The embassy-stm32 HAL aims to provide a safe, idiomatic hardware abstraction layer for all STM32 families. The HAL implements both blocking and async APIs for many peripherals. Where appropriate, traits from both blocking and asynchronous versions of embedded-hal v0.2 and v1.0 are implemented, as well as serial traits from embedded-io[-async].
- embassy-stm32 on crates.io
- Documentation (Important: use docs.embassy.dev rather than docs.rs to see the specific docs for the chip you’re using!)
STM32 microcontrollers come in many families and flavors, and supporting all of them is a big undertaking. Embassy takes advantage of the fact that the STM32 peripheral versions are shared across chip families. For example, instead of re-implementing the SPI peripheral for every STM32 chip family, embassy has a single SPI implementation that depends on code-generated register types that are identical for STM32 families with the same version of a given peripheral.
In practice, this works as follows:
- You tell the compiler which chip you’re using with a feature flag
- The stm32-metapac module generates register types for that chip at compile time, based on data from the stm32-data module
- The embassy-stm32 HAL picks the correct implementation each peripheral based on automatically-generated feature flags, and applies any other tweaks which are required for the HAL to work on that chip
Be aware that, while embassy-stm32 strives to consistently support all peripherals across all chips, this approach can lead to slightly different APIs and capabilities being available on different families. Check the documentation for the specific chip you’re using to confirm exactly what’s available.
time-driver-* feature is enabled, embassy-stm32 provides a time driver for use with embassy-time. You can pick which hardware timer is used for this internally via the
time-driver-tim* features, or let embassy pick with
embassy-time has a default tick rate of 1MHz, which is fast enough to cause problems with the 16-bit timers currently supported by the embassy-stm32 time driver (specifically, if a critical section delays an IRQ by more than 32ms). To avoid this, it’s recommended to pick a lower tick rate. 32.768kHz is a reasonable default for many purposes.
This crate can run on any executor.
Optionally, some features requiring
embassy-time can be activated with the
time feature. If you enable it,
you must link an
embassy-time driver in your project.
low-power feature integrates specifically with
embassy-executor, it can’t be ued on other executors for now.
rt(enabled by default) — Enable
memory-x— Automatically generate
unstable-pac— Re-export stm32-metapac at
embassy_stm32::pac. This is unstable because semver-minor (non-breaking) releases of embassy-stm32 may major-bump (breaking) the stm32-metapac version. If this is an issue for you, you’re encouraged to directly depend on a fixed version of the PAC. There are no plans to make this stable.
time— Enables additional driver features that depend on embassy-time
time-driver-any— Use any time driver
time-driver-tim2— Use TIM2 as time driver
time-driver-tim3— Use TIM3 as time driver
time-driver-tim4— Use TIM4 as time driver
time-driver-tim5— Use TIM5 as time driver
time-driver-tim9— Use TIM9 as time driver
time-driver-tim11— Use TIM11 as time driver
time-driver-tim12— Use TIM12 as time driver
time-driver-tim15— Use TIM15 as time driver
time-driver-tim21— Use TIM21 as time driver
time-driver-tim22— Use TIM22 as time driver
PXY_C singletons. Digital impls are on
PXY, Analog impls are on
If disabled, you get only the
PXY singleton. It has both digital and analog impls.
split-pa0— Split PA0
split-pa1— Split PA1
split-pc2— Split PC2
split-pc3— Split PC3
_split-pins-enabled— internal use only
Select your chip by specifying the model as a feature, e.g.
Cargo.toml for the latest list of supported chips.
Important: Do not forget to adapt the target chip in your toolchain,
pub use stm32_metapac as pac;
- Analog to Digital Converter (ADC)
- Cyclic Redundancy Check (CRC)
- Direct Memory Access (DMA)
- External Interrupts (EXTI)
- Flash memory (FLASH)
- General-purpose Input/Output (GPIO)
- Inter-Integrated-Circuit (I2C)
- Interrupt definitions.
- Types for the peripheral singletons.
- Reset and Clock Control (RCC)
- Serial Peripheral Interface (SPI)
- Time units
- Timers, PWM, quadrature decoder.
- Unique ID (UID)
- Universal Synchronous/Asynchronous Receiver Transmitter (USART, UART, LPUART)
- Watchdog Timer (IWDG, WWDG)
- Macro to bind interrupts to handlers.
- Convenience converting into reference.
- An exclusive reference to a peripheral.
- Struct containing all the peripheral singletons.
- Number available in the NVIC for configuring priority
- Trait for any type that can be used as a peripheral of type
- Initialize the
embassy-stm32HAL with the provided configuration.