ds18b20.txt

本程序采用AVR单片机实现对温度传感器DS18B20的控制

*----------------------------------------------------------
PC3 采 集 信 号
LED数码管，B口段，D口位，PC3为单总线数据口
  罗 一 鸣
v1.1
修改时间：6月4日
修改内容：显示10进制，温度为0.1度阶梯
-----------------------------------------------------------*/
#include <iom8v.h> 
#include <macros.h> 

/*-----显示控制全局变量------*/
const char DispCode[]={0x3f,0x06,0x5b,0x4F,0x66,0x6d,0x7d,0x07,0x7f,0x6f,
0x77,0x7C,0x39,0x5E,0x79,0x71,0x80,0x00,0x40}; //数码管译码表

const char DispBit[] = {0b11101111,0b11011111,0b10111111,0b01111111};

/*常规延时*/
void delay(void)
{
  unsigned char i;
  for(i=0;i<0xff;i++)
  {}
}

void delay_time(unsigned int time)
{ 
  unsigned int i;
  for(i=0;i<time;i++) 
  {}
}

/*显示函数*/
void display(unsigned char des[4])
{
PORTB=DispCode[des[0]];//显示小数位
PORTD=DispBit[0];
delay_time(200);
PORTB=DispCode[des[1]]+(1<<7);//显示小数点
PORTD=DispBit[1];
delay_time(200);
PORTB=DispCode[des[2]];
PORTD=DispBit[2];
delay_time(200); 
PORTB=DispCode[des[3]];
PORTD=DispBit[3];
delay_time(200);
PORTB=0x00;
}

/* 十 六 进 制 显 示 调 整 ，供 显 示 十 六 进 制 使 用 */
void dis_hex(unsigned int num,unsigned char num_hex[4])
{
num_hex[0]=num&0xf;
num_hex[1]=(num>>4)&0xf;
num_hex[2]=(num>>8)&0xf;
num_hex[3]=(num>>12)&0xf;
}

void dis_dec(unsigned int temp_num,unsigned char num_dec[4])
{
signed char temp;
temp=(char)(temp_num>>4); 
num_dec[3]=temp/100;
num_dec[0]=temp%100;
if ((temp>>15)==1)
  {num_dec[3]=18;}
num_dec[2]=num_dec[0]/10;
num_dec[1]=num_dec[0]%10;
temp=((char)(temp_num)&0xf)*6/10;
num_dec[0]=temp;
}

/*  1.5us  延  时  */
void delay_us(unsigned int x)  //1.5us左右 
{ 
     while(x) 
    { 
       x--; 
    } 
} 

/* 18b20 初 始 化 */
void init_18b20() 
{ 
    PORTC|=(1<<3);    
    PORTC&=~(1<<3); 
    delay_us(320);    //480us以上 
    PORTC|=(1<<3); 
    DDRC&=~(1<<3); 
    delay_us(40);     //15~60us 
    while(PINC&(1<<3)) 
    { 
    ;
} 
    DDRC|=(1<<3); 
    PORTC|=(1<<3); 
    delay_us(150);   //60~240us 
} 

/*  18b20 写 操 作 函 数，写 一 个 指 令*/

write_18b20(unsigned char x) 
{    
     unsigned char m; 
    for(m=0;m<8;m++) 
    { 
       PORTC&=~(1<<3); 
       if(x&(1<<m))    //写数据，从低位开始 
       PORTC|=(1<<3); 
       else 
       PORTC&=~(1<<3); 
       delay_us(40);   //15~60us 
       PORTC|=(1<<3); 
    } 
     PORTC|=(1<<3); 
} 

/*  18b20 读 取 操 作*/
unsigned char read_18b20() 
{     
    unsigned char temp,k,n; 
           temp="0"; 
      DDRC|=(1<<3); 
for(n=0;n<8;n++) 
    { 
      PORTC&=~(1<<3); 
      PORTC|=(1<<3); 
      DDRC&=~(1<<3); 
      k=(PINC&(1<<3));    //读数据,从低位开始 
      if(k) 
      temp|=(1<<n); 
      else 
      temp&=~(1<<n); 
      delay_us(40); //60~120us     
      DDRC|=(1<<3); 
    } 
    return (temp); 
}  

/*cahr 转 int*/
unsigned int turn_char_int(unsigned char chl,unsigned char chh)
{
unsigned int ch;
ch=chl+(int)(chh<<8);
return (ch);
}
/*端 口 初 始 化*/
void port_init(void)
{
DDRB=0xff;
DDRD=0xff;
DDRC=0b111111;
PORTB=0x00;
PORTC=0x00;
PORTD=0x00;
}

main()
{
char d[4];
volatile unsigned int pid;

OSCCAL=0x9d;
port_init();
WDTCR = 0x0F;
WDR();
while(1)
{
  unsigned char teml,temh,temp,cyc;
  unsigned int tem;
  init_18b20();
  write_18b20(0xcc);   
  write_18b20(0x44); 
  delay_us(400); 
  init_18b20(); 
  WDR();
  write_18b20(0xcc);  
  write_18b20(0xbe); 
  teml=read_18b20();  
  temh=read_18b20();
  tem=turn_char_int(teml,temh);
  WDR();
  dis_dec(tem,d);
  cyc=0xff;
  while(cyc)
   {
   display(d);
   WDR();
   cyc--;
   }
}

}