STM32F030的PWM输出疑虑

xiaohai8272

原子哥，各位朋友好：
     小弟借这里，想问问PWM输出的问题，我现在用PWM输出，想知道能否进PWM中断，识别什么时候是高电平，什么时候是低电平状态，我这里有个示例，我想问问各位能解释吗
static void TIM1PwmInit(FunctionalState flag)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

NVIC_InitTypeDef NVIC_InitStructure;


RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, flag/*ENABLE*/);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, flag/*ENABLE*/); //使能定时器1

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure); 

GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_2);// 第2 功能TIM1

//**************************************************************************
//     定时器1设置： 2分频，24KHz频率，
//**************************************************************************
TIM_TimeBaseStructure.TIM_Period = 65535;    // 设置自动重装周期值
TIM_TimeBaseStructure.TIM_Prescaler = 9;//1;   //2分频
TIM_TimeBaseStructure.TIM_ClockDivision = 0;//设置时钟分割
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;// 向上计数

TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);//初始化定时1

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;//TIM_OCMode_PWM2;//;//PWM2模式
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;//比较输出使能
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;//TIM_OCPolarity_High;//;//输出高
TIM_OCInitStructure.TIM_Pulse = 480;//50;       // 300-1 30%占空比
TIM_OC1Init(TIM1, &TIM_OCInitStructure);


TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Disable);//
//TIM_OC1PreloadConfig(TIM1, ENABLE);

/* TIM1 enable counter */
TIM_Cmd(TIM1, flag/*ENABLE*/);

//TIM_CtrlPWMOutputs(TIM1,flag/*ENABLE*/);

TIM_ITConfig(TIM1,TIM_IT_CC1,flag/*ENABLE*/);

NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 5;
NVIC_InitStructure.NVIC_IRQChannelCmd = flag;//ENABLE;
NVIC_Init(&NVIC_InitStructure);



}

void TIM1_CC_IRQHandler(void)
{
//TIM1_CH1 输出频率2k
if (TIM_GetITStatus(TIM1, TIM_IT_CC1) != RESET)
{
 TIM_ClearITPendingBit(TIM1, TIM_IT_CC1 );
 capture = TIM_GetCapture1(TIM3);
 if(cc1_sig)
 {
TIM_SetCompare1(TIM1, capture + 480 );
cc1_sig =0;
 }
 else
 {
TIM_SetCompare1(TIM1, capture + 1920 );
cc1_sig =1;
 }
 
}



}

这个是2KHZ的PWM，占空比是20%，TIM_SetCompare1(TIM1, capture + 480 );我问中断里这个地方是不是高电平的状态，TIM_SetCompare1(TIM1, capture + 1920 );是不是低电平的状态，谢谢

正点原子

1,PWM2模式有什么特点?请找资料回答.
2,进入中断,是什么条件?
3,当cnt>ccrx的时候,IO是什么电平?小于的时候,又是什么情况?(根据问题1回答.)

能回答以上3个问题,就知道是高电平还是低电平了.

另外,不想动脑子的话,  就直接仿真,用万用表测量