RadonMCU

Experimental MCU (Microcontroller Unit)

RadonMCU is an FPGA-based soft-core microcontroller platform built around Intel Nios II. The repository includes both hardware design (Quartus + Platform Designer) and software examples (Nios II SBT/Eclipse) used to validate the system on real hardware.

Project overview

Current platform profile (based on generated BSP):

• Device family: Intel MAX 10
• CPU: Nios II Gen2 (tiny implementation)
• CPU clock: 50 MHz
• On-chip RAM: 32 KB
• Console I/O: JTAG UART

This project is intended for iterative hardware/software co-design:

• modify the SoC in Platform Designer,
• regenerate HDL and compile in Quartus,
• regenerate BSP and rebuild software examples.

Repository structure

• RadonMCU.qpf, RadonMCU.qsf: top-level Quartus project files
• RadonMCUSystemDesign/: Platform Designer system source and generated HDL wrapper files
• SoftwareExamplesForRadonMCU/: Nios II software workspace
• SoftwareExamplesForRadonMCU/RadonHelloWorld/: example application
• SoftwareExamplesForRadonMCU/RadonHelloWorld_bsp/: generated BSP for the application

Toolchain requirements

• Intel Quartus Prime Lite 18.1 (or compatible with this project)
• Nios II EDS / Nios II SBT for Eclipse
• Device support for MAX 10

Important:

• Build software from the Nios II Command Shell or Nios II Eclipse environment.
• Running plain system shells without Nios II environment may fail due to missing tools such as make, nios2-elf-gcc, and nios2-download in PATH.

If Eclipse reports "Program make not found in PATH", you can set PATH inside Eclipse:

1. Open Window -> Preferences -> C/C++ -> Build -> Environment.
2. Add a variable:
   • Name: PATH
   • Value: C:\intelfpga_lite\18.1\nios2eds\bin\gnu\H-x86_64-mingw32\bin;C:\intelfpga_lite\18.1\nios2eds\bin\gnu\H-x86_64-mingw32\bin\utils;C:\intelfpga_lite\18.1\quartus\bin64\cygwin\bin;${PATH}
3. Apply and close Preferences.
4. Restart Eclipse.

Build workflow

1. Hardware build

1. Open project in Quartus using RadonMCU.qpf.
2. Open Platform Designer and update the system if needed.
3. Generate HDL from Platform Designer.
4. Compile the Quartus project.

2. Software build

1. Open SoftwareExamplesForRadonMCU in Nios II SBT for Eclipse.
2. Regenerate BSP for RadonHelloWorld_bsp after hardware changes.
3. Clean and build RadonHelloWorld_bsp.
4. Clean and build RadonHelloWorld.
5. Run download-elf target or debug configuration to program and start the app.

Expected output from sample app:

• Hello from Nios II!

Common issue: ELF not generated

If RadonHelloWorld.elf is not created and linker reports:

• section .bss is not within region RAM

then software image does not fit into available RAM.

Typical mitigations:

• reduce BSP footprint (for example lower file descriptor count, enable small C library),
• reduce application memory usage,
• increase on-chip memory in hardware design.

After changing BSP settings, regenerate BSP and rebuild both BSP and app.

Notes about generated files

The repository tracks key design sources and selected generated artifacts needed for reproducible builds. Temporary editor/build outputs are ignored through .gitignore (for example local .qsys_edit cache and software build outputs).

License

BSD 3-Clause License