说明：  单片机控制的DS18B20驱动程序，可以通过数码管显示，并能通过串口发送给上位机（上位机发送$字符就可得到温度值）
(DS18B20 driver, microprocessor controlled via the digital display through the serial port to send to the host computer (the host computer to send $ character can get temperature value))