Crate embassy_stm32

Embassy STM32 HAL

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!)
• Source
• Examples

embassy-stm32 supports all STM32 chip families

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:

1. You tell the compiler which chip you’re using with a feature flag
2. The stm32-metapac module generates register types for that chip at compile time, based on data from the stm32-data module
3. 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.

Embedded-hal

The embassy-stm32 HAL implements the traits from embedded-hal (v0.2 and 1.0) and embedded-hal-async, as well as embedded-io and embedded-io-async.

embassy-time time driver

If a 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 time-driver-any.

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.

Interoperability

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.

The low-power feature integrates specifically with embassy-executor, it can’t be used on other executors for now.

Feature flags

• rt (enabled by default) — Enable stm32-metapac’s rt feature
• defmt — Use defmt for logging
• memory-x — Automatically generate memory.x file based on the memory map from stm32-metapac
• trustzone-secure — Use secure registers when TrustZone is enabled
• 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.
• unchecked-overclocking — Enable this feature to disable the overclocking check. DO NOT ENABLE THIS FEATURE UNLESS YOU KNOW WHAT YOU’RE DOING.

Time

• time — Enables additional driver features that depend on embassy-time
• time-driver-any — Use any time driver
• time-driver-tim1 — Use TIM1 as 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-tim8 — Use TIM8 as time driver
• time-driver-tim9 — Use TIM9 as time driver
• time-driver-tim12 — Use TIM12 as time driver
• time-driver-tim15 — Use TIM15 as time driver
• time-driver-tim20 — Use TIM20 as time driver
• time-driver-tim21 — Use TIM21 as time driver
• time-driver-tim22 — Use TIM22 as time driver
• time-driver-tim23 — Use TIM23 as time driver
• time-driver-tim24 — Use TIM24 as time driver

Analog Switch Pins (Pxy_C) on STM32H7 series

Get PXY and PXY_C singletons. Digital impls are on PXY, Analog impls are on PXY_C 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
• _dual-core — internal use only

Chip-selection features

Select your chip by specifying the model as a feature, e.g. stm32c011d6. Check the Cargo.toml for the latest list of supported chips.

Important: Do not forget to adapt the target chip in your toolchain, e.g. in .cargo/config.toml.

Re-exports

pub use stm32_metapac as pac;

Modules

adc

Analog to Digital Converter (ADC)

can

Controller Area Network (CAN)

crc

Cyclic Redundancy Check (CRC)

cryp

Crypto Accelerator (CRYP)

dac

Digital to Analog Converter (DAC)

dcmi

Digital Camera Interface (DCMI)

dma

Direct Memory Access (DMA)

eth

Ethernet (ETH)

exti

External Interrupts (EXTI)

flash

Flash memory (FLASH)

fmc

Flexible Memory Controller (FMC) / Flexible Static Memory Controller (FSMC)

gpio

General-purpose Input/Output (GPIO)

hash

Hash generator (HASH)

hrtim

High Resolution Timer (HRTIM)

hsem

Hardware Semaphore (HSEM)

i2c

Inter-Integrated-Circuit (I2C)

i2s

Inter-IC Sound (I2S)

interrupt

Interrupt definitions.

lptim

Low-power timer (LPTIM)

ltdc

LTDC - LCD-TFT Display Controller See ST application note AN4861: Introduction to LCD-TFT display controller (LTDC) on STM32 MCUs for high level details This module was tested against the stm32h735g-dk using the RM0468 ST reference manual for detailed register information

mode

Operating modes for peripherals.

opamp

Operational Amplifier (OPAMP)

peripherals

Types for the peripheral singletons.

qspi

Quad Serial Peripheral Interface (QSPI)

rcc

Reset and Clock Control (RCC)

rng

Random Number Generator (RNG)

rtc

Real Time Clock (RTC)

sai

Serial Audio Interface (SAI)

sdmmc

Secure Digital / MultiMedia Card (SDMMC)

spdifrx

S/PDIF receiver

spi

Serial Peripheral Interface (SPI)

time

Time units

timer

Timers, PWM, quadrature decoder.

uid

Unique ID (UID)

usart

Universal Synchronous/Asynchronous Receiver Transmitter (USART, UART, LPUART)

usb

Universal Serial Bus (USB)

wdg

Watchdog Timer (IWDG, WWDG)

Macros

bind_interrupts

Macro to bind interrupts to handlers.

Structs

Config

embassy-stm32 global configuration.

Peri

An exclusive reference to a peripheral.

Peripherals

Struct containing all the peripheral singletons.

Constants

NVIC_PRIO_BITS

Number available in the NVIC for configuring priority

Traits

PeripheralType

Marker trait for peripheral types.

Functions

init

Initialize the embassy-stm32 HAL with the provided configuration.

Attribute Macros

interrupt