超声波测试

#include <reg51.h>
#include <intrins.h>

typedef  unsigned char     uchar;
typedef  unsigned int     uint;


sbit LS138A = P2^2;
sbit LS138B = P2^3;
sbit LS138C = P2^4;

unsigned int lednum[8]={0};
unsigned char code Disp_Tab[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x40}; 



uchar sta=0;
uchar high=0;
uchar low=0;

int dist=0;

 void delay(unsigned int i)
{
    char j;
    for(i; i > 0; i--)
        for(j = 200; j > 0; j--);
}


void InitUART(void)
{
    TMOD = 0x20;
    SCON = 0x50;

    TH1 = 0xFD;
    TL1 = TH1;

    EA = 1;
    ES = 1;
    TR1 = 1;
}

void SendOneByte(unsigned char c)
{
    SBUF = c;
    while(!TI);
    TI = 0;
}


void main(void)
{

   uint i ;

    InitUART();

    while(1)
    {
     SendOneByte(0x55);
    
     for( i=0; i<8; i++)
     {         
        P0=Disp_Tab[lednum[i]];
        LS138A = i &1;
        LS138B = (i >> 1) &1;
        LS138C = (i >> 2) &1;        
        delay(100);
      }

    
    dist=256*high+low;

    lednum[0]=dist%100000000/100000;
    lednum[1]=dist%10000000/100000;
    lednum[2]=dist%1000000/100000;
    lednum[3]=dist%100000/10000;
    lednum[4]=dist%10000/1000;
    lednum[5]=dist%1000/100;
    lednum[6]=dist%100/10;
    lednum[7]=dist%10;
    

    }
    

}
  
void UARTInterrupt(void) interrupt 4
{
    if(RI)
    {
        RI = 0;
        sta++;
    if(sta==1)    high=SBUF;
    else if(sta==2)    
    {
        low=SBUF;
        sta=0;
    }
    else
        TI = 0;
}

}