STM32普通定時器實現延時函數

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/* SystemFrequency / 1000    1ms中斷一次 * SystemFrequency / 100000     10us中斷一次 * SystemFrequency / 1000000 1us中斷一次 */#define SYSTICKPERIOD                    0.000001#define SYSTICKFREQUENCY            (1/SYSTICKPERIOD)/**  * @brief  定時器2的初始化,，定時周期1ms  * @param  無  * @retval 無  */void TIM2_Init(void){    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;    /*AHB = 72MHz,RCC_CFGR的PPRE1 = 2，所以APB1 = 36MHz,TIM2CLK = APB1*2 = 72MHz */    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);        /* Time base configuration */             TIM_TimeBaseStructure.TIM_Period = 999;    TIM_TimeBaseStructure.TIM_Prescaler = SystemCoreClock/SYSTICKFREQUENCY -1;    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);        TIM_ARRPreloadConfig(TIM2, ENABLE);        /* 設定更新要求源只在計數器上溢或下溢時產生中斷 */    TIM_UpdateRequestConfig(TIM2,TIM_UpdateSource_Global);     TIM_ClearFlag(TIM2, TIM_FLAG_Update);}/**  * @brief   ms延時程式,1ms為一個單位  * @param    *        @arg nTime: Delay_ms( 10 ) 則實現的延時為 10 * 1ms = 10ms  * @retval  無  */void Delay_ms(__IO uint32_t nTime){         /* 清零計數器並使能滴答定時器 */      TIM2->CNT   = 0;      TIM_Cmd(TIM2, ENABLE);         for( ; nTime > 0 ; nTime--)    {     /* 等待一個延時單位的結束 */     while(TIM_GetFlagStatus(TIM2, TIM_FLAG_Update) != SET);     TIM_ClearFlag(TIM2, TIM_FLAG_Update);    }    TIM_Cmd(TIM2, DISABLE);}

 

STM32普通定時器實現延時函數