neorv32_soc

Playing around with the neorv32 SoC on a Gecko4Education Board with an Intel Cyclone IV E FPGA.

Initially I have used this project to recreate a greatest-common-denomitator accelerator as was teached in class. In class we used the NIOS II from Intel / Altera. This project then ported this over to the neorv32 which is a RISC-V cpu architecture. Afterwards the project took a turn and I'm now focusing it on symmetric multiprocessing aka SMP and have the goal to implement a SMP system based on the neorv32. As such the relevant GCD parts were moved or changed. But remnants of the VHDL hardware descriptions can be found in vhdl/gcd and for the software in sw/gcd. A working state of the GCD system would be in git commit 774e708a13.

Project structure

.
├───sim     # ModelSim / QuestaSim workdir, files are generated with scripts/sim_*.tcl scripts.
├───quartus # Quartus workdir, files are generated with scripts/quartus_*.tcl scripts.
├───scripts # Tcl skripts to generate and manage project files.
├───vhdl    # VHDL RTL descriptions of project entities and toplevel.
└───lib     # Libraries as git submodules of the NEORV32 and other RTL entities.

Simulation

Simulation of the different entities or modules and their corresponding testbenches can be done with the following commands. The commands have to be issued in a cli within sim working directory.

1. Compile:

vsim -c -do ../scripts/sim_compile.tcl

2. Running the testbenches:

vsim -c -do ../scripts/sim_test.tcl

• (optional) View signal waves of testbench (opens ModelSim or QuestaSim GUI):

vsim -c -do ../scripts/sim_open.tcl <name_of_testbench>

Synthesis

Synthesis of the project with quartus can be done with the following commands. Run it in the quartus subfolder.

1. Generate the quartus project:

quartus_sh -t ../scripts/quartus_project.tcl

2. Synthesis:

quartus_sh -t ../scripts/quartus_compile.tcl

3. Load the bitstream onto the GECKO-Board:

quartus_pgm -c USB-Blaster --mode jtag --operation='p;top.sof'

• (optional) Flash the bitstream onto the GECKO-Board:

quartus_cpf -c ../../scripts/quartus_flash.cof
quartus_pgm ../../scripts/quartus_flash.cdf

• (optional) Open the Quartus GUI:

quartus top.qpf

License

MIT © Niklaus Leuenberger.