51单片机ds18b20和lcd1602显示温度.doc

/*本程序为基于51单片机的DS18b20与lcd1602显示温度程序，1602数据线友P0口提供*/ #includereg51.h #define uchar unsigned char #define uint unsigned int sbit DQ=P2^0;//ds18b20 sbit lcd_rw=P2^5; sbit lcd_rs=P2^6; sbit lcd_en=P2^7; unsigned char code str1[]={temperature: }; unsigned char code str2[16]={ }; uchar data disdata[5]; uint value;//温度值 uchar flag;//正负标志 /*************************lcd1602程序**************************/ void delay1ms(unsigned int ms)//延时1毫秒（不够精确的） { unsigned int i,j; for(i=0;ims;i++) for(j=0;j100;j++); } void write_com(unsigned char com)//写指令// { delay1ms(1); lcd_rs=0; lcd_rw=0; lcd_en=0; P0=com; delay1ms(1); lcd_en=1; delay1ms(1); lcd_en=0; } void write_dat(unsigned char dat)//写数据// { delay1ms(1);; lcd_rs=1; lcd_rw=0; lcd_en=0; P0=dat; delay1ms(1); lcd_en=1; delay1ms(1); lcd_en=0; } void lcd_init()//初始化设置// { write_com(0x38);delay1ms(5); write_com(0x08);delay1ms(5); write_com(0x01);delay1ms(5); write_com(0x06);delay1ms(5); write_com(0x0c);delay1ms(5); } void display(unsigned char *p)//显示// { while(*p!=\0) { write_dat(*p); p++; delay1ms(1); } } init_play()//初始化显示 { lcd_init(); write_com(0x80); display(str1); write_com(0xc0); display(str2); } void delay_18B20(unsigned int i)//延时1微秒 { while(i--); } void ds1820rst()/*ds1820复位*/ { unsigned char x=0; DQ = 1; //DQ复位 delay_18B20(4); //延时 DQ = 0; //DQ拉低 delay_18B20(100); //精确延时大于480us DQ = 1; //拉高 delay_18B20(40); } uchar ds1820rd()/*读数据*/ { unsigned char i=0; unsigned char dat = 0; for (i=8;i0;i--) { DQ = 0; //给脉冲信号 dat=1; DQ = 1; //给脉冲信号 if(DQ) dat|=0x80; delay_18B20(10); } return(dat); } void ds1820wr(uchar wdata)/*写数据*/ {unsigned char i=0; for (i=8; i0; i--) { DQ = 0; DQ = wdata0x01; delay_18B20(10); DQ = 1; wdata=1; } } read_temp()/*读取温度值并转换*/ {uchar a,b; ds1820rst(); ds1820wr(0xcc);//*跳过读序列号*/ ds1820wr(0x44);/