#define HCSR04_PORT GPIOA
#define HCSR04_CLK RCC_APB2Periph_GPIOA
#define HCSR04_TRIG GPIO_Pin_4
#define HCSR04_ECHO GPIO_Pin_0
#define TRIG_Send PAout(4)
#define ECHO_Reci PAin(0)
u16 msHcCount = 0;//整型变量用于ms计数
extern u16 TIM2CH1_CAPTURE_STA,TIM2CH1_CAPTURE_VAL;
void Hcsr04_Init(u32 arr,u32 psc)
{
TIM_ICInitTypeDef TIM_ICInitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(HCSR04_CLK, ENABLE);
//IO初始化
GPIO_InitStructure.GPIO_Pin =HCSR04_TRIG; //TRIG输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//推挽输出
GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
GPIO_ResetBits(HCSR04_PORT,HCSR04_TRIG);
GPIO_InitStructure.GPIO_Pin = HCSR04_ECHO; //ECHO输入
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;//下拉输入
GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
//初始化定时器TIM2
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //使能RCC时钟
TIM_DeInit(TIM2);
TIM_TimeBaseStructure.TIM_Period = arr; //计数周期为1000/1ms
TIM_TimeBaseStructure.TIM_Prescaler =psc; //1M的计数频率 1US计数
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
// TIM_ICStructInit(&TIM_ICInitStructure);//设置缺省值
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //上升沿捕获
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //映射到TI1上
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //配置输入分配
TIM_ICInitStructure.TIM_ICFilter = 0x00; //IC2F=0000 配置输入滤波器 0 不滤波
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; //IC1映射到TI1
TIM_ICInit(TIM2, &TIM_ICInitStructure);
// TIM_ClearFlag(TIM2, TIM_FLAG_Update); //清除更新中断
TIM_ITConfig(TIM2,TIM_IT_Update|TIM_IT_CC1,ENABLE); //打开定时器更新中断
TIM_CtrlPWMOutputs(TIM2,ENABLE); //主输出使能
Hcsr04_NVIC();
TIM_Cmd(TIM2, ENABLE);
}
void Hcsr04_NVIC(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
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);
}
//TIM2的中断服务函数
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
{
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)//捕获1发送捕获事件
{
if(TIM2CH1_CAPTURE_STA&0X40) //捕获到一个下降沿
{
TIM2CH1_CAPTURE_STA|=0X80; //标记成功捕获到一次上升沿
TIM2CH1_CAPTURE_VAL=TIM_GetCapture1(TIM2);
TIM_OC1PolarityConfig(TIM2,TIM_ICPolarity_Rising); //CC1P=0 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); //CCC1P=1 设置为下降沿捕获
}
}
TIM_ClearITPendingBit(TIM2, TIM_IT_CC1|TIM_IT_Update); //清楚中断标志位
}
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