DS18B20温度计C程序

DS18B20温度计C程序 #include”reg51.h” #include”intrins.h” #define Disdatea p1 #define discan P3

#define uchar unsigned char #define uint unsigned int Sbit DQ=P3^7; Sbit DIN=P1^7; uint h;

Uchar code ditab[16]=

{0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x04,0x05,0x06,0x06,0x07,0x08,0x08,0x09,0x09}; uchar code dis_7[12]={0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0xff,0xbf}; uchar data scan_con[4]={0xfe,0xfd,0xfb,0xf7}; uchar data temp_data[2]={0x00,0x00};

Uchar data display[5]={0x00,0x00,0x00,0x00,0x00};

Void delay(uint t) {

For(;t>0;t--); }

Scan() {

Char k;

For(k=0;kk<4;k++) {

Disdata=dis_7[display[k]]; If(k==1){DIN=0;}

Discan=scan_con[k];delay（90）；discan=0xff; }

ow_reset(void) {

char presence=1; While(presence) {

DQ=1; }

void write_byte(uchar val) {

uchar i;

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

DQ=1;_nop_();_nop_()；

DQ=0;_nop_();_nop_();_nop_();_nop_();_nop_(); DQ=val&0x01; delay(6)； val=val/2; } DQ=1; delay(1); }

uchar read_byte)(void） {

uchar i;

uchar value=0; for(i=8;i>0;i--) {

DQ=1;_nop_();_nop_()； value>>=1; DQ=0;

_nop_();_nop_();_nop_();_nop_();

DQ=1;_nop_();_nop_();_nop_();_nop_(); if(DQ)value|=0x80; delay(6); } DQ=1;

return(value); }

read_temp() {

ow_reset();

write_byte(0xCC); write_byte(0xBE);

temp_data[0]=read_byte(); temp_data[1]=read_byte(); ow_reset();

write_byte(0xCC); write_byte(0x44); }

work_temp() {

uchar n=0;

if(temp_data[1]>127)

{temp_data[1]=(256-temp_data[1]);temp_data[0]=(256-temp_data[0])；n=1;} display[4]=temp_data[0]&0x0f;display[0]=ditab[display[4]]; display[4]=((temp_data[0]&0x0f)>>4)|((temp_data[1]&0x0f)<<4); display[3]=display[4]/100;

display[1]=display[4]0; display[2]=display[1]/10; display[1]=display[1];

if(! display[3]){display[3]=0x0A;if(! display[2]){display[2]=0x0A;}} if(n){display[3]=0x0B;} }

main() {

Display=0xff; display=0xff;

for(h=0;h<4;h++){display[h]=8;} ow_reset();

write_byte(0xCC); wtite_byte(0x44); for(h=0;h<500;h++) {scan();} while(1) {

read_temp(); work_temp();

for(h=0;h<500;h++) {scan();} } }