Nios V on DE1-SoC (1/5): First run

Goal of this first run: prove that a known software program can run on a real Nios V processor inside the DE1-SoC FPGA, and learn which parts of the system are fixed before you start editing code in later lessons.

An FPGA is a reconfigurable chip: its internal logic can be configured to behave like a digital system. In this lab, the DE1-SoC FPGA is already configured with the FPGAcademy DE1-SoC Computer with Nios V. You will not upload a custom .sof hardware image in this workshop.

RISC-V is an instruction set architecture: a specification for the instructions, registers, and basic execution model a compatible processor understands. Nios V is Intel's FPGA soft-core implementation of a RISC-V processor. "Soft-core" means the CPU is built from FPGA logic instead of being a separate fixed processor chip.

What you control in this lesson is the selected software program: a prebuilt Nios V ELF file. The .sof describes the FPGA hardware system: CPU, memory, and memory-mapped peripherals. The .elf contains the program instructions and data that the Nios V CPU executes inside that already-configured hardware system.

You will not edit source code in this first lesson. Code editing starts in Lesson 2. Here, the point is to connect the file you upload with the evidence you see: the JTAG UART terminal should print the message from the program.

The prebuilt hello.elf comes from a tiny program like this:

#include <stdio.h>

int main(void) {
    printf("Hello from Nios V\n");
    while (1) {
    }
}

Useful references:

- Intel Nios V Processor
- Intel FPGA and Embedded Processors Overview
- FPGAcademy DE1-SoC Computer with Nios V
- RISC-V International: About RISC-V

You do not need to read all of those references before continuing. For this first lesson, use the explanations above as the required subset. The links are there so you can verify where Nios V, RISC-V, and the FPGAcademy DE1-SoC system fit in the larger ecosystem.

Open the Nios V upload lab and use the preloaded hello.elf program. This upload-only entry lets you select and run an ELF file; it does not show or edit the program source code.

The upload-only workflow has several steps. Each step exists for a reason.