51单片机加外设，利用实验板提供的键盘扫描电路和显示电路,做一个扫描键盘和数码显示实验，把按键输入的键码在六位数码管上显示出来。(51 SCM plus peripherals, the use of the experimental board keyboard scanning circuit and display circuit, do a scan keyboard and digital display experiment, the key input code in six digital tube display)