Embassy
embassy-stm32

Crates

git

Versions

stm32f439vi

Flavors

Crate embassy_stm32

Source
Expand description

§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 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)
i2c
Inter-Integrated-Circuit (I2C)
i2s
Inter-IC Sound (I2S)
interrupt
Interrupt definitions.
low_power
Low-power support.
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.
peripherals
Types for the peripheral singletons.
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)
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