使用定时器1计时时间慢了好多

z2500053109 · 发表于 2015-5-6 12:55:57

TIM1设置的应该是50MS触发一次中断，可实际运行效果慢了好多，而且每次进中断时间还不一定下面是TIM1设置求大神看看问题在哪
TIM1-CNT的值每次进中断都不一样

[mw_shl_code=c,true]void TIM1_init(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; NVIC_InitTypeDef NVIC_InitStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE); TIM_TimeBaseStructure.TIM_Period = 4999; TIM_TimeBaseStructure.TIM_Prescaler =(7200-1); TIM_TimeBaseStructure.TIM_ClockDivision = 0; TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure); NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //先占优先级0级 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //从优先级3级 TIM_ITConfig(TIM1,TIM_IT_Update,ENABLE); NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn; //TIM3中断 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能 NVIC_Init(&NVIC_InitStructure); //初始化NVIC寄存器 TIM_Cmd(TIM1, ENABLE); // TIM_Cmd(TIM3, ENABLE); //使能TIMx } void TIM1_UP_IRQHandler(void) { if (TIM_GetITStatus(TIM1, TIM_IT_Update) != RESET) LED0=!LED0; TIM_ClearITPendingBit(TIM1, TIM_FLAG_Update); //清中断 } [/mw_shl_code]