函數原形void RCC_GetClocksFreq(RCC_ClocksTypeDef* RCC_Clocks)

RCC_ClocksTypeDef定義于文件“stm32f10x_rcc.h”：

typedef struct
{
uint32_t SYSCLK_Frequency; /*!< SYSCLK clock frequency expressed in Hz */
uint32_t HCLK_Frequency; /*!< HCLK clock frequency expressed in Hz */
uint32_t PCLK1_Frequency; /*!< PCLK1 clock frequency expressed in Hz */
uint32_t PCLK2_Frequency; /*!< PCLK2 clock frequency expressed in Hz */
}RCC_ClocksTypeDef;

例：
/* Get the frequencies of different on chip clocks */
RCC_ClocksTypeDef RCC_Clocks;
RCC_GetClocksFreq(&RCC_Clocks);

執行完后，直接查看RCC_Clocks，在各成員中取出所需要時鐘頻率就行了。