1.宏定义

.c —-就当前c文件使用
.h —-可能多个文件使用
数据封装

2.位段操作

  1. /* ------------ RCC registers bit address in the alias region ----------- */  RCC位段
  2. #define RCC_OFFSET                (RCC_BASE - PERIPH_BASE)   偏移
  4. /* --- CR Register ---*/
  6. /* Alias word address of HSION bit */
  7. #define CR_OFFSET                 (RCC_OFFSET + 0x00) 基地址
  8. #define HSION_BitNumber           0x00           位
  9. #define CR_HSION_BB               (PERIPH_BB_BASE + (CR_OFFSET * 32) + (HSION_BitNumber * 4)) 别名区地址 BIT Band
  11. /* Alias word address of PLLON bit */
  12. #define PLLON_BitNumber           0x18
  13. #define CR_PLLON_BB               (PERIPH_BB_BASE + (CR_OFFSET * 32) + (PLLON_BitNumber * 4))
  15. #ifdef STM32F10X_CL
  16.  /* Alias word address of PLL2ON bit */
  17.  #define PLL2ON_BitNumber          0x1A
  18.  #define CR_PLL2ON_BB              (PERIPH_BB_BASE + (CR_OFFSET * 32) + (PLL2ON_BitNumber * 4))
  20.  /* Alias word address of PLL3ON bit */
  21.  #define PLL3ON_BitNumber          0x1C
  22.  #define CR_PLL3ON_BB              (PERIPH_BB_BASE + (CR_OFFSET * 32) + (PLL3ON_BitNumber * 4))
  23. #endif /* STM32F10X_CL */ 
  25. /* Alias word address of CSSON bit */
  26. #define CSSON_BitNumber           0x13
  27. #define CR_CSSON_BB               (PERIPH_BB_BASE + (CR_OFFSET * 32) + (CSSON_BitNumber * 4))

3.位掩码

移位
按位取反等
在库中已经构造好了

Reset是位或清零
Set是与或置1

  1. /* CR register bit mask */
  2. #define CR_HSEBYP_Reset           ((uint32_t)0xFFFBFFFF)      //置0
  3. #define CR_HSEBYP_Set             ((uint32_t)0x00040000)      //
  4. #define CR_HSEON_Reset            ((uint32_t)0xFFFEFFFF)
  5. #define CR_HSEON_Set              ((uint32_t)0x00010000)
  6. #define CR_HSITRIM_Mask           ((uint32_t)0xFFFFFF07)
  8. /* CFGR register bit mask */
  9. #if defined (STM32F10X_LD_VL) || defined (STM32F10X_MD_VL) || defined (STM32F10X_HD_VL) || defined (STM32F10X_CL) 
  10.  #define CFGR_PLL_Mask            ((uint32_t)0xFFC2FFFF)
  11. #else
  12.  #define CFGR_PLL_Mask            ((uint32_t)0xFFC0FFFF)
  13. #endif /* STM32F10X_CL */ 
  15. #define CFGR_PLLMull_Mask         ((uint32_t)0x003C0000)
  16. #define CFGR_PLLSRC_Mask          ((uint32_t)0x00010000)
  17. #define CFGR_PLLXTPRE_Mask        ((uint32_t)0x00020000)
  18. #define CFGR_SWS_Mask             ((uint32_t)0x0000000C)
  19. #define CFGR_SW_Mask              ((uint32_t)0xFFFFFFFC)
  20. #define CFGR_HPRE_Reset_Mask      ((uint32_t)0xFFFFFF0F)
  21. #define CFGR_HPRE_Set_Mask        ((uint32_t)0x000000F0)
  22. #define CFGR_PPRE1_Reset_Mask     ((uint32_t)0xFFFFF8FF)
  23. #define CFGR_PPRE1_Set_Mask       ((uint32_t)0x00000700)
  24. #define CFGR_PPRE2_Reset_Mask     ((uint32_t)0xFFFFC7FF)
  25. #define CFGR_PPRE2_Set_Mask       ((uint32_t)0x00003800)
  26. #define CFGR_ADCPRE_Reset_Mask    ((uint32_t)0xFFFF3FFF)
  27. #define CFGR_ADCPRE_Set_Mask      ((uint32_t)0x0000C000)

分频

  1. static __I uint8_t APBAHBPrescTable[16] = {0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9};
  2. static __I uint8_t ADCPrescTable[4] = {2, 4, 6, 8};

assert断言：
C语言用来判断一个东西是对的还是错的，如果是对的就忽略过去，如果错的以某种方式告诉我们
断言机制使用最多的是：库函数中用断言来检查用户调用该库函数的参数对不对

4.使用标准库实现RCC切换

  1. #include "clock.h"
  3. void Set_SysClockTo72M(void)
  4. {
  5.     ErrorStatus sta = ERROR;
  7.     //先关闭HSEON再打开HSEON
  8.     RCC_HSEConfig(RCC_HSE_ON);
  10.     //do while 等待HSEON稳定
  11.     sta = RCC_WaitForHSEStartUp();
  13.     if(sta == SUCCESS)
  14.     {
  15.         //设置FLASH
  16.         FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
  18.         FLASH_SetLatency(FLASH_Latency_2);
  19. //        FLASH->ACR |= 0x10;
  20. //        FLASH->ACR &= (~0x03);
  21. //        FLASH->ACR |= (0x02);
  22.         // 到这里HSE就ready了，下面再去配PLL并且等待他ready
  24.         //配HLCK为SYSCLK/1
  25.         RCC_HCLKConfig(RCC_SYSCLK_Div1);
  26.         //配置PLCK1为AHB的2分频
  27.         RCC_PCLK1Config(RCC_HCLK_Div2);
  28.         //配置PLCK2为AHB2的1分频
  29.         RCC_PCLK2Config(RCC_HCLK_Div1);
  31.         //设置HSE/1为PLL原始种，PLL倍频系数为9
  32.         RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);
  34.         //使能PLL
  35.         RCC_PLLCmd(ENABLE);
  37.         while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
  38.     {
  39.     }
  41.     //设置PLL为系统时钟
  42.     RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
  44.     //等待PLL设置好时钟
  45.     while(RCC_GetSYSCLKSource() != 0x08)
  46.     {
  47.     }
  48.     }
  49.     else
  50.     {
  51.         while(1)
  52.         {
  53.         } 
  54.     }
  55. }

PS：
注意：
在启动文件中
调用SystemInit函数，会初始化为72
我们关掉之后就可以看到速度的差别了

  1.                 EXPORT  Reset_Handler             [WEAK]
  2.                 IMPORT  __main
  3.                 IMPORT  SystemInit
  4.                 ;LDR     R0, =SystemInit
  5.                 ;BLX     R0               
  6.                 LDR     R0, =__main
  7.                 BX      R0
  8.                 ENDP
  1. #include "stm32f10x.h"
  2. #include "clock.h"
  5. void led_init(void);
  6. void Delay(void);
  7. void flash(void);
  9. int main(void)
  10. {
  11.     led_init();
  12.     flash();
  14.     Set_SysClockTo72M();
  16.     while(1)
  17.     {
  18.         flash();
  19.     };
  20.     return 0;
  21. }
  25. void led_init(void)
  26. {
  27.     RCC->APB2ENR = 0x00000100;
  28.     GPIOG->CRL = (0x33 << 24);
  29. }
  32. void Delay(void)
  33. {
  34.     unsigned int i = 0, j = 0;
  35.     for( i = 0; i < 2000; i++)
  36.     {
  37.             for( j = 0; j < 2000; j++);
  38.     }
  39. }
  41. void flash(void)
  42. {
  43.         GPIOG->BSRR = 0x000000080;
  44.         Delay();
  45.         GPIOG->BSRR = 0x00000040;
  46.         Delay();
  47.         GPIOG->BSRR = 0x00ff0000;
  48.         Delay();
  49. }