用键盘显示接口芯片8279接收按键键值，并在七段数码管上显示出来，通过判断键值进入相应音乐播放处理程序。在音乐播放程序中，使用定时器/计数器8253的计数器2，使其工作在方式¬ ¬ 3—方波发生器，通过查表依次取出乐曲频率值送入计数器作为计数初值，经out2输出方波，驱动扬声器发出不同频率的声音，在每个音阶之间加入相应的延迟时间，即实现了音乐的播放-8279 with a keyboard and display interface chip receives key key, and on the seven-segment display, by determining the appropriate key to enter the music player process. In the music player, use the timer/counter 2 counter 8253 to work in the way ¬　¬　3- square wave generator, followed by table look-up music out into the frequency counter as the count initial value, the output side by out2 wave-driven speakers sound different frequencies in each scale by adding the appropriate delay between the time that the music player to achieve a