STM32F4的相關資料：http://www.stmcu.org/document/list/index/category-523
一、標准固件庫簡介
本文下載的是STM32F4xx_DSP_StdPeriph_Lib_V1.5.0，其文件夾如下圖所示：
其中Project文件夾為各個開發環境（MDK-ARM、EWARM、TrueSTUDIO）的模板工程，Utilities文件夾為官方評估板的標准固件庫應用例程，而真正的標准固件庫在Libraries文件夾中。在Libraries文件夾中：CMSIS文件夾主要包含於內核相關的文件；STM32F4xx_StdPeriph_Driver文件夾為STM32F4xx處理器外設相關的底層驅動。
以下為固件庫移植時CMSIS文件夾中的重要源文件：
core_cm4.h ：內核功能的定義，比如NVIC相關寄存器的結構體和Systick配置。在CMSIS/Include中
core_cmFunc.h ：內核核心功能接口頭文件。在CMSIS/Include中
core_cmInstr.h ：包含一些內核核心專用指令。在CMSIS/Include中
core_cmSimd.h ：包含與編譯器相關的處理。在CMSIS/Include中
stm32f4xx.h ：包含了stm32f4的寄存器結構體的定義(類似於c51的reg52.h)。在CMSIS\Device\ST\STM32F4xx\Include中
system_stm32f4xx.h ：system_stm32f4xx.c的頭文件。在CMSIS\Device\ST\STM32F4xx\Include中
system_stm32f4xx.c ：stm32f4的系統時鍾配置。在CMSIS\Device\ST\STM32F4xx\Source\Templates中
startup_stm32f40_41xxx.s：啟動文件：設定SP的初始值；設置PC的初始值；設置中斷向量表的地址；配置時鍾；設置堆棧；調用main。
這個 啟動文件先調用system_stm32f4xx.c里面的systeminit()在調用main()之前。
在CMSIS\Device\ST\STM32F4xx\Source\Templates\arm中。
對於STM32F4xx_StdPeriph_Driver，其重要源文件為：
stm32f4xx_ppp.h：外設頭文件。這里的ppp只是一個代碼，在實際上是具體的外設名字，如ADC，DMA等。在實際使用時根據所需的外設選擇性移植。
在STM32F4xx_StdPeriph_Driver\inc中
stm32f4xx_ppp.c：外設源文件。這里的ppp只是一個代碼，在實際上是具體的外設名字，如ADC，DMA等。在實際使用時根據所需的外設選擇性移植。
在STM32F4xx_StdPeriph_Driver\src中
stm32f4xx_conf.h：外設驅動配置文件。通過修改該文件中所包含的外設頭文件，用戶啟動或禁用外設驅動。
此外，在此文件夾打開宏定義USE_FULL_ASSERT，通過預處理啟 用或禁用標准外設庫運行時的故障檢測。
在Project\STM32F4xx_StdPeriph_Templates中。
stm32f4xx_it.h ：頭文件。包括所有中斷處理程序原型。在Project\STM32F4xx_StdPeriph_Templates中。
stm32f4xx_it.c ：中斷源程序模板，中斷函數的名稱要與啟動文件中中斷向量表的名稱一致。在Project\STM32F4xx_StdPeriph_Templates中。
此外，對於stm32f4的標准外設固件庫，在CMSIS文件夾中還有相應的DSP庫：DSP_Lib和Lib。DSP_Lib主要為DSP函數庫的實例和源碼；Lib為編譯好的，且對於不同內核的STM32系列MCU所使用的lib文件。
二、標准固件庫移植過程中的注意事項（這里以僅以Keil-MDK為例）
1、在stm32f4xx.h文件中選擇芯片以及宏定義USE_STDPERIPH_DRIVER。
#if !defined(STM32F40_41xxx) && !defined(STM32F427_437xx) && !defined(STM32F429_439xx) && !defined(STM32F401xx) && !defined(STM32F411xE) && \ !defined(STM32F446xx) #define STM32F40_41xxx /*!< STM32F405RG, STM32F405VG, STM32F405ZG, STM32F415RG, STM32F415VG, STM32F415ZG, STM32F407VG, STM32F407VE, STM32F407ZG, STM32F407ZE, STM32F407IG, STM32F407IE, STM32F417VG, STM32F417VE, STM32F417ZG, STM32F417ZE, STM32F417IG and STM32F417IE Devices */ /* #define STM32F427_437xx */ /*!< STM32F427VG, STM32F427VI, STM32F427ZG, STM32F427ZI, STM32F427IG, STM32F427II, STM32F437VG, STM32F437VI, STM32F437ZG, STM32F437ZI, STM32F437IG, STM32F437II Devices */ /* #define STM32F429_439xx */ /*!< STM32F429VG, STM32F429VI, STM32F429ZG, STM32F429ZI, STM32F429BG, STM32F429BI, STM32F429NG, STM32F439NI, STM32F429IG, STM32F429II, STM32F439VG, STM32F439VI, STM32F439ZG, STM32F439ZI, STM32F439BG, STM32F439BI, STM32F439NG, STM32F439NI, STM32F439IG and STM32F439II Devices */ /* #define STM32F401xx */ /*!< STM32F401CB, STM32F401CC, STM32F401RB, STM32F401RC, STM32F401VB, STM32F401VC STM32F401CD, STM32F401RD, STM32F401VD, STM32F401CExx, STM32F401RE and STM32F401VE Devices */ /* #define STM32F411xE */ /*!< STM32F411CD, STM32F411RD, STM32F411VD, STM32F411CE, STM32F411RE and STM32F411VE Devices */ /* #define STM32F446xx */ /*!< STM32F446MC, STM32F446ME, STM32F446RC, STM32F446RE, STM32F446VC, STM32F446VE, STM32F446ZC and STM32F446ZE Devices */ #endif /* Old STM32F40XX definition, maintained for legacy purpose */ #ifdef STM32F40XX #define STM32F40_41xxx #endif /* STM32F40XX */ /* Old STM32F427X definition, maintained for legacy purpose */ #ifdef STM32F427X #define STM32F427_437xx #endif /* STM32F427X */ /* Tip: To avoid modifying this file each time you need to switch between these devices, you can define the device in your toolchain compiler preprocessor. */ #if !defined(STM32F40_41xxx) && !defined(STM32F427_437xx) && !defined(STM32F429_439xx) && !defined(STM32F401xx) && !defined(STM32F411xE) && \ !defined(STM32F446xx) #error "Please select first the target STM32F4xx device used in your application (in stm32f4xx.h file)" #endif #if !defined (USE_STDPERIPH_DRIVER) /** * @brief Comment the line below if you will not use the peripherals drivers. In this case, these drivers will not be included and the application code will be based on direct access to peripherals registers */ #define USE_STDPERIPH_DRIVER #endif /* USE_STDPERIPH_DRIVER */
2、根據實際的外部晶振修改stm32f4xx.h文件中默認的系統外部晶振時鍾HSE_VALU。在本例中使用了16MHz的外部晶振，因此設為16000000。
#if defined(STM32F40_41xxx) || defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F401xx) || defined(STM32F411xE) #if !defined (HSE_VALUE) #define HSE_VALUE ((uint32_t)16000000) /*!< Value of the External oscillator in Hz */ #endif /* HSE_VALUE */ #elif defined(STM32F446xx) #if !defined (HSE_VALUE) #define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */ #endif /* HSE_VALUE */ #endif /* STM32F40_41xxx || STM32F427_437xx || STM32F429_439xx || STM32F401xx || STM32F411xE */ /** * @brief In the following line adjust the External High Speed oscillator (HSE) Startup Timeout value */ #if !defined (HSE_STARTUP_TIMEOUT) #define HSE_STARTUP_TIMEOUT ((uint16_t)0x05000) /*!< Time out for HSE start up */ #endif /* HSE_STARTUP_TIMEOUT */ #if !defined (HSI_VALUE) #define HSI_VALUE ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/ #endif /* HSI_VALUE */
3、修改system_stm32f4xx.c文件中PLL_M，PLL_Q，PLL_N和PLL_P。
對於STM32F40_41xxx，系統時鍾為168MHZ，一般只需修改PLL_M的值，PLL_N默認為336（若主時鍾為168MHz則N值默認336，若主時鍾為180MHz則N值默認360），PLL_P默認為2，PLL_Q默認為7。
/************************* PLL Parameters *************************************/ #if defined(STM32F40_41xxx) || defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F401xx) /* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N */ #define PLL_M 16 #elif defined (STM32F446xx) #define PLL_M 8 #elif defined (STM32F411xE) #if defined(USE_HSE_BYPASS) #define PLL_M 8 #else #define PLL_M 16 #endif /* USE_HSE_BYPASS */ #endif /* STM32F40_41xxx || STM32F427_437xx || STM32F429_439xx || STM32F401xx */ /* USB OTG FS, SDIO and RNG Clock = PLL_VCO / PLLQ */ #define PLL_Q 7 #if defined(STM32F446xx) /* PLL division factor for I2S, SAI, SYSTEM and SPDIF: Clock = PLL_VCO / PLLR */ #define PLL_R 7 #endif /* STM32F446xx */ #if defined(STM32F40_41xxx) || defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F446xx) #define PLL_N 336 /* SYSCLK = PLL_VCO / PLL_P */ #define PLL_P 2 #endif /* STM32F40_41xxx || STM32F427_437x || STM32F429_439xx || STM32F446xx */ #if defined(STM32F401xx) #define PLL_N 336 /* SYSCLK = PLL_VCO / PLL_P */ #define PLL_P 4 #endif /* STM32F401xx */ #if defined(STM32F411xE) #define PLL_N 400 /* SYSCLK = PLL_VCO / PLL_P */ #define PLL_P 4 #endif /* STM32F411xx */ /******************************************************************************/
#if defined(STM32F40_41xxx) uint32_t SystemCoreClock = 168000000; #endif /* STM32F40_41xxx */ #if defined(STM32F427_437xx) || defined(STM32F429_439xx) || defined(STM32F446xx) uint32_t SystemCoreClock = 180000000; #endif /* STM32F427_437x || STM32F429_439xx || STM32F446xx */ #if defined(STM32F401xx) uint32_t SystemCoreClock = 84000000; #endif /* STM32F401xx */ #if defined(STM32F411xE) uint32_t SystemCoreClock = 100000000; #endif /* STM32F401xx */
4、若需要使用FPU，則還需要在system_stm32f4xx.c中的SystemInit函數開頭添加相關語句，並在keil工程配置中選擇use FPU(Use Single Precision)
注意：__FPU_PRESENT == 1在stm32f4xx.h中已默認設置，__FPU_USED == 1在core_cm4.h中已默認設置。
/* FPU settings ------------------------------------------------------------ * If no this settings,it maybe enter HardFault_Handler() interrupt when mdk complier chose "Use FPU"(or "Use Single Precision") to use FPU instruction. */ #if (__FPU_PRESENT == 1) && (__FPU_USED == 1) SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */ #endif