stm32 PWM输出，在中断中改占空比，怎么不行啊。

stm32怎么搞啊 · 发表于 2014-7-8 14:03:42

回复【5楼】 x1213378204 :
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请问下，我在中断改占空比，我的想法是第一周期是50%占空比，第二个70%占空比，如此循环下去，怎么出来，只有一个占空比。求各位大神，这个我琢磨好多天了，不是一个周期后进入中断吗？
程序在下面：
void TIM2_PWMOUTPUT_INIT(void){
       TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
       GPIO_InitTypeDef GPIO_InitStructure;
       TIM_OCInitTypeDef TIM_OCInitStructure;
       NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
/* GPIOA and GPIOB clock enable */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
/*--------------------------------- GPIO Configuration -------------------------*/
/* GPIOA Configuration: Pin 6 and 7 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;

GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_TIM4);
//GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_TIM3);

/* Compute the prescaler value */
PrescalerValue = (uint16_t) (SystemCoreClock / 8000000) - 1;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 7999;
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);


NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
// TIM_OCInitStructure.TIM_Pulse =5199;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

TIM_OC3Init(TIM4, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM4, ENABLE);

/* TIM3 enable counter */
TIM_Cmd(TIM4, ENABLE);
TIM_ITConfig(TIM4,TIM_IT_CC3|TIM_IT_Update,ENABLE);

   }
void TIM4_IRQHandler(void)
{ //TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;


        if (TIM_GetITStatus(TIM4, TIM_IT_CC3|TIM_IT_Update) != RESET)
   {    TIM_ClearITPendingBit(TIM4, TIM_IT_CC3|TIM_IT_Update);

              capture=zkb[t];

          TIM_SetCompare3(TIM4,capture);
                  t++；
            if（t == 2）
                t = 0；}}