<stm32系列>定时器和时钟设置

    //定时器4中断设置

    NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;   //定时器4

    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x1;

    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;  

    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

    NVIC_Init(&NVIC_InitStructure);  

//定时器4

void TIM4_Config(void)

{

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    TIM_DeInit(TIM4);                                               //复位TIM4定时器   

    TIM_TimeBaseStructure.TIM_Period = 200 - 1;         //2ms   

    TIM_TimeBaseStructure.TIM_Prescaler = 7200 - 1;     //分频36000   36M APB1频率 自动倍频 72M / 7200  

    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;   //时钟分频    不分频

    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数方向向上计数

    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

    TIM_ClearFlag(TIM4, TIM_FLAG_Update);    //清除TIM4溢出中断标志

    TIM_ITConfig(TIM4, TIM_IT_Update, ENABLE);    //TIM4溢出中断允许

// TIM_ARRPreloadConfig(TIM4, ENABLE);                                       //该函数会让当前还是按原来设定的值进行中断 下一次还是为新的值

//    TIM_Cmd(TIM4, ENABLE);           //允许tim4计数

}

TIM_SetCounter(TIM4, 0); //计数器清零

TIM_SetAutoreload(TIM4, 100); //数据重载

ErrorStatus HSEStartUpStatus;

RCC_DeInit(); //复位RCC模块的寄存器位缺省值

RCC_HSEConfig(RCC_HSE_ON); //开启HSE时钟，用HSE的时钟作为PLL时钟源

HSEStartUpStatus = RCC_WaitForHSEStartUp(); //获取HSE启动状态

if(HSEStartUpStatus == SUCCESS) //HSE启动成功 如果不成功会转换为HSI的时钟源提供给PLL

{

FLASH_PrefetchBufferCmd(ENABLE); //开启FLASH预取功能

FLASH_SetLatency(FLASH_Latency_2); //FLASH延迟2个周期

RCC_HCLKConfig(RCC_SYSCLK_Div1); //配置HCLK

RCC_PCLK2Config(RCC_HCLK_Div1); //配置PCLK2 对应APB2

RCC_PCLK1Config(RCC_HCLK_Div2); //配置PCLK1 对应APB1

RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9); //倍频为9倍 用HSE作为时钟源

RCC_PLLCmd(ENABLE); //启动PLL

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)

{

} //等待PLL启动完成

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); //配置系统时钟

while(RCC_GetSYSCLKSource() != 0x08)

{

} //用于检测是否将HSE9倍频后未做系统时钟

}