#include "delay.h"
#include "sys.h"
#include "usart.h"
#include "led.h"
#include "key.h"
/***************************************************
硬件連接
串口1：RX PA10 TX PA9
超聲波：Trig PB11 ECHG PB10
備注：以下代碼非原創(chuàng)，只是經(jīng)過修改適配成STM32F103C8T6
若侵權(quán)，請告知。
***************************************************/
//超聲波硬件接口定義
#define HCSR04_PORT GPIOB
#define HCSR04_CLK RCC_APB2Periph_GPIOB
#define HCSR04_TRIG GPIO_Pin_11
#define HCSR04_ECHO GPIO_Pin_10
//超聲波計數(shù)
u16 msHcCount = 0;
//定時器4設(shè)置
void hcsr04_NVIC()
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
//IO口初始化 及其他初始化
void Hcsr04Init()
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(HCSR04_CLK, ENABLE);
GPIO_InitStructure.GPIO_Pin =HCSR04_TRIG;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
GPIO_ResetBits(HCSR04_PORT,HCSR04_TRIG);
GPIO_InitStructure.GPIO_Pin = HCSR04_ECHO;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(HCSR04_PORT, &GPIO_InitStructure);
GPIO_ResetBits(HCSR04_PORT,HCSR04_ECHO);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
TIM_DeInit(TIM2);
TIM_TimeBaseStructure.TIM_Period = (1000-1);
TIM_TimeBaseStructure.TIM_Prescaler =(72-1);
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
TIM_ClearFlag(TIM4, TIM_FLAG_Update);
TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);
hcsr04_NVIC();
TIM_Cmd(TIM4,DISABLE);
}
//打開定時器4
static void OpenTimerForHc()
{
TIM_SetCounter(TIM4,0);
msHcCount = 0;
TIM_Cmd(TIM4, ENABLE);
}
//關(guān)閉定時器4
static void CloseTimerForHc()
{
TIM_Cmd(TIM4, DISABLE);
}
//定時器4終中斷
void TIM4_IRQHandler(void)
{
if (TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET)
{
TIM_ClearITPendingBit(TIM4, TIM_IT_Update );
msHcCount++;
}
}
//獲取定時器4計數(shù)器值
u32 GetEchoTimer(void)
{
u32 t = 0;
t = msHcCount*1000;
t += TIM_GetCounter(TIM4);
TIM4->CNT = 0;
delay_ms(50);
return t;
}
//通過定時器4計數(shù)器值推算距離
float Hcsr04GetLength(void )
{
u32 t = 0;
int i = 0;
float lengthTemp = 0;
float sum = 0;
while(i!=5)
{
TRIG_Send = 1;
delay_us(20);
TRIG_Send = 0;
while(ECHO_Reci == 0);
OpenTimerForHc();
i = i + 1;
while(ECHO_Reci == 1);
CloseTimerForHc();
t = GetEchoTimer();
lengthTemp = ((float)t/58.0);//cm
sum = lengthTemp + sum ;
}
lengthTemp = sum/5.0;
return lengthTemp;
}
//測試主函數(shù)
int main(void)
{
float length;
delay_init(); //延時函數(shù)初始化
NVIC_Configuration(); //設(shè)置NVIC中斷分組2:2位搶占優(yōu)先級，2位響應(yīng)優(yōu)先級
uart_init(9600); //串口初始化為9600
Hcsr04Init();
printf("大海電子串口測試\r\n");
Hcsr04Init();
printf("超聲波初始化成功!\n");
while(1)
{
length = Hcsr04GetLength();
printf("距離為:%.3fcm\n",length);
delay_ms(1000);
}
}
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