用AT89S51的并行口P1接4×4矩阵键盘，以P1.0－P1.3作输入线，以P1.4－P1.7作输出线；在数码管上显示每个按键的“0－F”序号。,AT89S51 using the parallel port P1 then 4 × 4 matrix keyboard to P1.0-P1.3 as input lines to P1.4-P1.7 for output line　in the digital control button displayed on each of the "0-F "serial number.