PWM停止输出时管脚电平状态无法锁定？

lhl_forever 提问时间：2011-12-13 16:44 /

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);