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Modern embedded framework, using Rust and async.
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Merge #559 
559: USART DMA example for the STM32F7 r=Dirbaio a=olofwalker

This small PR adds the USART DMA write an example for the STM32F7. The example has been tested on a Nucleo-f767zi board.

Output from `DEFMT_LOG=info cargo run --bin usart_dma`
```
Running `probe-run --chip STM32F767ZITx target/thumbv7em-none-eabihf/debug/usart_dma`
(HOST) INFO  flashing program (108 pages / 108.00 KiB)
(HOST) INFO  success!
────────────────────────────────────────────────────────────────────────────────
0 INFO  Hello World!
└─ usart_dma::__cortex_m_rt_main @ src/bin/usart_dma.rs:39
1 INFO  wrote DMA
└─ usart_dma::main_task::task::{generator#0} @ src/bin/usart_dma.rs:31
```

Co-authored-by: Robert Walker <rgit@walker.st>
2022-01-01 11:18:17 +00:00
.github stm32: add gpio HIL test 2021-12-06 22:05:41 +01:00
.vscode Add all example crates to linked projects (commented out) 2021-12-09 19:44:41 -06:00
docs Update stm32.adoc 2021-12-30 09:17:06 +08:00
embassy Use cortex-m only on cortex-m archs. 2021-12-23 13:53:26 +01:00
embassy-hal-common Provides AsyncWrite with flush 2021-12-10 12:16:08 +11:00
embassy-lora Remove unneeded rustfmt::skip 2021-12-16 11:37:53 +01:00
embassy-macros Update rust-toolchain 2021-12-16 11:34:20 +01:00
embassy-net Use smoltcp 0.8.0 from crates.io. 2021-12-12 15:32:36 +01:00
embassy-nrf Lower some verbose logs to trace. 2021-12-23 13:43:14 +01:00
embassy-rp Update rust-toolchain 2021-12-16 11:34:20 +01:00
embassy-stm32 Merge #558 2022-01-01 10:51:14 +00:00
embassy-traits Some API documentation fixes in traits 2021-12-19 08:49:19 +01:00
examples Review changes 2021-12-29 08:17:51 +01:00
stm32-data@0615166fee Update stm32-data with f3 Timer reg changes 2021-12-23 17:05:11 +05:30
stm32-gen-features [manual] Add stm32f3 family to stm32-gen-features 2021-12-13 13:49:41 +05:30
stm32-metapac stm32-metapac: add pac feature to allow building only the macrotables. 2021-11-24 01:04:23 +01:00
stm32-metapac-gen Update stm32-data: rcc regs info comes from yamls now. 2021-11-29 02:28:02 +01:00
tests/stm32 stm32/tests: add uart, uart_dma tests. 2021-12-08 05:43:39 +01:00
xtask Update lots of deps 2021-09-11 01:35:23 +02:00
.gitignore Enable running ci.sh locally multiple-times. 2021-12-09 12:37:44 +01:00
.gitmodules Add stm32-metapac crate, with codegen in rust 2021-05-31 02:40:58 +02:00
ci.sh Merge #540 2021-12-16 07:30:03 +00:00
LICENSE-APACHE First commit 2020-09-22 18:03:43 +02:00
LICENSE-MIT First commit 2020-09-22 18:03:43 +02:00
README.md Some notes in the readme about docs 2021-12-13 13:23:18 +01:00
rust-toolchain.toml Update rust-toolchain 2021-12-16 11:34:20 +01:00

README.md

Embassy

Embassy is a project to make async/await a first-class option for embedded development. For more information and instructions to get started, go to https://embassy.dev.

Traits and types

embassy provides a set of traits and types specifically designed for async usage.

  • embassy::io: AsyncBufRead, AsyncWrite. Traits for byte-stream IO, essentially no_std compatible versions of futures::io.
  • embassy::traits::flash: Flash device trait.
  • embassy::time: Clock and Alarm traits. Std-like Duration and Instant.
  • More traits for SPI, I2C, UART async HAL coming soon.

Executor

The embassy::executor module provides an async/await executor designed for embedded usage.

  • No alloc, no heap needed. Task futures are statically allocated.
  • No "fixed capacity" data structures, executor works with 1 or 1000 tasks without needing config/tuning.
  • Integrated timer queue: sleeping is easy, just do Timer::after(Duration::from_secs(1)).await;.
  • No busy-loop polling: CPU sleeps when there's no work to do, using interrupts or WFE/SEV.
  • Efficient polling: a wake will only poll the woken task, not all of them.
  • Fair: a task can't monopolize CPU time even if it's constantly being woken. All other tasks get a chance to run before a given task gets polled for the second time.
  • Creating multiple executor instances is supported, to run tasks with multiple priority levels. This allows higher-priority tasks to preempt lower-priority tasks.

Utils

embassy::util contains some lightweight async/await utilities, mainly helpful for async driver development (signaling a task that an interrupt has occured, for example).

HALs

Hardware Absraction Layers with asynchronous behaviors are provided for a variety of platforms. For example, the embassy-nrf crate contains implementations for nRF 52 series SoCs.

  • uarte: UARTE driver implementing AsyncBufRead and AsyncWrite.

  • qspi: QSPI driver implementing Flash.

  • gpiote: GPIOTE driver. Allows awaiting GPIO pin changes. Great for reading buttons or receiving interrupts from external chips.

  • saadc: SAADC driver. Provides a full implementation of the one-shot sampling for analog channels.

  • rtc: RTC driver implementing Clock and Alarm, for use with embassy::executor.

Examples

Examples are found in the examples/ folder seperated by the chip manufacturer they are designed to run on. For example:

  • examples/nrf are designed to run on the nrf52840-dk board (PCA10056) but should be easily adaptable to other nRF52 chips and boards.
  • examples/rp are for the RP2040 chip.
  • examples/stm32 are designed for the STM32F429ZI chip but should be easily adaptable to other STM32F4xx chips.
  • examples/std are designed to run locally on your pc.

Running examples

  • Setup git submodules (needed for STM32 examples)
git submodule init
git submodule update
  • Install probe-run with defmt support.
cargo install probe-run
  • Change directory to the sample's base directory. For example:
cd examples/nrf
  • Run the example

For example:

cargo run --bin blinky

Developing Embassy with Rust Analyzer based editors

The Rust Analyzer is used by Visual Studio Code and others. Given the multiple targets that Embassy serves, there is no Cargo workspace file. Instead, the Rust Analyzer must be told of the target project to work with. In the case of Visual Studio Code, please refer to the .vscode/settings.json file's rust-analyzer.linkedProjectssetting.

Minimum supported Rust version (MSRV)

Required nightly version is specified in the rust-toolchain.toml file. Nightly is required for:

  • generic_associated_types: for trait funcs returning futures.
  • type_alias_impl_trait: for trait funcs returning futures implemented with async{} blocks, and for static-executor.

Stable support is a non-goal until these features get stabilized.

Documentation

Embassy documentation is located in the docs/ folder. The documentation is built in embassy-book and published to https://embassy.dev by CI.

Why the name?

EMBedded ASYnc! :)

License

This work is licensed under either of

at your option.