PWM波调速程序，每改变一次占空比延时10S,但实际延时30S求解答

linzheng · 发表于 2017-3-12 11:18:34

不知道是不是这里不该用延时函数，该写中断延时函数，麻烦大神解答下，第一次提问好紧张，谢谢啦

代码如下：
void TIM2_PWM_Init(u32 arr,u32 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_TIM2);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA,&GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_SetBits(GPIOA,GPIO_Pin_4);
  GPIO_ResetBits(GPIOA,GPIO_Pin_5);

  TIM_TimeBaseStructure.TIM_Prescaler=psc;
  TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
  TIM_TimeBaseStructure.TIM_Period=arr;
  TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
  TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructurE);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OC1Init(TIM2, &TIM_OCInitStructure);

TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM2,ENABLE);
TIM_Cmd(TIM2, ENABLE);
}

int main(void)//首先将占空比设为0，然后设为20%，延时10s过后设为70%占空比。实际运行时电机在20%占空比处会循环三次，转30s(刚好是设置的10s的三倍)，然后切换成70%占空比
{
  u16 pwmval=1000;
  delay_init(168);
  TIM2_PWM_Init(1000-1,84-1);
  TIM_SetCompare1(TIM2,pwmval);
  delay_us(100);

pwmval=800;
TIM_SetCompare1(TIM2,pwmval);
delay_ms(10000);

pwmval=300;
TIM_SetCompare1(TIM2,pwmval);

/*delay_ms(1000);
pwmval=1000;
TIM_SetCompare1(TIM2,pwmval);*/ 如果多出这三句，程序原本意图是20%占空比转10s，70%占空比转1s然后停下。实际情况是慢10s快1s，慢10s快1s，慢10s快1s（也是刚好三个循环）然后停下
}