基于结构体和12864的多层菜单系统，易于移植，不依赖与硬件-Structure and 12864 multilayer menu system, based on the easy to transplant, do not rely on hardware

这是介绍OLED的一个三级菜单制作的pdf，通过结构体实现，里面附有详细的程序代码。 -This is the introduction of a OLED three level menu making PDF, realized by the structure, which includes a detailed code. This is the introduction of a OLED three level menu making PDF, realized by the str