stm32定時器輸入捕獲配置步驟及實例筆記

輸入捕獲的一般配置步驟：

1. 初始化定時器和通道對應IO的時鐘。
2. 初始化IO口，模式爲輸入：GPIO_Init(); GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
3. 初始化定時器ARR，PSC：TIM_TimeBaseInit();
4. 初始化輸入捕獲通道：TIM_ICInit();
5. 如果要開啓捕獲中斷：TIM_ITConfig(); NVIC_Init();
6. 使能定時器： TIM_Cmd();
7. 編寫中斷服務函數： TIMx_IRQHandler();
   輸入捕獲整體初始化函數（含步驟1-6）

//定時器2通道1輸入捕獲設置
void TIM2_Cap_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
TIM_ICInitTypeDef TIM2_ICInitStructure;
//使能相應時鐘 對應步驟1
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //使能TIM2時鐘
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIO時鐘
//初始化IO口 對應步驟2
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
GPIO_Init(GPIOA, &GPIO_InitStructure); //PA0初始化成下拉輸入模式
GPIO_ResetBits(GPIOA,GPIO_Pin_0); //將PA0設置爲高電平
//初始化定時器2的ARR，PSC 對應步驟3
TIM_TimeBaseStructure.TIM_Period = arr;
TIM_TimeBaseStructure.TIM_Prescaler =psc;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
//初始化輸入捕獲通道（輸入捕獲參數） 對應步驟4
TIM2_ICInitStructure.TIM_Channel = TIM_Channel_1;
TIM2_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM2_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM2_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM2_ICInitStructure.TIM_ICFilter = 0x00;
TIM_ICInit(TIM2, &TIM2_ICInitStructure);
//初始化中斷設置 對應步驟5
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
//開啓定時器相應中斷（此處爲更新中斷和捕獲中斷） 對應步驟5
TIM_ITConfig(TIM2,TIM_IT_Update|TIM_IT_CC1,ENABLE);
//使能定時器2 對應步驟6
TIM_Cmd(TIM2,ENABLE );
}

注：GPIO作爲輸入端口時可以不需要設置speed（串口傳輸速率）
輸入捕獲中斷服務函數（含步驟7）
u8 TIM2CH1_CAPTURE_STA=0; //輸入捕獲狀態
u16 TIM2CH1_CAPTURE_VAL; //輸入捕獲值
void TIM2_IRQHandler(void)
{ if((TIM2CH1_CAPTURE_STA&0X80)==0) //還未成功捕獲
{ if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
{ if(TIM2CH1_CAPTURE_STA&0X40) //已經捕獲到高電平
{ if((TIM2CH1_CAPTURE_STA&0X3F)==0X3F) //高電平太長了
{
TIM2CH1_CAPTURE_STA|=0X80; //標記成功捕獲了一次
TIM2CH1_CAPTURE_VAL=0XFFFF;
}else TIM2CH1_CAPTURE_STA++;
}
}
if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET) //發生捕獲事件
{
if(TIM2CH1_CAPTURE_STA&0X40) //捕獲到一個下降沿
{
TIM2CH1_CAPTURE_STA|=0X80;
TIM2CH1_CAPTURE_VAL=TIM_GetCapture1(TIM2);
TIM_OC1PolarityConfig(TIM2,TIM_ICPolarity_Rising); //設置爲上升沿捕獲
}
else //還未開始，第一次捕獲上升沿
{
TIM2CH1_CAPTURE_STA=0; //清空
TIM2CH1_CAPTURE_VAL=0;
TIM_SetCounter(TIM2,0);
TIM2CH1_CAPTURE_STA|=0X40; //標記捕獲到了上升沿
TIM_OC1PolarityConfig(TIM2,TIM_ICPolarity_Falling); //設置爲下降沿捕獲
}
}
}
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1|TIM_IT_Update); //清除中斷標誌位
}

extern u8 TIM2CH1_CAPTURE_STA; //輸入捕獲狀態
extern u16 TIM2CH1_CAPTURE_VAL; //輸入捕獲值
int main(void)
{
u32 temp=0;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //中斷優先級分組
delay_init(); //初始化延時
uart_init(9600); //波特率設置爲9600
TIM2_Cap_Init(0XFFFF,72-1); //以1MHz的頻率計數
while(1)
{
delay_ms(10);
TIM_SetCompare1(TIM1,TIM_GetCapture1(TIM1)+1);
if(TIM_GetCapture1(TIM1)==300)TIM_SetCompare1(TIM1,0);
if(TIM2CH1_CAPTURE_STA&0X80) //成功捕獲到了一次高電平
{
temp=TIM2CH1_CAPTURE_STA&0X3F;
temp*=65536; //溢出時間總和
temp+=TIM2CH1_CAPTURE_VAL; //總的高電平時間
printf(“HIGH:%d us\r\n”,temp); //打印
TIM2CH1_CAPTURE_STA=0; //開始下一次捕獲
}
}
}