| /* # 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。 | |
| */ | |
| // | |
| 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; | |
| } | |
| unsigned int read_temptuer() | |
| { | |
| unsigned char MSB; | |
| unsigned char LSB; | |
| init_ds18b20(); | |
| Write_DS18B20(0xcc); | |
| Write_DS18B20(0x44); | |
| init_ds18b20(); | |
| Write_DS18B20(0xcc); | |
| Write_DS18B20(0xbe); | |
| LSB=Read_DS18B20(); | |
| MSB=Read_DS18B20(); | |
| return (MSB<<8|LSB); | |
| } | |