天翔电子的430开发板RS232程序，用固定频率的方波驱动蜂鸣器，共16种音调；在蜂鸣器发出不同音调的同时，一个数码管显示音调的编号。PC机发送字符决定蜂鸣器发出何种鸣响音-Tianxiang 430 development board RS232 electronic procedures, with a fixed frequency square wave drive buzzer, a total of 16 kinds of tone　the buzzer sounds of different tones at the same time, a digital display tone of the number. PC, send the characters decide what ring tone buzzer