说明：  用通用单片机制作MIDI键盘 一、MIDI信号及声卡的MIDI接口 二、 单片机如何产生MIDI信号 三、控制板电路 四、用玩具琴键盘改装MIDI键盘
(General MIDI keyboard with the production of a single chip, MIDI sound card, MIDI interface, the signal and the second, third microcontroller how to generate MIDI signals, four-panel circuit, toy piano keyboard with a MIDI keyboard modification)