利用JD51开发板上的按键S1~S4和蜂鸣器设计的电子音调发生器，（1）利用JD51开发板上的按键S1~S4进行音调选择，即按下不同的开关产生不同的音调，依次按动S1~S4 及组合按键，蜂鸣器发出1234567i八个音调；并在数码管上显示。（2）编写2支歌曲，并可进行选择播放。(Using the key S1~S4 and the buzzer designed on the JD51 board, the electronic tone generator (1) uses the key S1~S4 on the JD51 development board to make the tone selection, that is to press the different switches to produce different tones, and then press the S1~S4 and the combination keys in turn. The buzzer sends out the eight tones of the tone; and it is displayed on the digital tube. (2) write 2 songs and choose to play.)