18b20是单总线数字温度传感器，可以在一根总线上挂接多个18b20，这里就需要发匹配ROM命令，需要传感器的64位ROM,本程序可以读出64的数据，在电脑里用串口助手显示出，为多18b20操作做好准备。-18b20 is a single-bus digital temperature sensor can be mounted on the bus in a multiple 18b20, where you need to send Match ROM command, you need the sensor 64 ROM, the program can read the 64 data in the computer with the serial assistant shows that a multi-18b20 ready for operation.