104 lines
1.3 KiB
C
104 lines
1.3 KiB
C
/* # 单总线代码片段说明
|
|
1. 本文件夹中提供的驱动代码供参赛选手完成程序设计参考。
|
|
2. 参赛选手可以自行编写相关代码或以该代码为基础，根据所选单片机类型、运行速度和试题
|
|
中对单片机时钟频率的要求，进行代码调试和修改。
|
|
*/
|
|
|
|
#include <onewire.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;
|
|
}
|
|
|
|
float Tempr_Read()
|
|
{
|
|
unsigned char low;
|
|
unsigned char high;
|
|
|
|
init_ds18b20();
|
|
Write_DS18B20(0xcc);
|
|
Write_DS18B20(0x44);
|
|
Delay_OneWire(200);
|
|
|
|
init_ds18b20();
|
|
Write_DS18B20(0xcc);
|
|
Write_DS18B20(0xbe);
|
|
|
|
low = Read_DS18B20();
|
|
high = Read_DS18B20();
|
|
|
|
return ((high << 8) | low) /16.0;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|