HAL USART migration: List of applicable concepts

This section provides information about the HAL USART applicable architecture concepts.

Concepts for USART

Concept	Description
Separation of initialization and configuration functions	The initialization has been split into separate init and config functions: HAL_USART_Init(): Initializes the handle and links it to a USART instance. HAL_USART_SetConfig(): Sets the basic configuration to enable the use of the USART instance.
Removal and conversion of init structure to configuration structure	The init structure USART_InitTypeDef has been removed from the handle.
Renaming of the handle structure	The handle structure has been renamed to hal_usart_handle_t.
Renaming unitary init structures	The structure USART_InitTypeDef is no longer available and has been replaced by hal_usart_config_t.
Remove MspInit and MspDeInit callbacks	hal_usart_MspInit() and hal_usart_MspDeInit() are no longer available and have been replaced by a user sequence to initialize and configure the USART.
Unitary configuration APIs	New APIs are available to get and set USART features.
Dedicated DMA link APIs replace generic __HAL_LINKDMA macro	The __HAL_LINKDMA macro is no longer provided and new functions HAL_USART_SetTxDMA() and HAL_USART_SetRxDMA() are provided to link a USART HAL handle to a DMA HAL handle.
Introduction of HAL user data set/get APIs	Two functions to set and get user data are available: HAL_USART_SetUserData() and HAL_USART_GetUserData().
Individual callback registration APIs replace global register and unregister functions	The callback registration is handled by specific functions for each USART event. These functions are used to register callback functions for different USART events.
HAL implementation with LL inline functions	HAL USART APIs now rely on LL APIs rather than performing direct register access.
Define statements and enumerations redirected to LL equivalents	HAL USART define statements and enumerations are based on LL define statements.
Removal of hardware-related macros in HAL2	All hardware macros have been removed from the HAL USART driver, and equivalent services are ensured through the LL APIs.
Revised and optimized HAL state machine	The USART Driver uses a state machine to manage its operations. The states are: HAL_USART_STATE_RESET HAL_USART_STATE_INIT HAL_USART_STATE_IDLE HAL_USART_STATE_RX_ACTIVE HAL_USART_STATE_TX_ACTIVE HAL_USART_STATE_TX_RX_ACTIVE HAL_USART_STATE_ABORT
Revised and optimized HAL API status returns	The HAL USART functions were updated to return: HAL_INVALID_PARAM: in case of a NULL p_config structure pointer. HAL_ERROR: in case of an error. HAL_TIMEOUT: in case of a user timeout. HAL_BUSY: in case of an ongoing process. HAL_OK: in case of a successfully completed operation.
Revised and optimized HAL error management	Redesign the error handling mechanisms within the HAL to improve the detection, reporting, and handling of errors. This rework aims to provide more detailed and consistent error information such as HAL_USART_ERROR_PE and HAL_USART_ERROR_ORE.
New APIs for filtering optional asynchronous process interrupts	New HAL USART Transmit APIs with interrupt filtering capability are provided, such as HAL_USART_Transmit_IT_Opt() and HAL_USART_Transmit_DMA_Opt().
Replaced TypeDef suffix with _t in type names	All TypeDef parts of the HAL USART driver have been removed and replaced by _t.
Replaced multi-line macros with inline functions	For the HAL USART driver, large macros have been replaced by inline functions to maintain code consistency, improve readability, and benefit from compiler optimization. Inline functions also offer better support for debugging and strict type management, reducing the risk of errors.
Replaced nonmodifiable pointers with const keywords	Const keywords have been added to non-modifiable pointers to ensure that either the pointer itself or the data it points to cannot be modified. This enhances code safety and readability, prevents unintended modifications, and renders code more robust and maintainable.
Assertion implementation and usage in HAL1	The parameters and state are checked using ASSERT_DBG_STATE and ASSERT_DBG_PARAM macros.
Merge HAL extension files with common ones and remove the EX prefix from APIs.	Only one HAL USART header file remains and all macros, define statements, and functions from hal_usart_ex.h have been moved to hal_usart.h.
Provide RTOS-compatible acquire/release bus services for communication peripheral drivers.	New HAL_USART_AcquireBus() and HAL_USART_ReleaseBus() functions are provided, allowing the acquisition and release of a HAL USART handle to protect a full sequence.
Add HAL PPP Services for Drivers with Handle to Retrieve Corresponding Peripheral Clock Frequency.	HAL USART Driver provides a new API to retrieve clock frequency: HAL_USART_GetClockFreq().
Replace Finite Parameter Defines (Including PPP Instances) with Enum Types at HAL Levels.	Finite parameters (including USART instances) have been converted into enumerated types (enums) at HAL level. This improves code readability, maintainability, and type safety.
Add HAL_PPP Prefix to All HAL Peripheral APIs (Defines, Macros, Types, and Functions).	All HAL USART functions start with HAL_USART.

Other HAL USART changes

Concept	Consideration
Remove HAL_USART_DMASTOP()	This function’s functionality is already covered by HAL_DMA_Abort_IT().