140 lines
3.9 KiB
Markdown
140 lines
3.9 KiB
Markdown
---
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title: Embedded Rust
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subtitle: Intro and Ecosystem Overview
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author: Levi Pearson
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...
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# Overview
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## Background
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I am:
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+ A very experienced embedded systems programmer
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+ A moderately experienced Rustacean
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+ Pretty new at the combination
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## Questions to answer
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+ What are embedded systems?
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+ What makes Rust interesting in that context?
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+ What resources are there right now?
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+ How do I get started?
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# Embedded Systems?
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## A (very general) definition
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> When a device has a computerized, software-controlled component as part of its
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> mechanism, which supports its primary function rather than the computer *being*
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> its primary function, that component constitutes an embedded system.
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## Examples
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+ A digital scale's control system
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+ The engine management computer in a car
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+ The disk controller in a hard drive
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+ A factory process control computer
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## They are everywhere
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+ Microcontrollers start in the ~$0.01 price range
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+ They can be as small as a grain of rice
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+ They are in credit cards and SIM cards
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+ They are also often off-the-shelf Windows boxes
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## Microcontrollers
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+ Single-chip computers specialized for embedded control
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+ Much wider variety of architecture
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+ Integrated peripherals:
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- Memory (RAM/Flash)
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- Timers
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- Sensors
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- Communication bus interfaces
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- Display controllers
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# Why Rust?
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## The landscape today
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+ Most embedded systems are still done in C
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+ C was a big step up from assembly
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+ C is still very error-prone
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+ We are putting more software in more things
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## Why not other safe languages?
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+ Real-time response requirements
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+ Resource (often RAM/Flash) constraints
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+ Memory layout and representation control
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+ Perception (no one thinks of Ada)
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## Big wins
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+ The big enabler: `#[no_std]` and powerful, alloc-free `core` library
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+ Static resource analysis via ownership and hiding
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+ Modularity without overhead via traits
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+ Flexible, easy-to-use builds including cross-compiling with cargo
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+ Industrial strength multi-arch compiler back-end via LLVM
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# Rusty resources
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## Compiler and tools
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+ `rustup target list | grep none` for no-OS embedded targets
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+ `cargo install cargo-binutils` for `cargo size`, `cargo nm`, etc.
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+ `rustup component add llvm-tools-preview` for LLVM-native binutils
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+ `gdb` built for the target arch for debugging
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+ `openocd` to drive the programmer/debugger module
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## Embedded-wg
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+ Embedded Rust Book
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+ Awesome / Not-Yet-Awesome Lists
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+ `svd2rust` and Peripheral Access Crates
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+ `embedded-hal` and HAL Crates
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+ Board Support Crates
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+ `rtfm` "Real-Time For The Masses" framework
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## Levels of maturity
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+ Compiler back-ends for ARM and some other architectures are solid
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+ Much work is now possible with stable Rust
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+ Some patterns for safety are well-defined, others are still experimental
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+ Patterns for modular, reusable code are still in progress
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+ Ferrous Systems - works with **embedded-wg** and provides training/support
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# Where to start?
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## Emulation!
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+ QEMU emulates a pair of ARM Cortex-M3 evaluation boards
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+ The `ml3s6965` board has a minimal peripheral support crate
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+ Both the Embedded Book and RTFM Book walk through starting with it
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## Development boards
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+ Vendor-developed boards can be expensive, but have nice components
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+ Many hobbyist-oriented boards are available, usually cheaper!
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+ Cheap knock-offs of open-hardware boards are *really* cheap
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+ Stay away from AVR-architecture Arduino-style boards for now!
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+ Risc-V and MSP-430 have llvm support, but not as much community support
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## Sensors, actuators, etc.
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+ Many boards have LEDs, buttons, capacitive touch, etc.
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+ Adafruit, Sparkfun, Pololu have interesting, well-designed break-outs
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+ Lots of cheap stuff from China, of varying quality!
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+ Salvage from old electronics junk
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# Time left?
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## Discussion/Demos
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+ General or rust-specific embedded Q&A
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+ Walk-through tool + qemu install and first program
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+ Look at some example code
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+ Interest in future workshop w/real hardware?
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