide tools for working with Lattice Nexus bitstreams
• Project Apicula tools for working with Gowin bitstreams
• Project Peppercorn tools for working with Cologne Chip GateMate bitstreams

FPGA board programming tools

• openFPGALoader universal utility for programming FPGA
• dfu-util Device Firmware Upgrade Utilities
• ecpprog basic driver for FTDI based JTAG probes, to program ECP5 FPGAs
• ecpdap program ECP5 FPGAs and attached SPI flash using CMSIS-DAP probes in JTAG mode
• fujprog ULX2S / ULX3S JTAG programmer
• openocd Open On-Chip Debugger

Simulation/Testing

• GTK Wave fully featured GTK+ based wave viewer
• Surfer A waveform viewer with a focus on a snappy usable interface, and extensibility.
• verilator Verilog/SystemVerilog simulator
• iverilog Verilog compilation system
• cocotb coroutine based cosimulation library for writing VHDL and Verilog testbenches in Python

Support libraries

• Python 3 language interpreter is provided in all supported platforms.
• Python 2 language interpreter is provided in Linux platforms in form of library only.
• Ubuntu 26.04 distribution development packages are used and shared libraries used are provided in package.
• macports distribution system for macOS is used to obtain all libraries used, and they are provided in package.
• MinGW Minimalist GNU for Windows library packages from Fedora 43 are used in compilation and provided in package.

Installation

1. Download an archive matching your OS from the releases page.
2. Extract the archive to a location of your choice (for Windows it is recommended that path does not contain spaces)
3. On macOS to allow execution of quarantined files xattr -d com.apple.quarantine oss-cad-suite-darwin-arm64-yyymmdd.tgz on downloaded file, or run: ./activate in extracted location once.
4. Set the environment as described below.

Linux and macOS

export PATH="<extracted_location>/oss-cad-suite/bin:$PATH"

# or

source <extracted_location>/oss-cad-suite/environment

Linux and macOS (fish shell)

fish_add_path "<extracted_location>/oss-cad-suite/bin"

# or

source <extracted_location>/oss-cad-suite/environment.fish

Windows

from existing CMD prompt:
<extracted_location>\oss-cad-suite\environment.bat

from existing PowerShell prompt:
. <extracted_location>\oss-cad-suite\environment.ps1

to create new CMD prompt:
<extracted_location>\oss-cad-suite\start.bat

NOTE: when environment is set, python3 from package becomes available as well, this enables usage of Migen and Amaranth HDL and LiteX libraries scripts as usual. When OSS CAD Suite is just added in PATH to use packaged python3 use tabbypy3 to start python environment. For Windows, there are no wrappers and using environment.bat is only choice.

Using LiteX

We provide you with Python 3.11 and all required software to be able to use LiteX. After activating environment it is possible to perform installation same as usual:

mkdir -p litex
cd litex
wget https://raw.githubusercontent.com/enjoy-digital/litex/master/litex_setup.py
python3 litex_setup.py init
python3 litex_setup.py install

Supported Architectures

linux-x64

Any personal Linux based computer should just work; no additional packages need to be installed on the system to make OSS CAD Suite work. Distributed libraries are based on Ubuntu 26.04, but everything is packaged in such a way so it can be used on any Linux distribution.

darwin-x64

Any macOS 13.00 or later with Intel CPU should use this distribution package.

darwin-arm64

Any macOS 13.00 or later with M1/M2/M4 CPU should use this distribution package.

windows-x64

This architecture is supported for Windows 10 and 11.

linux-arm64

ARM64 based Linux devices using 64bit CPU as in Raspberry Pi 4,5 and 400 (with 64bit version of OS installed), and also laptops like the MNT Reform 2 can use this distribution package.

Contributing

To be able to build OSS CAD Suite yourself, you need to install docker (please note this only works on x64 platforms or under rosetta on macos-arm) and python 3.6 or higher, with the click library.

After that just running ./builder.py should work fine.

To build default build:

./builder.py build 

To skip update of source code, you can always:

./builder.py build --no-update

To build specific target and architecture:

./builder.py build --target=yosys --arch=linux-arm64

Alternatives

If your project is primarily written in Python (using tools such as Amaranth or LiteX), and you only need synthesis and PnR tools, you might find YoWASP more suited to your needs since it allows managing installation and versioning of these tools in the same way as any other Python package dependencies.