官方提供的底层代码(存在修改),原理简单了解即可,解释依据函数紧随代码:
#include "reg52.h"
sbit DQ = P1^4;
void Delay_OneWire(unsigned int t)
{
unsigned char i;
while(t--) for(i=0;i<12;i++);
}
void Write_DS18B20(unsigned char dat)
{
unsigned char i;
for(i=0;i<8;i++)
{
DQ = 0;
DQ = dat&0x01;
Delay_OneWire(5);
DQ = 1;
dat >>= 1;
}
Delay_OneWire(5);
}
unsigned char Read_DS18B20(void)
{
unsigned char i;
unsigned char dat;
for(i=0;i<8;i++)
{
DQ = 0;
dat >>= 1;
DQ = 1;
if(DQ)
{
dat |= 0x80;
}
Delay_OneWire(5);
}
return dat;
}
bit init_ds18b20(void)
{
bit initflag = 0;
DQ = 1;
Delay_OneWire(12);
DQ = 0;
Delay_OneWire(80);
DQ = 1;
Delay_OneWire(10);
initflag = DQ;
Delay_OneWire(5);
return initflag;
}
void rd_temperature(unsigned char *zhen1,unsigned char *zhen2)
{
init_ds18b20();
Write_DS18B20(0xcc);
Write_DS18B20(0x44);
Delay_OneWire(10);
init_ds18b20();
Write_DS18B20(0xcc);
Write_DS18B20(0xbe);
*zhen1=Read_DS18B20();
*zhen2=Read_DS18B20();
}
#ifndef __ONEWIRE_H
#