stm32定时器输入捕获配置步骤及实例笔记

输入捕获的一般配置步骤：

1. 初始化定时器和通道对应IO的时钟。
2. 初始化IO口，模式为输入：GPIO_Init(); GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
3. 初始化定时器ARR，PSC：TIM_TimeBaseInit();
4. 初始化输入捕获通道：TIM_ICInit();
5. 如果要开启捕获中断：TIM_ITConfig(); NVIC_Init();
6. 使能定时器： TIM_Cmd();
7. 编写中断服务函数： TIMx_IRQHandler();
   输入捕获整体初始化函数（含步骤1-6）

//定时器2通道1输入捕获设置
void TIM2_Cap_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
TIM_ICInitTypeDef TIM2_ICInitStructure;
//使能相应时钟 对应步骤1
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //使能TIM2时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIO时钟
//初始化IO口 对应步骤2
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
GPIO_Init(GPIOA, &GPIO_InitStructure); //PA0初始化成下拉输入模式
GPIO_ResetBits(GPIOA,GPIO_Pin_0); //将PA0设置为高电平
//初始化定时器2的ARR，PSC 对应步骤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);
//初始化输入捕获通道（输入捕获参数） 对应步骤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);
//初始化中断设置 对应步骤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);
//开启定时器相应中断（此处为更新中断和捕获中断） 对应步骤5
TIM_ITConfig(TIM2,TIM_IT_Update|TIM_IT_CC1,ENABLE);
//使能定时器2 对应步骤6
TIM_Cmd(TIM2,ENABLE );
}

注：GPIO作为输入端口时可以不需要设置speed（串口传输速率）
输入捕获中断服务函数（含步骤7）
u8 TIM2CH1_CAPTURE_STA=0; //输入捕获状态
u16 TIM2CH1_CAPTURE_VAL; //输入捕获值
void TIM2_IRQHandler(void)
{ if((TIM2CH1_CAPTURE_STA&0X80)==0) //还未成功捕获
{ if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET)
{ if(TIM2CH1_CAPTURE_STA&0X40) //已经捕获到高电平
{ if((TIM2CH1_CAPTURE_STA&0X3F)==0X3F) //高电平太长了
{
TIM2CH1_CAPTURE_STA|=0X80; //标记成功捕获了一次
TIM2CH1_CAPTURE_VAL=0XFFFF;
}else TIM2CH1_CAPTURE_STA++;
}
}
if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET) //发生捕获事件
{
if(TIM2CH1_CAPTURE_STA&0X40) //捕获到一个下降沿
{
TIM2CH1_CAPTURE_STA|=0X80;
TIM2CH1_CAPTURE_VAL=TIM_GetCapture1(TIM2);
TIM_OC1PolarityConfig(TIM2,TIM_ICPolarity_Rising); //设置为上升沿捕获
}
else //还未开始，第一次捕获上升沿
{
TIM2CH1_CAPTURE_STA=0; //清空
TIM2CH1_CAPTURE_VAL=0;
TIM_SetCounter(TIM2,0);
TIM2CH1_CAPTURE_STA|=0X40; //标记捕获到了上升沿
TIM_OC1PolarityConfig(TIM2,TIM_ICPolarity_Falling); //设置为下降沿捕获
}
}
}
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1|TIM_IT_Update); //清除中断标志位
}

extern u8 TIM2CH1_CAPTURE_STA; //输入捕获状态
extern u16 TIM2CH1_CAPTURE_VAL; //输入捕获值
int main(void)
{
u32 temp=0;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //中断优先级分组
delay_init(); //初始化延时
uart_init(9600); //波特率设置为9600
TIM2_Cap_Init(0XFFFF,72-1); //以1MHz的频率计数
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) //成功捕获到了一次高电平
{
temp=TIM2CH1_CAPTURE_STA&0X3F;
temp*=65536; //溢出时间总和
temp+=TIM2CH1_CAPTURE_VAL; //总的高电平时间
printf(“HIGH:%d us\r\n”,temp); //打印
TIM2CH1_CAPTURE_STA=0; //开始下一次捕获
}
}
}