Referneces:

• STM32函数固件库
• CMSIS_6 -> 此为arm提出的cmsis6的标准，各个用arm作内核的mcu厂商在写自家的固件库时应该遵守的标准。以后以stm32为例说明
• 【STM32】驱动库的选择：CMSIS Driver、SPL、HAL、LL | 在ARM MDK、STM32Cube中如何选择？ -> 感觉这篇文里对于cmsis库的描述有些不准。cmsis库不是对硬件操作的实现，而是一个模板

以下基于cmsis和stm32 std库进行一个对比

对比前准备工作

下载cmsis

arm官方提供的cmsis可以在github找到。链接如下：
https://github.com/ARM-software/CMSIS_6
（以上仅用于对比）

repo目录如下：

为构建stm32工程，配置好cmsis以及stm32 std库

随便在keil官网里找一款stm32的package，然后导入keil中。链接如下：https://www.keil.arm.com/packs/stm32f1xx_dfp-keil/versions/
然后还有cmsis的package，下载好之后导入keil中。链接如下：
https://www.keil.arm.com/packs/cmsis-arm/versions/
（用于对stm32 std工程的创建，因为stm32的std库是基于cmsis的描述进行构建的）

完成之后可以用两种方式查看是否导入成功：
1)查看keil目录
cmsis：

stm32 package

2)在keil中的Pack Installer查看

基于构建stm32 std库构建工程

对比

先看stm32工程，然后对比cmsis。

1. stm32 std库工程对于core_cm3.h的头文件包含关系如下，即core_cm3.h包含于stm32f10x.h包含于stm32f10x_gpio.h
   

2. 之后观察CMSIS/Core/Template/Device_M目录下system_Device.c和system_Device.h
   
   然后对比stm32工程下的system_stm32f10x.c和system_stm32f10x.h文件

   // file name: system_stm32f10x.c
   /**
     * @brief  Setup the microcontroller system
     *         Initialize the Embedded Flash Interface, the PLL and update the 
     *         SystemCoreClock variable.
     * @note   This function should be used only after reset.
     * @param  None
     * @retval None
     */
   void SystemInit (void)
   {
     /* Reset the RCC clock configuration to the default reset state(for debug purpose) */
     /* Set HSION bit */
     RCC->CR |= (uint32_t)0x00000001;
   
     /* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
   #ifndef STM32F10X_CL
     RCC->CFGR &= (uint32_t)0xF8FF0000;
   #else
     RCC->CFGR &= (uint32_t)0xF0FF0000;
   #endif /* STM32F10X_CL */   
   
     /* Reset HSEON, CSSON and PLLON bits */
     RCC->CR &= (uint32_t)0xFEF6FFFF;
   
     /* Reset HSEBYP bit */
     RCC->CR &= (uint32_t)0xFFFBFFFF;
   
     /* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
     RCC->CFGR &= (uint32_t)0xFF80FFFF;
   
   #ifdef STM32F10X_CL
     /* Reset PLL2ON and PLL3ON bits */
     RCC->CR &= (uint32_t)0xEBFFFFFF;
   
     /* Disable all interrupts and clear pending bits  */
     RCC->CIR = 0x00FF0000;
   
     /* Reset CFGR2 register */
     RCC->CFGR2 = 0x00000000;
   #elif defined (STM32F10X_LD_VL) || defined (STM32F10X_MD_VL) || (defined STM32F10X_HD_VL)
     /* Disable all interrupts and clear pending bits  */
     RCC->CIR = 0x009F0000;
   
     /* Reset CFGR2 register */
     RCC->CFGR2 = 0x00000000;      
   #else
     /* Disable all interrupts and clear pending bits  */
     RCC->CIR = 0x009F0000;
   #endif /* STM32F10X_CL */
   
   #if defined (STM32F10X_HD) || (defined STM32F10X_XL) || (defined STM32F10X_HD_VL)
     #ifdef DATA_IN_ExtSRAM
   	SystemInit_ExtMemCtl(); 
     #endif /* DATA_IN_ExtSRAM */
   #endif 
   
     /* Configure the System clock frequency, HCLK, PCLK2 and PCLK1 prescalers */
     /* Configure the Flash Latency cycles and enable prefetch buffer */
     SetSysClock();
   
   #ifdef VECT_TAB_SRAM
     SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
   #else
     SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
   #endif 
   }
   

   // file name: system_Device.c
   /*---------------------------------------------------------------------------
     System initialization function
    *---------------------------------------------------------------------------*/
   void SystemInit (void)
   {
   /* ToDo: Add code to initialize the system.
   		 Do not use global variables because this function is called before
   		 reaching pre-main. RW section maybe overwritten afterwards. */
   
   /* ToDo: Initialize VTOR if available */
   #if defined (__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
     SCB->VTOR = (uint32_t)(&__VECTOR_TABLE[0]);
   #endif
   
   /* ToDo: Enable co-processor if it is used */
   #if (defined (__FPU_USED) && (__FPU_USED == 1U)) || \
   	(defined (__ARM_FEATURE_MVE) && (__ARM_FEATURE_MVE > 0U))
     SCB->CPACR |= ((3U << 10U*2U) |           /* enable CP10 Full Access */
   				 (3U << 11U*2U)  );         /* enable CP11 Full Access */
   #endif
   
   /* ToDo: Initialize SAU if TZ is used */
   #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
     TZ_SAU_Setup();
   #endif
   
     SystemCoreClock = SYSTEM_CLOCK;
   }
   

   可以发现stm32工程下的SystemInit是根据cmsis下的ToDo注释实现的。

   在stm32工程中，除了还有一个名为stm32f10x.h的头文件，与system_stm32f10x.c和system_stm32f10x.h基于cmsis的实现有紧密相关