PWM输入检测是输入捕获的一个特例，可以测量频率与占空比
与输入捕获不同的是PWM输入模式会将同一个输入信号（TI1或TI2）连接到两个捕获装置（IC1和IC2）。这两个捕获装置一个捕获上升沿一个捕获下降沿。TI1FP1、TI2FP2它们中的一个被选择为触发输入且从模式控制器被配置为复位模式。
注意：只有TI1FP1和TI2FP2连到了从模式控制器，所以PWM输入模式只能使用TIMx_CH1 /TIMx_CH2信号。
1 //Timer4 CH2测周期，CH1测占空比，PB7引脚来输入 2 //这个捕捉的周期的范围是1-65535us，如果需要测更高频率的话更改里面的两种方式： 3 //1,TIM_TimeBaseStructure.TIM_Prescaler =(72-1);更改分配系数调整精度 4 //溢出计数也可以使用 5 void TIM4_CH2_CH1_PB7_PWMInPut_Init(void) 6 { 7 8 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; 9 NVIC_InitTypeDef NVIC_InitStructure; 10 TIM_ICInitTypeDef TIM4_ICInitStructure; 11 GPIO_InitTypeDef GPIO_InitStructure; 12 13 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //Open TIM4 clock 14 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //open gpioB clock 15 16 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //GPIO?? 17 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; 18 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; 19 GPIO_Init(GPIOB, &GPIO_InitStructure); 20 21 TIM_TimeBaseStructure.TIM_Period = 0xffff; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 22 TIM_TimeBaseStructure.TIM_Prescaler =(72-1); //设置用来作为TIMx时钟频率除数的预分频值 23 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim 24 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式 25 TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位 26 27 28 /*配置中断优先级*/ 29 NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn; 30 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; 31 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; 32 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; 33 NVIC_Init(&NVIC_InitStructure); 34 35 TIM4_ICInitStructure.TIM_Channel = TIM_Channel_2; 36 TIM4_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; 37 TIM4_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; 38 TIM4_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; 39 TIM4_ICInitStructure.TIM_ICFilter = 0x0; 40 TIM_PWMIConfig(TIM4, &TIM4_ICInitStructure); //PWM输入配置 41 42 TIM_SelectInputTrigger(TIM4, TIM_TS_TI2FP2); //选择有效输入端 43 TIM_SelectSlaveMode(TIM4, TIM_SlaveMode_Reset); //配置为主从复位模式 44 TIM_SelectMasterSlaveMode(TIM4, TIM_MasterSlaveMode_Enable); 45 TIM_ITConfig(TIM4, TIM_IT_CC2|TIM_IT_Update, ENABLE); //中断配置 46 47 TIM_ClearITPendingBit(TIM4, TIM_IT_CC2|TIM_IT_Update); //清除中断标志位 48 TIM_Cmd(TIM4, ENABLE); 49 }
1 void TIM4_IRQHandler(void) 2 { 3 4 if(TIM_GetITStatus(TIM4,TIM_IT_Update)!=RESET) 5 { 6 // LED1_Toggle(); 7 TIM_ClearITPendingBit(TIM4,TIM_IT_Update); 8 } 9 10 if(TIM_GetITStatus(TIM4,TIM_IT_CC1)!=RESET) 11 { 12 13 TIM_ClearITPendingBit(TIM4,TIM_IT_CC1); 14 } 15 16 if(TIM_GetITStatus(TIM4,TIM_IT_CC2)!=RESET) 17 { 18 19 printf("TIM4 frequency=%d , duty=%d ",(1000/TIM_GetCapture2(TIM4)),(100*TIM_GetCapture1(TIM4)/TIM_GetCapture2(TIM4))); 20 TIM_ClearITPendingBit(TIM4,TIM_IT_CC2); 21 } 22 23 if(TIM_GetITStatus(TIM4,TIM_IT_CC4)!=RESET) 24 { 25 TIM_ClearITPendingBit(TIM4,TIM_IT_CC4); 26 } 27 28 }
注意，如果用CH2测量频率，CH1测量占空比的话，只需要设置CH2，开启CC2中断即可，测量频率的CHX设置为上升沿捕获，
设置函数为： TIM_PWMIConfig(TIM4, &TIM4_ICInitStructure);
而不是TIM_ICInit(TIM4, &TIM4_ICInitStructure);如果选择这个函数初始化的话还需要设置CH1。
同样如果是CH2测量频率的话TIM_TS_TI2FP2，TIM_SelectInputTrigger(TIM4, TIM_TS_TI2FP2); //选择有效输入端
如果CH1测量频率则为TIM_TS_TI1FP1
下面是TIMER3 配置CH1频率，CH2占空比
1 //Timer3 CH1测周期，CH2测占空比，PA6引脚来输入 2 //这个捕捉的周期的范围是1-65535us，如果需要测更高频率的话更改里面的两种方式： 3 //1,TIM_TimeBaseStructure.TIM_Prescaler =(72-1);更改分配系数调整精度 4 //溢出计数也可以使用 5 void TIM3_CH1_CH2_PA6_PWMInPut_Init(void) 6 { 7 8 TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; 9 NVIC_InitTypeDef NVIC_InitStructure; 10 TIM_ICInitTypeDef TIM3_ICInitStructure; 11 GPIO_InitTypeDef GPIO_InitStructure; 12 13 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIOA时钟 14 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟使能 15 16 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; //PA0 清除之前设置 17 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD; //PA0 输入 18 GPIO_Init(GPIOA, &GPIO_InitStructure); 19 GPIO_ResetBits(GPIOA,GPIO_Pin_6); 20 21 TIM_TimeBaseStructure.TIM_Period = 0xffff; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 计数到5000为500ms 22 TIM_TimeBaseStructure.TIM_Prescaler =(72-1); //设置用来作为TIMx时钟频率除数的预分频值 1Mhz的计数频率 23 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim 24 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式 25 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位 26 27 //pwm输入模式ch1配置 28 TIM3_ICInitStructure.TIM_Channel = TIM_Channel_1; //选择输入端 IC1映射到TI1上 29 TIM3_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕获 30 TIM3_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上 //CC1S=01 31 TIM3_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频,不分频 32 TIM3_ICInitStructure.TIM_ICFilter = 0x00;//IC1F=0000 配置输入滤波器 不滤波 33 TIM_PWMIConfig(TIM3, &TIM3_ICInitStructure); //PWM输入配置 34 // TIM_ICInit(TIM3, &TIM3_ICInitStructure); 35 36 // //pwm输入模式ch2配置 37 // TIM3_ICInitStructure.TIM_Channel = TIM_Channel_2; //选择输入端 IC2映射到TI1上 38 // TIM3_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling; //下降沿捕获 39 // TIM3_ICInitStructure.TIM_ICSelection = TIM_ICSelection_IndirectTI; //映射到TI1上 //CC2S=10 40 // TIM3_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分频,不分频 41 // TIM3_ICInitStructure.TIM_ICFilter = 0x00;//IC1F=0000 配置输入滤波器 不滤波 42 // TIM_ICInit(TIM3, &TIM3_ICInitStructure); 43 44 TIM_SelectInputTrigger(TIM3, TIM_TS_TI1FP1); //选择有效输入端 45 TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Reset); //配置为主从复位模式 46 TIM_SelectMasterSlaveMode(TIM3, TIM_MasterSlaveMode_Enable); 47 TIM_ITConfig(TIM3,TIM_IT_Update|TIM_IT_CC1,ENABLE ); //使能指定的TIM3中断,允许更新中断 48 49 NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //TIM3中断 50 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占优先级0级 51 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //从优先级3级 52 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能 53 NVIC_Init(&NVIC_InitStructure); //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器 54 55 TIM_Cmd(TIM3, ENABLE); //使能TIMx外设 56 }
1 void TIM3_IRQHandler(void) 2 { 3 4 if(TIM_GetITStatus(TIM3,TIM_IT_Update)!=RESET) 5 { 6 LED2_Toggle(); 7 TIM_ClearITPendingBit(TIM3,TIM_IT_Update); 8 } 9 10 if(TIM_GetITStatus(TIM3,TIM_IT_CC1)!=RESET) 11 { 12 printf("TIM3 frequency=%d , duty=%d ",(1000/TIM_GetCapture1(TIM3)),(100*TIM_GetCapture2(TIM3)/TIM_GetCapture1(TIM3))); 13 TIM_ClearITPendingBit(TIM3,TIM_IT_CC1); 14 } 15 16 if(TIM_GetITStatus(TIM3,TIM_IT_CC2)!=RESET) 17 { 18 19 TIM_ClearITPendingBit(TIM3,TIM_IT_CC2); 20 } 21 22 23 }