lcd1602函数库，把lcd1602显示字符，字符串，数字等功能封装成函数库，使用时讲本头文件包含到工程中即可直接调用显示函数-lcd1602 library, the lcd1602 display characters, strings, numbers, and other functions packaged into libraries, speak of the header file that contains the project when you can directly call display function