Lightning
Embedded Development
with Rust

NerdNight19 - OpenLab Augsburg

no std, no main, no cry

Rust(Yourself)Up

https://rustup.rs

• rustc
• rustfmt
• clippy
• cargo
• rust-analyzer
• rust-docs
• rustup target add thumbv6m-none-eabi

Probe-rs

https://probe.rs

• ”the user-friendly & flexible embedded toolkit”
• Every ARM or RISC-V target
• Supports many debug probes
• Easy debugging (in VSCode) with RTT/GDB

HAL (Hardware Abstraction Layer)

… are sets of routines in software that emulate some platform-specific details, giving programs direct access to hardware resources

… write device-independent, high performance applications by providing standard operating system (OS) calls to hardware

Hot Tipp: svd2rust

Project Overview

myCoolRustProject
├── Cargo.toml
├── Embed.toml
├── README.md
├── rust-toolchain.toml
├── .cargo
│   └── config.toml
└── src
└── bin
├── blinky.rs
├── hello.rs
├── main.rs
├── …

rust-toolchain.toml

[toolchain]
channel = “stable”
components = [ “rustfmt” ]
targets = [ “thumbv6m-none-eabi” ]

• Version Pinning
• Simplified Dependency Management
• Reproducible Builds

Cargo.toml

1  [package]
2  name = “stm32_app”
3  version = “0.1.0”
4  edition = “2021”
5  authors = [“wieerwill”]
6  resolver = “2”
7
8  [dependencies]
9  cortex-m-rt = “0.7.0”
10 defmt = “0.3”
11 defmt-rtt = “0.4”
12 embassy-time = { version = “0.3.1”, features = [
13     “defmt”, “defmt-timestamp-uptime”,
14     “tick-hz-32_768”,
15 ] } …
16
17 # cargo build/run —release
18 [profile.release]
19 codegen-units = 1        # reduce Code Generation Units
20 debug = false
21 debug-assertions = false
22 incremental = false
23 lto = true               # Link Time Optimization
24 opt-level = “z”          # Optimize for size “s” or “z”
25 overflow-checks = true
26 strip = “symbols”   # or true, removes all output from rtt
27 panic = “abort”   # abort immediately rather than unwind
28 location-detail=“none”    # Remove Location Details
29
30 [target.stm32l010rb]
31 runner = ‘probe-rs run —chip stm32l010rbtx’

config.toml

1  [target.thumbv6m-none-eabi]
2  runner = ‘probe-rs run —chip STM32L010RBTx’
3
4  rustflags = [
5      “-C”, “link-arg=—nmagic”,
6      “-C”, “link-arg=-Tlink.x”,
7      “-C”, “link-arg=-Tdefmt.x”,
8      “-C”, “link-arg=—no-rosegment”
9  ]
10
11 [build]
12 target = “thumbv6m-none-eabi”
13
14 [env]
15 DEFMT_LOG = “trace”
16
17 [alias]
18 main = “embed —release —bin main”
19 rb = “embed —release —bin”
20 s = “size —bin main — -B -x”
21

hello_world.rs

1  #![no_std]
2  #![no_main]
3
4  use {defmt_rtt as _, panic_probe as _};
5

6  #[embassy_executor::main]
7  async fn main(_spawner: embassy_executor::Spawner) -> ! {
8      let _p = embassy_stm32::init(Default::default());
9      loop {
10        embassy_time::Timer::after_secs(10).await;
11        defmt::info!(“Hello World”);
12        defmt::error!(“Error”);
13        defmt::warn!(“Warn”);
14        defmt::debug!(“Debug”);
15        defmt::trace!(“Trace”);
16    }
17 }

hello_world_shorter.rs

1  #![no_std]
2  #![no_main]
3
4  use defmt::{info, error, warn, debug, trace};
5  use embassy_executor::Spawner;
6  use embassy_time::Timer;
7  use {defmt_rtt as _, panic_probe as _};
8
9  #[embassy_executor::main]
10 async fn main(_spawner: Spawner) -> ! {
11     let _p = embassy_stm32::init(Default::default());
12     loop {
13         Timer::after_secs(10).await;
14         info!(“Hello World”);
15         error!(“Error”);
16         warn!(“Warn”);
17         debug!(“Debug”);
18         trace!(“Trace”);
19     }
20 }

blinky.rs

8  …
9  #[embassy_executor::main]
10 async fn main(_spawner: Spawner) {
11     let p = embassy_stm32::init(Default::default());
12     let mut led = Output::new(
13       p.PA9, Level::High, Speed::Low
14     );
15
16     loop {
17         info!(“high”);
18         led.set_high();
19         Timer::after_millis(500).await;
20
21         info!(“low”);
22         led.set_low();
23         Timer::after_millis(500).await;
24     }
25 }

button.rs

8  …
9  #[embassy_executor::main]
10 async fn main(spawner: Spawner) {
11     let p = embassy_stm32::init(Default::default());
12     let mut button = ExtiInput::new(
13       p.PC2, p.EXTI2, Pull::None);
14
15     loop {
16         button.wait_for_rising_edge().await;
17         info!(“rising edge”);
18         button.wait_for_falling_edge().await;
19         info!(“falling edge”);
20     }
21 }

tick_tack_tasks.rs

8  …
9  #[embassy_executor::task]
10 async fn run() {
11     loop {
12         Timer::after_secs(1).await;
13         info!(“Tick”);
14     }
15 }
16
17 #[embassy_executor::main]
18 async fn main(spawner: Spawner) -> ! {
19     let _p = embassy_stm32::init(Default::default());
20

21     spawner.spawn(run()).unwrap();
22     loop {
23         Timer::after_secs(2).await;
24         info!(“Tack”);
25     }
26 }

button_multi.rs

8  …
9  #[embassy_executor::task]
10 async fn alert_button_task(mut button_alert: ExtiInput<‘static>) {
11     loop {
12         button_alert.wait_for_rising_edge().await;
13         Timer::after_millis(10).await; // Debounce
14         info!(“Alert button pressed”);
15     }
16 }
17
18 #[embassy_executor::task]
19 async fn reset_button_task(mut button_reset: ExtiInput<‘static>) {
20     loop {
21         button_reset.wait_for_falling_edge().await;
22         Timer::after_millis(10).await; // Debounce
23         info!(“reset button pressed”);
24
25         button_reset.wait_for_rising_edge().await;
26         Timer::after_millis(10).await; // Debounce
27         info!(“reset button released”);
28     }
29 }
30
31 #[embassy_executor::main]
32 async fn main(spawner: Spawner) {
33     let p = embassy_stm32::init(Default::default());
34
35     let button_alert = ExtiInput::new(
36       p.PC3, p.EXTI3, Pull::Up
37     );
38     let button_reset = ExtiInput::new(
39       p.PC4, p.EXTI4, Pull::Up
40     );
41
42     // Spawn tasks for each button
43     spawner.spawn(alert_button_task(button_alert)).unwrap();
44     spawner.spawn(reset_button_task(button_reset)).unwrap();
45 }

pwm.rs

8  …
9  #[embassy_executor::main]
10 async fn main(_spawner: Spawner) -> ! {
11     let p = embassy_stm32::init(Default::default());
12
13     let buzz_pin = PwmPin::new_ch1(p.PB13, PushPull);
14     let mut pwm = SimplePwm::new(
15         p.TIM21,        // Timer
16         Some(buzz_pin), // ch1
17         None,           // ch2
18         None,           // ch3
19         None,           // ch4
20         hz(2000),       // default Frequence
21         EdgeAlignedUp,  // counting mode
22     );
23
24     let max_duty = pwm.get_max_duty();
25     pwm.set_duty(Channel::Ch2, max_duty / 2); //Duty Cycle to 50%
26
27     pwm.enable(Channel::Ch2);
28
29     let mut frequence = 300;
30     loop {
31         info!(“on, freq hz”, frequence);
32         pwm.set_frequency(hz(frequence));
33         pwm.enable(Channel::Ch2);
34         Timer::after_millis(1000).await;
35
36         info!(“off”);
37         pwm.disable(Channel::Ch2);
38         Timer::after_millis(500).await;
39         frequence += 20;
40     }
41 }

Source of Truth

• The Embedded Rust Book
• RTIC RS
• Embassy Dev
• RustUp
• Probe RS
• svd2rust

Zeit fuer eure Fragen
& Diskussionen

WieErWill.dev/vcard.vcf