说明：  本程序主要通过外部中断INT0及3.3端口读取PS2键盘值并通过LCD1602显示，键扫描码的解码通过数组方式解码，程序的解码功能主要针对数字及大小写字母和常用标点符号 硬件描述：PS2键盘的时钟线（clk）接89S51的INT0（P3.2）,数据线data接（P3.3） LCD的控制端口分别为： RS = P2^7，RW = P2^6，EP = P2^5，数据端口为P0，液晶显示偏压VL必须接
(This procedure mainly through external interrupt INT0 and 3.3 read PS2 keyboard port value through LCD1602 display, key scan code decoder way through an array of decoding, the procedure for decoding function of the major figures and upper and lower case letters and punctuation marks commonly used hardware description: PS2 keyboard clock line (clk) then 89S51 the INT0 (P3.2), data lines data access (P3.3) LCD control port, respectively: RS = P2 ^ 7, RW = P2 ^ 6, EP = P2 ^ 5, data ports for the P0, LCD bias VL must be received)