//这是hc_sr04.h文件
#include "hc_sr04.h"
#include "stm32f10x.h"
#include "delay.h"
#include "usart.h"
//记录定时器溢出次数
u16 overcount=0;
//设置中断优先级
void NVIC_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructer;
//NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructer.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructer.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructer.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructer.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructer);
}
//初始化模块的GPIO以及初始化定时器TIM2
void HC_SR04_Init(void)
{
//定义结构体
GPIO_InitTypeDef GPIO_InitStructer;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructer;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
//TRIG触发信号 PA.8
GPIO_InitStructer.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_Out_PP; //推挽输出
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_8;
GPIO_Init(GPIOB, &GPIO_InitStructer);
GPIO_InitStructer.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_Out_PP; //推挽输出
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_6;
GPIO_Init(GPIOB, &GPIO_InitStructer);
//ECOH回响信号 PA.9
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空输入
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_9;
GPIO_Init(GPIOB, & GPIO_InitStructer);
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空输入
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_7;
GPIO_Init(GPIOB, & GPIO_InitStructer);
//定时器TIM2初始化
TIM_DeInit(TIM2);
TIM_TimeBaseInitStructer.TIM_Period = 1000-1; //定时周期为1000
TIM_TimeBaseInitStructer.TIM_Prescaler = 72-1; //分频系数72
TIM_TimeBaseInitStructer.TIM_ClockDivision = TIM_CKD_DIV1; //不分频
TIM_TimeBaseInitStructer.TIM_CounterMode = TIM_CounterMode_Up;//向上计数
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStructer);
//开启更新中断
TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
//中断参数设置
NVIC_Config();
//关闭定时器使能
TIM_Cmd(TIM2,DISABLE);
}
float Senor_Using(void)
{
float length=0,sum=0;
u16 tim;
u16 i=0;
/*测5次数据计算一次平均值*/
while(i!=5)
{
PBout(8) = 1; //拉高信号，作为触发信号
delay_us(20); //高电平信号超过10us
PBout(8) = 0;
//等待回响信号
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_9)==RESET);
TIM_Cmd(TIM2,ENABLE); //回响信号到来，开启定时器计数
i += 1; //每收到一次回响信号+1，收到5次就计算均值
//回响信号消失
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_9)==SET);
TIM_Cmd(TIM2,DISABLE); //关闭定时器
tim = TIM_GetCounter(TIM2); //获取计TIM2数寄存器中的计数值，一边计算回响信号时间
length=(tim+overcount*1000)/58.0; //通过回响信号计算距离
sum = length+sum;
TIM2->CNT = 0; //将TIM2计数寄存器的计数值清零
overcount = 0; //中断溢出次数清零
delay_ms(10);
}
length = sum/5;
return length; //距离作为函数返回值
}
float Senor_Using0(void)
{
float length=0,sum=0;
u16 tim;
u16 i=0;
/*测5次数据计算一次平均值*/
while(i!=5)
{
PBout(6) = 1; //拉高信号，作为触发信号
delay_us(20); //高电平信号超过10us
PBout(6) = 0;
//等待回响信号
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7)==RESET);
TIM_Cmd(TIM2,ENABLE); //回响信号到来，开启定时器计数
i += 1; //每收到一次回响信号+1，收到5次就计算均值
//回响信号消失
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7)==SET);
TIM_Cmd(TIM2,DISABLE); //关闭定时器
tim = TIM_GetCounter(TIM2); //获取计TIM2数寄存器中的计数值，一边计算回响信号时间
length=(tim+overcount*1000)/58.0; //通过回响信号计算距离
sum = length+sum;
TIM2->CNT = 0; //将TIM2计数寄存器的计数值清零
overcount = 0; //中断溢出次数清零
delay_ms(10);
}
length = sum/5;
return length; //距离作为函数返回值
}
//中断，当回响信号很长是，计数值溢出后重复计数，用中断来保存溢出次数
void TIM2_IRQHandler(void)
{
if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
{
//清除中断标志
TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
overcount++;
}
}
我的测试模块为：US-100带温度补偿（减少温度对测量结果的影响）
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