Embedded Rust on RISC-V: A Practical Guide

Two of the most exciting open movements in computing — the RISC-V open ISA and the Rust programming language — turn out to fit together beautifully. If you want memory-safe firmware running on open hardware, embedded Rust on RISC-V is one of the most satisfying stacks you can build. Here is how to get started.

Why Rust and RISC-V Belong Together

Both are open, modern, and built without legacy baggage. The RISC-V ISA gives you a clean, royalty-free instruction set; Rust gives you memory safety without a garbage collector. On a microcontroller — where a stray pointer can hard-fault a device in the field — that safety is worth a great deal. And because Rust is built on LLVM, which has strong RISC-V code generation, the two have grown up alongside each other.

Picking a Target

Rust identifies platforms with target triples. For RISC-V the common ones are:

• riscv32imac-unknown-none-elf — bare-metal RV32 microcontrollers
• riscv64gc-unknown-none-elf — bare-metal RV64
• riscv64gc-unknown-linux-gnu — full Linux userspace on RV64

The letters after riscv32/riscv64 are the ISA extensions you are compiling for. Adding a bare-metal target is one command:

rustup target add riscv32imac-unknown-none-elf

The no_std World

Firmware has no operating system, so embedded Rust is #![no_std] — it drops the OS-dependent standard library and uses the core library instead. A minimal entry point leans on the riscv-rt runtime crate for startup and the #[entry] attribute:

#![no_std]
#![no_main]

use riscv_rt::entry;
use panic_halt as _;

#[entry]
fn main() -> ! {
    loop {
        // your firmware logic
    }
}

The -> ! return type says “this never returns” — exactly right for firmware that runs until power-off.

PACs and HALs: Talking to Hardware

You rarely poke registers by hand. The embedded Rust ecosystem layers two abstractions:

• PAC (Peripheral Access Crate): a generated, type-safe map of a specific chip’s registers.
• HAL (Hardware Abstraction Layer): an ergonomic API on top of the PAC (GPIO, timers, UART) that often implements the shared embedded-hal traits.

Because many drivers target embedded-hal, a sensor driver written for one board frequently works on a RISC-V chip with little or no change — a quiet but powerful form of portability.

Flashing and Debugging

Building produces an ELF; getting it onto silicon uses the same hardware path as C. Tools like probe-rs (and classic OpenOCD + GDB) flash the binary over JTAG and let you set breakpoints on real hardware. For pure experimentation you can also run firmware under QEMU before touching a board.

cargo build --release --target riscv32imac-unknown-none-elf
# then flash with probe-rs / openocd

Great Boards to Start With

Affordable RISC-V microcontrollers with good Rust support make this approachable — see my development boards guide and the embedded/IoT overview for picks. A cheap board plus a debug probe is all you need to go from cargo build to blinking an LED on hardware you fully understand.

The Bottom Line

Embedded Rust on RISC-V pairs an open ISA with a memory-safe language, and the toolchain is genuinely ready: pick a target with rustup, write #![no_std] firmware on riscv-rt, reach hardware through a PAC and an embedded-hal HAL, and flash with probe-rs. You get C-level control with compile-time safety, on hardware whose design is open all the way down. For anyone building the next generation of reliable embedded devices, it is hard to imagine a more future-proof foundation.

Part of my RISC-V series. See also the embedded/IoT guide and development boards.