基于AT 8 9 C 5 2 为控制核心的数字音乐盒，利用单片机技术、无源蜂鸣器为音频输出、4 ×4 键

盘，实现原理图设计到电路板设计开发，并用C 语言进行键盘识别程序设计和音频脉冲输出程序的设

计。-Based on AT 8 9 C 5 2 as the core to control the digital music box, using single chip computer technology, no source for audio output, buzzer 4 x 4 key

Dish, realize the principle diagram design to the circuit board design development, and C language on the keyboard identification programming and audio pulse output program set

Plan.