说明：  此代码适用P89V51（东南大学电子）利用实验板和串口助手设计程序：先从串口助手发送四个十六进制数据（0～F）到实验板，数码管DS1-DS4显示此数据。 并且拨码开关某位（自选）为ON时，接下来从串口发送的数据从左进入到显示序列，如原本数码管显示 ”0FE6”，在串口发送 ”A” 后变为为 ”A0FE”。 拨码为OFF时，发送 ”A” 会使显示变为 “FE6A”，也就是数据从右边进入显示。
(This code applies P89V51 (Southeast University Electronics) using experimental and serial board design program assistant: assistant serial start sending four hexadecimal data (0 ~ F) to experimental board, digital DS1-DS4 display this data. And by a DIP switch (optional) is ON, the next serial data sent from the left into the display sequence, such as the original digital display " 0FE6" , after the serial port " A" goes to " A0FE" . DIP is OFF, send " A" will display becomes " FE6A" , that is, the right to enter the data from the display.)