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/*中断分组初始化*/
NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn; /*TIM5中断*/
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; /*先占优先级2级*/ NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; /*从优先级0级*/ NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; /*IRQ通道被使能*/ NVIC_Init(&NVIC_InitStructure);
TIM_ITConfig(TIM5,TIM_IT_Update|TIM_IT_CC1,ENABLE);/*允许更新中断 ,允许CC1IE捕获中断*/ TIM_Cmd(TIM5,ENABLE); /*使能定时器5*/ }
u8 TIM5CH1_CAPTURE_STA=0; //输入捕获状态 u16 TIM5CH1_CAPTURE_VAL; //输入捕获值 /**
* 定时器5中断服务程序 */
void TIM5_IRQHandler(void) {
if((TIM5CH1_CAPTURE_STA&0X80)==0)//还未成功捕获 {
if(TIM_GetITStatus(TIM5,TIM_IT_Update) != RESET) {
if(TIM5CH1_CAPTURE_STA&0X40)//已经捕获到高电平了 {
if((TIM5CH1_CAPTURE_STA&0X3F)==0X3F)//高电平太长了 {
TIM5CH1_CAPTURE_STA|=0X80;//标记成功捕获了一次 TIM5CH1_CAPTURE_VAL=0XFFFF; }else TIM5CH1_CAPTURE_STA++; } }
if(TIM_GetITStatus(TIM5,TIM_IT_CC1) !=RESET) {
if(TIM5CH1_CAPTURE_STA & 0x40) {
TIM5CH1_CAPTURE_STA|=0X80; //标记成功捕获到一次上升沿 TIM5CH1_CAPTURE_VAL = TIM_GetCounter(TIM5);
TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Rising); //CC1P=0 设置为上升沿捕获 } else
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{
TIM5CH1_CAPTURE_STA=0; //清空 TIM5CH1_CAPTURE_VAL=0;
TIM_SetCounter(TIM5,0);
TIM5CH1_CAPTURE_STA|=0X40; //标记捕获到了上升沿
TIM_OC1PolarityConfig(TIM5,TIM_ICPolarity_Falling); //CC1P=1 设置为下降沿捕获 } } }
TIM_ClearITPendingBit(TIM5,TIM_IT_CC1|TIM_IT_Update); /*清除中断标志位*/ }
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extern u16 TIM5CH1_CAPTURE_VAL; //输入捕获值 int main(void) {
u32 temp=0;
delay_init(); //延时函数初始化
NVIC_Configuration(); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级 uart_init(9600); //串口初始化为9600 LED_Init(); //LED端口初始化
TIM5_Cap_Init(0XFFFF,72-1); //以1Mhz的频率计数 while(1) {
delay_ms(10);
if(TIM5CH1_CAPTURE_STA&0X80)//成功捕获到了一次上升沿 {
temp=TIM5CH1_CAPTURE_STA&0X3F; temp*=65536;//溢出时间总和
temp+=TIM5CH1_CAPTURE_VAL;//得到总的高电平时间 printf(\打印总的高点平时间 TIM5CH1_CAPTURE_STA=0;//开启下一次捕获 } } }
以下笔记始发于观海听涛，原创人Apache，转载请说明
输入捕获作为定时器的一个功能，在工业测速上有很大的应用。STM32的一些定时器具有四个外部通道，可利用一个定时器采集外部四路脉冲频率，节约硬件资源和软件代码
extern u8 TIM5CH1_CAPTURE_STA; //输入捕获状态
如需要测量一个或多个外部方波脉冲频率，频率低于单片机运行频率，可如下操作：（以TIM4为例）
初始化：(省略GPIO配置，将TIM4的四个通道引脚配置为上拉或浮空输入，省略定时器RCC配置，省略中断NVIC配置)
1. void TIM_Configuration(void){ 2. TIM_ICInitTypeDef 3. TIM_ICInitStructure; 4. TIM_TimeBaseInitTypeDef
5. TIM_TimeBaseStructure; // TIM4 时基 6. TIM_DeInit(TIM4);
7. TIM_TimeBaseStructure.TIM_Period = 0xffff; //自动重装值
TIM_TimeBaseStructure.TIM_Prescaler = 719; //预分频值, 使TIMx_CLK=1MHz 8. TIM_TimeBaseStructure.TIM_ClockDivision = 9. TIM_CKD_DIV1; //输入时钟不分频
10. TIM_TimeBaseStructure.TIM_CounterMode = 11. TIM_CounterMode_Up; //向上计数
12. TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //TIM4_TimeBase
13. // TIM_ICInitStructure.TIM_ICMode = TIM_ICMode_ICAP; //输入捕捉方式 14. TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;//| 15. TIM_Channel_2; //输入通道
16. TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //捕捉上升沿 17. TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //捕捉中断 18. TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //捕捉不分频 19. TIM_ICInitStructure.TIM_ICFilter = 0x0; //捕捉输入不滤波 20. TIM_ICInit(TIM4, &TIM_ICInitStructure);
21. TIM_ICInitStructure.TIM_Channel = TIM_Channel_2 ;//| TIM_Channel_2; //输入通道 22. TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //捕捉上升沿 23. TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //捕捉中断 24. TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //捕捉不分频 25. TIM_ICInitStructure.TIM_ICFilter = 0x0; //捕捉输入不滤波 26. TIM_ICInit(TIM4, &TIM_ICInitStructure);
27. TIM_ICInitStructure.TIM_Channel = TIM_Channel_3 ;//| TIM_Channel_2; //输入通道 28. TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //捕捉上升沿 29. TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //捕捉中断
30. TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //捕捉不分频 31. TIM_ICInitStructure.TIM_ICFilter = 0x0; //捕捉输入不滤波 32. TIM_ICInit(TIM4, &TIM_ICInitStructure);
33. TIM_ICInitStructure.TIM_Channel = TIM_Channel_4 ;//| TIM_Channel_2; //输入通道 34. TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //捕捉上升沿 35. TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //捕捉中断 36. TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //捕捉不分频 37. TIM_ICInitStructure.TIM_ICFilter = 0x0; //捕捉输入不滤波 38. TIM_ICInit(TIM4, &TIM_ICInitStructure); 39. /* TIM enable counter */ 40. TIM_Cmd(TIM4, ENABLE);
41. /* Enable the CC2 Interrupt Request */ 42. TIM_ITConfig(TIM4, 43. TIM_IT_CC1, ENABLE);
44. TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE); 45. TIM_ITConfig(TIM4, TIM_IT_CC3, ENABLE); 46. TIM_ITConfig(TIM4, TIM_IT_CC4, ENABLE);
复制代码 其中：
TIM_TimeBaseStructure.TIM_Period = 0xffff;为自动重装值，与普通单片机一样
TIM_TimeBaseStructure.TIM_Prescaler = 719; 预分频值, 使TIMx_CLK=100KHz ，系统时钟运行于72M时720分频，定时器运行于100KHZ，即10us每分度
TIM_ICInitStructure.TIM_ICMode = TIM_ICMode_ICAP; 此句选择定时器为输入捕获模式，但在我的库函数下未定义，所以注释掉，未影响程序执行
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;配置通道1 TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;上升沿捕获 TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;捕获中断 TIM_ICInitStructure.TIM_ICFilter = 0x0;不滤波 TIM_ICInit(TIM4, &TIM_ICInitStructure);将配置应用
以上每个通道都需要将整个配置再写一遍，使用与'|'是无效的。 TIM_Cmd(TIM4, ENABLE);使能定时器4 TIM_ITConfig(TIM4, TIM_IT_CC1, ENABLE); TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE); TIM_ITConfig(TIM4, TIM_IT_CC3, ENABLE);
TIM_ITConfig(TIM4, TIM_IT_CC4, ENABLE);打开四个通道的捕获中断 以上将TIM配置完成，下面是中断内代码：
1. void
2. TIM4_IRQHandler(void){ //频率缓冲区计数 3. static u16 this_time_CH1 = 0; 4. static u16
5. last_time_CH1 = 0;
6. static u8 capture_number_CH1 = 0; 7. vu16 8. tmp16_CH1;
9. static u16 this_time_CH2 = 0; 10. static u16 last_time_CH2 = 0; 11. static u8 capture_number_CH2 = 0; 12. vu16 tmp16_CH2;
13. static u16 this_time_CH3 = 0; 14. static u16 last_time_CH3 = 0; 15. static u8 capture_number_CH3 = 0; 16. vu16 tmp16_CH3;
17. static u16 this_time_CH4 = 0; 18. static u16 last_time_CH4 = 0; 19. static u8 capture_number_CH4 = 0; 20. vu16 tmp16_CH4;
21. if(TIM_GetITStatus(TIM4, TIM_IT_CC1) == SET) { 22. TIM_ClearITPendingBit(TIM4, TIM_IT_CC1);
23. if(capture_number_CH1 == 0) { 24. capture_number_CH1 = 1; 25. last_time_CH1 = TIM_GetCapture1(TIM4); }
26. else if(capture_number_CH1 == 1) 27. capture_number_CH1 = 0;
28. this_time_CH1 = TIM_GetCapture1(TIM4); 29. if(this_time_CH1 > last_time_CH1) {
30. tmp16_CH1 = (this_time_CH1 - last_time_CH1); } else { 31. tmp16_CH1 = ((0xFFFF - last_time_CH1) + this_time_CH1); } //TIM2 32. counter clock = 1MHz