Compile, Program and Run a FPGA using Python scripts

Using an IDE is good for development, but when the work is done, there is no big reason to continue to open the IDE and click “Compile, Program, Run…”. So, the best solution is to run scripts and automate the process!

The FPGA needs to compile, be programmed and then run the C file over Nios 2 processor. The compiling and programming can be done only using Quartus tools, but, in order to Run a C file, it is necessary to use the Nios 2 Command Shell. Therefore, compiling and programming will be done using the Quartus Tools while building and running a C file can be done using the Nios 2 Command Shell.

Before starting, note that everything is done in a Windows computer. In a Linux computer the steps would be similar, yet different.

All the documentation is available online. A good reference is the Quartus II Scripting Reference Manual and the Nios II Software Developer Handbook, for Quartus Tools and Nios 2 Command Shell, respectively.

Quartus Tools

Compile

Using quartus_sh is possible to run commands using a shell, which has a very small foorprint.

quartus_sh --flow compile <top file>

Running this command allows us to compile using the top file of the project.

Program

To program, it is not used the quartus_sh anymore but the quartus_pgm instead.

quartus_pgm -l # to display the list of available hardware

Note: try this command above to check if there are any USB-Blaster connected.

After testing connection, try to run the following command to program the previous compiled files to the FPGA:

quartus_pgm -c USB-Blaster -m jtag -o p;<path to .sof file>

If the command does not fail, the FPGA is now successfully programmed through USB-Blaster using JTAG.

Nios 2 Command Shell

This shell uses Windows Subsystem for Linux and, although some things are similar, others are not.

Nios 2 Command Shell uses the Linux terminal instead of Windows’ Power Shell, so it’s possible to use Linux terminal commands like cd or make.

After programming the FPGA, the system is changed - this means that the board support package (BSP) also needs to be refreshed or updated with new system parameters or characteristics. (Check older articles about this)

Updating BSP

To update the BSP the command is the following:

Nios II Command Shell.bat nios2-bsp-generate-files.exe --bsp-dir <path_to_bsp_files> --settings <path_to_settings.bsp>

Nios II Command Shell.bat opens the Linux terminal necessary to use the followed commands, like nios2-bsp-generate-files.exe

Note: if the software folder project name is adcnios the BSP directory will be adcnios_bsp.

After updating the BSP is now ok to build and run the C program written.

Build

To build, run:

Nios II Command Shell.bat make all -C <path to software project folder>

The make command builds the C file and checks if there is any error!

Run

If there are no errors, it is safe to proceed by running:

Nios II Command Shell.bat nios2-download -g <path to .elf file>

The terminal should output some text informing the processor is being programmed with the new C file and is running.

Note: ‘-g’ enables the processor to run. If the ‘-g’ is not specified, the processor will be paused even though the code is flashed.

Scripting with Python

To run terminal commands using Python there are a few possibilities. The most part of developers recommend to use the subprocess library.

By using this library, running a terminal command in python is as easy as:

import subprocess
 
subprocess.run([quartus_sh , '--flow' , 'compile', ADC_TOP_PATH], shell = True)

Inside [ ] is the first command in the Quartus Tools, the equivalent to:

quartus_sh --flow compile <top file>

And ADC_TOP_PATH is a string variable pointing to the path of the top file of the project.

By using subprocess to all of the previous commands, it is possible to get something like this:

import subprocess
 
## QUARTUS SIDE
# Compiles project
compileFPGA = subprocess.run([QUARTUS_SH, '--flow' , 'compile', ADC_TOP_PATH], shell = True)
 
# Program FPGA
programFPGA = subprocess.run([QUARTUS_PGM, '-c' , 'USB-Blaster', '-m', 'jtag', '-o', 'p;'+ ADC_SOF], shell = True)
 
## NIOS2 SIDE
# Update BSP and sent settings
update_bsp = subprocess.run([NIOS2SHELL, 'nios2-bsp-generate-files.exe', '--bsp-dir', ADC_BSP, '--settings', SETTINGS_BSP], shell = True)
 
# Fix PATH problems
#fix_path = subprocess.run([WSL, 'export', 'WSLENV=PATH/l:${WSLENV}'], shell = True)
 
# Build Makefile
build = subprocess.run([NIOS2SHELL, 'make', 'all', '-C', WSL_PATH + MAKEFILE], shell = True)
 
# Run
run = subprocess.run([NIOS2SHELL,'nios2-download','-g', ADC_ELF], shell = True)

Final Code

I’ve made some variables in order to create an-easy-to-manage-directory-variable-group, kinda. So the final code looks something like this:

🛠️ Nuno Nogueira

Explorer