stm32驱动超声波模块

#define HCSR04_PORT GPIOB
#define HCSR04_CLK RCC_APB2Periph_GPIOB
#define HCSR04_TRIG GPIO_Pin_8
#define HCSR04_ECHO GPIO_Pin_9
#define TRIG_Send(n) do{ \
if(n == 0) \
GPIO_ResetBits(HCSR04_PORT,HCSR04_TRIG);\
else if(n == 1) \
GPIO_SetBits(HCSR04_PORT,HCSR04_TRIG); \
}while(0)

#define ECHO_Reci GPIO_ReadInputDataBit(GPIOB,HCSR04_ECHO)

void UltrasonicInit(void)
{

GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(HCSR04_CLK, ENABLE);

//IO初始化
GPIO_InitStructure.GPIO_Pin = HCSR04_TRIG; //发送电平引脚
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; //返回电平引脚
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
GPIO_ResetBits(HCSR04_PORT,HCSR04_ECHO);

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; //生成用于定时器设置的结构体
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE); //使能对应RCC时钟

//配置定时器基础结构体
TIM_DeInit(TIM6);
TIM_TimeBaseStructure.TIM_Period = (1000-1); //设置在下一个更新事件装入活动的自动重装载寄存器周期的值计数到1000为1ms
TIM_TimeBaseStructure.TIM_Prescaler =(72-1); //设置用来作为TIMx时钟频率除数的预分频值 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(TIM6, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

TIM_ClearFlag(TIM6, TIM_FLAG_Update); //清除更新中断，免得一打开中断立即产生中断
TIM_ITConfig(TIM6,TIM_IT_Update,ENABLE); //打开定时器更新中断


NVIC_InitTypeDef NVIC_InitStructure;

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = TIM6_IRQn; //选择串口1中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //抢占式中断优先级设置为1
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //响应式中断优先级设置为1
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //使能中断
NVIC_Init(&NVIC_InitStructure);

TIM_Cmd(TIM6,DISABLE);
}

//定时器6中断服务程序
u32 msHcCount = 0;
void TIM6_IRQHandler(void) //TIM6中断
{
if (TIM_GetITStatus(TIM6, TIM_IT_Update) != RESET) //检查TIM3更新中断发生与否
{
TIM_ClearITPendingBit(TIM6, TIM_IT_Update); //清除TIMx更新中断标志
msHcCount++;
}
}

static void OpenTimerForHc() //打开定时器
{
TIM_SetCounter(TIM6,0); //清除计数
msHcCount = 0;
TIM_Cmd(TIM6, ENABLE); //使能TIMx外设
}

static void CloseTimerForHc() //关闭定时器
{
TIM_Cmd(TIM6, DISABLE); //使能TIMx外设
}

//获取定时器时间
u32 GetEchoTimer(void)
{
u32 t = 0;
t = msHcCount*1000; //将MS转换成US
t += TIM_GetCounter(TIM6); //得到总的US
TIM6->CNT = 0; //将TIM6计数寄存器的计数值清零
return t;
}

//一次获取超声波测距数据两次测距之间需要相隔一段时间，隔断回响信号
//为了消除余震的影响，取五次数据的平均值进行加权滤波。
float Hcsr04GetLength(void )
{

u32 t = 0;
int i = 0;
float lengthTemp = 0;
float sum = 0;

while(i!=5)
{
/*发送一个20ms的脉冲*/
TRIG_Send(1);
osDelay(20);
TRIG_Send(0);

while(ECHO_Reci == 0); //等待接收口高电平输出(超声波发出)
OpenTimerForHc(); //打开定时器
while(ECHO_Reci == 1); //等待超声波返回
CloseTimerForHc(); //关闭定时器
t = GetEchoTimer(); //获取时间,分辨率为1US
lengthTemp = ((float)t*17/1000.0);//cm
sum = lengthTemp + sum ;
i = i + 1;
}

lengthTemp = sum/5.0;
return lengthTemp;

}

stm32驱动超声波模块

猜你喜欢