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河北工程大学毕业设计（论文） 摘要

基于单片机AT89c51的数字万用表设计

摘要 :本次设计用单片机芯片

AT89c51 设计一个数字万用表，能够测量交、直流电

压值、直流电流、直流电阻以及电容，四位数码显示。此系统由分流电阻、分压电阻、基准电阻、电容测试芯片电路、51 单片机最小系统、显示部分、报警部分、AD 转换和控制部分组成。为使系统更加稳定，使系统整体精度得以保障，本电路使用了AD0809 数据转换芯片，单片机系统设计采用AT89S51 单片机作为主控芯片，配以RC上电复位电路和11.0592MHZ 震荡电路，显示芯片用TEC6122，驱动8 位数码管显示。程序每执行周期耗时缩到最短，这样保证了系统的实时性。

本文全面、深入、系统地介绍了4 3/4位智能数字万用表的系统设计与研究。设计中采用了美国MAXIM公司生产的专配万用表芯片MAX134，以及Intel 公司生产的MCS8051单片机。整个系统结构由MAX134外加一些外围元件构成，然后再与单片机8051相连，驱动LED数码显示。文章主要介绍了MAX134的性能特点、内部结构、数字接口、输入输出数据及一些功能和原理。整个设计包括硬件电路设计及软件设计。硬件电路设计包括处理器、外部设备元件的选择及电路设计，而软件设计则主要是实现仪表的各功能的控制。

关键词 数字万用表 AT89S51 单片机 AD转换与控制

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河北工程大学毕业设计（论文） Abstract

Abstract

This design is design a digital universal meter with chip AT89s51 of one-chip computer, can measure and hand in , direct current pressing value , direct current flow , the direct current is hindered, four numbers show. This system is shunted resistance, resistance of partial pressure, basic resistance, minimum system of 51 one-chip computers, shown that some , warning part , AD change and control making up partly. In order to make the system more steady, make the whole precision of the system be ensured, this circuit has used AD0809 data to change the chip, the one-chip computer system is designed to adopt AT89S51 one-chip computer as the top management chip, the electricity is restored to the throne the circuit and 11.0592MHZ and shaken the circuit to match on RC, show that the chip uses TEC6122, urge 8 numbers to be in charge of showing. The every execution cycle consuming time of procedure contracts to get shortest, in this way the real-time character of the security system.

In order to make the system more steady, make the whole precision of the system be ensured, this circuit has used AD0809 data to change the chip, the one-chip computer system is designed to adopt AT89S51 one-chip computer as the top management chip, the electricity is restored to the throne the circuit and 11.0592MHZ and shaken the circuit to match on RC, show that the chip uses TEC6122, urge 8 numbers to be in charge of showing.

Keyword: Digital universal meter AT89S51 one-chip computer AD changes and

controls

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河北工程大学毕业设计（论文） 目录

目 录

摘 要 ................................................................. i Abstract ............................................................. ii 1. 绪论 ................................................................ 4

1.1 数字万用表的主要特点 ............................................ 4 1.2 数字万用表设计背景 ............................................................................................ 6

1.2.1 数字万用表的设计目的和意义 ........................................................................... 6 1.2.2 数字万用表的设计依据 ...................................... 6 1.2.3 数字万用表的设计目的和意义 ................................ 6 1.3万用表发展趋势 .................................................. 7 2. 数字万用表总体设计方案 .............................................. 8

2.1数字万用表的基本原理 ............................................ 8 2.2数字万用表的硬件系统设计总体框架图 ............................. 15 3. 选用芯片介绍及硬件电路设计方案 ..................................... 16

3.1 芯片选择及功能简介 ............................................. 16

3.1.1 AT89c51 芯片功能特性描述 ................................. 16 3.1.2 ADC0809 介绍 ............................................. 19 3.1.2 TEC6122 简述 ............................................. 21 3.2设计方案及数字万用表的硬件设计 ................................. 24

3.2.1 设计方案 ................................................. 24 3.2.2 数字万用表的硬件设计 ..................................... 26

3.2.2.1 分模块详述系统各部分的实现方法 .................... 26 3.2.2.2 数字万用表控制硬件整体结构图 ...................... 32 3.2.2.1电路的工作过程描述 ................................. 32

4. 系统软件与流程图 ................................................... 33

4.1 电路功能模块 ................................................... 33 4.2系统总流程图 ................................................... 33 4.3物理量采集处理流程 ............................................. 35 4.4电压测量过程流程图 ............................................. 36 4.5电流的测量过程流程图 ........................................... 37 4.6电阻的测量过程流程图 ........................................... 38 4.7电容测量过程流程图 ............................................. 39 结 论 ................................................................ 40 致 谢 ................................................................ 41 参考文献 .............................................................. 42 附录 .................................................................. 42

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