说明：  该源码实现基于51单片机的激光雕刻机部分功能，都是单个的子模块，包括ＳＤ卡在ＳＰＩ模式下的读写，通过数码管显示读取内容，可配合激光雕刻机实现脱机打印，以及激光雕刻机和上位机的通讯，以及圆弧和直线插补程序，用来解析Ｇ代码，最后附上俩个小程序，一个是光立方，另外一个是超声波测距
(The source code based on 51 single-chip laser engraving machine part of the function, are a single sub-module, including the SD card in the SPI mode to read and write, read through the digital display content, with laser engraving machine to achieve offline printing, and Laser engraving machine and the host computer communication, and arc and linear interpolation program, used to resolve the G code, and finally with two small procedures, one is the optical cube, the other is the ultrasonic ranging)