{
ErrorStatus HSEStartUpStatus;
RCC_DeInit(); //时钟管理重置 /* RCC system reset(for debug purpose) */
RCC_HSEConfig(RCC_HSE_ON); //打开外部晶振 //Enable HSE
HSEStartUpStatus = RCC_WaitForHSEStartUp(); //等待外部晶振就绪 //Wait till HSE is ready
if(HSEStartUpStatus == SUCCESS)
{
RCC_HCLKConfig(RCC_SYSCLK_Div1); //AHB使用系统时钟 //HCLK = SYSCLK
RCC_PCLK2Config(RCC_HCLK_Div1); //APB2为HCLK/1 //PCLK2 = HCLK/1
RCC_PCLK1Config(RCC_HCLK_Div2); //APB1为HCLK/2 //PCLK1 = HCLK/2
RCC_ADCCLKConfig(RCC_PCLK2_Div4); //设置ADC时钟频率
//注：AHB主要负责外部存储器时钟。PB2负责AD，I/O，高级TIM，串口1。APB1负责DA，USB，SPI，I2C，CAN，串口2345，普通TIM。
FLASH_SetLatency(FLASH_Latency_2); //flash操作的延时 //Flash 2 wait state
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable); //flash读取缓冲，加速 //Enable Prefetch Buffer
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9); //PLLCLK = 8MHz * 9 = 72MHz
RCC_PLLCmd(ENABLE); //启动PLL //Enable PLL
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET) //等待PLL启动 /* Wait till PLL is ready */
{
}
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); //将PLL设置为系统时钟源 /* Select PLL as system clock source */
while(RCC_GetSYSCLKSource() != 0x08) //等待系统时钟源的启动 /* Wait till PLL is used as system clock source */
{
}
}
｝
void RCC_Configuration(void)