STM32串口乱码

库函数默认8MHz晶振，应根据实际硬件选择

# CMSIS/stm32f10x.h

#define HSE_VALUE   ((uint32_t)12000000)

#if !defined  HSE_VALUE
 #ifdef STM32F10X_CL
  #define HSE_VALUE    ((uint32_t)25000000) /*!< 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 */