STM32

求助：如何在停止pwm后，置输出为0

2019-07-21 07:09发布

站内问答 / STM32/STM8
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求助：如何在停止pwm后，置输出为0 原子哥，我有一个问题，我想在用停止pwm以后，想置输出电平为0，即pwm=0%. 但是在我的程序中，停止pwm以后，输出电平时而为0，时而为1，即pwm=0%或pwm=100%. 请问如果解决呢？ 谢谢   我的程序如下，用的是STM32F105中的PA2作为PWM（TIM5_Ch3）的输出脚 /******初始化程序，这里和原子哥的程序基本一致PWM_Init(900,0);          ******/   void Scrubber_PWW_Init(u16 arr,u16 psc) {                                                                                                                               RCC->APB1ENR|=1<<3;       // enable TIM5 clock                                GPIOA->CRL&=0XFFFFF0FF;//PA2 output               GPIOA->CRL|=0X00000B00;//alternater function push-pull 50Mhz                         GPIOA->ODR|=1<<2; //PA2        pull up                 TIM5->ARR=arr; // set auto-Reload Register                TIM5->SC=psc;//          PWM_Init(900,0);          //non prescaler, PWM frequency=72000KHz/900=80Khz                               TIM5->CCMR2|=7<<4;  //CH3 mode PWM CCMR2 bit6:4(commence à bit12) OC3M[2:0]=111;                             TIM5->CCMR2|=1<<3; //channel 3 Output Compare   preload enable              OC3PE               TIM5->CCER|=1<<8;  //channel 3 Capture/Compare  output enable    CC3E               TIM5->CR1=0x0080;   //enalbe ARPE     Auto-reload preload enable               TIM5->CR1|=0x01;    //enable Time5                                                                                                                       }                 /******如果收到信息sMessTexte 的第8位(sMessTexte[8])为0：停止计数器Tim5， 如果sMessTexte 的第8位(sMessTexte[8])为1：置Pwm=20%，开计数器Tim5 如果sMessTexte 的第8位(sMessTexte[8])为2：置Pwm=40%，开计数器Tim5******/   void scrubber(u8* sMessTexte)               {                             switch(sMessTexte[8])                                            {                                                          case '0':                                                                                                    TIM5->CR1&=0x00;    //disable Time5                                                                                                    break;                                                          case '1':                                                                                                    SCRUBBER_PWM=40; //Pwm=20%                                                                                                         TIM5->CR1|=0x01;    //enable Time5                                                                                                    break;                                                          case '2':                                                                                                    SCRUBBER_PWM=80;//20%                                                                                                    TIM5->CR1|=0x01;    //enable Time5                                                                                                    break;                                                                                                     }                             }          谢谢大家帮助！！  
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6条回答
guillet
2019-07-21 12:18
回复【2楼】正点原子:
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谢谢原子哥。但是这么做，要再开pwm，我得重新初始化pwm，而不能随时改变pwm的占空比.
有没有更简单的方式呢？

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