01 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟配置
02 RCC_APP2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
03
04 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //GPIO配置
05 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
06 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
07 GPIO_Init(GPIOA, &GPIO_InitStructure);
08
09 NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //NVIC配置
10 NVIC_InitStructure.NVIC_IRQChannePreemptionPriority = 0;
11 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
12 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
13 NVIC_Init(&NVIC_InitStructure);
14
15 TIM_ICInitStructure.TIM_Channel = TIM_Channel_2; //通道选择
16 TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿触发
17 TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //管脚与寄存器对应关系
18 TIM_ICInitStructure.TIM_ICPSC_DIV1;//输入预分频,意思是控制在多少个输入周期做一个捕获,如果输入的信号频率没有变,测得的周期也不会变,比如选择四分频,则没四个输入周期做一次捕获,这昂再输入信号不频繁的情况下,可以减少软件被不断中断的次数
19
20 TIM_ICInitStructure.TIM_ICFiter = 0x0; //滤波设置,经历几个周期跳变认定波形稳定0x0-0xf;
21 TIM_PWMIConfig(TIM3, &TIM_ICInitStructure); //根据参数配置TIM外设信息
22 TIM_SelectInputTrigger(TIM3, TIM_TS_TI2FP2);
23 TIM_SelectMasterSalveMode(TIM3, TIM_MasterSlaveMode_Enable);
24 TIM_Cmd(TIM3, ENABLE);
25 TIM_ITConfig(TIM3, TIM_IT_CC2, ENABLE);
26
27 void TIM3_IRQHandler(void)
28 {
29 TIM_CLearITPendingBit(TIM3, TIM_IT_CC3);
30 IC2Value = TIM_GetCapture2(TIM3);
31 if(IC2Value != 0)
32 {
33 DutyCyle = (TIM_GetCapture1(TIM3) * 100) / IC2Value;
34 Frequency = 72000000 / IC2Value;
35 }
36 else
37 {
38 DutyCycle = 0;
39 Frequency = 0;
40 }
41
42 }
43
44 注(一):若想改变测量的PWM频率范围,可将TIM时钟频率做分频处理
45
46 TIM_TimeBaseStructure.TIM_Period = 0xFFFF; //周期0~FFFF
47 TIM_TimeBaseStructure.TIM_Prescaler = 5; //时钟分频,分频数为5+1即6分频
48 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //时钟分割
49 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//模式
50 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);//基本初始化
51 注注(二):定时器TIM的倍频器X1或X2。在APB分频为1时,倍频值为1,否则为2
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