说明：  1. LED的显示原理： 16×16扫描LED点阵的工作原理同8位扫描数码管类似。它有16个共阴极输出端口,每个共阴极对应有16个LED显示灯，所以其扫描译码地址需4位信号线（sel0-sel3），其汉字扫描码由16位段地址（l0-l15）输入。 通过时钟的每列扫描显示完整汉字。 2. 本试验实现输出“欢迎光临”四个汉字，采用两种格式输出：（1）依次从右向左连续输出；（2）单个汉字从上及下刷新输出。
(1. LED display Principle: 16 × 16 dot matrix LED scanning the working principle of the same 8-bit digital tube similar scan. It has a total of 16 cathode output ports, each corresponding to a total of 16 cathode LED display lights, so the scan decoding addresses of four signal lines (sel0-sel3), its characters scanned by the 16-bit code segment address (l0- l15) input. Through the clock out of every scan revealed a complete character. 2. In this study, the achievement of output, " Welcome to the" four Chinese characters, the use of output in two formats: (1) followed by continuous output from right to left (2) a single character from the previous and the next refresh the output.)