nextpnr -- a portable FPGA place and route tool
nextpnr aims to be a vendor neutral, timing driven, FOSS FPGA place and route tool.
Currently nextpnr supports:
- Lattice iCE40 devices supported by Project IceStorm
- Lattice ECP5 devices supported by Project Trellis
- (experimental) a "generic" back-end for user-defined architectures
There is some work in progress towards support for Xilinx devices but it is not upstream and not intended for end users at the present time. We hope to see more FPGA families supported in the future. We would love your help in developing this awesome new project!
A brief (academic) paper describing the Yosys+nextpnr flow can be found on arXiv.
Here is a screenshot of nextpnr for iCE40. Build instructions and getting started notes can be found below.
The following packages need to be installed for building nextpnr, independent of the selected architecture:
- CMake 3.3 or later
- Modern C++11 compiler (
clang-formatrequired for development)
- Qt5 or later (
qt5-defaultfor Ubuntu 16.04)
- Python 3.5 or later, including development libraries (
- on Windows make sure to install same version as supported by vcpkg
- Boost libraries (
libboost-dev libboost-filesystem-dev libboost-thread-dev libboost-program-options-dev libboost-python-dev libboost-iostreams-dev libboost-devor
- Eigen3 (
libeigen3-devfor Ubuntu) is required to build the analytic placer
- Latest git Yosys is required to synthesise the demo design
- For building on Windows with MSVC, usage of vcpkg is advised for dependency installation.
- For 32 bit builds:
vcpkg install boost-filesystem boost-program-options boost-thread boost-python qt5-base eigen3
- For 64 bit builds:
vcpkg install boost-filesystem:x64-windows boost-program-options:x64-windows boost-thread:x64-windows boost-python:x64-windows qt5-base:x64-windows eigen3:x64-windows
- For static builds, add
-staticto each of the package names. For example, change
- A copy of Python that matches the version in vcpkg (currently Python 3.6.4). You can download the Embeddable Zip File and extract it. You may need to extract
python36.zipwithin the embeddable zip file to a new directory called "Lib".
- For 32 bit builds:
- For building on macOS, brew utility is needed.
Install all needed packages
brew install cmake python boost boost-python3 qt5 eigen
Do not forget to add qt5 in path as well
echo 'export PATH="/usr/local/opt/qt/bin:$PATH"' >> ~/.bash_profile
NOTE: this change is effective in next terminal session, so please re-open terminal window before next step
To build the iCE40 version of nextpnr, install icestorm with chipdbs installed in
/usr/local/share/icebox, or another location, which should be passed as
-DICEBOX_ROOT=/path/to/share/icebox (ensure to point it to
share/icebox and not where the icebox binaries are installed) to CMake. Then build and install
nextpnr-ice40 using the following commands:
cmake -DARCH=ice40 . make -j$(nproc) sudo make install
On Windows, you may specify paths explicitly:
cmake -DARCH=ice40 -DICEBOX_ROOT=C:/ProgramData/icestorm/share/icebox -DCMAKE_TOOLCHAIN_FILE=C:/vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-windows -G "Visual Studio 15 2017 Win64" -DPYTHON_EXECUTABLE=C:/Python364/python.exe -DPYTHON_LIBRARY=C:/vcpkg/packages/python3_x64-windows/lib/python36.lib -DPYTHON_INCLUDE_DIR=C:/vcpkg/packages/python3_x64-windows/include/python3.6 cmake --build . --config Release
To build a static release, change the target triplet from
x64-windows-static and add
A simple example that runs on the iCEstick dev board can be found in
ice40/examples/blinky/blinky.*. Usage example:
cd ice40/examples/blinky yosys -p 'synth_ice40 -top blinky -json blinky.json' blinky.v # synthesize into blinky.json nextpnr-ice40 --hx1k --json blinky.json --pcf blinky.pcf --asc blinky.asc # run place and route icepack blinky.asc blinky.bin # generate binary bitstream file iceprog blinky.bin # upload design to iCEstick
Running nextpnr in GUI mode:
nextpnr-ice40 --json blinky.json --pcf blinky.pcf --asc blinky.asc --gui
(Use the toolbar buttons or the Python command console to perform actions such as pack, place, route, and write output files.)
For ECP5 support, you must download Project Trellis, then follow its instructions to download the latest database and build libtrellis. (for example:
-DTRELLIS_INSTALL_PREFIX=/usr tells nextpnr to look in
cmake -DARCH=ecp5 -DTRELLIS_INSTALL_PREFIX=/path/to/prjtrellis . make -j$(nproc) sudo make install
- Examples of the ECP5 flow for a range of boards can be found in the Project Trellis Examples.
The generic target allows running placement and routing for arbitrary custom architectures.
cmake -DARCH=generic . make -j$(nproc) sudo make install
Additional notes for building nextpnr
-D options to specify which version of nextpnr you want to build.
-DARCH=... to set the architecture. It is a semicolon separated list. Use
cmake . -DARCH=all to build all supported architectures.
The following runs a debug build of the iCE40 architecture without GUI, without Python support, without the HeAP analytic placer and only HX1K support:
cmake -DARCH=ice40 -DCMAKE_BUILD_TYPE=Debug -DBUILD_PYTHON=OFF -DBUILD_GUI=OFF -DBUILD_HEAP=OFF -DICE40_HX1K_ONLY=1 . make -j$(nproc)
To make static build relase for iCE40 architecture use the following:
cmake -DARCH=ice40 -DBUILD_PYTHON=OFF -DBUILD_GUI=OFF -DSTATIC_BUILD=ON . make -j$(nproc)
The HeAP placer's solver can optionally use OpenMP for a speedup on very large designs. Enable this by passing
-DUSE_OPENMP=yes to cmake (compiler support may vary).
You can change the location where nextpnr will be installed (this will usually default to
/usr/local) by using
It is possible to pre-generate
.bba files. This can come in handy when building on time-constrained cloud instances, or in situations where python is unable to use modules. To do this, specify the path to pre- generated
.bba files by passing
-DPREGENERATED_BBA_PATH= to cmake.
Notes for developers
- All code is formatted using
clang-formataccording to the style rules in
.clang-format(LLVM based with increased indent widths and brace wraps after classes).
- To automatically format all source code, run
- See the wiki for additional documentation on the architecture API.
Recording a movie
- To save a movie recording of place-and-route click recording icon in toolbar and select empty directory where recording files will be stored and select frames to skip.
- Manualy start all PnR operations you wish
- Click on recording icon again to stop recording
- Go to directory containing files and exeecute
ffmpeg -f image2 -r 1 -i movie_%05d.png -c:v libx264 nextpnr.mp4
- To build test binaries as well, use
make testto run them, or you can run separate binaries.
- To use code sanitizers use the
-DSANITIZE_MEMORY=ON -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
- Running valgrind example
valgrind --leak-check=yes --tool=memcheck ./nextpnr-ice40 --json ice40/blinky.json
- Running tests with code coverage use
-DBUILD_TESTS=ON -DCOVERAGEand after
- After that open
ice40-coverage/index.htmlin your browser to view the coverage report
- Note that
lcovis needed in order to generate reports
Links and references
Synthesis, simulation, and logic optimization
FPGA bitstream documentation (and tools) projects
- Project IceStorm (Lattice iCE40)
- Project Trellis (Lattice ECP5)
- Project X-Ray (Xilinx 7-Series)
- Project Chibi (Intel MAX-V)