STM32F4时钟树简图

//STM32F4

//1.外设时钟使能和失能
HAL库使能某个外设时钟的方法，如：
_HAL_RCC_GPIOA_CLK_ENABLE();_/使能GPIOA时钟
HAL_RCC_GPIOA_CLK_DISABLE();/禁止GPIOA时钟

//2.HAL_RCC-OscConfig()函数
HAL_StatusTypeDef HAL_RCC_OscConfig(RCC_OscInitTypeDef*RCC_OscInitStruct)

typedef struct
{
	uint32_t OscilatorType;//choose  type of  oscillator
	uint32_t HSEState;//State of HSE
	uint32_t LSEState;
	uint32_t HSIState;
	uint32_t HSICablibrationValue;//Calibrated fine-tuned values of HSI 
	uint32_t LSIState;
	RCC_PLLInitTypeDef PLL;
}RCC_OscInitTypeDef;

typedef struct
{
	uint32_t PLLState;
	uint32_t PLLSource;
	uint32_t PLLM;
	uint32_t PLLN;
	uint32_t PLLP;
	uint32_t PLLQ;
}RCC_PLLInitTypeDef;