SymbiFlow examples

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

The repository includes:

• examples - Example FPGA designs including:

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

• .travis.yml - Travis CI configuration file

Toolchain installation

This section describes how to install the toolchain. This procedure is divided in two steps:

• Installing the Conda package manager
• Downloading the architecture definitions and installing the toolchain

1. Conda

wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O conda_installer.sh

2. Toolchain

For the Artix-7 devices:

INSTALL_DIR="/opt/symbiflow/xc7"
bash conda_installer.sh -b -p $INSTALL_DIR/conda && rm conda_installer.sh
source "$INSTALL_DIR/conda/etc/profile.d/conda.sh"
conda update -y -q conda

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 install -y -c symbiflow yosys yosys-plugins vtr-no-gui
conda install -y make lxml simplejson intervaltree git pip
conda activate
pip install python-constraint
pip install git+https://github.com/symbiflow/fasm
conda deactivate

Build Example Designs

With the toolchain installed, you can build the example designs. The example designs are provided in separate directories:

• examples/xc7 directory for the Artix-7 devices

Example designs for the Artix-7 devices:

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 built following the linux on litex vexriscv instructions. The linux_litex example is already provided with working Linux images.

To build the examples, run the following commands:

export INSTALL_DIR="/opt/symbiflow/xc7"
# adding symbiflow toolchain binaries to PATH
export PATH="$INSTALL_DIR/install/bin:$PATH"
source "$INSTALL_DIR/conda/etc/profile.d/conda.sh"
conda activate
git clone https://github.com/SymbiFlow/symbiflow-examples && cd symbiflow-examples
# counter example
pushd examples/xc7/counter_test && make && popd
# picosoc example
pushd examples/xc7/picosoc_demo && make && popd
# litex example
pushd examples/xc7/linux_litex_demo && make && popd