编程使小键盘的数字键1，2，3，4，5，6，7作为电子琴按键，输入对应的七个音阶，通过实验箱的喇叭发出声音，并通过七段数码管显示输入音阶；若小键盘输入“R”则返回DOS，结束程序。-Programming small keyboard's numeric keypad ,36.2 as flower button. 7 corresponding to the input scale, experimental box speakers to make their voices hear