说明：  基于单片机试验板设计一个能对模拟电压进行测量并对电压值在数码管上进行显示的系统。 扩展要求： 通过设置按钮来调节一个报警的上限和下限电压值，当被测电压超过限定值后通过蜂鸣器给出超限报警，可以同时配合数码管上的显示内容闪烁。
(Based on single chip microcomputer test plate can design a measure to the analog voltage and the voltage value on the digital tube display system. Extension requirements: By setting the button to adjust an alarm the upper and lower limits of voltage, when the voltage being measured by transfinite alarm buzzer given after more than limit, can at the same time cooperate with digital tube display content on the blink.)