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Modern embedded framework, using Rust and async.
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Merge #427 
427: New nrf PPI api (with DPPI support for nRF91 & nRF53) r=Dirbaio a=diondokter

- Added _ppi and _dppi features to distinguish between the new and the old peripheral.
- Removed ConfigurableChannel and added capacity numbers to the channels
- Replaced the PPI api with a new one using the DPPI terminology (publish & subscribe)
- Updated all tasks and event registers for DPPI

My proposal for the new API.
Tested on my nRF52840 and nRF9160.

Biggest changes for nRF52 is that there's no longer a distinction made between fork task and normal task. You now subscribe tasks to a channel and at runtime it is checked whether or not there's still room for another subscription.
Same for events.

There are differences between the PPI and DPPI though:
- With the PPI you have a limited amount of tasks and events per channel, but a task or event can be used on multiple channels at the same time.
- With the DPPI you have an unlimited amount of tasks and events per channel, but every task or event can only be used on 1 channel.
This is all checked at runtime.

Currently you need to track which tasks and events are assigned to a channel in order to unassign them. For the PPI this data is stored centrally in the registers, so it would be easy to create e.g. `clear_all` and `get_subscribed_tasks` functions. But for the DPPI that data is stored decentrally and so would need some manual tracking.

If there are requests for tracking functionality, then it should be able to be made relatively easy. But for now this API is fine I think.

Co-authored-by: Dion Dokter <dion@tweedegolf.com>
Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>
2021-10-26 15:00:46 +00:00
.github Merge #423 2021-10-13 21:11:41 +00:00
.vscode Clippy fixes 2021-10-18 01:05:29 +02:00
embassy Fix time calculation 2021-10-20 14:36:16 +02:00
embassy-hal-common Clippy fixes 2021-10-18 01:05:29 +02:00
embassy-lora Use upstream version of rust-lorawan 2021-10-22 19:33:15 +02:00
embassy-macros Clippy fixes 2021-10-18 01:05:29 +02:00
embassy-net Clippy fixes 2021-10-18 01:05:29 +02:00
embassy-nrf ppi: simplify driver creation. 2021-10-26 16:52:51 +02:00
embassy-rp Update version of critical-section 2021-09-13 17:05:17 +02:00
embassy-stm32 Merge #456 2021-10-26 11:59:14 +00:00
embassy-traits Clippy fixes 2021-10-18 01:05:29 +02:00
examples Fixed examples 2021-10-26 14:47:33 +02:00
stm32-data@bae2d34445 feat: Add spi support for STM32F1 variants 2021-10-11 22:39:48 +02:00
stm32-gen-features Initial STM32F1 family support with two examples for STM32F103C8 (Blue Pill) 2021-09-28 18:31:04 +02:00
stm32-metapac Support for STM32L1 2021-09-21 14:50:23 +02:00
stm32-metapac-gen Workaround duplicity of DMA channel declaration when the target chip specifies more than one request, by processing only the first declared request for the channel. 2021-10-22 11:36:47 +02:00
xtask Update lots of deps 2021-09-11 01:35:23 +02:00
.gitignore Update lots of deps 2021-09-11 01:35:23 +02:00
.gitmodules Add stm32-metapac crate, with codegen in rust 2021-05-31 02:40:58 +02:00
Cargo.example.toml std: fold into embassy core, add non-hacky time driver. 2021-08-25 21:06:27 +02:00
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 Extend SAADC one shot support 2021-10-09 11:25:18 +11:00
rust-toolchain.toml Update nightly 2021-10-18 01:26:06 +02:00

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, click here.

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).

embassy-nrf

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:

  • 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
  • Run the example
cargo run --bin rtc_async

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.

Why the name?

EMBedded ASYnc! :)

License

This work is licensed under either of

at your option.