单片机做21个音阶的电子琴答:// 8键电子琴C程序 自己扩展一下就可以了。include <AT89X51.H> sbit SPEAKER = P3^7;define KEY P1 unsigned char MUSIC;unsigned char STH0;unsigned char STL0;unsigned int code tab[]={ 64021,64103,64260,64400,//低音3开始 64524,64580,64684,64777,64820,64898,64968,65030...