可以读写单个的18了20，也可以在一个IO上挂多个18B20，都可以正常读取。主要包括：unsignedcharinit_1820();voidwrite_1820(unsignedcharx);unsignedcharread_1820();unsignedintMultidropGetTemp(unsignedchar*p);unsignedintgettemp(void);voidDs18b20ReadID(unsignedchar*p);