关于动态改变STM32 PWM占空比的问题

2015-11-12 来源：eefocus

  while (1)
  {
    Delay(500);
if(CCR4_Val>1)
{
   CCR4_Val--;
   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

   TIM_OC4Init(TIM3, &TIM_OCInitStructure);
}
else
{
   CCR4_Val=990;
   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
   TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

   TIM_OC4Init(TIM3, &TIM_OCInitStructure);
}
  }
}
在主程序里改变对比值来改变PWM占空比，上面的程序是不是太笨了，有没有其他方法，请高手指点

MCU2008 (2008-9-12 10:43:53)

是太笨了...

sunke9 (2008-9-12 10:47:56)

我的用法和你一样
while (1)
  {
      Delay(0x0000FFFF);
      CCR1_Val = ADC_ConvertedValue*4;
      CCR2_Val = 16000 - ADC_ConvertedValue*4;

      TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
      TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
      TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
      TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

      TIM_OC1Init(TIM2, &TIM_OCInitStructure);

      TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);

  }

nomoneyiv (2008-9-12 11:29:08)

在中断里搞！

nomoneyiv (2008-9-12 11:33:22)

比如：
void TIM1_UP_IRQHandler(void)
{
TIM1_SetCompare1(pwm_val_c1);
TIM1_SetCompare3(pwm_val_c3);
TIM1_SetCompare2(pwm_val_c2);
TIM1_ClearITPendingBit(TIM1_IT_Update);

}
然后在主循环里，更改值

pwm_val_c1++; 之类的。

020411 (2008-9-12 15:21:42)

谢谢STM32青菜

yemingxp (2008-9-12 20:02:26)

aleyn (2008-9-15 14:05:15)

此贴最终解惑者是谁？

sw笨笨 (2009-2-24 07:31:01)

while (1)                                        //无限循环
{
  CCR4_Val=CCR4_Val+0x1000;             //变量递增
  if(CCR4_Val >= 0xffff) CCR4_Val=0;       //变量归零

  TIM_SetCompare4(TIM3, CCR4_Val); //变更长度
  Delay(0xffff);                                                 //延时

}

selina (2009-12-12 15:28:56)

好像只能在中断内做吧

wslaurora (2010-1-26 15:48:33)

通过tim更新时间触发DMA传输（循环模式），岂不是更简单？

TIM_DMACmd(TIM1, TIM_DMA_Update, ENABLE);

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)TIM1_CCR1_Address;    //TIM1通道1外设捕获/比较寄存器首地址
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)SRC_Buffer; //内存数据缓存首地址
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;    //外设作为数据传输的目的
DMA_InitStructure.DMA_BufferSize = 256;    //DMA缓存大小为256

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动态改变 STM32 PWM 占空比

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