对固件库结构的理解

stm32固件库分为4层：

• 应用层（application layer）
• 板级支持包BSP（BSP（board specific package）
• 硬件抽象层HAL（hardware abstraction layer）
• 硬件层（hardware）

1. 应用层：包含有函数使用的工程模板（和相应的开发工具对应）
2. BSP：这个给外设用的比如led、lcd之类的东西的功能函数库（对应的设备是官方的STMicroelectronics evaluation boards）
3. HAL：这个是用来控制寄存器的函数库
   • CMSIS：内核外设访问接口，STM32F4xx外设接口，Cortex-M系列的信号处理函数
   • STM32F4xx 标准外设驱动：给所有的外设提供头函数和驱动函数，通过CMSIS访问STM32F4的寄存器

固件库头文件之间的包含关系

• stm32f4xx_conf.h
  Peripheral’s drivers configuration file
  The user can enable or disable peripheral header file inclusion by using the template
  This file can also be used to enable or disable the Library run-time failure detection before compiling the firmware library drivers, through the preprocessor define USE_FULL_ASSERT

• stm32f4xx_ppp.h
  Header file of PPP peripheral
  This file includes the PPP peripheral function and variable definitions used within these functions.

• stm32f4xx_ppp.c
  Driver source code file of PPP peripheral written in C language

• stm32f4xx_it.h
  Header file including all interrupt handlers prototypes

• stm32f4xx_it.c
  Template source file containing the interrupt service routine (ISR) for Cortex-M4F exceptions.
  User can add additional ISR(s) for the used peripheral(s) (for the available peripheral interrupt handler’s name, please refer to the startup file startup_stm32f4xx.s).

• stm32f4xx.h
  CMSIS Cortex-M4F STM32F4xx device peripheral access layer header file.
  The file is the unique include file that the application programmer is using in the C source code, usually in main.c.

• system_stm32f4xx.h
  CMSIS Cortex-M4F STM32F4xx devices peripheral access layer system header file

• system_stm32f4xx.c
  CMSIS Cortex-M4F STM32F4xx devices peripheral access layer system source file.

• startup_stm32f4xx.s
  STM32F4xx devices startup file, one file per compiler…