DS18B20测负温度程序

//main.c

#include

#include

#include "18B20.h"

#include"disp.h"

#define uint unsigned int

#define uchar unsigned char

const uchar shu[10]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,

0x82,0xF8,0x80,0x90};

const uchar bshu[3]={0xff,0xf9,0xbf};

//延时函数在4M时延时1ms

void s_1ms(unsigned int ms)

{

unsigned int aa;

for(;ms>=1;ms--)

{

for(aa=0;aa<=800;aa++)

{;}

}

}

void main()

{

uint wendu,xiao,ge,shi,bai;

uchar fh;

DDRA = 0xff;

PORTA = 0xff;

s_1ms(200); //延时200ms

ds1820_reset(); //DS18B20复位

while (1)

{

ds1820_start();

wendu = ds1820_read_temp(); //读取温度数值

fh=ds1820_fh();

if(fh)

{

wendu=~(wendu)+1;

wendu = (wendu * 10)/ 16; //数值处理

wendu = wendu % 1000;

shi= wendu / 100; //显示第2位

wendu = wendu % 100;

ge= wendu / 10; //显示ge位

xiao=wendu % 10; // 显示小数位

display(0,shu[xiao]); //小数位

display(1,shu[ge]&0x7f); //个位

display(2,shu[shi]); //shi

display(3,bshu[2]); //bai位,0不显示

}

else

{

wendu = (wendu * 10) / 16; //数值处理

bai = wendu / 1000; //bai位

wendu = wendu % 1000;

shi= wendu / 100; //显示第2位

wendu = wendu % 100;

ge= wendu / 10; //显示ge位

xiao=wendu % 10; // 显示小数位

display(0,shu[xiao]); //小数位

display(1,shu[ge]&0x7f); //个位

display(2,shu[shi]); //shi

display(3,bshu[bai]); //bai位,0不显示

}

}

}

//18B20.h

#define uchar unsigned char

#define uint unsigned int

//设置成输入

#define DQ_INPUT DDRC &= ~BIT(7)

//设置成输出

#define DQ_OUT DDRC |= BIT(7)

//设置成低电平

#define DQ_LO PORTC &= ~BIT(7)

//设置成高电平

#define DQ_HI PORTC |= BIT(7)

//读出

#define DQ_R PINC & BIT(7)

//中断标志

uchar init_f;

//延时函数

void delay_us(uint ms)

{

uchar tm;

while(ms--)

{

for(tm=0;tm<2;tm++);

}

}

//DS18B20复位

void ds1820_reset(void)

{

uchar i;

//中断保护

init_f = SREG;

//关中断

CLI();

DQ_OUT;

DQ_LO;

delay_us(80); //延时500us

DQ_HI;

DQ_INPUT;

delay_us(10); //延时80us

i = DQ_R;

delay_us(80); //延时500us

if (init_f & 0x80) //恢复中断状态

{

SEI();

}

}

//DS18B20字节读取

uchar ds1820_read_byte(void)

{

uchar i;

uchar value = 0;

//中断保护

init_f = SREG;

//关中断

CLI();

for (i = 8; i != 0; i--) {

value >>= 1;

DQ_OUT;

DQ_LO;

delay_us(2);

DQ_HI;

DQ_INPUT;

if (DQ_R)

{

value|=0x80;

}

delay_us(10); //延时60us

}

if (init_f&&0x80) //恢复中断状态

{

SEI();

}

return(value);

}

//DS18B20字节写入

void ds1820_write_byte(unsigned char value)

{

uchar i;

init_f = SREG;

CLI();

for (i = 8; i > 0; i--)

{

DQ_OUT;

DQ_LO;

if (value & 0x01)

{

DQ_HI;

}

delay_us(10); //延时80us

DQ_HI;

value >>= 1;

}

if (init_f & 0x80)//恢复中断状态

{

SEI();

}

}

//启动ds1820转换

void ds1820_start(void)

{

ds1820_reset();

ds1820_write_byte(0xCC); //勿略ROM

ds1820_write_byte(0x44); //启动转换

}

//读温度

uint ds1820_read_temp(void)

{

uint i,wendu;

uchar buf[2];

ds1820_reset();

ds1820_write_byte(0xCC); //勿略ROM

ds1820_write_byte(0xBE); //读温度

for (i = 0; i < 2; i++)

{

buf[i] = ds1820_read_byte();

}

wendu = (buf[1]<<8)|buf[0];

return wendu;

}

uint ds1820_fh(void) //读正负温度符号

{

uint i,bb;

uchar buf[2];

ds1820_reset();

ds1820_write_byte(0xCC); //勿略ROM

ds1820_write_byte(0xBE); //读温度

for (i = 0; i < 2; i++)

{

buf[i] = ds1820_read_byte();

}

bb=buf[1]&0xf0;

return bb;

}

//disp.h

#define uchar unsigned char

#define uint unsigned int

#define SHCP_0 PORTA&=~BIT(1)

#define SHCP_1 PORTA|=BIT(1)

#define DS_0 PORTA&=~BIT(3)

#define DS_1 PORTA|=BIT(3)

#define STCP_0 PORTA&=~BIT(2)

#define STCP_1 PORTA|=BIT(2)

void CKin()

{

SHCP_0;

NOP();

SHCP_1;

}

void Dataout() //并行输出

{

STCP_0;

NOP();

STCP_1;

}

void Datein( uchar date ) //数据串行输入

{

uchar i,mod;

DDRA=0xff;

for(i=0;i<8;i++)

{

mod=date&0x80;

if(mod==0x80)

{DS_1;}

else

{DS_0;}

CKin();

date<<=1;

}

Dataout(); //并行输出

}

void weihao(uchar add)

{

DDRA=0xff;

switch(add)

{

case 0:PORTA=0x1f;break;

case 1:PORTA=0x1f|0x80;break;

case 2:PORTA=0x1f|0x40;break;

case 3:PORTA=0x1f|0xc0;break;

case 4:PORTA=0x1f|0x20;break;

case 5:PORTA=0x1f|0xA0;break;

case 6:PORTA=0x1f|0x60;break;

case 7:PORTA=0x1f|0xE0;break;

default:break;

}

}

void DELAY(uint tt)

{

uint mm;

while(tt--)

{

for(mm=30;mm>0;mm--);

}

}

void display(uchar wei,uchar data)

{

weihao(wei);

Datein(data);

DELAY(20);

weihao(wei);

Datein(0xff);

}