lhl_forever 发表于 2011-12-13 16:44:18

PWM停止输出时管脚电平状态无法锁定?

我用TIM2产生一个20KHZ的频率进行斩波,但是当我用TIM_Cmd(TIM2,DISABLE);后PA1的状态不确定,有时是高电平,有时是低电平,我必须要它在没有PWM输出的时候维持高电平,该怎么做啊?急!望那位前辈赐教,谢谢!程序配置如下:
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; 
   GPIO_Init(GPIOA, &GPIO_InitStructure);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
    TIM_TimeBaseStructure.TIM_Prescaler = 359;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseStructure.TIM_Period = 9;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;  
    TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);
 
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;                      
    TIM_OCInitStructure.TIM_Pulse = 5;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;           
    TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;  
                
 TIM_OC2Init(TIM2,&TIM_OCInitStructure);
 TIM_OC2PreloadConfig(TIM2,TIM_OCPreload_Enable);  
 TIM_ARRPreloadConfig(TIM2,ENABLE);

发表于 2011-12-13 21:53:54

RE:PWM停止输出时管脚电平状态无法锁定?

你需要将GPIO设置为输出高电平。
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