---
title: Embedded Rust
subtitle: Intro and Ecosystem Overview
author: Levi Pearson
...

# Overview

## Background

I am:

+ A very experienced embedded systems programmer 
+ A moderately experienced Rustacean
+ Relatively new at the combination

## Questions to answer

+ What are embedded systems?
+ What makes Rust interesting in that context?
+ What resources are there right now?
+ How do I get started?

# Embedded Systems?

## A (very general) definition

> When a device has a computerized, software-controlled component as part of its
> mechanism, which supports its primary function rather than the computer *being*
> its primary function, that component constitutes an embedded system.

## Examples

+ A digital scale's control system

+ The engine management computer in a car

+ The management controller in a hard drive

## They are everywhere

+ Microcontrollers start in the ~$0.01 price range

+ They can be as small as a grain of rice

+ They are in credit cards and SIM cards

+ They are also often off-the-shelf Windows boxes

## Microcontrollers

+ Computers specialized for embedded control duty
+ Much wider variety of architecture
+ Integrated peripherals:
  - Timers
  - Sensors
  - Communication bus interfaces
  - Display controllers
  
# Why Rust?

## The landscape today

+ Most embedded systems are still done in C
+ C was a big step up from assembly
+ C is still very error-prone
+ We are putting more software in more things

## Why not other safe languages?

+ Real-time response requirements

+ Resource (often RAM/Flash) constraints

+ Memory layout and representation control

+ Perception

## Big wins

+ The big enabler: `#[no_std]` and powerful, alloc-free `core` library
+ Static resource analysis via ownership and hiding
+ Modularity without overhead via traits
+ Flexible, easy-to-use builds including cross-compiling with cargo
+ Industrial strength multi-arch compiler back-end via LLVM 

# Rusty resources

## Compiler and tools

+ `rustup target list | grep none` for no-OS embedded targets
+ `cargo install cargo-binutils` for `cargo size`, `cargo nm`, etc.
+ `rustup component add llvm-tools-preview` for LLVM-native binutils
+ `gdb` built for the target arch for debugging
+ `openocd` to drive the programmer/debugger module

## Embedded-wg resources

+ Embedded Rust Book
+ Awesome / Not-Yet-Awesome Lists
+ `svd2rust` and Peripheral Access Crates
+ `embedded-hal` and HAL Crates
+ Board Support Crates
+ `rtfm` "Real-Time For The Masses" framework