SymbiFlow examples

This repository provides example FPGA designs that can be built using SymbiFlow open source toolchain. The examples target the Artix-7 devices.

The repository includes:

• Travis CI configuration file

• Build scripts to generate the environment:

  • Conda configurations
  • Python requirements
  • Environment setup

• Example FPGA designs including:

  • Verilog code
  • Pin constraints files
  • Timing constraints files
  • Makefiles for running the SymbiFlow toolchain

Description

Travis-based CI in this repository runs all the steps required to build the example designs and generate bitstreams for programming the FPGA devices.

The CI performs the following steps:

• Miniconda installation and configuration

• Installation of the required conda packages (toolchains and Python modules). Note that Python packages can be installed using any Python package manager:

  • VTR
  • Yosys
  • Yosys-plugins
  • lxml, simplejson, intervaltree, python-constraint, git, pip and fasm

Toolchain installation

This block of code regards the toolchain installation. It is divided in three main steps:

• Conda setup
• Conda packages installation
• Architecture definitions installation

INSTALL_DIR=/opt/symbiflow
wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
bash Miniconda3-latest-Linux-x86_64.sh -b -p $INSTALL_DIR/conda && rm Miniconda3-latest-Linux-x86_64.sh
source $INSTALL_DIR/conda/etc/profile.d/conda.sh
conda config --set always_yes yes --set changeps1 no
conda config --add channels conda-forge
conda config --add channels symbiflow
conda update -q conda
conda activate
conda install -c symbiflow yosys
conda install -c symbiflow yosys-plugins
conda install -c symbiflow vtr=8.0.0.rc2_3575_g253f75b6d
conda install lxml simplejson intervaltree python-constraint git pip
pip install git+https://github.com/symbiflow/fasm
wget -qO- https://storage.googleapis.com/symbiflow-arch-defs/artifacts/prod/foss-fpga-tools/symbiflow-arch-defs/continuous/install/4/20200416-002215/symbiflow-arch-defs-install-a321d9d9.tar.xz | tar -xJ -C $INSTALL_DIR
conda deactivate

Build Example Designs

With the toolchain installed, you can build the example designs.

The example designs are provided in separate directories:

1. counter - simple 4-bit counter driving LEDs. The design targets the Basys3 board .
2. picosoc - picorv32 based SoC. The design targets the Basys3 board.
3. linux_litex - LiteX based system with Linux capable VexRiscv core. The design includes DDR and Ethernet controllers. The design targets the Arty board.

The Linux images for the linux_litex example can be build following the linux on litex vexriscv instructions. The linux_litex example is already provided with working Linux images.

To build the examples, run following commands from the project root directory:

conda activate
# adding symbiflow toolchain binaries to PATH
export PATH=$INSTALL_DIR/install/bin:$PATH
# counter example
pushd counter_test && make && popd
# picosoc example
pushd picosoc_demo && make && popd
# litex example
pushd linux_litex_demo && make && popd