基于89C52单片机的HC-SR04超声波测距系统程序

#include

#include

#define uint unsigned int

#define uchar unsigned char

sbit DU=P2^6;

sbit WE=P2^7;

sbit RS=P1^0;

sbit RW=P1^1;

sbit EN=P2^5;

sbit RX=P3^2;

sbit TX=P1^5;

uint time=0;

unsigned long S=0;

bit flag=0;

uchar disdat[]={0,0,0,0};

void delay(uint xms)

{

    uint x,y;

for(x=xms;x>0;x--)

   for(y=112;y>0;y--);

}

void write_com(uchar com)

{

    RS=0;

RW=0;

P0=com;

delay(5);

EN=1;

delay(5);

EN=0;

}

void write_dat(uchar dat)

{

    RS=1;

RW=0;

P0=dat;

delay(5);

EN=1;

delay(5);

EN=0;

}

void write_1602(uchar add,uchar dat2)

{

    write_com(0x80+0x40+add);

write_dat(dat2);

}

void ZIFU(uchar *ch)

{

    while(*ch!=0)

{

   write_dat(*ch++);

delay(20);

}

}

void init()

{

    DU=0;

WE=0;

EN=0;

write_com(0x38);

delay(2);

write_com(0x0f);

write_com(0x06);

write_com(0x80);

write_com(0x01);

ZIFU("  From JM Xiao");

}

void count()

{

    time=TH0*256+TL0;//计时时间

TH0=0;

TL0=0;

S=time/58;

disdat[0]=S%1000/100;

disdat[1]=S%1000%100/10;

disdat[2]=S%1000%10%10;

write_1602(1,'D');

write_1602(2,'i');

write_1602(3,'s');

write_1602(4,'t');

write_1602(5,'a');

write_1602(6,'n');

write_1602(7,'c');

write_1602(8,'e');

write_1602(9,':');

write_1602(10,disdat[0]+0x30);

write_1602(11,disdat[1]+0x30);

write_1602(12,disdat[2]+0x30);

write_1602(13,'C');

write_1602(14,'M');

}

void start()

{

    TX=1;

_nop_(); _nop_();

_nop_();     _nop_();

_nop_();   _nop_();

_nop_();     _nop_();

_nop_(); _nop_();

_nop_();     _nop_();

_nop_();     _nop_();

_nop_();     _nop_();

    TX=0;

}

void timer0() interrupt 1

{

    flag=1;

}

void main()

{

    delay(400);

init();

TMOD=0x01;

TH0=0;

TL0=0;

EA=1;

ET0=1;

while(1)

{

   start();

while(!RX);

TR0=1;

while(RX);

   TR0=0;

count();

delay(20);

}

}