计算机控制系统课设报告

目录

目录 ·································································································································································· 1 1 题目背景与意义 ········································································································································· 2 2 设计题目介绍 ············································································································································· 3 2.1设计目的 ········································································································································ 3 2.2设计意义 ········································································································································ 3 3 系统总体框架 ············································································································································· 4 4 系统硬件设计 ············································································································································· 5 4.1单片机选型 ···································································································································· 5 4.1.1 AT89C51功能介绍： ············································································································ 5 4.1.2晶振电路 ································································································································· 6 4.1.3复位电路 ································································································································· 6 4.2 A/D转换电路 ································································································································ 7 4.2.1 ADC0809功能介绍： ············································································································ 7 4.2.2 A/D转换电路图 ····················································································································· 8 4.3 D/A转换电路 ································································································································ 9 4.3.1 DAC0832功能 ······················································································································· 9 4.3.2 D/A转换电路图 ··················································································································· 10 4.5调理电路 ······································································································································ 10 4.6 报警指示灯电路 ························································································································· 11 4.7 键盘、显示控制电路 ················································································································· 12 4.7.1键盘电路 ······························································································································· 12 4.7.2显示电路 ······························································································································· 12 5 系统软件设计 ··········································································································································· 14 5.1 主程序框图 ································································································································· 14 5.2数据程序框图 ······························································································································ 15 5.3 键盘程序框图 ····························································································································· 16 5.4显示程序框图 ······························································································································ 17 6 总结 ··························································································································································· 18 7总体设计电路原理图 ······························································································································· 19

1

1 题目背景与意义

在自动控制系统的实际工程中，经常需要检测被测对象的一些物理参数，如温度、流量、压力、速度等，这些参数都是模拟信号的形式。它们要由传感器转换成电压信号，再经A/D转换器变换成计算机能够处理的信号。同样，计算机控制外设，如电动调节阀、模拟调速系统时，就需要将计算机输出的数字信号经过D/A转换器变换成外设能接受的模拟信号。 本次《计算机控制系统》课程设计的目的就是让同学们在理论学习的基础上，通过完成一个涉及MCS-51单片机A/D和D/A多种资源应用并具有综合功能的小系统目标板的设计与编程应用，使我们不但能够将课堂上学到的理论知识与实际应用结合起来，而且能够对电子电路、电子元器件、等方面的知识进一步加深认识，同时在系统设计、软件编程、相关仪器设备的使用技能等方面得到较全面的锻炼和提高。帮助同学们增进对单片机的感性认识，加深对单片机理论方面的理解，从而更好的掌握单片机的内部功能模块的应用以及A/D和D/A功能的实现。使学生了解和掌握单片机应用系统的软硬件设计过程、方法及实现，为以后设计和实现单片机应用系统打下良好基础。

2

2 设计题目介绍

2.1设计目的

设计一个基于单片机的具有A/D和D/A功能的信号测控装置。要求该信号测控装置能够接入典型传感器、变送器信号，同时可输出标准电压/电流信号。并满足抗干扰、通用性、安全性、性价比等原则性要求。标准电压/电流信号定为：0～5V/4～20mA (0～20mA)

2.2设计意义

通过设计此信号测控装置，加深对控制系统的理解，全面掌握所学的知识并灵活运用起来。

3

3 系统总体框架

模拟量输入

模数转换模块 数模转换模块 键盘模块 模拟量输出

8051 声光报警 稳压电源 显示模块

图1 系统总体框架图

4

4 系统硬件设计

4.1单片机选型

由于80C51单片机采用的是CHMOS工艺，高速度、高密度、低功耗，具有

价格便宜、易上手、抗干扰能力强、稳定性好等优点，且满足我所设计的系统要求的条件，所以此次设计选用80C51单片机作为处理核心。其结构如图2所示：

U1119XTAL1P0.0/AD0P0.1/AD1P0.2/AD2P0.3/AD3P0.4/AD4P0.5/AD5P0.6/AD6P0.7/AD7P2.0/A8P2.1/A9P2.2/A10P2.3/A11P2.4/A12P2.5/A13P2.6/A14P2.7/A15P3.0/RXDP3.1/TXDP3.2/INT0P3.3/INT1P3.4/T0P3.5/T1P3.6/WRP3.7/RD39383736353433322122232425262728101112131415161718XTAL29RST293031PSENALEEA12345678P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.780C51 图2 80C51结构

4.1.1 AT89C51功能介绍：

Vss(20脚) : 接地。

VCC（40脚）: 主电源+5V。

XTAL1（19脚）:接外部晶体的一端。在片内它是振荡电路反相放大器的输入端。对于CHMOS单片机，此引脚作为驱动端。

XTAL2（18脚）: 接外部晶体的另一端。在片内它是一个振荡电路反相放大器的输出端，振荡电路的频率是晶体振荡频率。对于CHMOS单片机，此引脚应悬浮。

RST（9脚）: 单片机刚接上电源时，其内部各寄存器处于随机状态，在该脚输入24个时钟周期宽度以上的高电平将使单片机复位（RESET）。

PSEN（29脚）: 外ROM读选通信号。

ALE/PROG（30脚）: 地址锁存允许/片内EPROM编程脉冲。 EA/VPP（31脚）: 当EA端输入高电平时，CPU从片内程序存储器地址0000H单元开始执行程序。当地址超出4KB时，将自动执行片外程序存储器的程序。当EA输入低电平时，CPU仅访问片外程序存储器。

输入/输出引脚：

（1）P0.0—P0.7 (39脚—32脚) 作为数据总线 （2）P1.0—P1.7 （1脚—8脚） （3）P2.0—P2.7 （26脚—21脚）

5

（4）P3.0—P3.7 （10脚—17脚）具有第二功能，用于特殊信号输入输出和控制信号，属控制总线。

4.1.2晶振电路

单片机是一种时序电路，必须供给脉冲信号才能正常工作，所以在XTAL1 XTAL2引脚接入一个振荡电路，电路如图3所示：

图3 晶振电路

4.1.3复位电路

单片机系统中需要一个硬件复位电路，用于用户的手动复位，80C51是高电平复位有效。最简单的复位电路由一个电阻、一个电解电容、一个按钮形成，电路如图4所示：

图4 复位电路

6

图 5 8051单片机最小系统

4.2 A/D转换电路

为了完成A/D转换功能，我选择的是A/D0809转换器，它具有易于和微处理器接口或独立使用，可满量程工作，可用地址逻辑多路器选通各输入通道，单5V供电，输入范围为0~5V，输入和输出与TTL、CMOS电平兼容等优点。

ADC0809是8通道8位CMOS逐次逼近式A/D转换芯片，可以和单片机直接接口，由一个8路模拟量通道选择开关、一个地址锁存与译码器、一个A/D转换器和一个三态输出锁存器组成。多路开关可选通8个模拟通道，允许8路模拟量分时输入，共用A/D转换器进行转换。三态输出锁器用于锁存A/D转换完的数字量，当OE端为高电平时，才可以从三态输出锁存器取走转换完的数据。因ADC0809的内部没有时钟电路，所需时钟信号必须由外界提供，通常使用频率为500KHZ。

4.2.1 ADC0809功能介绍：

7

图6 ADC0809芯片图

D7-D0：8 位数字量输出引脚。 IN0-IN7：8 位模拟量输入引脚。 VCC：+5V 工作电压。 GND：地。 REF（+）：参考电压正端。 REF（-）：参考电压负端。

START：A/D 转换启动信号输入端。 ALE：地址锁存允许信号输入端。 （以上两种信号用于启动A/D 转换）.

EOC：转换结束信号输出引脚，开始转换时为低电平，当转换结束时为高电平。

OE：输出允许控制端，用以打开三态数据输出锁存器。 CLK：时钟信号输入端（一般为500KHz）。 4.2.2 A/D转换电路图

图7 A/D转换电路

8

4.3 D/A转换电路

D/A转换电路我选择的是DAC0832，它具有与微处理器完全兼容，价格低廉、接口简单、转换控制容易等优点。DAC0832是8位D/A转换器，它采用CMOS工艺制作，内部有两个寄存器，而这两个寄存器的控制信号有五个，输入寄存器由ILE、CS、WR1控制，DAC寄存器由WR2、Xref控制，用软件指令控制这五个控制端可实现三种工作方式：直通方式、单缓冲方式、双缓冲方式。

直通方式是将两个寄存器的五个控制端预先置为有效，两个寄存器都开通只要有数字信号输入就立即进入D/A转换。

单缓冲方式使DAC0832的两个输入寄存器中有一个处于直通方式，另一个处于受控方式，可以将WR2和Xfer相连在接到地上，并把WR1接到89C51的WR上，ILE接高电平，CS接高位地址或地址译码的输出端上。

双缓冲方式把DAC0832的输入寄存器和DAC寄存器都接成受控方式，这种方式可用于多路模拟量要求同时输出的情况下。

三种工作方式区别是：直通方式不需要选通，直接D/A转换；单缓冲方式一次选通；双缓冲方式二次选通。

4.3.1 DAC0832功能

图8 DAC0832芯片图

D0～D7：8位数据输入线，TTL电平，有效时间应大于90ns(否则锁存器的数据会出错)。

ILE：数据锁存允许控制信号输入线，高电平有效。 CS：片选信号输入线（选通数据锁存器），低电平有效。 WR1：数据锁存器写选通输入线，负脉冲（脉宽应大于500ns）有效。由ILE、CS、WR1的逻辑组合产生LE1，当LE1为高电平时，数据锁存器状态随输入数据线变换，LE1的负跳变时将输入数据锁存。

XFER：数据传输控制信号输入线，低电平有效，负脉冲（脉宽应大于500ns）有效。

WR2：DAC寄存器选通输入线，负脉冲（脉宽应大于500ns）有效。由WR2、XFER的逻辑组合产生LE2，当LE2为高电平时，DAC寄存器的输出随寄存器的输入而变化，LE2的负跳变时将数据锁存器的内容打入DAC寄存器并开始D/A转换。

9

IOUT1：电流输出端1，其值随DAC寄存器的内容线性变化。 IOUT2：电流输出端2，其值与IOUT1值之和为一常数。

Rfb：反馈信号输入线，改变Rfb端外接电阻值可调整转换满量程精度。 Vcc：电源输入端，Vcc的范围为+5V～+15V。

VREF：基准电压输入线，VREF的范围为-10V～+10V。 AGND：模拟信号地 。 DGND：数字信号地。

4.3.2 D/A转换电路图

图9 D/A转换电路

4.5调理电路

在工业控制中各类传感器常输出标准电流信号4~20mA，为此，常要先将其转换成0~5V的标准电压信号，以便送给各类设备进行处理。电路见图10所示。

10

图10 调理电路

4.6 报警指示灯电路

当系统正常运行时，绿灯亮。当传感器所采集的信息通过单片机处理，如果超过设置的上限值或低于下限值时，蜂鸣器进行报警，红灯亮起。其电路图如图11所示。

11

图11 报警电路

4.7 键盘、显示控制电路

加入键盘是为了便于人机互动，方便工作人员即时调整工况，调节系统的允

许工作范围。以AT89S51为核心，来完成键盘控制电路的设计，目的是当按下一个键时，数码管上要显示相应的数字。 4.7.1键盘电路

所用键盘是一种常开型按钮开关，常态时，键盘的两个触点处于断开状态；按下时，两个触点闭合。通过按键在常态与被按下时的通断，操作人员就可以通过键盘向微控制系统输入数据或者控制命令等，从而实现简单的人机通信。

\\

图12 键盘控制电路

4.7.2显示电路

加入LED显示是为了便于人机互动，方便工作人员及时了解此时工况。为了简化电路、降低成本，采用八位数码管，将所有位的段选线并联在一起，由一个8位的I/O口控制。结构如图13所示：

12

图13 数码管结构

（1）数码管功能介绍：

由于所有8位段选线皆由一个I/O口控制，因此，在每一瞬间，8位数码管会显示相同的字符。要想每位显示不同的字符，就必须采用扫描方法轮流点亮各位LED，即在每一瞬间只使某一位显示字符。在此瞬间，段选控制I/O口输出相应字符段选码，而每位选择控制I/O口在该显示位送入选通电平，以保证该位显示相的字符。如此轮流，是每位分时显示该位该显示字符。

图14 LED显示电路

13

5 系统软件设计

5.1 主程序框图

开始 开中断 设置报警电路初始值 设置上下限初始值 设置DPTR初始值 启动A/D转换，同时将A中的数据送入D/A启动转换 踏步等待

图15 主程序框图

14

5.2数据程序框图

开始 关中断保护现场 读取A/D转换的结果 结果是否大于上限 Y N 结果是否小于下限 Y N 调用显示子程序 报警 启动下一次转换 调用显示子程序 现场恢复返回

图16 数据转换框图

15

5.3 键盘程序框图

图17 键盘程序框图

16

5.4显示程序框图

开始 cp由高到底电平触发 发送显示数据 数据传送到数码管 在数码管中显示出传感器输入的数值 图18 显示程序框图

17

6 总结

面对课程设计，觉得自己的专业知识掌握的不够全面，对于各个芯片的了解不够充分，经过这次课程设计之后，使得自己对于所学的知识进行了一次综合性的整理，通过查阅相关资料，不仅学习了更多的知识，也提高了自己的实践能力。通过本次课程设计，我总结了以下几点：

（1）在开始课程设计之前,要对所选择的芯片内部结构有一个系统的了解,知道芯片内有哪些资源，各个引脚的功能是什么.

（2）在进行课程设计时,不能妄想一次就将整个程序设计好,\反复修改,不断改进\是程序设计的必经之路.

（3）在课程设计过程中遇到问题是正常的,我们应该积极寻找解决问题的办法，并分析清楚产生问题的原因,以免下次再碰到同样的问题.

（4）认真审题，不能盲目设计，要理解课程设计的方向，做到能把课题完成又能锻炼自己的能力。

（5）课程设计可以分块进行设计，之后再组合到一起完成整个的设计。 （6）自己完成了整个课程设计之后，不仅熟悉了课程设计的过程，更系统的锻炼了自己。

18

7总体设计电路原理图

图29 总电路图

19

参考文献

[1] J. Basak, B. Chanda, D.D. Manjumder, On edge and line linking with connectionist models,

IEEE Trans. Systems, Man Cybernet. 24 (3) 413–428, 1994.

[2] 冯显英, 葛荣雨. 基于数字温湿度传感器SHT11的温湿度测控系统. 自动化仪表, 2006,

27(1): 59-61

20

课 程 设 计 报 告

学生姓名院级目

: 学 : 班

: 题

:

单鲲鹏 学 号： 1007240313

自动化工程学院

自动103 计算机控制系统

指导教师： 李波 职称: 副教授

指导教师： 王恭 职称: 副教授

21

2013年6月21日

22

本文来源：https://www.bwwdw.com/article/z5l6.html