In routine maintenance, teaching and research, voltage meter is indispensable. A direct current digital voltage meter has been designed, which is based on MCU, and has a simple structure, reliable, flexible.
Firstly,this paper introduced the development of the base on MCU digital voltage meter and the purpose and significanceof topic. Then in details this paper described the design principle of hardware and software systems. And in details the hardware part present a discussion in hardware selection, design principles, instructions and the function, further more,some of the interface circuit have been introduced. The software part introduced the programming language and programming ideas used in codes. Finally, the circuit debugging, the printed plate of PCB production and the anti-jamming system were designed to further analysis and synthesis.
The digital voltage meter designed here, have less components in the hardware part, lower cost and easier testing; software used C programming language which is high flexibility and strong readability. After theoretical research, principle design and debugging, the experimental results suppose it is feasible of choosing this program.
设计中采用的是8段LED数码管sm420364来显示电压值。LED具有耗电低、亮度高、视角大、线路简单、耐震及寿命长等优点,它由8个发光二极管组成,其中7个按‘8’字型排列,另一个发光二极管为圆点形状,位于右下角,常用于显示小数点。把8个发光二极管连在一起,公共端接高电平,叫共阳极接法,相反,公共端接低电平的叫共阴极接法,根据ZLG7289的要求我们采用共阴极接法。当发光二极管导通时,相应的一段笔画或点就发亮,从而形成不同的发光字符。其8段分别命名为dp g f e d c b a。例如,要显示“0”,则dp g f e d c b a分别为:1100 0000B;要显示“A”,则dp g f e d c b a分别为:0001 0001B(共阳极)。若要显示多个数字,只要让若干个数码管的位码循环为低电平就可以了。