超声波测距数据不能精确测出，怎么解决
#include <reg52.h>
#include <intrins.h>
#include <lcd.h>
#define uchar unsigned char
#define uint unsigned int
sbit key1=P3^0; //设置键
sbit key2=P3^1; //加键
sbit key3=P3^2; //减键
sbit key4=P3^3; //开始键
sbit beep=P2^4;
sbit trig=P1^7;
sbit echo=P1^6;
sbit RS=P2^0;
sbit RW=P2^1;
sbit EN=P2^2;
uchar djshi,djfen=45,djmiao;
uchar r,num,s,i;
uchar distance,t;
bit flag=0;
bit flag1s=0;
uchar code table1[]={"time: 00:00:00 "};
uchar code table2[]={" "};
uchar code table3[13]={'0',};
uchar code table4[]={"xdz："};
uchar cc[4]={0,0,0,0};
void startmodule();
void start();
void count();
void LcdInit() //LCD初始化子程序
{
uchar i;
lcd_writecom(0x38); //开显示
lcd_writecom(0x0c); //开显示不显示光标
lcd_writecom(0x06); //写一个指针加1
lcd_writecom(0x01); //清屏
lcd_writecom(0x80); //设置数据指针起点
for(i=0;i<16;i++)
{
lcd_writedate(table1[i]);
}
}
void Timer0Init(void) //
{
TMOD |= 0x01; //使用定时器T0的模式1 定时器T1的模式1
TL0 = 15536%256; //设置定时0初值
TH0 = 15536/256; //设置定时0初值
TR0 = 1; //定时器0开始计时
ET0=1;
EA=1;
}
void Timer1Init(void) //
{
TMOD |= 0x10; //使用定时器T0的模式1 定时器T1的模式1
TL1 = 0; //设置定时0初值
TH1 = 0; //设置定时0初值
TF1=0;
TR1 = 1; //定时器0开始计时
ET1=1;
EA=1;
}
void Delay1ms(uint n)
{
uint x,y;
for(x=n;x>0;x--)
for(y=110;y>0;y--);
}
void write_sfm(uchar add,uchar date)
{
lcd_writecom(0x80+add);
lcd_writedate(date/10+0x30);
lcd_writedate(date%10+0x30);
lcd_writecom(0x80+add+1);
}
void keyscan()
{
if(key1==0)
{
Delay1ms(5);
if(key1==0)
{
num++;
TR0=0;
while(!key1);
if(num==1)
{
lcd_writecom(0x0f);
lcd_writecom(0x8D);
}
if(num==2)
{
lcd_writecom(0x8A);
}
if(num==3)
{
lcd_writecom(0x87);
}
if(num==4)
{
num=0;
}
}
}
if(num==1)
{
if(key2==0)
{
Delay1ms(5);
if(key2==0)
{
djmiao++;
while(!key2);
if(djmiao==60)
djmiao=0;
lcd_writecom(0x8c);
lcd_writedate(djmiao/10+0x30);
lcd_writedate(djmiao%10+0x30);
lcd_writecom(0x8D);
}
}
if(key3==0)
{
Delay1ms(5);
if(key3==0)
{
djmiao--;
while(!key3);
if(djmiao==255)
djmiao=59;
lcd_writecom(0x8c);
lcd_writedate(djmiao/10+0x30);
lcd_writedate(djmiao%10+0x30);
lcd_writecom(0x8D);
}
}
}
if(num==2)
{
if(key2==0)
{
Delay1ms(5);
if(key2==0)
{
djfen++;
while(!key2);
if(djfen==60)
djfen=0;
lcd_writecom(0x89);
lcd_writedate(djfen/10+0x30);
lcd_writedate(djfen%10+0x30);
lcd_writecom(0x8A);
}
}
if(key3==0)
{
Delay1ms(5);
if(key3==0)
{
djfen--;
while(!key3);
if(djfen==255)
djfen=59;
lcd_writecom(0x89);
lcd_writedate(djfen/10+0x30);
lcd_writedate(djfen%10+0x30);
lcd_writecom(0x8A);
}
}
}
if(num==3)
{
if(key2==0)
{
Delay1ms(5);
if(key2==0)
{
djshi++;
while(!key2);
if(djshi==24)
djshi=0;
lcd_writecom(0x86);
lcd_writedate(djshi/10+0x30);
lcd_writedate(djshi%10+0x30);
lcd_writecom(0x87);
}
}
if(key3==0)
{
Delay1ms(5);
if(key3==0)
{
djshi--;
while(!key3);
if(djshi==255)
djshi=23;
lcd_writecom(0x86);
lcd_writedate(djshi/10+0x30);
lcd_writedate(djshi%10+0x30);
lcd_writecom(0x87);
}
}
}
if(key4==0)
{
Delay1ms(5);
if(key4==0)
{
TR0=1;
lcd_writecom(0x0c);
}
}
}
void fmq()
{
beep=1;
Delay1ms(5);
beep=0;
Delay1ms(5);
}
void main()
{
LcdInit();
Timer0Init();
Timer1Init();
trig=0;
while(1)
{
if(flag1s)
{
flag1s=0;
startmodule();
start();
count();
}
keyscan();
if(djshi==0 && djfen==0 &&djmiao==0) //倒计时时间到
{
TR0=0; //停止计时
fmq();
}
}
}
void Timer0() interrupt 1
{
TL0 = 15536%256; //设置定时初值
TH0 = 15536/256; //设置定时初值
r++;
if(r==20)
{
r=0;
djmiao--;
if(djmiao==255)
{
djmiao=59;
djfen--;
if(djfen==255)
{
djfen=59;
djshi--;
if(djshi==255)
{
djshi=0;
}
if(djshi==0)
djfen=59;
if(djfen==0&djshi==0)
djfen=0;
write_sfm(6,djshi);
}
write_sfm(9,djfen);
}
write_sfm(12,djmiao);
flag1s=1;
}
}
void Timer1() interrupt 3
{
flag=1;
}
void startmodule()
{
trig=1;
_nop_(); _nop_(); _nop_(); _nop_();
_nop_(); _nop_(); _nop_(); _nop_();
_nop_(); _nop_(); _nop_(); _nop_();
_nop_(); _nop_(); _nop_(); _nop_();
_nop_(); _nop_(); _nop_(); _nop_();
_nop_(); _nop_(); _nop_(); _nop_();
trig=0;
}
void start()
{
while(!echo); //当Echo为零时等待
TR1=1; //开启
while(echo); //当Echo为1计数并等待
TR1=0; //关闭
}
void count()
{
t=TH1256+TL1;
TH1=15546;
TL1=0;
distance=t/58.0;
cc[0]=distance/100%10;
cc[1]=distance/10%10;
cc[2]=distance/1%10;
cc[3]=distance1%10;
lcd_writechar(1, 1, table3[cc[0]]);
lcd_writechar(2, 1, table3[cc[1]]);
lcd_writechar(3, 1, table3[cc[2]]);
lcd_writechar(4, 1, table3[cc[3]]);
}
