测距模块程序.c

keilC平台下的单片机超声测距程序

#include <reg51.h>
#include <stdio.h>

#define uchar unsigned char;
#define uint unsigned int; 
#define C=340;


//D1--D4:四位数码管COM端，在本例中为共阴极；DP：小数位。
sbit D1=P1^7;
sbit D2=P1^6;
sbit D3=P1^5;
sbit D4=P1^4;
sbit DP=P0^7;
sbit BLNH=P1^1;
sbit BLNK=P1^2;


sbit INIT=P1^0;
bit flag;

float t,s;

uchar xm0,xm1,xm2,xm3,buffer[4];
uchar code TABLE[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
uint i;



void Delay(i)
{
    unsigned int j;
	while(i--)
	{
		for(j=0;j<125;j++)
		{;}
	}
	
}

void timeToBuffer()      //转换段码功能模块
{
 xm0=((int)s)/100;
 xm1=((int)(((int)(s*10))/100))%10;
 xm2=((int)s)%10;
 xm3=((int)(s*10))%10;
 buffer[3]=TABLE[xm3];
 buffer[2]=TABLE[xm2];
 buffer[1]=TABLE[xm1];
 buffer[0]=TABLE[xm0];
	P0=buffer[0];
	D1=0;
	Delay(1);
	D1=1;

	P0=buffer[1];
	D2=0;
	Delay(1);
	D2=1;

	P0=buffer[2];
	D3=0;
	DP=1;
	Delay(1);
	D3=1;

	P0=buffer[3];
	D4=0;
	Delay(1);
	D4=1;
}

time0()interrupt 3 using 1   //p1.0口发送脉冲
{
INIT=0;
TR0=0;
TH0=0;
TL0=0;

Delay(5);

INIT=1;
TR0=1;
TH1=(65536-30000)/256;
TL1=(65536-30000)%256;
}

void service_echo()interrupt 0 using 2    //回波，外部中断
{
int y;
TR0=0;
t=TH0;
t=t*256+TL0;
t=(t-16)*4.5/420000+16*8.5/420000;
s=t*34000/2;
TH0=0;
TL0=0;
TR0=1;
for(y=0;y<10;y++)
{
timeToBuffer();
}
}

main()
{
TMOD=0x15;
TH1=(65536-30000)/256;
TL1=(65536-30000)%256;
BLNH=0;
BLNK=0;

TH0=0;
TL0=0;
IP=0x01;
EA=1;

EX0=1;
ET1=1;
TR0=1;
TR1=1;
IT0=1;

for(;;)
{
}
}