A chip-agnostic architecture for bare-metal embedded Rust

Sat, 01 Aug 2026 16:26:42 +0000

Embedded Rust has excellent building blocks like HALs, PACs, and async executors. But very little is published about how to structure a serious firmware project on top of them. Most examples stop at blinky with a HAL. What does the architecture look like when you have a real protocol stack, a motor control loop, a dozen interacting peripherals, and the ambition to support more than one chip? And what if you are bare-metal, with no RTOS and no async executor, just interrupt handlers and a main loop?

This article documents the architecture OpenServoCore ’s firmware actually uses, in enough detail to build it for your own project. Overview first, then a zoom into every layer with its internal organization and a code example, all the way down to the discrete-event simulation. The architecture has earned some trust the hard way. The firmware’s entire wire protocol was ripped out and replaced mid-project, and the layering held. The logic layers compile and unit-test on a desktop with no hardware attached. And the simulation caught over a dozen real bugs before they ever reached silicon.

The code examples are teaching-sized but structurally faithful to the shipping code, and the codebase itself is public if you want the full-scale version. If you are new here, the project overview has the background.

Architecture on Aaron Qian

A chip-agnostic architecture for bare-metal embedded Rust