STM32CubeF3 architecture overview

UM1766

9/29

DocID026352 Rev 8

2.1.1

Board Support Package (BSP)

This layer offers a set of APIs relative to the hardware components in the hardware boards

(such as LCD, Audio, microSD, MEMS drivers). It is composed of two parts:

•

Component

This is the driver relative to the external device on the board and not related to the

STM32. The component driver provides specific APIs to the BSP driver external

components and can be portable on any other board.

•

BSP driver

It permits to link the component driver to a specific board and provides a set of friendly

used APIs. The APIs naming rule is BSP_FUNCT_Action().

Example: BSP_LED_Init(),BSP_LED_On()

The BSP is based on a modular architecture allowing an easy porting on any hardware

by implementing the low level routines.

2.1.2

Hardware Abstraction Layer (HAL) and Low Layer (LL)

The STM32CubeF3 HAL and LL are complementary and cover a wide range of applications

requirements.

•

The HAL drivers offer high-level function-oriented highly-portable APIs. They hide the

MCU and peripheral complexity to end user.

The HAL drivers provide generic multi-instance feature-oriented APIs which simplify

user application implementation by providing ready to use process. As example, for the

communication peripherals (I2S, UART…), it provides APIs allowing initializing and

configuring the peripheral, managing data transfer based on polling, interrupt or DMA

process, and handling communication errors that may raise during communication.

The HAL driver APIs are split in two categories:

–

Generic APIs providing common and generic functions to all the STM32 Series

–

Extension APIs, which provide specific and customized functions for a specific

family or a specific part number.

•

The Low Layer APIs provide low-level APIs at register level, with better optimization but

less portability. They require a deep knowledge of MCU and peripheral specifications.

The LL drivers are designed to offer a fast light-weight expert-oriented layer that is

closer to the hardware than the HAL. Contrary to the HAL, LL APIs are not provided for

peripherals where optimized access is not a key feature, or for those requiring heavy

software configuration and/or complex upper-level stack (such as USB).

The LL drivers feature:

–

A set of functions to initialize peripheral main features according to the parameters

specified in data structures

–

A set of functions used to fill initialization data structures with the reset values

corresponding to each field

–

Function for peripheral de-initialization (peripheral registers restored to their

default values)

–

A set of in-line functions for direct and atomic register access

–

Full independence from HAL and capability to be used in standalone mode

(without HAL drivers)

–

Full coverage of the supported peripheral features.