Prepare the environment

We still recommend you work with a 64-bit Ubuntu (14.04 LTS). Everything except using the FPGA boards should also work out-of-box in a virtual machine.

For more details follow the instructions of the previous tutorial.

Ensure you have all the necessary packages installed:

sudo apt-get install autoconf automake autotools-dev curl \
libmpc-dev libmpfr-dev libgmp-dev gawk build-essential bison \
flex texinfo gperf libncurses5-dev libusb-1.0-0 libboost-dev \
swig git libtool libreadline-dev libelf-dev python-dev

Download the code

The code is hosted in the lowRISC chip git repository. All external repositories are fetched as submodules. You need to clone the proper branch (debug-v0.3):

git clone -b debug-v0.3 --recursive
cd lowrisc-chip

Structure of the git repository

The structure is similar to the one described here. Essentially one folder was added that contains the Open SoC Debug repositories:

Next steps

To set the correct environment variables for running lowRISC, you need to source the script (formerly in the base directory:


It is possible to override the default values by exporting variables before sourcing the script. The following variables are overridable:

$TOP                Path to the lowrisc-chip directory ($PWD).
$RISCV              Path to the riscv toolchain ($TOP/riscv).
$OSD_ROOT           Path to the Open SoC Debug tools ($TOP/tools).
$FPGA_BOARD         The tager FPGA board (nexys4_ddr).

Next, you should follow the following steps: