DS18b20_shumaguan.zip_DS18B20_shumaguan

/*本程序实现的功能为：使用一个数字温度传感器ds18b20不断的检测当前温度， 同时将所测温度值用数码管显示出来，可以设法改变18b20的表面温度 来观察改程序所实现的功能。*/ #include<reg52.h> #include<intrins.h> #define uchar unsigned char uchar Init18b20(void); void Write18b20(uchar com); int Read18b20(void); void delay(int time); float Convert(int temperature); void display(int disdate);//数码管显示函数 sbit B20 = P2^7; sbit M_LE = P3^6; sbit M_OE = P3^7; sbit WEI_LE = P2^0; sbit DUAN_LE= P2^1; char code smdate[11] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x40}; //数码管显示所需数据表0,1,2,3,4,5,6,7,8,9,"-" void main() { int temdata = 0x0000; float temperature18b20 = 0.0; uchar i = 0; WEI_LE = 1; //关数码管 DUAN_LE= 1; P0 = 0x00; WEI_LE = 0; DUAN_LE= 0; M_OE = 0; M_LE = 1; //打开管理锁存器 P2 = 0x08; //关不必要资源 M_LE = 0; while(1) { B20 = 1; Init18b20();//初始化18b20 Write18b20(0xcc);//跳过ROM操作，因为我们只使用了一个18b20 Write18b20(0x44);//让18b20启动数据转换 for(i=200;i>0;i--) { display(temperature18b20);//将温度显示到液晶上 delay(5); } //延时1秒，等待18b20转换数据 Init18b20();//再次初始化 Write18b20(0xcc);//跳过ROM操作 Write18b20(0xbe);//发送读取温度命令 temdata = Read18b20();//读取温度数值 temperature18b20 = Convert(temdata);//数值转换 } } void display(int disdate)//数码管显示函数 { uchar i,t; uchar dis[3] = {0}; dis[2] = disdate/100; dis[1] = (disdate%100)/10; dis[0] = disdate%10; for(i=3,t=0x01; i>0; i--)//数码管动态显示 { DUAN_LE = 1; P0 = smdate[dis[i-1]]; DUAN_LE = 0; WEI_LE = 1; P0 = t; WEI_LE = 0; t <<= 1; delay(1); WEI_LE = 1; P0 = 0x00; WEI_LE = 0; //消隐 } } uchar Init18b20(void) { uchar tt; int con; B20 = 0; for(con = 0; con<70; con++) { _nop_(); } B20 = 1; for(con = 0; con<10; con++) { _nop_(); } if(0 == B20) { tt = 0xff; } else { tt = 0x00; } for(con = 0; con<90; con++) { _nop_(); } return tt; } void Write18b20(uchar com)//向18b20写数据函数，具体操作时序请参阅18b20数据手册 { uchar mask = 0x01; uchar icon; uchar jcon; B20 = 1; for(icon = 0; icon<8; icon++)//从低位开始，依次将数据写入18b20中 { if(mask&com) { B20 = 0; _nop_(); _nop_(); B20 = 1; } else { B20 = 0; } for(jcon = 0; jcon<18; jcon++) { _nop_(); } B20 = 1; mask <<= 1; _nop_(); } } int Read18b20(void)//度温度函数，此函数实现从18b20中读出16位温度值，具体操作时序见18b20使用手册 { uchar rcom; uchar dtim; uchar tt; unsigned int date = 0x0000; B20 = 1; for(rcom = 0; rcom<16; rcom++) { date >>= 1; B20 = 0; _nop_(); _nop_(); B20 = 1; _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); _nop_(); tt = B20; if(1 == tt) { date |= 0x8000; } for(dtim = 0; dtim<18; dtim++) { _nop_(); } } return date; } void delay(int time)//延时一毫秒程序 { int i,j; for(i = 0; i<time; i++) { for(j = 125; j>0; j--); } } float Convert(int temperature)//数值转换函数，将从18b20中读出的二进制数转换为浮点型数据 { float temperdate = 0.0; if(0x8000&temperature) { temperature =~temperature + 0x0001;//对于负温度的处理，如果是负温度，先将数据逐位取反再加1 } if(0x0001&temperature) temperdate += 0.0625; if(0x0002&temperature) temperdate += 0.125; if(0x0004&temperature) temperdate += 0.25; if(0x0008&temperature) temperdate += 0.5; if(0x0010&temperature) temperdate += 1; if(0x0020&temperature) temperdate += 2; if(0x0040&temperature) temperdate += 4; if(0x0080&temperature) temperdate += 8; if(0x0100&temperature) temperdate += 16; if(0x0200&temperature) temperdate += 32; if(0x0400&temperature) temperdate += 64; return temperdate; }