nextpnr/machxo2

nextpnr-machxo2

Experimental FOSS Place And Route backend for the Lattice MachXO2 family of FPGAs. Fuzzing takes place as a subproject of prjtrellis.

Known to work:

• Basic routing from pads to SLICEs and back!
• Basic packing of one type of FF and LUT into half of a SLICE!
• Using the internal oscillator OSCH as a clock
• LOGIC SLICE mode

Things that probably work but are untested:

• Any non-3.3V I/O standard that doesn't use bank VREFs.

Things remaining to do include (but not limited to):

• More intelligent and efficient packing
• Global Routing (exists in database/sim models, nextpnr-machxo2 doesn't use it yet)
• Secondary High Fanout Nets
• Edge Clocks (clock pads work, but not routed to global routing yet)
• PLLs
• Synchronous Release Global Set/Reset Interface (SGSR)
• Embedded Function Block (EFB)
• All DDR-related functionality
• Bank VREFs
• Embedded Block RAM (EBR)
• CCU2 and DPRAM SLICE modes

Quick Start

The following commands are known to work on a near-fresh Linux Mint system (thank you securelyfitz!):

Prerequisites

sudo apt install cmake clang-format libboost-all-dev build-essential
qt5-default libeigen3-dev build-essential clang bison flex libreadline-dev
gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3
libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
python3-setuptools python3-serial

Installation

Use an empty directory to hold all the cloned repositories. Upstream repos can be used as well (e.g. YosysHQ/prjtrellis, etc.).

git clone git@github.com:cr1901/prjtrellis.git
cd prjtrellis
git checkout facade
git submodule update --init --recursive
cd libtrellis
cmake -DCMAKE_INSTALL_PREFIX=/usr
make -j 8
sudo make install

cd ../../

git clone git@github.com:cr1901/yosys.git
cd yosys/
git checkout machxo2
make config-gcc
make
sudo make install

cd ../

git clone git@github.com:tinyfpga/TinyFPGA-A-Programmer.git
cd TinyFPGA-A-Programmer/
sudo python setup.py install

cd ../

git clone git@github.com:cr1901/nextpnr.git
cd nextpnr
git checkout machxo2
git submodule update --init --recursive
cmake . -DARCH=machxo2 -DBUILD_GUI=OFF  -DTRELLIS_INSTALL_PREFIX=/usr -DBUILD_PYTHON=OFF 
make

Although uncommon, the facade and machxo2 branches of the above repos are occassionally rebased; use git pull -f if necessary.

Demo

If you have a TinyFPGA Ax2 board with the TinyFPGA Programmer, the following script will build a blinky bitstream and load it onto the MachXO2; the gateware will flash the LED!

cd machxo2/examples/
sh demo.sh tinyfpga

The tinyfpga.v code used in demo.sh is slightly modified from the user's guide to accommodate (* LOC = "pin" *) constraints and the built-in user LED.