温度传感器18B20的C语言底层程序，多函数可调用，实时显示当前温度，附带7289的按键芯片的测试代码代码。

可用于单片机小系统。-Temperature sensor 18B20 bottom of the C language program, multi-function calls, real-time displays the current temperature, spin-off of the 7289 chip test code button code. Can be used for small single-chip system.