STM32F107的时钟设置由25M修改成8M

1.首先找到stm32f10x.h， system_stm32f10x.c这两个文件；

2. system_stm32f10x.c修改

#if defined (STM32F10X_LD_VL) || (defined STM32F10X_MD_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

3.stm32f10x.h修改

#if !defined  HSE_VALUE
 #ifdef STM32F10X_CL   
  #define HSE_VALUE    ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
 #else
  #define HSE_VALUE    ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */
 #endif /* STM32F10X_CL */
#endif /* HSE_VALUE */