摘要:基于Proteus的数字式电压表设计以AT89C51单片机、ADC0808模数转换器、键盘输入电路、7段LED显示电路、复位电路，时钟电路等外围器件构成系统硬件。采用51单片机C语言进行软件程序设计，源程序的录入、编辑和编译借助KEIL软件完成。本设计按照硬件系统电路设计原理，借助Proteus仿真软件进行了硬件系统的仿真搭建和原理图布图。将KEIL软件编译完成的HEX目标代码文件加载到Proteus的单片机中，仿真运行检查、调试了系统功能的实现情况。系统通过5路可变电阻引入模拟测量电压，可变电阻引起的电压变化可以通过并联的电压表直接显示。系统运行过程中切换五个按键开关即可以分别完成对5路模拟电压信号的实时测量显示。测量电压的范围是0~5V，测量误差在50mV以内。软硬件联合仿真运行情况表明：硬件电路设计合理，软件设计正确，系统能够正常完成预定的设计任务。基本达到了毕业设计的要求。　　

关键词：单片机 数字电压表 A/D转换器 ADC0808 Proteus

ABSTRACT:Based on Proteus digital voltmeter designed to AT89C51 microcontroller, ADC0808 ADC, keyboard input circuit, 7-segment LED display circuit, reset circuit, clock circuit and other peripheral devices constitute the system hardware. 51 single-chip C language software programming, source input, edit and compile with KEIL software. The design of the system in accordance with the hardware circuit design principles, with Proteus simulation software to build the hardware system simulation and schematic layout. The KEIL software compiled object code of the HEX file is loaded into the microcontroller in Proteus simulation run a check, debug the system function achievement. 5-way system through the introduction of the analog variable resistance measuring voltage, the voltage change caused by the variable resistor in parallel voltmeter can be displayed directly. The system is running five key switches which can be switched separately to complete the five-channel analog voltage signal real-time measurement display. Measuring voltage range is 0 ~ 5V, the measurement error in less than 50mV. Operation of hardware and software co-simulation showed that: hardware circuit design is reasonable, the software design is correct, the system can complete normally predetermined design tasks. Basically reached the graduation requirements.

Keywords: Single chip microcomputer；digital Voltmeter；A/Dswitch ；ADC0808；Proteus

　　　数字电压表是诸多数字化仪表的核心和基础，电压表的数字化技术就是将连续的直流电压转换成不连续的离散的数字形式并加以显示的仪表。这有别于传统的以指针和刻度盘进行读数的方法，避免了持续读数造成的视差误差和视觉疲劳。现代数字电压表的内部核心部件是A/D转换器，转换器的精度很大程度上影响着数字电压表的准确性。本文的A/D转换器采用八位模拟信号ADC0808对输入的模拟信号进行转换，控制核心单片机AT89C51再对转换的结果进行进一步的运算和处理，最后传送到显示装置，显示数字电压信号。