From c12337920f9bae4b3a775dd23964b1ad1607f866 Mon Sep 17 00:00:00 2001 From: Ulf Lilleengen Date: Thu, 9 Dec 2021 10:06:17 +0100 Subject: [PATCH] Initial PoC of embassy book --- docs/antora.yml | 5 +++++ docs/modules/ROOT/nav.adoc | 4 ++++ docs/modules/ROOT/pages/index.adoc | 24 ++++++++++++++++++++++++ docs/modules/ROOT/pages/nrf.adoc | 3 +++ docs/modules/ROOT/pages/runtime.adoc | 3 +++ docs/modules/ROOT/pages/stm32.adoc | 3 +++ docs/modules/ROOT/pages/traits.adoc | 3 +++ 7 files changed, 45 insertions(+) create mode 100644 docs/antora.yml create mode 100644 docs/modules/ROOT/nav.adoc create mode 100644 docs/modules/ROOT/pages/index.adoc create mode 100644 docs/modules/ROOT/pages/nrf.adoc create mode 100644 docs/modules/ROOT/pages/runtime.adoc create mode 100644 docs/modules/ROOT/pages/stm32.adoc create mode 100644 docs/modules/ROOT/pages/traits.adoc diff --git a/docs/antora.yml b/docs/antora.yml new file mode 100644 index 00000000..807c97c3 --- /dev/null +++ b/docs/antora.yml @@ -0,0 +1,5 @@ +name: embassy +title: Embassy +version: dev +nav: + - modules/ROOT/nav.adoc diff --git a/docs/modules/ROOT/nav.adoc b/docs/modules/ROOT/nav.adoc new file mode 100644 index 00000000..228ead78 --- /dev/null +++ b/docs/modules/ROOT/nav.adoc @@ -0,0 +1,4 @@ +* xref:runtime.adoc[Runtime] +* xref:traits.adoc[Traits] +* xref:nrf.adoc[Nordic nRF HAL] +* xref:stm32.adoc[STM32 HAL] diff --git a/docs/modules/ROOT/pages/index.adoc b/docs/modules/ROOT/pages/index.adoc new file mode 100644 index 00000000..5bc35ef4 --- /dev/null +++ b/docs/modules/ROOT/pages/index.adoc @@ -0,0 +1,24 @@ += Embassy + +Embassy is a project to make async/await a first-class option for embedded development. + +== 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. diff --git a/docs/modules/ROOT/pages/nrf.adoc b/docs/modules/ROOT/pages/nrf.adoc new file mode 100644 index 00000000..21c388f6 --- /dev/null +++ b/docs/modules/ROOT/pages/nrf.adoc @@ -0,0 +1,3 @@ += Embassy nRF HAL + +TODO diff --git a/docs/modules/ROOT/pages/runtime.adoc b/docs/modules/ROOT/pages/runtime.adoc new file mode 100644 index 00000000..2704f298 --- /dev/null +++ b/docs/modules/ROOT/pages/runtime.adoc @@ -0,0 +1,3 @@ += Embassy runtime + +TODO diff --git a/docs/modules/ROOT/pages/stm32.adoc b/docs/modules/ROOT/pages/stm32.adoc new file mode 100644 index 00000000..328f69e2 --- /dev/null +++ b/docs/modules/ROOT/pages/stm32.adoc @@ -0,0 +1,3 @@ += Embassy STM32 HAL + +TODO diff --git a/docs/modules/ROOT/pages/traits.adoc b/docs/modules/ROOT/pages/traits.adoc new file mode 100644 index 00000000..843cc293 --- /dev/null +++ b/docs/modules/ROOT/pages/traits.adoc @@ -0,0 +1,3 @@ += Embassy Traits + +TODO