老哥们，我现在在做一个普通IO口模拟PWM输出控制LED的呼吸灯

年糕 · 发表于 2020-11-7 14:22:12

老哥们，我现在在做一个普通IO口模拟PWM输出控制LED的呼吸灯，现在LED灯一直常亮，没找到具体的原因。求指点
u8 dir = 1;
u8 ledpwmval;
int ledpwmcount;
u8 timecount;
void TIM4_IRQHandler(void)//200us
{
printf("TIM4.......\n");
      if(TIM_GetITStatus(TIM4,TIM_FLAG_Update))
      {
            if(++timecount > 100)
            {
                     timecount = 0;
                     if((dir==1)&&(ledpwmcount<=799))
                     {
                              ledpwmcount++;
                              if(ledpwmcount > 799)
                              {
                                    ledpwmcount =799;
                                    dir = 0;
                              }
                     }
                     if((dir==0)&&(ledpwmcount>0))
                     {
                              ledpwmcount--;
                              if(ledpwmcount == 0)
                              {
                                    ledpwmcount = 0;
                                    dir = 1;
                              }
                     }
                              ledpwmval = ledpwmcount;
            }
            if(ledpwmval>0)
            {
               GPIO_ResetBits(GPIOC,LED0);
               ledpwmval--;
            }
            else
               GPIO_SetBits(GPIOC,LED0);
      }
      TIM_ClearITPendingBit(TIM4,TIM_IT_Update);
}
定时器4部分

void TIM4_Int_Init(u16 arr,u16 psc)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStrue;
NVIC_InitTypeDef NVIC_InitStructture;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);

TIM_TimeBaseInitStrue.TIM_Period = arr;
TIM_TimeBaseInitStrue.TIM_Prescaler = psc;
TIM_TimeBaseInitStrue.TIM_CounterMode =TIM_CounterMode_Up;
TIM_TimeBaseInitStrue.TIM_ClockDivision =0;
TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStrue);

TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);

NVIC_InitStructture.NVIC_IRQChannel = TIM4_IRQn;
NVIC_InitStructture.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructture.NVIC_IRQChannelSubPriority = 3;
NVIC_InitStructture.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructture);

TIM_Cmd(TIM4,ENABLE);
}
void TIM4_PWM_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStrue;
TIM_OCInitTypeDef TIM_OCInitTypeStrue;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_AFIO,ENABLE);

GPIO_InitStructure.GPIO_Pin = LED0;    // ¶Ë¿úÅäÖÃ
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;    //IO¿úËù¶èÎa50MHz
   GPIO_Init(GPIOC, &GPIO_InitStructure);

TIM_TimeBaseInitStrue.TIM_Period = arr;
TIM_TimeBaseInitStrue.TIM_Prescaler = psc;
TIM_TimeBaseInitStrue.TIM_CounterMode =TIM_CounterMode_Up;
TIM_TimeBaseInitStrue.TIM_ClockDivision =0;
TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStrue);

TIM_OCInitTypeStrue.TIM_OCMode =TIM_OCMode_PWM2;
TIM_OCInitTypeStrue.TIM_OCNPolarity =TIM_OCPolarity_High;
TIM_OCInitTypeStrue.TIM_OutputState =TIM_OutputState_Enable;
TIM_OC3Init(TIM4, &TIM_OCInitTypeStrue);

TIM_OC3PreloadConfig(TIM4,TIM_OCPreload_Enable);
TIM_Cmd(TIM4,ENABLE);
}

nashui_sx · 发表于 2020-11-7 14:22:13

u8 dir = 1,flag;
u16 timecount,timecount_all;
#define led_all 200  //周期
s16 led_low=-20;    //低（-20使得低灭彻底）
s16 led_high=led_all;//高
void TIM4_IRQHandler(void)//TIM4_Int_Init(19,71);  20us(稍微修改变呼吸频率)
{
if(TIM_GetITStatus(TIM4,TIM_FLAG_Update))
{
      timecount++;
      timecount_all++;
      if(timecount>=led_low & flag==0)//低
      {
         timecount=0;
         LED0=!LED0;
         flag=1;
      }
      if(timecount>=led_high & flag==1)//高
      {
         timecount=0;
         LED0=!LED0;
         flag=0;
      }
      if(timecount_all>led_all)//每个周期结束更改占空比
      {
         timecount_all=0;
         if(dir==1)
         {
            led_low=led_low+1;
            led_high=led_high-1;
            if(led_low>led_all)
                  dir = 0;
         }
         if(dir==0)
         {
            led_low=led_low-1;
            led_high=led_high+1;
            if(led_high>led_all)
                  dir = 1;
         }
      }
      TIM_ClearITPendingBit(TIM4,TIM_IT_Update);
}
}