# Release Notes for STM32CubeU0 HAL and LL drivers

Copyright © 2024 STMicroelectronics

# Purpose

The STM32Cube HAL and LL, an STM32 abstraction layer embedded software, ensure maximized portability across STM32 portfolio.

The portable APIs layer provides a generic, multi instanced and simple set of APIs to interact with the upper layer (application, libraries and stacks). It is composed of native and extended APIs set. It is directly built around a generic architecture and allows the build-upon layers, like the middleware layer, to implement its functions without knowing in-depth the used STM32 device. This improves the library code reusability and guarantees an easy portability on other devices and STM32 families.

The Low Layer (LL) drivers are part of the STM32Cube firmware HAL that provides a basic set of optimized and one-shot services. The Low layer drivers, contrary to the HAL ones are not fully portable across the STM32 families; the availability of some functions depends on the physical availability of the relative features on the product. The Low Layer (LL) drivers are designed to offer the following features:

- New set of inline functions for direct and atomic register access
- One-shot operations that can be used by the HAL drivers or from application level
- Full independence from HAL and standalone usage (without HAL drivers)
- Full features coverage of all the supported peripherals

# Update History

V1.3.0 / 04-June-2025

## Main Changes

Third maintenance release of HAL and LL drivers for STM32U083 / STM32U073 / STM32U031 devices

## Contents

HAL and LL driver third maintenance release

- HAL drivers:
  - HAL ADC driver:
    - Update the “HAL_ADCEx_Calibration_Start” function to use properly “LL_ADC_GetCalibrationFactor”.
  - HAL CRYP driver:
    - Rename AES suspend registers according last update in STM32U0 reference manual.
  - HAL CRC driver:
    - Improve performance of “CRC_Handle_8” function.
  - HAL RTC driver:
    - Minors implementation enhancements.
  - HAL SPI driver:
    - Implementation enhancements.
  - HAL UART driver:
    - Implementation enhancements.
  - LL ADC driver:
    - Update the “LL_ADC_GetChannelSamplingTime” to return correct value when multiple channels configured.
  - LL COMP driver:
    - Update the “IS_LL_COMP_POWER_MODE” macro to support the “LL_COMP_POWERMODE_ULTRALOWPOWER”.
  - LL SPI driver:
    - Minors implementation enhancements.

## Known Limitations

- None

## Backward Compatibility

- Not applicable

V1.2.0 / 30-October-2024

## Main Changes

Second maintenance release of HAL and LL drivers for STM32U083 / STM32U073 / STM32U031 devices

## Contents

HAL and LL driver second maintenance release

- HAL drivers:
  - HAL UART driver:
    - Fix DMA Rx abort procedure impact on ongoing UART Tx transfer in polling mode.
  - HAL RCC driver:
    - Minors implementation enhancements.
  - LL UTILS driver:
    - Add LL_SetFlashLatency API based on a call of UTILS_SetFlashLatency.

## Known Limitations

- None

## Backward Compatibility

- Not applicable

V1.1.0 / 05-June-2024

## Main Changes

Maintenance release of HAL and LL drivers for STM32U083 / STM32U073 / STM32U031 devices

## Contents

HAL and LL driver maintenance release

- HAL drivers:
  - HAL UART driver:
    - Minors implementation enhancements.
  - HAL RNG driver:
    - Minors implementation enhancements.
  - HAL LPTIM driver:
    - Remove the redundant private macro IS_LPTIM_AUTORELOAD (redundant with IS_LPTIM_PERIOD macro).
  - LL RCC driver:
    - Minors implementation enhancements.

## Known Limitations

- None

## Backward Compatibility

- Not applicable

V1.0.0 / 12-February-2024

## Main Changes

First official release of HAL and LL drivers for STM32U083 / STM32U073 / STM32U031 devices

## Contents

HAL and LL driver beta version for all peripherals

- HAL: ADC, CORTEX, COMP, CRC, CRYP, DAC, DMA, EXTI, GPIO, I2C, I2S, IRDA, IWDG, LPTIM, OPAMP, LTDC, PCD, PWR, RCC, RNG, RTC, SMARTCARD, SPI, TIM, UART, USART, WWDG

- LL: ADC, COMP, CRC, CRS, DAC, DMA, EXTI, GPIO, I2C, LPTIM, LPUART, OPAMP, PWR, RCC, RNG, RTC, SPI, TIM, USART, USB, UTILS

## Known Limitations

- None

## Backward Compatibility

- Not applicable