//這是hc_sr04.h文件
#include "hc_sr04.h"
#include "stm32f10x.h"
#include "delay.h"
#include "usart.h"
//記錄定時器溢出次數(shù)
u16 overcount=0;
//設(shè)置中斷優(yōu)先級
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);
}
//初始化模塊的GPIO以及初始化定時器TIM2
void HC_SR04_Init(void)
{
//定義結(jié)構(gòu)體
GPIO_InitTypeDef GPIO_InitStructer;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructer;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
//TRIG觸發(fā)信號 PA.8
GPIO_InitStructer.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_Out_PP; //推挽輸出
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; //推挽輸出
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_6;
GPIO_Init(GPIOB, &GPIO_InitStructer);
//ECOH回響信號 PA.9
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空輸入
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_9;
GPIO_Init(GPIOB, & GPIO_InitStructer);
GPIO_InitStructer.GPIO_Mode = GPIO_Mode_IN_FLOATING; //浮空輸入
GPIO_InitStructer.GPIO_Pin = GPIO_Pin_7;
GPIO_Init(GPIOB, & GPIO_InitStructer);
//定時器TIM2初始化
TIM_DeInit(TIM2);
TIM_TimeBaseInitStructer.TIM_Period = 1000-1; //定時周期為1000
TIM_TimeBaseInitStructer.TIM_Prescaler = 72-1; //分頻系數(shù)72
TIM_TimeBaseInitStructer.TIM_ClockDivision = TIM_CKD_DIV1; //不分頻
TIM_TimeBaseInitStructer.TIM_CounterMode = TIM_CounterMode_Up;//向上計數(shù)
TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStructer);
//開啟更新中斷
TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
//中斷參數(shù)設(shè)置
NVIC_Config();
//關(guān)閉定時器使能
TIM_Cmd(TIM2,DISABLE);
}
float Senor_Using(void)
{
float length=0,sum=0;
u16 tim;
u16 i=0;
/*測5次數(shù)據(jù)計算一次平均值*/
while(i!=5)
{
PBout(8) = 1; //拉高信號，作為觸發(fā)信號
delay_us(20); //高電平信號超過10us
PBout(8) = 0;
//等待回響信號
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_9)==RESET);
TIM_Cmd(TIM2,ENABLE); //回響信號到來，開啟定時器計數(shù)
i += 1; //每收到一次回響信號+1，收到5次就計算均值
//回響信號消失
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_9)==SET);
TIM_Cmd(TIM2,DISABLE); //關(guān)閉定時器
tim = TIM_GetCounter(TIM2); //獲取計TIM2數(shù)寄存器中的計數(shù)值，一邊計算回響信號時間
length=(tim+overcount*1000)/58.0; //通過回響信號計算距離
sum = length+sum;
TIM2->CNT = 0; //將TIM2計數(shù)寄存器的計數(shù)值清零
overcount = 0; //中斷溢出次數(shù)清零
delay_ms(10);
}
length = sum/5;
return length; //距離作為函數(shù)返回值
}
float Senor_Using0(void)
{
float length=0,sum=0;
u16 tim;
u16 i=0;
/*測5次數(shù)據(jù)計算一次平均值*/
while(i!=5)
{
PBout(6) = 1; //拉高信號，作為觸發(fā)信號
delay_us(20); //高電平信號超過10us
PBout(6) = 0;
//等待回響信號
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7)==RESET);
TIM_Cmd(TIM2,ENABLE); //回響信號到來，開啟定時器計數(shù)
i += 1; //每收到一次回響信號+1，收到5次就計算均值
//回響信號消失
while(GPIO_ReadInputDataBit(GPIOB,GPIO_Pin_7)==SET);
TIM_Cmd(TIM2,DISABLE); //關(guān)閉定時器
tim = TIM_GetCounter(TIM2); //獲取計TIM2數(shù)寄存器中的計數(shù)值，一邊計算回響信號時間
length=(tim+overcount*1000)/58.0; //通過回響信號計算距離
sum = length+sum;
TIM2->CNT = 0; //將TIM2計數(shù)寄存器的計數(shù)值清零
overcount = 0; //中斷溢出次數(shù)清零
delay_ms(10);
}
length = sum/5;
return length; //距離作為函數(shù)返回值
}
//中斷，當回響信號很長是，計數(shù)值溢出后重復(fù)計數(shù)，用中斷來保存溢出次數(shù)
void TIM2_IRQHandler(void)
{
if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
{
//清除中斷標志
TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
overcount++;
}
}
我的測試模塊為：US-100帶溫度補償（減少溫度對測量結(jié)果的影響）
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