我手头有一片nucelo STM32F411RE 板子,是透过有源振荡器,osc in ,osc out (空接),然后这个振荡器是由 through STLINK MCO pin of STM32F103 microcontroller. The frequencycannot be changed and is fixed at 8 MHz. 我找不到这两个宏定义STM32F411xE,#define USE_HSE_BYPASS,这个在那边可以找的到
#if defined(STM32F411xE) /*!< Uncomment the following line if you need to clock the STM32F411xE by HSE Bypass
through STLINK MCO pin of STM32F103 microcontroller. The frequency cannot be changed
and is fixed at 8 MHz.
Hardware configuration needed for Nucleo Board:
?SB54, SB55 OFF
?R35 removed
?SB16, SB50 ON */
/* #define USE_HSE_BYPASS */ //这叙述为何被屏蔽掉
#if defined(USE_HSE_BYPASS)
#define HSE_BYPASS_INPUT_FREQUENCY 8000000
#endif /* USE_HSE_BYPASS */
#endif /* STM32F411xE */
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