读写DS18B20 C程序

#include <aT89X52.H rel='nofollow' onclick='return false;'> #define DQ P3_0 unsigned char code dispcode[]={0xc0,0xf9,0xa4,0xb0,0x99, 0x92,0x82,0xf8,0x80,0x90}; unsigned char fuhao; void delay1(int d1,int d2) { int i,j; for(i=0;i<d1;i++) { ; for(j=0;j<d2;j++) ; } } void xianshi(unsigned int t)//显示数据(共阳） {unsigned char g,s; //w=p; //temp=t/2; s=t/10; g=t%10; { P3_3=0;//4 P3_4=0;//4 P3_5=0;//3 P3_6=0;//1 P3_7=0;//2 } P2=dispcode[g]; P2_7=0; P3_5=1;//1; delay1(4,60); { P3_3=0;//4 P3_4=0;//4 P3_5=0;//3 P3_6=0;//1 P3_7=0;//2 } P2_7=1; P2=dispcode[s]; P3_4=1;//1; delay1(4,60); if(fuhao==1) {{ P3_3=0;//4 P3_4=0;//4 P3_5=0;//3 P3_6=0;//1 P3_7=0;//2 } P2_7=1; P2=0xbf; P3_3=1;//1; delay1(4,60);} } void show_poit(unsigned int t)//显示数据(共阳） {unsigned char g; //w=p; //temp=t/2; g=t; { P3_3=0;//4 P3_4=0;//4 P3_5=0;//3 P3_6=0;//1 P3_7=0;//2 } P2=dispcode[g]; P3_6=1;//1; delay1(4,50); { P3_3=0;//4 P3_4=0;//4 P3_5=0;//3 P3_6=0;//1 P3_7=0;//2 } P2=0xC6; P3_7=1;//1; delay1(4,50); } void delay(unsigned char time) { //unsigned char s; //for(s=0;s<time;s++); while(--time); } unsigned char ow_reset(void) { unsigned char presence; DQ=0; delay(250);//保持DQ低480US DQ=1; delay(10); presence=DQ; delay(211); return(presence); } void write_bit(char bitval) { DQ=0; if(bitval==1) DQ=1; delay(29); DQ=1; } void write_byte(char val) { unsigned char i; unsigned char temp; for(i=0;i<8;i++) { temp=val>>i; temp&=0x01; write_bit(temp); } } unsigned char read_bit(void) { //unsigned char i; DQ=0; delay(1); DQ=1; delay(5); return(DQ); } unsigned char read_byte(void) { unsigned char i; unsigned char value=0; for(i=0;i<8;i++) { if(read_bit()) value|=0x01<<i; delay(29); } return(value); } void main(void) { unsigned int temp,temp1; unsigned char lt,ht; while(1) { for(;;) { if(ow_reset()) break; } write_byte(0xcc); write_byte(0x44); for(;;) { if(DQ==1) break; } for(;;) { if(ow_reset()) break; } write_byte(0xcc); write_byte(0xbe); lt=read_byte(); ht=read_byte(); for(;;) { if(ow_reset()) break; } temp=(unsigned int)lt; temp1=(unsigned int)ht; temp1=temp1<<8; temp=temp1+temp; if(temp>=0x1000) { temp=~temp+1; fuhao=1; } else fuhao=0; temp1=temp; temp=temp/16; temp1=temp1%16; temp1=temp1*625; temp1=temp1/1000; xianshi(temp); show_poit(temp1); } }