STM32F1一种相对简单的使用HSI配置系统时钟为64MHz的方法

    最近因为项目成本需要，必须使用片内晶振作为系统的时钟源，所以对正点原子的项目模板时钟配置做了一些修改。使时钟倍频至64MHz供系统使用。

    有需要的同学可以参考一下，代码如下：

#if defined (STM32F10X_LD_VL) || (defined STM32F10X_MD_VL) || (defined STM32F10X_HD_VL)
/* #define SYSCLK_FREQ_HSE    HSE_VALUE */
 #define SYSCLK_FREQ_24MHz  24000000
#else
/* #define SYSCLK_FREQ_HSE    HSE_VALUE */
/* #define SYSCLK_FREQ_24MHz  24000000 */ 
/* #define SYSCLK_FREQ_36MHz  36000000 */
/* #define SYSCLK_FREQ_48MHz  48000000 */
/* #define SYSCLK_FREQ_56MHz  56000000 */
/* #define SYSCLK_FREQ_72MHz  72000000 */			
#endif

这里先将宏定义注释掉；

#ifdef SYSCLK_FREQ_HSE
  uint32_t SystemCoreClock         = SYSCLK_FREQ_HSE;        /*!< System Clock Frequency (Core Clock) */
#elif defined SYSCLK_FREQ_24MHz
  uint32_t SystemCoreClock         = SYSCLK_FREQ_24MHz;        /*!< System Clock Frequency (Core Clock) */
#elif defined SYSCLK_FREQ_36MHz
  uint32_t SystemCoreClock         = SYSCLK_FREQ_36MHz;        /*!< System Clock Frequency (Core Clock) */
#elif defined SYSCLK_FREQ_48MHz
  uint32_t SystemCoreClock         = SYSCLK_FREQ_48MHz;        /*!< System Clock Frequency (Core Clock) */
#elif defined SYSCLK_FREQ_56MHz
  uint32_t SystemCoreClock         = SYSCLK_FREQ_56MHz;        /*!< System Clock Frequency (Core Clock) */
#elif defined SYSCLK_FREQ_72MHz
  uint32_t SystemCoreClock         = SYSCLK_FREQ_72MHz;        /*!< System Clock Frequency (Core Clock) */
#else /*!< HSI Selected as System Clock source */
  //uint32_t SystemCoreClock         = HSI_VALUE;        /*!< System Clock Frequency (Core Clock) */
  uint32_t SystemCoreClock         = 64000000;			
#endif

接着将SystemCoreClock替换为64MHz；

/*使用内部RC振荡器，设置系统时钟为64MHz*/
static void Intn_RC_Init(void)
{
    RCC_DeInit();
    RCC_HSICmd(ENABLE); 
    while(RCC_GetFlagStatus(RCC_FLAG_HSIRDY)== RESET);
    RCC_HCLKConfig(RCC_SYSCLK_Div1);                         //设置AHB时钟（HCLK） = 系统时钟
    RCC_PCLK2Config(RCC_HCLK_Div1);                          //设置AHB2时钟 = HCLK
    RCC_PCLK1Config(RCC_HCLK_Div1);                          //设置AHB1时钟 = HCLK
    FLASH_SetLatency(FLASH_Latency_2);                       //设置FLASH存储器延时时钟周期数
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
    RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_16);    //设置PLL时钟源及倍频系数，频率为8/2*16=64MHz
    RCC_PLLCmd(ENABLE);
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
    while(RCC_GetSYSCLKSource() != 0x08);
}

这样就完成了系统时钟的配置！