181818.c

本程序主要内容18b20+s52+uart单点测温详细c51程序

#include<reg52.h>
#include <intrins.h>
sbit DQ=P3^3;
unsigned char c[2];
unsigned char x,y;
displaycode[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xC6,0xA1};//0,1,2,3,4,5,6,7,8,9
unsigned char t[2]={0};
sbit P2_1=P2^1;
sbit P2_0=P2^0;
sbit P2_2=P2^2;
sbit P2_3=P2^3;
sbit P2_4=P2^4;
sbit P2_5=P2^5;
void delayms(unsigned int t)    //1ms的延时子程序
{
 unsigned int i,j;
 for(i=0;i<t;i++)
  for(j=0;j<120;j++) ;
   }

void delay(unsigned char time)
{while(--time);
}
bit ow_reset(void)
{
 bit presence;
 DQ=0;
 delay(255);//515us
 DQ=1;
 delay(30);//65us
 presence=DQ;
 delay(100);//205us
 return(presence);
 }

void write_byte(unsigned char val)
{
 unsigned char i;
 for(i=8;i>0;i--)
 {DQ=0;
  delay(2);//9us
  DQ=val&0x01;
  delay(20);//45us
  DQ=1;
  val=val/2;
 }
}

unsigned char Read_byte(void)
{
 unsigned char i;
 unsigned char value=0;
 for(i=8;i>0;i--)
  {
  value>>=1;
  DQ=0;
  delay(2);//9us
  DQ=1;
  if(DQ) value|=0x80;           
  delay(20);//45us
  }
return(value);
 }


void tem()
{  if(DQ==0);
   while(ow_reset()); 
   write_byte(0xcc);
   write_byte(0xbe);
   c[0]=Read_byte();
   c[1]=Read_byte();
   x=c[0];
   y=c[1]; 
   x=x>>4;
   x=x&0x0f;
   y=y<<4;
   y=y&0xf0;
   x=x|y;
   t[1]=x/10;
   t[0]=x%10;
   SBUF=x;
   while(TI==0);
   TI=0;
   while(ow_reset()); 
   write_byte(0xcc);
   write_byte(0x44);
}
void display()
 { 
   P2=0xff;
   P2_1=0;
   P0=displaycode[t[1]]; 
   delayms(1);
   P2_1=1;
   P2_3=0;
   P0=displaycode[t[0]];
   delayms(1);
   P2_3=1;
}
void main(void) 
{ 
  TMOD=0x21; 
  TH0=0xA1;
  TL0=0x12; 
  ET0=1; 
  EA=1;
  TH1=0xfd;
  TL1=0xfd;
  SCON=0x50;
  TR1=1;
  while(ow_reset());
  write_byte(0xcc);
  write_byte(0x44);
  TR0=1; 
  while(1);
} 
void t0(void) interrupt 1 using 0 
{ TR0=0;
  TH0=0xA1;
  TL0=0x12;
  tem(); 
  display();
  TR0=1;
}