STM32 輸入捕獲

woshizmxin 2013-09-30

展開全文

01  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //時鐘配置
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; //通道選擇
16  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿觸發(fā)
17  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //管腳與寄存器對應(yīng)關(guān)系
18  TIM_ICInitStructure.TIM_ICPSC_DIV1;//輸入預(yù)分頻，意思是控制在多少個輸入周期做一個捕獲，如果輸入的信號頻率沒有變，測得的周期也不會變，比如選擇四分頻，則沒四個輸入周期做一次捕獲，這昂再輸入信號不頻繁的情況下，可以減少軟件被不斷中斷的次數(shù)
19
20  TIM_ICInitStructure.TIM_ICFiter = 0x0; //濾波設(shè)置，經(jīng)歷幾個周期跳變認(rèn)定波形穩(wěn)定0x0-0xf;
21  TIM_PWMIConfig(TIM3, &TIM_ICInitStructure); //根據(jù)參數(shù)配置TIM外設(shè)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）：若想改變測量的PWM頻率范圍，可將TIM時鐘頻率做分頻處理
45
46  TIM_TimeBaseStructure.TIM_Period = 0xFFFF;     //周期0～FFFF
47  TIM_TimeBaseStructure.TIM_Prescaler = 5;       //時鐘分頻，分頻數(shù)為5+1即6分頻
48  TIM_TimeBaseStructure.TIM_ClockDivision = 0;   //時鐘分割
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）：定時器TIM的倍頻器X1或X2。在APB分頻為1時，倍頻值為1，否則為2