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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