实验板的AVR程序，矩阵4*4键盘键值显示，驱动蜂鸣器发出按键声。

接线定义：SW1～8打开，SW2-1,2,3,4,打开，SW2-6为LED的电源，SW3-8为系统复位脚。

PA2(SW5-7)为蜂鸣器输出端，PB(SW4-1～8)为键盘接入

记事：本程序旨在对矩阵键盘扫描的理解与演示，程序适合初学者使用。

使用器件：ATMEGA8535，可更换。 默认片内1MHz晶振

功能：初始LED显示 - ，按下那个按键显示按键的键值。使用的是4×4矩阵键盘。-AVR Experiment board procedures, the matrix 4* 4 keyboard keys show keys issued driver buzzer sound. Connection definition: SW1 ~ 8 open, SW2-1, 2,3,4, open, SW2-6 for the LED power, SW3-8 for the system reset pin. PA2 (SW5-7) for the buzzer output, PB (SW4-1 ~ 8) for keyboard access Notepad: The procedures are designed to scan the keyboard matrix understanding and demonstration of procedures suitable for beginners to use. The use of devices: ATMEGA8535, can be replaced. Default-chip crystal oscillator 1MHz function: the initial LED display- press the button that shows the key button. Using a 4 × 4 matrix keyboard.